value of the maximum allowable alternating current of a specified frequency, at which the capacitor may be operated continuously at a specified temperature 3.19 time constant product o
Unit and symbols
Units, graphical symbols, letter symbols and terminology shall, whenever possible, be taken from the following documents:
When further items are required they should be derived in accordance with the principles of the publications listed above.
Preferred values and class
General
The preferred values appropriate to the subfamily shall be prescribed in the sectional specification
NOTE It is not possible to specify the preferred values of rated voltage due to the nature of the capacitor.
Preferred values of nominal capacitance
The preferred values of nominal capacitance shall be taken from the R series specified in IEC 60063.
Class
The class of the capacitor shall be classified according to capacitance and internal resistance (application) See Annex A for details.
Marking
General
The identification criteria and other information to be marked on the capacitor and/or packaging shall be indicated in the sectional specification
The order of marking priority for small size capacitors shall be specified in the detail specification.
Coding
When coding is used for capacitance value, tolerance or date of manufacture, the method shall be selected from those given in IEC 60062.
Quality assessment procedures
General
The specification for sectional and/or blank details must outline the required tests, including the measurements to be taken before and after each test or subgroup, as well as the order in which these tests will be conducted It is essential that the stages of each test are performed in the specified sequence, and that the measuring conditions remain consistent for both initial and final measurements.
If national specifications within any quality assessment system include methods other than those specified in the above specifications, they shall be fully described
Limits given in all specifications are absolute limits The principle to take measurement uncertainty into account is given in Annex F.
Test and measurement requirements
Test conditions
Unless otherwise specified, all tests shall be made under standard atmospheric conditions for testing as given in IEC 60068-1:2013, 4.3
– air pressure : 86 kPa to 106 kPa.
Measurement conditions
Unless otherwise specified, all measurements shall be made under standard atmospheric conditions for testing as given in IEC 60068-1:2013, 4.3 with following exception:
All measurements shall be made after thermal equilibrium is accomplished, see 5.2.4.
Voltage treatment
The capacitor shall be charged up to U R and be held for 30 min by means of a d.c source The capacitor shall be discharged through a suitable discharge device.
Thermal treatment
The capacitors shall be stored at the temperature specified in 5.2.2 for a time sufficient to allow the entire capacitor to reach this temperature (thermal equilibrium, see Annex C).
Drying
Unless otherwise specified in the detail specification, the capacitor shall be conditioned for
96 h ± 4 h by heating in a circulating air oven at a temperature of 55 °C ± 2 °C and a relative humidity not exceeding 20 %
After removal from the oven, the capacitor must be cooled in a desiccator containing a suitable desiccant, like activated alumina or silica gel, and should remain there until the specified tests commence.
Visual examination and check of dimensions
Visual examination
The condition, workmanship and finish shall be satisfactory, as checked by visual examination
Marking shall be legible, as checked by visual examination and shall conform to the requirements of the detail specification.
Dimensions (gauging)
The dimensions indicated in the detail specification as being suitable for gauging shall be checked, and shall comply with the values prescribed
When applicable, measurements shall be made in accordance with IEC 60294 or IEC 60717.
Dimensions (detail)
All dimensions prescribed in the detail specification shall be checked and shall comply with the values prescribed.
Measurement method 1 for capacitance and internal resistance (constant
Basic circuit for measuring
The capacitance and the internal resistance shall be measured by using the constant current charging and discharging methods The basic circuit for measurement is given in Figure 1
Cx capacitor under test constant current discharger a) power supply for constant current charging- b) power supply for constant voltage charging-
Figure 1 − Basic circuit for measuring
Measuring equipment
The measuring equipment must support constant current and constant voltage charging, as well as constant current discharging It should continuously monitor the current and voltage between capacitor terminals over time, as illustrated in Figure 2 Additionally, the equipment must be capable of setting and measuring current and voltage with an accuracy of ±1% or better.
The power supply must deliver a constant charge current to the capacitor with 95% efficiency, along with a configurable duration for constant voltage charging The constant current discharger is required to maintain a specified discharging current as outlined in Table 1 or Table 2 Additionally, the d.c voltage recorder should be capable of measuring with a resolution of 5 mV and a sampling rate of 100 ms or less.
T CV constant voltage charging duration (min)
Figure 2 – Voltage–time characteristics between capacitor terminals in capacitance and internal resistance measurement
Measuring procedure
The measurement shall be carried out by analysing voltage-time characteristics between capacitor terminals
The measuring method shall be either in accordance with 5.5.3.2 or 5.5.3.3 corresponding to the class (refer to Annex A) and shall be specified in the detail specification
Voltage preconditioning and thermal treatment must be performed as outlined in sections 5.2.3 and 5.2.4, respectively Additionally, if indicated in the detailed specifications, drying procedures described in section 5.3 may be conducted prior to measurement.
The voltage between capacitor terminals shall be measured and recorded as a function of time throughout the measuring procedure
The measuring conditions are outlined in Table 1, unless specified otherwise The constant charging current (\$I_{cc}\$) is designed to charge the capacitor with 95% efficiency, calculated using the rated voltage (\$U_{R}\$) and the nominal internal resistance (\$R_{N}\$) with the formula \$I_{cc} = \frac{U_{R}}{38 R_{N}}\$ Additionally, the constant discharge currents are established for measuring capacitance and internal resistance, aligned with the capacitor's nominal capacitance.
The measuring procedure shall be as follows: a) the capacitor shall be charged with the constant charging current;
When the power supply output voltage reaches the specified level, the capacitor charging will continue at a constant voltage Subsequently, the capacitor will be discharged using a constant current discharger The time will be recorded from the beginning of the discharge until the voltage across the capacitor terminals drops to U₁ and U₂, respectively.
Table 1 – Measuring conditions for measuring method 1A
Constant current charging mA 95 % charging efficiency a
Constant voltage charging time min 30
Constant discharge current for capacitance measurement b mA 1 × C N 0,4 × C N U R 4 × C N U R 40 × C N U R
Constant discharge current for internal resistance measurement c mA 10 × C N 4 × C N U R 40 × C N U R 400 × C N U R
For class 3 and class 4, measuring method 1B may be used
The number of significant figures for the discharge current value of 10 A or less shall be one digit; the second digit of the calculated value should be rounded down
The number of significant figures for the discharge current value exceeding 10 A shall be two digits; the third digit of the calculated value should be rounded down
The nominal capacitance, denoted as \$C_N\$ in farads (F), and the rated voltage, represented as \$U_R\$ in volts (V), are crucial parameters in understanding charging and discharging efficiency For detailed insights, refer to Annex D If the voltage change, \$\Delta U_3\$, exceeds 5% of the charging voltage (\$0.05 \times U_R\$), the discharge current may be reduced by factors of one half, one fifth, or one tenth Similarly, if \$\Delta U_3\$ surpasses 20% of the charging voltage (\$0.2 \times U_R\$), the discharge current can also be diminished by the same factors.
The measuring conditions for the capacitor are specified in Table 2, unless stated otherwise The constant charging current (\$I_{cc}\$) is determined to achieve 95% charging efficiency, calculated using the rated voltage (\$U_{R}\$) and nominal internal resistance (\$R_{N}\$) with the formula \$I_{cc} = \frac{U_{R}}{38 R_{N}}\$ Similarly, the constant discharge current (\$I_{d}\$) is set to ensure 95% discharging efficiency, using the same rated voltage and nominal internal resistance, represented by the equation \$I_{d} = \frac{U_{R}}{40 R_{n}}\$.
The measuring procedure involves several key steps: first, the capacitor is charged using a constant charging current Once the power supply's output voltage reaches the specified level, the charging continues at a constant voltage Next, the capacitor is discharged through a constant current discharger Finally, the time is recorded from the beginning of the discharge until the voltage between the capacitor terminals reaches values U1 and U2, as illustrated in Figure 2.
Table 2 – Measuring conditions for measuring method 1B
Constant current charging mA 95 % charging efficiency a
Constant voltage charging time min 5
Constant current discharging 95 % discharging efficiency a
For class 3 and class 4, measuring method 1A may be used
The number of significant figures for the discharge current value of 10 A or less shall be one digit; the second digit of the calculated value should be rounded down
For discharge current values exceeding 10 A, the number of significant figures should be two digits, with the third digit rounded down For a comprehensive understanding of charging and discharging efficiency, refer to Annex D.
Calculation methods for capacitance
The capacitance shall be calculated by the straight line approximation method or the energy conversion method
5.5.4.2 Straight line approximation method (measuring method 1A)
The capacitance C of a capacitor shall be calculated by the following formula:
C is the capacitance of capacitor (F);
I cc is the discharge current (mA);
U 1 is the measuring start voltage (V);
The terminal voltage of a capacitor during discharge is measured as U 2 (V) The time it takes for the voltage to drop to U 1 from the start of the discharge is denoted as t 1, while t 2 represents the time taken for the voltage to reach U 2.
5.5.4.3 Energy conversion method (measuring method 1B)
The capacitance C of a capacitor shall be calculated by the following formula:
C is the capacitance of the capacitor (F);
W is the measured discharged energy (J), from start voltage U 1 to end voltage U 2 ;
U 1 is the measured start voltage;
U 2 is the measured end voltage.
Calculation methods for internal resistance
The internal resistance shall be calculated by the least square internal resistance calculation method or the intersection line internal resistance calculation method
The internal resistance R of a capacitor shall be calculated by the following formula: d
R is the internal resistance of the capacitor (Ω);
To measure the voltage drop, an auxiliary line is drawn by extending the straight segment of the time-varying voltages recorded between the capacitor terminals, as illustrated in Figure 2.
The internal resistance R of a capacitor shall be calculated by the following formula: d
R is the internal resistance of the capacitor (Ω);
Utilize the straight-line approximation to analyze the voltage drop characteristics from the initial voltage (U₁) to the final voltage (U₂) through the least squares method Determine the intercept voltage at the moment discharge begins The difference in voltage (∆U₃) is calculated as the gap between the intercept voltage and the predetermined constant voltage charging value (V).
Intersection line internal resistance calculation method (measuring method 1A)
Least square internal resistance calculation method (measuring method 1B)
Conditions to be prescribed in the detail specification
The detailed specification must outline the following: a) the classification of the method; b) the applied voltage that differs from the rated voltage; c) charging times that are not 30 minutes (refer to Table 2) or 5 minutes (refer to Table 3); d) constant current discharge values that vary from those listed in Table 2 or Table 3; e) the discharge voltage drop values U1 and U2 that are different from those in Table 2 or Table 3.
Measurement method 2 for capacitance and internal resistance
Constant resistance charging method for capacitance measurement
Measurements shall be carried out using the measuring circuit shown in Figure 3
Figure 3 − Circuit for constant resistance charging method
The measurement procedure involves several key steps: first, short-circuit the capacitor terminals for at least 30 minutes to ensure complete discharge Next, adjust the resistance value R to achieve a time constant τ between 60 and 120 seconds Finally, apply a direct current voltage U R, measure the time constant τ, and calculate the capacitance using the appropriate formula.
C is the capacitance (F); τ is the time constant: charging time up to 0,632 × U R (s);
Constant voltage power supply Cx
5.6.1.3 Conditions to be prescribed in the detail specification
The detail specification shall prescribe: a) the applied voltage other than the rated voltage; b) the series resistance R when the time constant is other than 60 s to 120 s.
AC internal resistance measuring method
Measurements shall be carried out using the measuring circuit shown in Figure 4
Figure 4 − Circuit for a.c resistance method
The measuring procedure requires a frequency of 1 kHz and an alternating current ranging from 1 mA to 10 mA Additionally, the internal resistance \( R_a \) of a capacitor must be calculated using a specified formula.
U is the root-mean-square value of a.c voltage (V);
I is the root-mean-square value of a.c current (A).
Leakage current
Measuring method
The measuring procedure shall be as follows
Before conducting the measurement, it is essential to fully discharge the capacitors, with the discharge procedure lasting between 1 to 24 hours as detailed in the specification The leakage current must be measured using the direct voltage (U R) suitable for the test temperature, following a maximum charge-up time of 30 minutes to achieve 95% of the applied voltage The electrification period can be selected from options ranging from 30 minutes to 48 hours, as specified in the detail specification A regulated power supply should be utilized as a steady power source, and unless otherwise stated, the voltage should be applied to the capacitor through a protective resistor of 1,000 Ω or less.
Items to be specified in the detail specification
The detail specification must outline the leakage current limit at a reference temperature of 20 °C and at other specified temperatures It should also include a correction factor for measurements taken at temperatures outside of 20 °C, provided they fall within the standard atmospheric testing conditions Additionally, the specification needs to state the electrification time and the resistance values of protective resistors that differ from 1,000 Ω.
Maintain voltage
Measuring method
The measurement procedure requires that capacitors be fully discharged prior to testing, with the discharge taking between 1 to 24 hours as detailed in the specifications Once discharged, the rated voltage \( U_R \) should be applied directly to the capacitor terminals without a protective resistor, unless otherwise stated in the specifications.
The capacitor requires 8 hours to charge, with a maximum of 30 minutes needed to reach 95% of the applied voltage After charging, it is essential to disconnect the capacitor terminals from the voltage source Unless stated otherwise in the detailed specifications, the capacitor should be maintained under standard conditions for 16 hours.
24 h, 48 h or 96 h d) The internal resistance of the d.c voltmeter used shall be 1 MΩ or higher
Figure 5 − Maintain voltage test diagram
Calculation of voltage maintenance rate
The voltage maintenance rate A shall be calculated by the following formula:
A is the voltage maintenance rate (%);
U end is the voltage between open capacitor terminals after 72 h (T OC1 ) have elapsed (V);
Conditions to be prescribed in the detail specification
The detailed specification must outline the discharge duration, specify an applied voltage that differs from the rated voltage, indicate a charging time that is not 8 hours, and define the time interval between disconnecting the capacitor from the charging voltage and the subsequent measurement.
Robustness of terminations
Test Ua1 – Tensile
The capacitors shall be subjected to IEC 60068-2-21, Test Ua1, as applicable
The force applied shall be:
– for terminations other than wire terminations: 20 N;
– for wire terminations: see Table 3
Nominal cross-sectional area ( S ) a mm 2
Corresponding diameter ( d ) for circular section wires mm
For circular-section wires, strips, or pins, the nominal cross-sectional area is determined based on the dimensions specified in the detail specification In the case of stranded wires, the nominal cross-sectional area is calculated by summing the cross-sectional areas of each individual strand as outlined in the detail specification.
Test Ub – Bending (half of the sample)
The capacitors shall be subjected to IEC 60068-2-21, Test Ub, as applicable
Method 1: Two consecutive bends shall be applied in each direction This test shall not apply if, in the detail specification, the terminations are described as rigid.
Test Uc – Torsion (remaining sample)
The capacitors shall be subjected to IEC 60068-2-21, Test Uc, as applicable
Method A, severity 2 (two successive rotations of 180°) shall be used
This test shall not apply if in the detail specification the terminations are described as rigid and to components with unidirectional terminations designed for printed wiring applications.
Test Ud – Torque (for terminations with threaded studs or screws and
The capacitors shall be subjected to IEC 60068-2-21, Test Ud, as applicable
The degree of severity to be used shall be specified in the detail specification (see Table 4)
Visual examination
After each of these tests, the capacitors shall be visually examined There shall be no visible damage.
Resistance to soldering heat
Preconditioning and initial measurement
When prescribed by the detail specification the capacitors shall be dried using the method of 5.3
The capacitors shall be measured as prescribed in the detail specification.
Test
Unless otherwise stated in the detail specification, one of the following tests as set out in the same specification shall be applied
The test conditions will be specified in the detail specification For all capacitors, except those specified in items b) and c), the applicable standard is IEC 60068-2-20, Test Tb, method 1 (solder bath) Additionally, for capacitors not intended for use on printed boards but designed for soldering connections as outlined in the detail specification, specific testing requirements will apply.
1) IEC 60068-2-20, Test Tb, method 1 (solder bath);
2) IEC 60068-2-20, Test Tb, method 2 (soldering iron) c) For surface mount capacitors, IEC 60068-2-58, reflow or solder bath method.
Recovery
The recovery period must be between 1 to 2 hours unless specified otherwise, while surface mount capacitors require a recovery period of 24 hours ± 2 hours, as outlined in section 5.3.
Final inspection, measurements and requirements
For all capacitors, except surface mount capacitors, the following shall apply:
– when the test has been carried out, the capacitors shall be visually examined;
– there shall be no visible damage and the marking shall be legible;
– the capacitors shall then be measured as prescribed in the detail specification
Surface mount capacitors shall be visually examined and measured and shall meet the requirements as prescribed in the detail specification.
Solderability
General
This test shall not be applicable to those terminations which the detail specification describes as not designed for soldering.
Preconditioning
The detail specification shall prescribe whether ageing is to be applied If accelerated ageing is required, one of the ageing procedures given in IEC 60068-2-20 shall be applied
Unless otherwise stated in the detail specification, the test shall be carried out with non- activated flux.
Capacitors with leads
Capacitors shall be subjected to Test Ta of IEC 60068-2-20 either using the solder bath method (method 1), or the soldering iron method (method 2) as prescribed by the detail specification
When the solder bath method (method 1) is specified, the following requirements apply
Unless otherwise stated in the detail specification, one of the following tests as set out in the same specification shall be applied
The test conditions shall be defined in the detail specification a) For all capacitors except those of item b) and c) below:
1) IEC 60068-2-20, Test Ta, method 1 (solder bath)
Depth of immersion (from the seating plane or component body): 2 − 0 0 , 5 mm, using a thermal insulating screen of 1,5 mm ± 0,5 mm thickness;
2) IEC 60068-2-20, Test Ta, method 2 (soldering iron);
3) IEC 60068-2-54 b) For capacitors not designed for use in printed boards, but with connections intended for soldering as indicated by the detail specification:
1) IEC 60068-2-20, Test Ta, method 1 (solder bath);
Depth of immersion (from the seating plane or component body): 3,5 − 0 0 , 5 mm;
2) IEC 60068-2-20, Test Ta, method 2 (soldering iron) c) For surface mount capacitors:
1) IEC 60068-2-58, reflow or solder bath method;
2) IEC 60068-2-69, solder bath or solder globule method
When the solder bath method is not applicable, the detail specification shall define the test method, test conditions and the requirements
5.11.3.3 Final inspection, measurements and requirements
The terminations shall be examined for good tinning as evidenced by free flowing of the solder with wetting of the terminations.
Surface mount capacitors
Capacitors must undergo testing as specified in Test Td of IEC 60068-2-58, which outlines the required severity and conditions for assessing wetting, dewetting, and resistance to metallization dissolution.
The detail specification shall also indicate the specific areas of the specimen to be examined after wetting
5.11.4.2 Final inspection, measurements and requirements
The surface mount capacitors shall meet the requirements as prescribed in the detail specification.
Rapid change of temperature
Initial measurement
The measurements prescribed in the detail specification shall be made.
Test
The capacitors shall be subjected to Test Na of IEC 60068-2-14, using the degree of severity as prescribed in the detail specification.
Final inspection, measurements and requirements
The capacitors shall be visually examined There shall be no visible damage.
Vibration
Initial measurement
The measurements prescribed in the detail specification shall be made.
Test
The capacitors shall be subjected to Test Fc of IEC 60068-2-6, using the mounting method and the degree of severity prescribed in the detail specification
During the final 30 minutes of the vibration test, electrical measurements must be conducted in each direction of movement to assess intermittent contact, as well as to identify any open or short circuits.
The method of measurement shall be prescribed in the detail specification
The duration of the measurement shall be the time needed for one sweep of the frequency range from one frequency extreme to the other.
Final measurement and requirements
After testing, capacitors must undergo a visual inspection to ensure there is no visible damage The testing requirements, as outlined in section 5.17.4, should be clearly detailed in the specification.
The measurements prescribed in the detail specification shall then be made.
Damp heat, steady state
Initial measurement
The measurements prescribed in the detail specification shall be made.
Test
The capacitors shall be subjected to Test Cab of IEC 60068-2-78, using the degree of severity corresponding to the detail specification.
Final measurement
The measurements prescribed in the detail specification shall then be made.
Endurance
Initial measurements
The measurements prescribed in the detail specification shall be made.
Test
IEC 60068-2-2:2007, Test Bb, shall be applied with the following exceptions:
– capacitors may be inserted in the test chamber at any temperature between room ambient temperature and the specified test temperature;
– a specified voltage shall be applied to the capacitor during the test, but the voltage shall not be applied to the capacitor before it has reached the chamber temperature
The capacitors shall be placed in the test chamber in such way that no capacitor is located within 5 mm from any other capacitor
The test conditions shall be as follows: a) applied voltage : rated voltage; b) test temperature : upper category temperature; c) test duration : 1 000 h or as specified in the detail specification.
Final measurement, inspection and requirements
After the designated time, capacitors must cool to standard atmospheric conditions before testing Additionally, as outlined in the detail specification, the capacitors should undergo a recovery process if specified.
The capacitors shall then be visually examined
The measurements outlined in the detail specification must be conducted, and a capacitor is deemed to have failed if it does not meet the specified requirements during or after the testing process.
Storage
Storage at high temperature
The measurements prescribed in the detail specification shall be made
The capacitors shall be subjected to IEC 60068-2-2:2007, Test Bb, using the following severities:
– test temperature : upper category temperature;
After recovery for at least 16 h, the measurements prescribed in the detail specification shall be made.
Storage at low temperature
The measurements prescribed in the detail specification shall be made
Capacitors must undergo testing according to IEC 60068-2-1:2007, specifically Test Ab They should be stored at a temperature of –40 °C for a minimum of 4 hours after achieving thermal stability, or for 16 hours, depending on which duration is shorter.
After recovery for at least 16 h, the measurements prescribed in the detail specification shall be made.
Characteristics at high and low temperature
General
The capacitors shall be subjected to the procedures of the dry heat and cold test (5.17.3 and 5.17.4 respectively) with the following details.
Test procedure
The severity level for these tests will match that of the dry heat and cold tests, while the detail specification may also include tests conducted at intermediate temperatures.
The measurements prescribed in the detail specification shall be made.
Dry heat
The capacitors shall be subjected to IEC 60068-2-2:2007, Test Bb, for 16 h, using the degree of severity of the upper category temperature, as prescribed in the detail specification
While still at the specified high temperature and at the end of the period of high temperature, the measurements prescribed in the detail specification shall be made.
Cold
The capacitors shall be subjected to IEC 60068-2-1:2007, Test Ab, for 2 h, using the degree of severity of the lower category temperature, as prescribed in the detail specification
While still at specified low temperature and at the end of the period of low temperature, the measurements prescribed in the detail specification shall be made.
Final measurement and requirements
The capacitors shall not exceed the limits prescribed in the detail specification.
Component solvent resistance
Initial measurements
The measurements prescribed in the detail specification shall be made.
Test
The components must undergo testing according to IEC 60068-2-45:1980, Test XA, which includes the use of 2-propanol as the solvent at a temperature of 23 °C ± 5 °C, unless specified otherwise The conditioning method employed will be Method 2, which does not involve rubbing, and a recovery time of 2 hours or more is required, unless stated differently in the detail specification.
Requirements
The measurements prescribed in the detail specification shall then be carried out and the specified requirements shall be met.
Solvent resistance of marking
Test
The components will undergo testing according to IEC 60068-2-45:1980, Test XA, utilizing 2-propanol as the solvent at a temperature of 23 °C ± 5 °C The conditioning method employed will be method 1, which involves rubbing with cotton wool Recovery time is not applicable unless specified otherwise in the detail specification.
Requirements
After the test, the marking shall be legible.
Passive flammability
Test procedure
Capacitors must be tested following the IEC 60695-11-5 standard The capacitor should be positioned in the flame to optimize burning, with pre-testing conducted if the ideal position is not specified Each specimen is to be exposed to the flame only once Testing will include the smallest, medium, and largest case sizes, with three specimens of both the maximum and minimum capacitance tested for each case size, totaling six specimens per size.
For the time of exposure to flame and burning time, see Table 5 If applicable, the detail specification shall specify the category of passive flammability.
Requirements
The burning time of any specimen shall not exceed the time specified in Table 5
Burning droplets or glowing parts falling down shall not ignite the tissue paper
Severities Flame exposure time, in seconds, for capacitor volume ranges a mm 3
C 5 10 20 30 30 a Test severities for capacitor volumes above 12 000 mm 3 are under consideration.
Pressure relief (if applicable)
Test
Unless otherwise specified in the detail specification, d.c voltage of an amplitude necessary to produce a current of 10 mA/F or more shall be applied to the capacitor in the forward direction.
Requirements
The pressure relief device shall open in such a way as to avoid any danger of explosion or fire
Classification according to capacitance and internal resistance
General
This annex describes classification of the capacitor, according to the capacitance value and internal resistance value depending upon the application.
Classification by capacitance and internal resistance
Measuring capacitance and internal resistance using the constant current discharge method and the d.c resistance method can be time-consuming, particularly when adhering to standardized conditions specific to these techniques To enhance efficiency, it is essential to choose optimal measuring conditions Consequently, a classification of applications has been developed, categorizing them into four distinct measuring conditions (refer to Figure A.1).
It has been proposed that a uniform discharge current condition could be suitable for measuring capacitance and internal resistance across all five classes of applications This classification is based on the accuracy of measurements, indicating that consistent measuring conditions can be applied to capacitance and internal resistance, provided that the capacitors used are capable of delivering precise measurements.
This class of capacitors is ideal for RAM memory backup, featuring discharge currents ranging from nA to àA They are characterized by relatively low capacitance and high internal resistance, making them suitable for this specific application.
This class is ideal for energy storage capacitors designed for prolonged operation, capable of discharging currents ranging from mA to A These capacitors feature high capacitance without factoring in internal resistance Additionally, this class accommodates higher internal resistance compared to the power application in Class 3.
This class of capacitors is ideal for motor driving applications, where they need to deliver discharge currents ranging from milliamps to amps These capacitors are characterized by their relatively high capacitance and low internal resistance, making them suitable for efficient power delivery.
This class is ideal for applications that demand instantaneous power, characterized by relatively high current over short operating durations The capacitors designed for such applications feature low capacitance and minimal internal resistance.
This class is ideal for applications in automotive and railway sectors that demand high power and endure heavy-duty charge/discharge cycles The capacitors designed for these applications feature higher capacitance values and lower internal resistance compared to Class 3 capacitors.
Figure A.1 – Conceptual rendering orientated by characteristics in each classification
Unless otherwise specified in the detail specifications, electrical performance and measuring methods should be selected according to Table A.1, by the above mentioned class related to the application
Table A.1 – Electrical performance and measuring method by class
Class Class 1 Class 2 Class 3 Class 4 Class 5
Selection classification A: use as a standard;
Selection classification shall be specified in the detail specification For capacitance, see Annex B
Class 2 energy storage low ← Internal resistance → high small ← Capacitance → high
Measuring method of capacitance and low resistance by low frequency a.c method (reference)
General
This method is suitable for capacitors with relatively low internal resistance, and can be used as a shortcut method to reduce the measuring time.
Measuring system
The measuring system, illustrated in Figure B.1, outlines a method for measuring capacitance at low frequencies This involves generating a sinusoidal voltage at the desired frequency using a frequency response analyzer, which is then applied to a capacitor through a potentiostat The potentiostat also detects the current flowing through the capacitor, maintaining a constant electrode potential, and converts this current into a voltage value for the frequency analyzer Finally, the impedance |Z| and phase angle φ of the capacitor are derived from the voltage and current measurements.
Figure B.1 – Capacitance measuring system by the low frequency a.c method
Calculation of capacitance
The calculation of capacitance shall be as follows a) Calculate the reactance X by the following formula:
|Z| is the impedance (Ω); φ is the phase angle b) Use the calculated reactance to calculate the capacitance C of the capacitor by the following formula: f
C is the capacitance (F); π is the circle ratio; f is the measuring frequency (Hz)
Frequency response analyser Potentiostat Capacitor
Measuring conditions
The measuring conditions require the use of specific frequencies, including 0.05 Hz, 0.1 Hz, 1 Hz, 10 Hz, or 100 Hz The measuring voltage must not exceed 3% of the rated voltage, while the bias voltage should be set between 50% and 95% of the rated voltage; however, if there is no uncertainty in judgment, the bias voltage may be omitted.
Thermal equilibrium time of capacitors
General
This annex describes the thermal equilibrium time of capacitors, as a reference in determining the soaking time for pre-treatment.
Thermal equilibrium time of capacitors
The thermal equilibrium time, defined as the duration needed for the central part of a capacitor to achieve a temperature difference of 1 °C from the external temperature, is influenced by the capacitor's external dimensions This relationship was confirmed by examining the temperature variations in the central regions of the capacitors.
The study investigated the thermal equilibrium time of capacitors at various environmental temperatures, revealing that this time is directly proportional to the external dimensions, such as the diameter for cylindrical capacitors and the thickness for cubic capacitors Figures C.1 and C.2 illustrate the thermal equilibrium times when capacitors transition to normal room temperature from high and low temperatures, respectively, with the dotted lines in the figures representing the anticipated longest thermal equilibrium times.
It is advisable to use these dotted straight lines as soaking time for pre-conditioning Figure C.3 shows the actual measured temperature changes in the capacitors’ central portions
Figure C.1 – Thermal equilibrium times of capacitors (from 85 °C to 25 °C)
Figure C.2 – Thermal equilibrium times of capacitors (from −40 °C to 25 °C) a) From 85 °C to 25 °C b) From –40 °C to 25 °C
Figure C.3 – Capacitor core temperature change with respect to time
Temperature of capacitors' central portions (°C)
Temperature of capacitors' central portions (°C)
Charging/discharging efficiency and measurement current
General
This annex describes the general concept regarding the charging and discharging efficiency and measured current, which are provided in 5.5.3.
Charging efficiency, discharging efficiency, and current
Charge Q after charging or discharging for time t at a constant current I, stored energy W, and energy L lost by resistance R are given by Formulas (D.1), (D.2), and (D.3), respectively
When a capacitor is charged or discharged at a constant current, its energy efficiency for charging (P c) or discharging (P d) can be calculated using specific formulas These formulas take into account the internal resistance (R) and capacitance (C) of the capacitor.
The proposed efficiency for charging or discharging is 95%, taking into account the exothermal effect and measurement time The time required to achieve this 95% efficiency is expressed by the formula \( t = 38RC \), which is derived from a previous equation.
Charge Q stored in a capacitor is given as a product of capacity C and charging voltage U, thus leading to Formula (D.7) Current I c for 95 % charging is given by Formula (D.8) derived from Formulas (D.1), (D.6), and (D.7)
Similarly, the time t needed for 95 % discharging is given by Formula (D.9) derived from Formula (C.5), and the current I d needed for 95 % discharging is given by Formula (D.10) t = 40RC (D.9)
Formulas (D.8) and (D.10) are recommended for calculating the current during charging or discharging tests After establishing the charging or discharging current, the maximum output at the desired efficiency can be computed.
Procedures for setting the measurement current of capacitor with uncertain nominal internal resistance
General
This annex describes the current setting procedures provided in 5.5.3.
Current setting procedures for measurement of capacitor
To measure the internal resistance of a capacitor with uncertain nominal values, follow these steps for 95% charging and discharging efficiency: First, use an estimated internal resistance to measure the voltage time characteristic between the capacitor terminals, then calculate the internal resistance If the internal resistance is unpredictable, temporarily set the charging and discharging currents to 30 A Next, with the calculated internal resistance, measure the voltage time characteristic again and recalculate the internal resistance Repeat this process until the difference between consecutive internal resistance values is less than 10% of the previous value.
When the change in internal energy, ∆U, exceeds 0.1 times the reference energy, UR, it is essential to follow procedures a) to c) using a reduced current before taking measurements Conversely, if the calculated internal resistance yields a negative value, it is necessary to repeat procedures a) to c) with an increased current prior to conducting the measurements.
Example of setting current for determining capacitor characteristics
Table E.1 shows examples of setting the measurement current The setting was performed in the order of setting conditions shown in Table E.1.
Table E.1 – Example of setting current for measurement of capacitor
Internal resistance value used for setting mΩ
2 4,6 (Calculated with the result of
3 5,0 (Calculated with the result of
Policy on uncertainty of measurement and inset limits
Objective
Specifications for electronic components outline the acceptable parametric limits for each component However, these limits often overlook the measurement uncertainties introduced by inaccuracies in testing equipment, testing methods, environmental factors, and occasionally, operator involvement.
This annex aims to establish a policy for calculating measurement uncertainty and setting limits to ensure consistent implementation It also addresses the specific scenario of outsetting limits.
Terms and definitions
For the purposes of this annex the following terms and definitions apply
The uncertainty of measurement refers to the defined limits within which the true value of a measurement is expected to fall, in relation to the recorded result, while maintaining a specified confidence level.
F.2.2 measuring equipment all of the instruments which are necessary in order to carry out a measurement
The policy requirements extend to items associated with measurement indicating instruments, including cables, connectors, handlers, handler cards, and other related fixtures.
Tightened inset limits are established by applying an allowance to the specified limits of a parameter This adjustment accounts for all influencing factors on the measurement instrument's indication, ensuring that devices outside the acceptable limits are not erroneously accepted due to measurement errors.
Relaxed limits refer to the adjustments made to the specified limits of a parameter, allowing for the consideration of all influencing factors on a measuring instrument's indication This approach ensures that limit devices are not unnecessarily rejected due to measurement errors.
Calculation of measurement uncertainty
The measurement uncertainty assessment of a performance requirement involves three key stages: first, identifying potential sources of error; second, quantifying the magnitude of each identified contribution; and third, calculating the overall measurement uncertainty.
Policy
Each performance requirement associated with qualification, capability, technology, and process approvals, as well as screening and periodic tests, must have a calculated measurement uncertainty value in accordance with the specifications.
F.4.2 Each measurement uncertainty value shall be used to apply an inset, of at least this value, to the relevant specification limits as defined in F.4.1
F.4.3 This inset shall be applied in accordance with F.5.2 for qualification approval, capability approval, technology approval and process approval and F.5.3 for product audit testing
Test reports and records must be compiled to demonstrate compliance with qualification and capability approvals, as well as screening and periodic tests specified in the relevant standards Each report should include the uncertainty value associated with every performance requirement.
Calculation of inset and outset limits
The fundamental principle states that limits should be adjusted inward from the specified values by the associated measurement uncertainty This approach enhances the likelihood that measurement results falling within these stricter limits, including marginal values, are genuinely within specification limits, ensuring that only devices that truly conform are accepted.
Product audit tests are an exception to the established limits, as they aim to minimize the risk of good products being incorrectly rejected due to measurement uncertainty By relaxing the limits during these tests, the likelihood increases that only truly nonconforming devices are identified and rejected, ensuring that marginal values are accurately assessed against specification limits.
For a component manufacturer, the upper specified value of a parameter is denoted as 'x', while the lower specified value is 'y' The measurement uncertainty is represented by 'a' Consequently, the "inset limits" for the parameter are defined as (x-a) and (y+a).
In an audit test, the upper specified value of a parameter is denoted as 'x', while the lower specified value is 'y', and the measurement uncertainty is represented by 'b' Consequently, the "outset limits" for the parameter are defined as (x + b) and (y - b).
The smaller the uncertainty of measurement, the lower the values of ‘a’ and ‘b’ become and the closer the manufacturer’s and the audit test’s inset/outset limits approach the specification limits.
Examples
General
Setting “inset limits” and “outset limits”.
Example 1: Resistor measurement
Uncertainty of measurement calculated to be: ±1,2 % = ±1,08 Ω and ±1,32 Ω
Example 2: Resistor measurement
Uncertainty of measurement calculated to be ±0,1 % = ±0,10 Ω and ±0,11 Ω
Example 3: Transistor measurement (gain)
Uncertainty of measurement calculated to be: 5
Example 4: Comparison between initial and final measurement results
Uncertainty of measurement calculated to be 0,1 %
Inset limits: 101,13 àF to 102,97 àF
Outset limits 100,93 àF to 103,17 àF
The drafting of this standard has resulted in a new structure The following table indicates the new clause and subclause numbers with respect to the IEC 62391-1:2006 (first edition)
IEC 62391-1:2015 this edition Clause/Subclause
1 1 Gerneral and scope are merged into one
1.2 2 In accordance with the ISO/IEC Directives, Part 2
2.2 3 In accordance with ISO/IEC Directives, Part 2
In accordance with the change of clause numbers
4.5 5.5, 5.6 Divide the measuring method into two
4.6 5.5, 5.6 Divide the measuring method into two
In accordance with the change of clause numbers
General
Overview
When this standard, and any related standards are used for the purpose of a full quality assessment system compliance with Clauses Q.5, Q.6 or Q.14 is required
When applying standards beyond quality assessment systems for design proving or type testing, it is essential to follow the procedures and requirements outlined in Q.5.1 and Q.5.3 b) If these standards are utilized, the tests and their respective components must be conducted in the sequence specified in the test schedules.
Manufacturers must secure their organization's approval in line with the established quality assessment system before qualifying components as per the procedures outlined in this annex.
The methods that are available for the approval of components of assessed quality and which are covered by the following subclauses, are:
For a specific subfamily of components, it is essential to have distinct sectional specifications for both qualification approval and capability approval Consequently, capability approval can only be granted once a relevant sectional specification has been published.
Applicability of qualification approval
Qualification approval is appropriate for a standard range of components manufactured to similar design and production processes and conforming to a published detail specification
The testing program outlined in the detailed specification for assessment and performance levels is directly applicable to the range of components to be qualified, as specified in Clause Q.5 and the corresponding sectional specification.
Applicability of capability approval
Capability approval is essential when components are produced using standardized design rules and shared manufacturing processes This approach is especially beneficial for creating components tailored to meet specific user requirements.
Under capability approval, detail specifications fall into the following three categories
Q.1.3.2 Capability qualifying components (CQCs), including process validation test vehicles
A detail specification shall be prepared for each CQC It shall identify the purpose of the CQC and include all relevant test severities and limits
When the manufacturer requires a component approved under the capability approval procedure, a capability approval detail specification complying with the blank detail specification (if any) shall be written
The content of the detail specification (often known as a customer detail specification (CDS)) shall be by agreement according to the specified quality assessment system (if any)
Further information on these detail specifications is given in the relevant sectional specification
Manufacturing facility approval is granted based on validated design rules, processes, and quality control procedures, along with test results on capability qualifying components, including process validation test vehicles For more details, refer to Clause Q.6 and the relevant sectional specification.
Applicability of technology approval
Technology approval is appropriate when the complete technological process (design, process realization, product manufacture, test and shipment) covers the qualification aspects common to all components determined by the technology.
Primary stage of manufacture
The primary stage of manufacture shall be specified in the sectional specification.
Subcontracting
If subcontracting of the primary stage of manufacture and/or subsequent stages is employed it shall be in accordance with the specified quality assessment system (if any)
The generic or sectional specification may
– either forbid this subcontracting on technical grounds, or
– where it is considered necessary, include any special requirements, for example for specified successive stages to be performed by the same manufacturer, or
Structurally similar components
The relevant sectional specification will outline the grouping of structurally similar components for qualification approval testing and quality conformance testing This includes guidelines for qualification approval, capability approval, and technology approval.
Qualification approval procedures
Eligibility for qualification approval
Qualification approval is only available to manufacturers who have received manufacturer's approval and meet the requirements outlined in this annex While these approvals can occur simultaneously, qualification approval cannot be granted before manufacturer's approval is obtained.
Application for qualification approval
The manufacturer shall comply with the specified quality assessment system (if any).
Test procedure for qualification approval
The manufacturer must demonstrate compliance with specification requirements through one of the following procedures: a) provide test evidence from three inspection lots for lot-by-lot inspection and one lot for periodic inspection, ensuring no major manufacturing process changes occur during this period; b) take samples according to IEC 61193-2, using normal inspection, and if zero non-conformances are found, additional specimens must be collected to meet the sample size for acceptance of one non-conforming item; c) produce test evidence based on a fixed sample size test schedule outlined in the sectional specification; d) select specimens randomly from current production or as agreed; e) ensure that sample sizes and permissible non-conformances are comparable, with consistent test conditions and requirements across both procedures.
Granting of qualification approval
Qualification approval shall be granted when the procedures in accordance with the specified quality assessment system (if any) have been completed satisfactorily.
Maintenance of qualification approval
Qualification approval shall be maintained by regular demonstration of compliance with the requirements for quality conformance (see Q.5.6).
Quality conformance inspection
The blank detail specifications linked to the sectional specification will outline the test schedule for quality conformance inspections, detailing the grouping, sampling, and frequency for both lot-by-lot and periodic inspections.
Operation of the switching rule for reduced inspection in Group C is permitted in all subgroups except endurance
Sampling plans and inspection levels shall be selected from those given in IEC 61193-2
If required, more than one schedule may be specified.
Capability approval procedures
General
– the complete design, material preparation and manufacturing techniques, including control procedures and tests;
– the performance limits claimed for the processes and products, that is, those specified for the capability qualifying components (CQCs) and process control parameters (PCPs);
– the range of mechanical structures for which approval is granted
For a general overview of capability approval, see Figure Q.1
Figure Q.1 – General scheme for capability approval
Eligibility for capability approval
The manufacturer shall comply with the requirements of the specified quality assessment system (if any).
Application for capability approval
The manufacturer shall comply with the requirements of the specified quality assessment system (if any), and with the requirements of the relevant sectional specification.
Description of capability
The capability will be outlined in a capability manual that adheres to the established quality assessment system and the relevant sectional specifications This manual must, at a minimum, include or reference specific essential elements.
– a general introduction and description of the technologies involved;
– aspects of customer liaison including provisions of design rules (if appropriate) and assistance to customers in the formulation of their requirements;
– a detailed description of the design rules to be used;
– the procedure for checking that the design rules are complied with for the relevant component technology manufactured to a detail specification;
– a list of all materials used, with reference to the corresponding purchasing specifications and goods inward inspection specifications;
– a flow chart for the total process, showing quality control points and permitted rework loops and containing references to all process and quality control procedures;
– a declaration of processes for which approval has been sought in accordance with the requirements of the relevant sectional specification;
Commence process control Prepare CQC test Program
Process control Lot-by-lot test
– a declaration of limits for which approval has been sought in accordance with the requirements of the relevant sectional specification;
This article presents a comprehensive list of Critical Quality Characteristics (CQCs) utilized to evaluate capability, accompanied by a general overview of each characteristic Additionally, it features a detailed table that illustrates how the declared limits of capability are evidenced by specific CQC designs.
– detail specification for each CQC;
A comprehensive control plan is essential for managing processes effectively, incorporating various Process Control Points (PCPs) Each PCP is described in detail, highlighting its significance in relation to the properties and performance of the final component This structured approach ensures that the connection between specific PCPs and the quality of the finished product is clearly established, enhancing overall process efficiency and product reliability.
– guidance on the application of structural similarity in sampling for quality conformance testing.
Demonstration and verification of capability
The manufacturer must validate their capabilities in line with the designated quality assessment system and adhere to the relevant sectional specifications.
The manufacturer must collaborate with the Certification Body (CB) to establish the process qualifying parameters and the range of capability qualifying components required to demonstrate the specified capability range outlined in the capability manual.
The demonstration will involve testing the specified range of Critical Quality Characteristics (CQCs), which must be designed and manufactured according to the capability manual, with controlled process parameters The selected CQCs must meet specific requirements, including representing all limits of the declared capability and demonstrating mutually attainable combinations of these limits The CQCs will fall into one of the defined categories.
– components specially designed to demonstrate a combination of limits of capability, or – components of designs used in general production, or
– a combination of both of these, provided the requirements of a) are met
When CQCs are designed and produced solely for capability approval, the manufacturer shall use the same design rules, materials and manufacturing processes as those applied to released products
Each CQC will have a detailed specification with a specific front page format that outlines its purpose, relevant stress levels, and test limits This specification may reference internal control documentation that details production testing and recording to ensure effective control and maintenance of processes and capability limits.
The limits of capability shall be described in the relevant sectional specification.
Programme for capability approval
The manufacturer must develop a program to assess the declared capability in line with the established quality assessment system This program should ensure that each declared capability limit is verified by a suitable Continuous Quality Control (CQC) process.
The programme shall include the following:
– a bar chart or other means of showing the proposed timetable for the approval exercise; – details of all the CQCs to be used with references to their detail specifications;
– a chart showing the features to be demonstrated by each CQC;
– reference to the control plans to be used for process control.
Capability approval test report
A capability approval test report will be issued in line with the established quality assessment system, if applicable This report must fulfill the specific criteria for capability approval and include essential information as outlined in the requirements.
– the issue number and date of the capability manual;
– the programme for capability approval in accordance with Q.6.6;
– all the test results obtained during the performance of the programme;
– reports on actions taken in the event of failure (see Q.6.10.2)
The designated management representative (DMR) must sign the report, confirming it as an accurate statement of the results obtained This report is then submitted to the appropriate body, as specified in national regulations, which is responsible for granting capability approval.
Abstract of description of capability
The abstract is intended for formal publication after capability approval has been granted
The abstract must provide a brief overview of the manufacturer's capabilities, detailing the technology, construction methods, and the variety of products for which the manufacturer has received approval.
Modifications likely to affect the capability approval
Any modifications likely to affect the capability approval shall satisfy the requirements of the specified quality assessment system (if any).
Initial capability approval
The approval is granted when
– the selected range of CQCs has collectively satisfied the assessment requirements of the CQC detail specifications, with no nonconforming item allowed;
– the control plan has been fully implemented in the process control system
Q.6.10.2 Procedure in the event of failure
See the specified quality assessment system (if any), with the following details
If the specimens fail to meet the test requirements, the manufacturer must indicate their intention to either modify the proposed scope of capability or conduct an investigation to determine the cause of the failure.
– failure of the test itself, for example, test equipment failure or operator error, or
If a test failure is determined to be due to the test itself, the failed specimen or a new one will be reintroduced to the test schedule after corrective actions are implemented When using a new specimen, it must undergo all tests in the specified sequence of the relevant test schedules associated with the initially failed specimen.
In cases where failure is attributed to design or process issues, a comprehensive test program must be implemented to confirm that the root cause has been eliminated and all corrective actions, including proper documentation, have been completed Once these steps are fulfilled, the test sequences that previously resulted in failure should be fully repeated using new Critical Quality Characteristics (CQCs).
After the action is complete the manufacturer shall send a report, and shall include a copy in the capability approval test report (see Q.6.7)
Q.6.10.3 General plan for the selection of PCPs and CQCs
Manufacturers are required to create a process flow chart that aligns with the example provided in the relevant sectional specification This flow chart must detail all process steps and include the associated process controls for each step.
Controls shall be denoted by the manufacturer as shown in the example in the relevant sectional specification
Test plans are integral to the manufacturer's process control system When employing statistical process control (SPC), implementation must adhere to its fundamental requirements The SPC plans serve as essential controls at various process nodes.
Manufacturers must regularly monitor process parameters at each step of production equipment usage and compare these readings to the established control and action limits.
Q.6.10.5 Test plans for CQCs demonstrating limits of capability
Test plans for CQCs for the demonstration of limits of capability shall be prescribed in the relevant sectional specification.
Granting of capability approval
Capability approval will be granted once the quality assessment procedures are satisfactorily completed and all requirements of the relevant sectional specification are fulfilled.
Maintenance of capability approval
To ensure capability approval, it is essential to adhere to the requirements of the designated quality assessment system, if applicable, and to follow the guidelines outlined in the capability manual, in accordance with the maintenance schedule specified in the relevant sectional specification.
Capability approval is valid for two years without the need for retesting The manufacturer is responsible for defining the retesting program for CQCs and must establish a control system for process control, with examples provided in the sectional specification To verify capability limits, all relevant test plans must be repeated at least biennially Quality conformance inspections of components can support the maintenance of capability approval, especially when the manufacturer has qualification approval for components produced by the same processes Additionally, the manufacturer must ensure that the range of CQCs accurately represents the products released and complies with the relevant sectional specifications.
– the processes specified in the capability manual, with the exception of any agreed additions or deletions following the procedure of Q.6.9, remain unchanged,
– no change has occurred in the place of manufacture, and final test,
The manufacturer has not experienced any production breaks exceeding six months under capability approval Additionally, the manufacturer is required to keep a record of the maintenance of the capability program, allowing for the identification of verified capability limits and those pending verification within the specified timeframe.
Extension of capability approval
Manufacturers can expand their capability approval limits by executing the test plan outlined in Q.6.10.5, specific to the type of limit being extended If the extension involves a different limit type than those in Q.6.10.5, the manufacturer must propose the necessary sampling and testing methods for approval Additionally, the manufacturer is required to implement process control for any new manufacturing processes needed to meet the new limits.
An application for an extension of capability shall be made in the same way as for the original approval.
Quality conformance inspection
The quality conformance test requirements are given in the detail specification and shall be carried out in accordance with the specified quality assessment system (if any).
Rework and repair
Rework
Rework, as outlined in the applicable quality assessment system, is not permitted if restricted by the relevant sectional specification This specification will indicate any limitations on the number of times rework can be performed on a particular component.
All rework shall be carried out prior to the formation of the inspection lot offered for inspection in accordance with the requirements of the detail specification
Rework procedures must be thoroughly detailed in the manufacturer's documentation and executed under the direct supervision of the DMR, with no subcontracting allowed.
Repair
Components which have been repaired as defined in the specified quality assessment system (if any), shall not be released.
Release for delivery
General
Components will be delivered in accordance with Q.5.6 and the established quality assessment system, following the completion of the quality conformance inspection outlined in the detailed specification.
Release for delivery under qualification approval before the completion
Once the criteria outlined in IEC 61193-2:2007 for transitioning to reduced inspection are met for all Group B tests, manufacturers are allowed to release components prior to the completion of these tests.
Certified test records of released lots
When certified test records are requested by a purchaser, they shall be specified in the detail specification
NOTE For capability approval, the certified test records refer only to tests carried out on capability qualifying components.
Delayed delivery
Components held for over two years, unless stated otherwise in the sectional specification, must be re-evaluated for solderability and electrical characteristics as outlined in the detail specification prior to delivery.
The re-examination procedure adopted by the manufacturer's DMR shall be approved
Once a lot has been satisfactorily re-inspected, its quality is reassured for the specified period.
Alternative test methods
See the specified quality assessment system (if any), with the following details
In case of dispute, for referee and reference purposes, only the specified methods shall be used.
Manufacture outside the geographical limits of IECQ CBs
See the requirements of the specified quality assessment system (if any).
Unchecked parameters
Only the parameters of a component that are detailed in the specification and have undergone testing can be considered to meet the specified limits It is not safe to assume that any parameters not specified will remain consistent across different components If there is a need to monitor additional parameters, a new and more comprehensive specification must be implemented.
The additional test method(s) shall be fully described and appropriate limits, sampling plans and inspection levels specified.
Technology approval procedures
General
The technology approval of components encompasses the entire technological process, enhancing traditional concepts of qualification and capability approval It mandates the implementation of in-process control methods, such as Statistical Process Control (SPC), and emphasizes a continuous quality improvement strategy Additionally, it requires monitoring of overall technologies and operations, procedural flexibility aligned with quality assurance management systems and market sector demands, and the acceptance of a manufacturer’s operational documentation to facilitate swift approval or extension of approval.
Eligibility for technology approval
The manufacturer shall comply with the specified quality assessment system (if any).
Application of technology approval
The manufacturer shall comply with the specified quality assessment system (if any).
Description of technology
The technology shall be described in a Technology Approval Declaration Document (TADD) and a Technology Approval Schedule (TAS) in accordance with the specified quality assessment system (if any).
Demonstration and verification of the technology
The manufacturer shall demonstrate and verify the technology in accordance with the specified quality assessment system (if any).
Granting of technology approval
Technology approval shall be granted when the procedures in accordance with the specified quality assessment system (if any) have been completely satisfied.
Maintenance of technology approval
Technology approval shall be maintained by complying with the requirements of the specified quality assessment system (if any).
Quality conformance inspection
The quality conformance test and requirements shall be carried out in accordance with the detail specification and technology approval schedules.
Failure rate level determination
The determination of failure rate level and certification shall be described in the detail specification.
Outgoing quality level
The definition shall be agreed between customer and manufacturer
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