The tests s own in this stan ard are group d ac ordin to the fol owin prin iples: P: pre aration/con itionin method V: vis al test method D: dimen ional test method C: c emical test meth
General
Errors and uncertainties are inherent in all measurement processes The information given below enables valid estimates of the amount of error and uncertainty to be taken into account
Test data serve a number of purposes which include
– enhancing of confidence in quality conformance;
– arbitration between customer and supplier
In any of these circumstances, it is essential that confidence can be placed upon the test data in terms of
– accuracy: calibration of the test instruments and/or system;
– precision: the repeatability and uncertainty of the measurement;
– resolution: the suitability of the test instrument and/or system.
Accuracy
The quality documentation of the testing supplier or agency must clearly outline the routine calibration procedures for test equipment, ensuring compliance with ISO 9001 standards.
Calibration must be performed by an accredited agency recognized by a national or international measurement standard institute, ensuring a continuous chain of calibration to uphold national or international standards.
Where calibration to a national or international standard is not possible, round-robin techniques may be used and documented to enhance confidence in measurement accuracy
The standard calibration interval is typically one year However, if equipment frequently falls outside acceptable accuracy limits, the calibration intervals will be shortened Conversely, equipment that consistently meets accuracy standards may qualify for extended calibration intervals.
Each instrument must have a comprehensive record of its calibration and maintenance history These records should include the uncertainty of the calibration technique expressed as a ± % deviation, allowing for the aggregation and determination of measurement uncertainties.
A procedure shall be implemented to resolve any situation where an instrument is found to be outside calibration limits.
Precision 9 3.4 Resolution 1 0 3.5 Report 1 0 3.6 Student’s t distribution 1 0 3.7 Suggested uncertainty limits 1 1
The uncertainty budget of any measurement technique is made up of both systematic and random uncertainties All estimates shall be based upon a single confidence level, the minimum being 95 %
Systematic uncertainties are usually the predominant contributor and will include all uncertainties not subject to random fluctuation These include
– errors due to the use of an instrument under conditions which differ from those under which it was calibrated;
– errors in the graduation of a scale of an analogue meter (scale shape error)
Random uncertainties result from numerous sources but can be deduced from repeated measurement of a standard item Therefore, it is not necessary to isolate the individual contributions These may include
Random fluctuations, often caused by variations in influence parameters, can significantly impact measurement repeatability, particularly due to changing atmospheric conditions Additionally, uncertainty in discrimination arises when setting a pointer to a fiducial mark or when interpolating between graduations on an analogue scale.
The geometric addition, or root-sum-square method, is commonly employed for aggregating uncertainties Typically, interpolation error is considered separately and is often accepted as 20% of the difference between the instrument's finest graduations.
Random uncertainties can be assessed through repeated measurements of a parameter, followed by statistical analysis of the collected data This method relies on the assumption that the data follows a normal (Gaussian) distribution.
U r is the random uncertainty; n is the sample size; t is the percentage point of the t distribution as shown in Table 1 ; σ is the standard deviation (σ n –1)
It is paramount that the test equipment used be capable of sufficient resolution Measurement systems used should be capable of resolving 1 0 % (or better) of the test limit tolerance
It is accepted that some technologies will place a physical limitation upon resolution (for example, optical resolution)
The report must include the test method, sample identity, test instrumentation, specified limits, an estimate of measurement uncertainty along with the working limits, detailed test results, the test date, and the operators' signature, in addition to the requirements outlined in the test specification.
Table 1 gives values of the factor t for 95 % and 99 % confidence levels, as a function of the number of measurements
The following target uncertainties are suggested: a) Voltage < 1 kV: ± 1 ,5 % b) Voltage > 1 kV: ± 2,5 % c) Current < 20 A: ± 1 ,5 % d) Current > 20 A: ± 2,5 %
Resistance e) Earth and continuity: ± 1 0 % f) Insulation: ± 1 0 % g) Frequency: ± 0,2 %
Time h) Interval < 60 s: ± 1 s i) Interval > 60 s: ± 2 % j) Mass < 1 0 g: ± 0,5 % k) Mass 1 0 g – 1 00 g: ± 1 % l) Mass > 1 00 g: ± 2 % m) Force: ± 2 % n) Dimension < 25 mm: ± 0,5 % o) Dimension > 25 mm: ± 0,1 mm p) Temperature < 1 00 °C: ± 1 ,5 % q) Temperature > 1 00 °C: ± 3,5 % r) Humidity (30 – 75) % RH: ± 5 % RH
Plating thicknesses s) Backscatter method: ± 1 0 % t) Microsection: ± 2 microns u) Ionic contamination: ± 1 0 %
4.1 Test 5-3X01 : Paste flux viscosity – T-Bar spindle method
This test method is designed to measure the viscosity of paste flux
The test specimen shall contain enough paste flux to fill a container with a minimum diameter of 4 cm to a minimum depth of approximately 1 0 cm
4.1 3 a) Viscometer with helipath stand and a T-C spindle (Brookfield RVTD 1 or equivalent) b) Water bath capable of holding (25 ± 0,5) °C c) Stopwatch d) Spatula
To measure the viscosity of paste flux, first, place the container in a water bath maintained at (25 ± 0.5) °C until thermal equilibrium is reached Next, position the container under the spindle at the center of the surface and initiate the Brookfield viscometer at 5 r/min while starting the helipath stand to descend After 2 minutes, record the viscosity value, ensuring the spindle does not touch the bottom of the container Finally, remove the spindle and vigorously stir the flux with a spatula.
(1 5-20) s and re-measure the viscosity
The viscosities are calculated from the values recorded after 2 min of medium penetration Both stirred and unstirred results should be recorded
Observe all appropriate precautions on material safety data sheets (MSDS) for chemicals involved in this test method
4.2 Test 5-3X02: Spread test, extracted solder flux, paste flux and solder paste
This test method gives an indication of activity of solder paste The test method offers two methods
Method A measures the solder spread area
Brookfield RVTD, a product from Brookfield Engineering Laboratories, Inc., is mentioned for user convenience and does not imply IEC endorsement Users may opt for equivalent products that demonstrate comparable results.
Method B measures the solder spread ratio
4.2.2.1 a) For extracted solder flux, a minimum of 1 0 ml that is furnished in a clean glass container b) For paste flux and solder paste flux, 1 0 ml of the diluted material (35 %)
The requirements for the experiment include five replicates of 0.25 mm thick 70/30 brass, each measuring approximately 40 mm × 75 mm Additionally, very fine degreased steel wool, such as #00, is necessary The solder wire must be from the specified alloys, including Sn63Pb37A or Sn96.5Ag3Cu0.5, or any other solder alloy mutually agreed upon by the user and supplier, in accordance with IEC 61190-1-3, with a diameter of 1.5 mm Finally, a solder pot with a minimum depth of 25 mm and containing at least 2 kg of solder is required.
To prepare the test specimen, first clean five brass coupons using steel wool Next, flatten each coupon by bending opposite sides to create parallel bends that align with the curve of the original metal coil Then, cut a 30 mm length of solid wire solder and wrap it around a 3 mm mandrel Finally, cut the coil into individual rings to form a preform of the solder.
To ensure proper soldering, maintain the solder bath temperature at (260 ± 3) °C for Sn60Pb40, (255 ± 3) °C for Sn96.5Ag3Cu0.5, or at (35 ± 3) °C above the liquidus temperature for other agreed solder alloys Position the preformed solder at the center of the test specimen, then add one drop (0.05 ml) of flux onto it Carefully immerse the coupon in the solder bath for 15 seconds, then remove it horizontally and place it on a flat surface to allow the solder to solidify undisturbed Finally, clean any flux residue using an appropriate solvent.
To measure the solder spread area, compare it to pre-drawn circles with areas similar to those in Table 2 The average spread from all five tested specimens should be reported Ensure to record the data and input it into Table 1.
Table 2 is intended as an aid in defining areas in mm 2
Table 2 – Typical spread areas defined in mm 2
Flux can be derived from various products, including solder paste and paste flux Solder wire, such as Sn63Pb37 or Sn96.5Ag3Cu0.5, or any other agreed-upon solder alloy as specified in IEC 61190-1-3, must be wrapped around a ring bar with a diameter of 3.3 mm.
The solder bath must have a minimum depth of 30 mm and dimensions of at least 100 mm × 150 mm, equipped with a temperature controller maintaining (50 ± 2) °C above the liquidus temperature of the solder An air convection oven is required, capable of sustaining a temperature of (150 ± 3) °C Proper tools, such as a tongue or other lifting device, are necessary for handling test pieces from the solder bath A scrubber should be available to easily remove oxidized solder film, along with a spatula for additional handling A metal mask with a thickness of 2.5 mm and a 6 mm diameter hole is essential, as well as a micrometer with a precision of 0.001 mm and a micro syringe or pipet measuring 0.05 ml The general experimental setup should consist of an all-glass device, waterproof abrasive paper, and reagent-grade ethyl alcohol and propan-2-ol A suitable washing solvent is needed to eliminate flux residue post-soldering, and a copper plate measuring 50 mm × 50 mm × 0.5 mm is required to prevent surface oxidation The solder used can be Sn63Pb37, Sn96.5Ag3Cu0.5, or any other alloy agreed upon by the user and supplier, as specified in IEC 61190-1-3.
To prepare an oxidated copper plate for testing, first clean the surface with alcohol, then polish one side with abrasive paper, followed by another alcohol cleaning and thorough drying at room temperature Place the plate in a dryer set at (150 ± 3) °C for 1 hour to oxidize it, and bend the four corners for easier tongue application For the solder test specimen, use a bar with a diameter of 3.2 mm, wound with wire solder of Sn63Pb37, Sn96.5Ag3Cu0.5, or any other solder alloy with a diameter of 1.6 mm Additionally, utilize resin/rosin flux cored solder and solder paste directly from the product.
To prepare the test pieces, first, place (0.025 ± 0.003) g of paste flux at the center of the copper plate and position the solder test piece on top, ensuring that five test specimens are prepared Next, stir the solder paste with a spatula at room temperature and apply it to the copper plate using a metal mask, again preparing five test specimens.
The test piece must be heated in a solder bath maintained at (233 ± 3) °C for Sn63Pb37, (255 ± 3) °C for Sn96.5Ag3Cu0.5, or at (35 ± 3) °C above the liquidus temperature for any other solder alloy as agreed upon by the user and supplier, and held at this temperature for 30 seconds after fusion After heating, the test piece should be lifted from the bath and allowed to cool, followed by the removal of flux residue using an appropriate solvent.
Test 5-3X07: Solder paste – Slump test
Test 5-3X08: Solder paste − Solder ball test
Test 5-3X09: Solder paste − Tack test
This test method outlines two approaches for assessing the capacity of a printed solder paste pattern to hold a probe, by measuring the force needed to detach the probe from the paste The time interval between the application of the solder paste and the placement of the probe is gradually extended to replicate variations encountered in the manufacturing process.
Method A applies a force of (3 ± 0,3) N to the specimen
Method B applies a force of (0,5 ± 0,05) N to the specimen
A representative sample of solder paste should be printed onto clean glass slides using a stencil, with at least six deposits made for each time data-point The final deposits must be circular, measuring 6.3 mm in diameter and 0.25 mm thick It is essential to mark each specimen for identification and to indicate the time for measuring tackiness The prepared specimens should be stored at a temperature of (25 ± 2) °C and a relative humidity of (50 ± 10)% To ensure proper drying, samples must not be kept in enclosed cabinets or containers that could trap solvent vapors around the printed paste.
A Chatillon tackiness tester or similar equipment must accurately measure force at a consistent velocity The device should feature a stainless steel test probe with a nominal diameter of (5.1 ± 0.1 3) mm, ensuring a smooth, flat surface that is parallel to the test specimen The probe must make contact with the specimen at a controlled speed while applying a fixed initial contact force Additionally, the equipment should allow for the controlled withdrawal of the test probe from the specimen's surface, recording the peak force needed to break contact.
To conduct the test, position the specimen slide beneath the test probe and align the probe with one of the three printed patterns Contact the printed paste specimen at a speed of (2.5 ± 0.5) mm/m while applying a force of (3 ± 0.3) N After 5 seconds, retract the probe at the same speed and measure the peak force needed to break contact Perform at least five additional measurements under identical conditions and calculate the average of all readings Additionally, document both the tack force and the time elapsed after paste printing.
Initial measurements should be taken immediately after printing, with additional force measurements conducted as necessary to accurately capture the rise and fall of tack force Tackiness data must be presented in graph form, plotting tack force as a function of time post-printing Additionally, the data can be reported by indicating: a) the time taken to reach 80% of the peak value, b) the peak tack force in grams along with the expected variation, and c) the duration for which the peak value is sustained or the time taken for the tack force to decrease to 80% of its peak value.
Record the data and enter it in Table 1 2
Solder paste is applied to a glass plate using a metal mask, creating five uniform circular patterns with a diameter of 6.5 mm and a thickness of 0.2 mm It is crucial that the thickness of these printed patterns remains consistent to prevent the separation of solder particles The prepared test specimen must then be maintained at a specified temperature.
(25 ± 2) °C with a relative humidity of (50 ± 1 0) % until the test is carried out
The tackiness measuring device includes several key components: a metal mask with a thickness of 0.2 mm featuring five holes, each 6.5 mm in diameter; a cylindrical probe made of stainless steel with a diameter of \(5.1 \pm 0.23\) mm, which is attached to the pressurizing system; a slide glass plate measuring 76 mm × 25 mm × 1 mm; and a fixing device to secure the slide glass plate Additionally, a suitable solvent, such as propan-2-ol, is required for effectively removing grease from the probe and dissolving the paste flux.
To assess the tackiness strength of solder paste, the test specimen is positioned under a probe, which is then centered on one of five printed patterns The probe is lowered into the paste at a speed of 2.0 mm/s and pressurized to (0.5 ± 0.05) N Following pressurization, the probe is pulled upward at a speed of 10 mm/s within 0.2 seconds, and the maximum load for separation is recorded This process is repeated five times under identical conditions, and the average load values are used to calculate the tackiness strength in kN/m² Additionally, the relationship between the elapsed time after printing the solder paste and the tackiness strength is established using the aforementioned procedures.
The tackiness of the solder paste shall be evaluated by the elapsed time after printing the solder paste and the tackiness strength
The eight equipment sources outlined below are the most recognized in the industry Users are encouraged to contribute any new source names as they emerge, ensuring that this list remains current and comprehensive.
AMETEK/Chatillon 8800 Somerset Drive, Largo, FL 33773, Phone; 1 (800) 527-9999
Malcom instruments Corp., 26226 industrial Blvd., Hayward, CA 94545,Phone: 1 (51 0) 293-0580
4.1 0 Test 5-3X1 0: Solder paste − Wetting test
Determine the ability of a solder paste to wet an oxidized copper surface and to qualitatively examine the amount of spatter of the solder paste during reflow
A copper-clad base material of 75 mm × 25 mm and of a thickness of 0,8 mm minimum The cladding thickness shall be 35 àm at least
The experiment requires several essential materials, including a flat hot plate, specimen tongs, and a 400 cm³ beaker Additionally, a magnifying glass with 10× magnification is necessary, along with liquid copper cleaner and deionized water Propan-2-ol will be used as a solvent for removing residual flux Lastly, a stencil measuring 76 mm × 25 mm × 0.2 mm, featuring at least three round holes with 6.5 mm diameter apertures and a minimum center-to-center distance of 10 mm, is also required.
The specimen must be thoroughly cleaned using a liquid copper cleaner, followed by a thorough wash with water After rinsing with propan-2-ol and drying, it should be immersed in boiling deionized water for 10 minutes and then air-dried.
To conduct the solder paste test, first, position the stencil on the test specimen and apply the solder paste pattern Next, execute the reflow process according to the guidelines specified in section 4.8.4.4 of test method 5-3X08 Finally, ensure that any residual flux is eliminated using an appropriate solvent.
This document provides information for user convenience and does not endorse the mentioned product by IEC Equivalent products may be utilized if they demonstrate the ability to achieve the same results.
At 10× magnification, the solder must uniformly wet the copper without any signs of dewetting or non-wetting, and there should be no solder spatter surrounding the printed dots Document the findings and input them into Table 1.
Good solder wetting, surface bond is uniform and no excess solder Solder wetted a part of the copper surface although some dewetting occurred
4.1 1 Test 5-3X1 1 : Determination of solder powder particle size distribution – Screen method for types 1 -4
To describe a method for determining whether or not the powder in a solder paste complies with the relevant powder type
The essential equipment for conducting vibratory test sieving includes a vibratory test sieving machine, test sieves with mesh openings of 150 µm, 75 µm, 45 µm, 38 µm, 25 µm, and 20 µm, as well as a sieve bottom receiver and lid Additionally, a balance with an accuracy of 0.01 g, a 400 ml to 600 ml beaker, a watch glass, solvent, acetone, and a spatula are required for the testing process.
Wait, if necessary, until the solder paste is at room temperature