Tiêu chuẩn iso 08636 2 2007

Microsoft Word C042230e doc Reference number ISO 8636 2 2007(E) © ISO 2007 INTERNATIONAL STANDARD ISO 8636 2 Second edition 2007 12 15 Machine tools — Test conditions for bridge type milling machines[.]

Classification

These machines are classified into the following types depending upon construction:

⎯ travelling bridge (gantry-type) milling machines with fixed cross-rail;

⎯ travelling bridge (gantry-type) milling machines with movable cross-rail (see Figure 1).

Descriptions of principal components

The principal components of these machines are described in Figure 1

The worktable (1) is positioned between two slideways forming the bed, providing a stable and precise work surface It can be manufactured as a single, integral piece or assembled from multiple components that are rigidly connected either through a foundation or directly to each other, ensuring durability and accuracy in machining operations.

NOTE The table can be replaced by a floorplate

4.2.2 Columns, top bridge and cross-rail

The columns (9) and (10) are rigid parts with vertical slideways, which either slide on the bed or are fixed rigidly to column slides (7) and (8) which slide horizontally on the bed

The top bridge (11) is a fixed part connecting the two columns near their top ends

The cross-rail (14) features horizontal slideways parallel to the table surface, playing a crucial role in machine stability and functionality In fixed cross-rail machines, it is integrated with the columns, serving as a top bridge for enhanced structural support Conversely, movable cross-rails slide vertically along the columns (12 and 13), allowing for adjustable positioning to accommodate various machining tasks.

One or more milling heads with vertical, horizontal or inclinable spindles are mounted on the cross-rail slideways

Copyright International Organization for Standardization

Milling heads (16) and (20) are mounted on head saddles (15) and (21) which move on the cross-rail or column slideways

The portion in direct contact with the cross-rail slideways is called the vertical head saddle (15)

The milling head can be mounted on a ram, allowing it to slide vertically along the head saddle in the direction of the spindle axis, enhancing machining flexibility Additionally, the spindle is often mounted within a quill that slides in the milling head, providing precise movement along the spindle axis Some milling heads also feature inclinable parts, enabling angled cuts and versatile machining operations.

Cutting motion is provided by the spindles and drive mechanisms of the milling heads

The following feed movements may be provided with a constant or variable feed rate:

⎯ horizontal movement of the movable gantry;

⎯ vertical movement of the movable cross-rail;

⎯ horizontal movement of the milling heads;

⎯ vertical movement of rams, if any;

⎯ rotational movement (tilt movements of milling heads)

NOTE 1 In general, rapid traverse is available in addition to feed movement

The vertical movement of the movable cross-rail can serve two purposes: it can function as a feed movement during operation or as a positioning movement between fixed working positions When used during operation, the cross-rail is considered "movable when working," enabling precise material handling Alternatively, during setup or repositioning, the cross-rail moves between fixed positions, and is referred to as "movable when being positioned." Understanding these movement functions is essential for optimizing machine performance and positioning accuracy.

5 Terminology and designation of axes

Terminology

Designation of axes

Provided by IHS under license with ISO

Figure 1 — Travelling bridge (gantry-type) machine with movable cross-rail (see Table 1)

Figure 2 — Machine with one milling head

1 Table (or floorplate) Table (ou taque) Tisch (oder Bodenplatte)

2 Clamping surface Surface de bridage Aufspannflọche

3 Left-hand part of the bed Banc gauche Linker Teil des Maschinenbetts

4 Right-hand part of the bed Banc droit Rechter Teil des Maschinenbetts

5 Left-hand bed slideways Glissières du banc gauche Linke Bett-Führungsbahnen

6 Right-hand bed slideways Glissières du banc droit Rechte Bett-Führungsbahnen

7 Left-hand column slide Chariot porte-montant gauche Linker Stọnderschlitten

8 Right-hand column slide Chariot porte-montant droit Rechter Stọnderschlitten

9 Left-hand column Montant gauche Linker Stọnder

10 Right-hand column Montant droit Rechter Stọnder

12 Left-hand column slideways Glissiốres du montant gauche Linke Stọnder-Fỹhrungsbahnen

13 Right-hand column slideways Glissiốres du montant droit Rechte Stọnder-Fỹhrungsbahnen

14 Cross-rail (movable or fixed) Traverse (mobile ou fixe) Traverse (beweglich oder fest)

15 Vertical head saddle Chariot porte-outils vertical Senkrechter Spindelstockschlitten

16 Vertical milling head Tờte de fraisage verticale Senkrechter Frọskopf

17 Quill (ram) Fourreau (coulant) Traghülse (Pinole)

18 Milling spindle Broche porte-fraise Frọsspindel

19 Tool (milling cutter) Outil (fraise) Werkzeug (Frọser)

20 Horizontal milling head Tờte de fraisage horizontale Waagerechter Frọskopf

21 Horizontal head saddle Chariot porte-outils horizontal Waagerechter Spindelstockschlitten

22 Reference T-slot Rainure à T de référence Referenz T-Nut

Figure 3 — Machine with one milling head swivelling on axes C and A

Measuring units

In ISO 8636, all linear dimensions, deviations, and corresponding tolerances are specified in millimeters, ensuring precision and consistency Angular dimensions are expressed in degrees, with angular deviations and tolerances primarily indicated as ratios (e.g., 0,00x/1 000), while microradians (µrad) or arcseconds (″) may be used for clarification It is important to always remember the equivalence between these different expressions to maintain accurate communication of measurement specifications.

Temperature conditions

The temperature conditions throughout the tests shall be specified by agreement between the supplier/manufacturer and user

This machining setup features two versatile configurations: either a swivelling (A-axis) milling head mounted on the cross-rail combined with a horizontal milling head on the right- or left-hand column, or two vertical milling heads mounted on the cross-rail These arrangements enable efficient and flexible manufacturing capabilities, optimizing machining processes for various applications Adhering to ISO 2007 standards ensures high-quality and precise performance across all operations.

Figure 4 — Machine with two milling heads (two examples)

Testing sequence

The order of tests outlined in ISO 8636 does not specify a mandatory sequence for practical testing To simplify instrument installation and measurement procedures, tests can be conducted in any preferred order This flexible approach ensures efficient testing without strict adherence to a prescribed sequence, facilitating smoother operational workflows.

Tests to be performed

When testing a machine, it is not always necessary or feasible to perform all the tests outlined in ISO 8636 For acceptance testing, the user must collaborate with the supplier or manufacturer to select specific tests focused on relevant components or properties of the machine These testing requirements should be explicitly specified at the time of ordering to ensure clarity Merely referencing ISO 8636 for acceptance testing without detailing which tests to conduct or agreeing on associated costs does not impose binding obligations on either party.

Measuring instruments

The measuring instruments specified in the following tests are examples only; alternative instruments that measure the same quantities with equal or lower measurement uncertainty may also be used to ensure accuracy and compliance with quality standards.

Minimum tolerance

When setting the tolerance for a measuring length that differs from the specifications in ISO 8636, it is important to note that the minimum tolerance value is 0.005 mm This ensures accurate measurement standards are maintained according to ISO 230-1:1996.

Machining tests

Machining tests shall be made with finishing cuts only Roughing cuts shall be avoided since they are liable to generate appreciable cutting forces.

Positioning tests

Positioning tests for numerically controlled machines must adhere to ISO 230-2 standards, ensuring consistent and accurate measurement practices While ISO 8636 provides tolerances for certain parameters, it is essential to follow ISO 230-2 when presenting test results to maintain compliance and reliability Accurate reporting of test outcomes in accordance with these standards guarantees proper assessment of machine positioning accuracy.

Tolerances are limited to machines with table sizes up to 3,000 mm by 10,000 mm For machines exceeding these dimensions, the tolerance must be mutually agreed upon between the supplier or manufacturer and the user, ensuring precise specifications for larger equipment.

Place the gantry at mid-stroke, with milling head at mid-position on cross-rail (or in symmetrical positions if several heads are available)

Axes of motion

Checking of straightness of movement of the column (X-axis) in the horizontal X-Y plane (EYX)

0,02 for measuring length up to 2 000

Add 0,01 to the preceding tolerance for each 1 000 increase in length beyond 2 000

Local tolerance: 0,01 for any measuring length of 1 000

Microscope/CCD camera and taut wire or other methods

Observations and references to ISO 230-1:1996, 5.232.12, 5.232.13 and 5.232.14

When using a microscope or CCD camera with a taut wire, ensure the camera is mounted on the head and the taut wire is securely fixed at both ends of the table, parallel to the X-axis This setup allows for accurate measurement of straightness deviation, as identical readings at both ends indicate proper alignment The maximum difference in readings between the two ends highlights the extent of straightness deviation, ensuring precise calibration and testing.

Traverse the column in the X-direction and record the readings

Checking of angular deviations of the movement of the column (X-axis): a) in the vertical Z-X plane (EBX: pitch); b) in the vertical Y-Z plane (EAX: roll); c) in the horizontal X-Y plane (ECX: yaw)

Add 0,01/1 000 to the preceding tolerance for each 1 000 increase in length larger than 4 000 b)

Add 0,005/1 000 to the preceding tolerance for each 1 000 increase in length larger than 4 000

Measuring instruments a) Precision level or optical angular deviation measuring instruments b) Precision level c) Autocollimator or other optical angular deviation measuring instruments

Observations and references to ISO 230-1:1996, 5.231.3 and 5.232.2

The level or instrument should be positioned on the movable component according to specific axes: the pitch (EBX) should be set vertically along the X-axis, the roll (EAX) should be aligned vertically along the Y-axis, and the yaw (ECX) should be placed horizontally using the autocollimator Proper placement of these instruments ensures accurate alignment and measurement in precision engineering and calibration processes.

If X-axis motion causes angular deviation of both the spindle head and work-holding table, differential measurements of the two angular movements shall be taken

Measurements shall be carried out at a minimum of five positions equally spaced along the travel, in both directions of movement

The difference between the maximum and minimum readings shall not exceed the tolerance

Checking of straightness of the horizontal movement of the milling head (Y-axis): a) in the horizontal X-Y plane (EXY); a) in the vertical Y-Z plane (EZY)

0,02 for measuring length up to 1 000

Add 0,01 to the preceding tolerance for each 1 000 increase in length beyond 1 000

Local tolerance: 0,01 for any measuring length of 500

Straightedge, linear displacement sensor/support and gauge blocks or optical methods or microscope and taut wire (for measurement in horizontal plane only)

Observations and references to ISO 230-1:1996, 5.232.11, 5.232.12 and 5.232.13

Fix the cross-rail in the mid-height and move the column in mid-travel

To assess straightness deviation, place a straightedge on the table aligned parallel to the Y-axis movement of the milling head For accurate measurements, position the straightedge both horizontally and vertically, ensuring that the linear displacement sensor readings at both ends of each movement are equal The maximum difference between these sensor readings indicates the straightness deviation of the milling head, which is crucial for maintaining precision in machining operations.

Attach a linear displacement sensor to the milling head The linear displacement sensor stylus shall be normal to the reference face of the straightedge

During the measurement process, traverse the milling head in the Y-direction along the designated measuring length and record the readings The measuring length typically spans between two columns, excluding the full length of the cross-rail, unless otherwise agreed upon by the supplier and user Ensuring accurate traversal and precise readings is essential for optimal machine calibration and performance.

This article discusses the inspection of angular deviations in the horizontal movement of the milling head (Y-axis) It focuses on three key planes: the vertical Y-Z plane, assessing pitch (EAY); the vertical Z-X plane, measuring roll (EBY); and the horizontal X-Y plane, evaluating yaw (ECY) Accurate measurement of these deviations is essential for ensuring precise milling operations and maintaining high-quality manufacturing standards Proper alignment and calibration of the milling head help optimize machine performance and ensure dimensional accuracy in machined parts.

Local tolerance: 0,02/1 000 for any measuring length of 300

Measuring instruments a) Precision level or optical angular deviation measuring instruments b) Precision level c) Autocollimator or other optical angular deviation measuring instruments

The level or instrument should be positioned on the movable component to ensure accurate alignment Specifically, the pitch (EAY) should be set vertically along the Y-axis, while the roll (EBY) must be aligned vertically along the X-axis Additionally, the yaw (ECY) should be measured horizontally using an autocollimator Proper placement and calibration of these components are essential for precise instrument alignment and optimal performance.

When Y-axis motion causes angular deviation of both the spindle head and work-holding table, differential measurements of the two angular movements shall be taken

When differential measurement is applied, the reference level should be placed on the work-holding table, and the column shall be in the middle of its travel range

Measurements shall be carried out at a minimum of five positions equally spaced along the travel, in both directions of movement

The difference between the maximum and the minimum readings shall not exceed the tolerance

Checking of squareness of milling carriage transverse displacement on cross-rail (Y-axis) to column displacement (X-axis) in a horizontal plane

Square and linear displacement sensor

Observations and references to ISO 230-1:1996, 5.522.4

Place column in mid-position, orient one arm of square parallel to column displacement (X-axis)

Fix linear displacement sensor support and linear displacement sensor on milling head

Place linear displacement sensor stylus against the other arm of the square Move milling head along cross-rail and read indication

Rotate square 180°, repeat checks in the same order and calculate the average value of the deviations determined

For large machines, repeat the operation in two extreme column positions

Checking of squareness of milling head vertical displacement (Z-axis) to: a) X-axis; b) Y-axis

NOTE This test is also applicable to additional vertical milling heads on the cross-rail

For a) and b): 0,02 for a measuring length of 300

Cylindrical square, surface plate, adjustable blocks and linear displacement sensor

Place bridge, cross-rail and milling head at mid-stroke

Fix linear displacement sensor on milling head Lock cross-rail on column, where possible

To ensure precise measurement, position the cylindrical square on a surface plate aligned with the X- and Y-axes, corresponding to the bridge's longitudinal and transverse displacements Next, place the linear displacement sensor stylus at point A1 within the longitudinal plane of the cylindrical square Move the Z-axis to reach point A2 and record the sensor reading to accurately capture displacement data.

Rotate cylindrical square 180° and repeat the measurement in the same order

Calculate the average value of the deviations determined

Then carry out measurement in the transverse (Y-Z) plane at points b 1 and b 2

For large machines, checking may be carried out at the mid-position and in two extreme positions of the milling head on the cross-rail

Checking of squareness of movable cross-rail vertical displacement (R-axis) to: a) X-axis; b) Y-axis

For a) and b): 0,02 for a measuring length of 300

Place bridge, cross-rail and milling head at mid-stroke

Fix dial-gauge support and linear displacement sensor on milling head Lock milling head on cross-rail, where possible

Place the cylindrical square on a surface plate aligned with the X- and Y-axis directions, corresponding to the bridge's longitudinal and transverse movements Next, position the linear displacement sensor stylus at point A1 on the cylindrical square within the longitudinal plane Move the cross-rail to point A2 and record the displacement reading, ensuring precise measurement of linear motion for accurate CNC machine calibration and quality control. -**Sponsor**Need help polishing your article and making it SEO-friendly? [editorr](https://pollinations.ai/redirect-nexad/fZjdzt1E) can assist! Our platform offers on-demand proofreading and editing services, ensuring clarity, grammar, and overall composition are top-notch Simply submit your content and receive instant feedback from qualified editors Transform your text into a compelling narrative that resonates with your audience, all while adhering to SEO best practices.

Rotate cylindrical square 180° and repeat the checking in the same order

Then check in the transverse plane at points b 1 and b 2

For large machines, checking may be carried out at the mid-position and in two extreme positions of the milling head on the cross-rail

Checking of slope variation of the cross-rail in its R-axis movement in the vertical Y-Z plane: a) in the lower position; b) in the mid-position; c) in the higher position

Place the level at the mid-position of the cross-rail on an adequate face and read the indication in the quoted positions

When R-axis motion causes angular deviation of both the cross-rail and the work-holding table, differential measurements of the two angular movements shall be taken

When differential measurement is applied, the reference level shall be placed on the work-holding table Place milling heads symmetrically relative to the work-holding table

For machines with only one milling head, it shall be placed in a central position

Lock the cross-rail at each position, where possible

Table

Checking of flatness of the table surface

For each additional increment of 1 000 in X: add 0,010

For each additional increment of 1 000 in Y: add 0,010

Precision levels and support with contact points 500 mm apart or optical or other equipment

Observations and references to ISO 230-1:1996, 5.322, 5.323, 5.324

Bridge at mid-travel (mid-position)

Place the support on the table surface and position the precision level accordingly Move the support along the O-X and O-Y directions in steps equal to the support length (500 mm), and record the readings at each position.

Test method G10 is also useful for the checking of flatness if finish-machining of table is not carried out after assembly

Checking of parallelism of the table surface to: a) the movement of the column (X-axis); b) the movement of the milling head (Y-axis)

Local tolerance: 0,02 for any measuring length of 1 000 b) Y u 1 000: 0,03 For each additional increment of 1 000: add 0,02 Max tolerance: 0,06 Local tolerance: 0,03 for any measuring length of 1 000

The specified tolerances assume that no finish-machining of the table is performed after assembly If finish-machining is necessary post-assembly, the tolerances must be mutually agreed upon between the supplier or manufacturer and the user to ensure proper fit and functionality.

Linear displacement sensor, straightedge and gauge blocks

Attach a linear displacement sensor to the milling spindle or the head near the spindle, ensuring it is perpendicular to the table surface and in direct contact or with a gauge block on the table Position the milling head at mid-travel, traverse the column in the X-direction, and record the maximum difference in sensor readings to assess machine accuracy.

Repeat the test in two other positions of the milling head, symmetrical to the previous position, and record the maximum difference of the readings in the same way

The largest of the maximum differences indicates the parallelism deviation of the X-axis To ensure accurate measurement, lock the cross-rail whenever possible Then, move the milling head in the Y-direction and record the maximum differences in readings to assess alignment accuracy.

Repeat the test in two other positions symmetrical to the previous position and record the maximum differences of the reading in the same way

The largest of the maximum differences gives the parallelism deviation of the Y-axis

Checking of the parallelism of median or reference T-slot to the movement of the column (X-axis)

0,03 for a measuring length up to 2 000

Add 0,01 to the preceding tolerance for each 1 000 increase in length

Local tolerance: 0,02 for any measuring length of 1 000

Linear displacement sensor, cross-square

Attach the linear displacement sensor to the milling spindle or the nearby head for accurate measurement Ensure the gauge stylus contacts the measurement face of the reference T-slot or use a properly shaped piece to achieve precise readings Proper sensor placement and contact are essential for reliable displacement measurements in machining operations.

Move the cross-rail and record the linear displacement sensor indicator variation

Milling head

Checking of run-out of internal taper of the milling spindle: a) close to the spindle nose; b) at a distance of 300 mm from the spindle nose

Carry out these tests for each milling spindle of the machine

D > 200 a) 0,015 b) 0,030 where D is the external diameter of the spindle-nose face

Linear displacement sensor and test mandrel

Attach the linear displacement sensor to a fixed part of the machine and insert the test mandrel into the spindle Position the sensor stylus as close as possible to point a) for accurate measurements Rotate the spindle and record the displacement readings to ensure precise alignment and performance of the machine.

Repeat the same operation at position b) at a distance of 300 mm from position a)

NOTE An alternative test (testing error motions of the axis of rotation) is presented in R1

Checking of the milling spindle for: a) run-out of external surface-nose face; b) camming of spindle-nose face (including periodic axial slip); c) periodic axial slip

Carry out these tests for each milling spindle of the machine in the vertical or horizontal position

D u 200 D > 200 a) 0,010 0,015 b) 0,015 0,020 c) 0,005 0,010 where D is the external diameter of the spindle-nose face

Observations and references to ISO 230-1:1996

Attach a linear displacement sensor support and a linear displacement sensor to a fixed part of the machine a) 5.612.2

Place the linear displacement sensor stylus normal to the generating line, rotate the milling spindle and record the indication b) 5.63.2

Place the linear displacement sensor stylus as close as possible to the outside edge of the flat face at position M, rotate the milling spindle and record the indication

Repeat the same operation at position N after moving the linear displacement sensor

Determine the average value c) 5.622.1 and 5.622.2 Insert a steel ball in the spindle centre (by auxiliary means if necessary)

Position the linear displacement sensor stylus to contact the steel ball, rotate the spindle and record the indication

The value and the direction of the force to be applied shall be specified by the supplier/manufacturer

When axially preloaded bearings are used, there is no need to apply the force F

NOTE An alternative test (testing error motions of the axis of rotation) is presented in R1

Checking of squareness of the vertical milling spindle axis of rotation to: a) X-axis; b) Y-axis

For a) and b): 0,03/500 (distance between the two measuring points touched)

Linear displacement sensor/support arm and straightedge or surface plate

Place a straightedge at the centre of the table parallel to the X-axis movement of the cross-rail in the vertical plane

Cross-rail at mid-height and locked, vertical milling head at mid-travel and locked, where possible Quill or ram 1/3 travel from the head

Attach the supporting arm with a linear displacement sensor to the milling spindle, then adjust the sensor's stylus to contact the straightedge and record the initial measurement Rotate the spindle 180° and record the new sensor indication Calculate the difference between the two readings over the measured distance to assess spindle alignment accuracy.

Repeat the above measurement with straightedge set parallel to the Y-axis movement

Swivelling milling head

Checking of parallelism of the milling-head swivel axis to the Y-Z plane when the milling head swivels

For linear displacement sensor placed at 100 mm from the spindle nose swivel axis

Square, surface plate, adjustable blocks and linear displacement sensor

Begin by placing a surface plate securely on the table and adjusting its top surface to be parallel to both the X- and Y-axes movements for accurate measurement Then, position the flat square on the surface plate, ensuring its vertical surface is aligned parallel to the Y-axis movement to achieve precise orientation.

Cross-rail fixed at mid-height, milling-head saddle fixed at mid-travel

Attach a linear displacement sensor to the milling head so that the stylus of a linear displacement sensor is

100 mm from the spindle nose

Apply the stylus of the linear displacement sensor to the flat-square face in the X-direction; rotate the milling head and record readings

Horizontal milling head (side milling head)

Checking of squareness between the vertical movement of the side milling head (W-axis) on a column and the: a) X-axis; b) Y-axis

For a) and b): 0,03 for measuring length of 500

Place column and vertical milling head at mid-stroke

Fix linear displacement sensor support and linear displacement sensor on side milling head

Position the cylindrical square on a surface plate, ensuring it is aligned parallel to the reference plane defined by the column’s longitudinal (X-axis) and vertical milling head’s transverse displacement (Y-axis) Place the linear displacement sensor stylus at point A1 on the cylindrical square within the longitudinal plane Then, move the side milling head to point A2 and record the measurement reading.

Rotate cylindrical square 180°and repeat the checking in the same order

Then carry out checking in the transverse plane at points b 1 and b 2

When installing a linear displacement sensor, it is crucial to consider whether the spindle can be locked If the spindle can be locked, the sensor should be mounted directly on it for accurate measurements Conversely, if the spindle cannot be locked, the linear displacement sensor must be positioned on a fixed, stable part of the machine to ensure precise readings Proper sensor placement based on spindle lockability is essential for optimal machine performance and measurement accuracy.

Checking of parallelism of the horizontal milling spindle axis to the Y-axis: a) in the vertical Y-Z plane; b) in the horizontal X-Y plane

NOTE Applicable only for the milling head with a horizontal spindle axis This check does not apply to removable milling heads

For a) and b): 0,03 for measuring length of 300

Test mandrel and linear displacement sensor

Attach the linear displacement sensor to the vertical milling head and carefully position the stylus to contact the test mandrel mounted on the horizontal milling spindle Ensure the sensor touches the mandrel both vertically and horizontally, positioning it as close as possible to the spindle nose for accurate measurement.

Horizontal milling head is locked in low-position Cross-rail is locked in mid-position, where possible

Move the vertical milling head (Y-axis) for the measuring length and record the indications

Record the maximum difference of linear displacement sensor readings

Tests shall be carried out at the mean position of the spindle rotation for both a) and b)

Checking of squareness between the axis of rotation of the horizontal milling spindle and the movement of the column (X-axis)

NOTE Applicable only for the milling head with a horizontal spindle axis This check does not apply to removable milling heads

1) Distance between the two measuring points touched

Straightedge, linear displacement sensor and support arm

Place a straightedge at the centre of the table parallel to the X-axis movement of the column in the horizontal plane The column is locked at mid-travel, where possible

Horizontal milling head at low-position and locked, where possible Quill or ram 1/3 travel from the horizontal milling head

Attach the support arm with the linear displacement sensor to the horizontal milling spindle and calibrate the stylus to contact the straightedge, noting the initial measurement Rotate the spindle by 180° and record the new reading, then determine the difference between these two measurements Calculating the variation over the distance between the measurement points helps assess the spindle's alignment accuracy This process ensures precise machine calibration and enhances overall manufacturing quality.

Flatness of test pieces by slab milling

Milling of four test pieces (face B) along X-axis for table length of up to 2 000 mm

For a table length in excess of 2 000 mm, six (or eight) test pieces as shown in the diagram may be used

The test setup involves a test piece with a length (l1) measuring 600 mm, while l2 denotes the distance between the extreme faces of successive test pieces mounted in sequence The dimensions of the test pieces are specified as b1 and h1 both equal to 150 mm, and b2 and h2 both equal to 110 mm The difference between the lengths, l1 and l2, is either fixed at 600 mm or defined through an agreement between the user and manufacturer.

Machining shall be carried out with an insert cutter mounted on a vertical milling spindle

All test conditions, including tool quality and dimensions, cutting speed, feed rate, depth of cut, and material of test pieces, must be specified by the supplier or manufacturer to ensure consistent and reliable results.

All test pieces shall have the same hardness

Tolerance a) Flatness of face B of each test piece: 0,015 b) Height h 1 of blocks shall be constant for one test piece or for: l 2 u 2 000 0,03

Straightedge and gauge blocks or linear displacement sensor and surface plate, micrometer

Observations and references to ISO 230-1:1996, 3.1, 3.22, 4.1, 4.2, 5.321 and 5.412.2

⎯ ensure that faces A are flat;

⎯ orient block(s) parallel to the movement of the table (X-axis)

With milling cutter mounted on milling spindle, the following tolerances are recommended: a) run-out u 0,02; b) camming u 0,03

Milling of lateral face

Milling of one of the lateral faces of two or three test pieces placed on the table along the X-axis

One face perpendicular to face B can be machined with the tool (milling head) guided on the right- or left- hand column

Test to be carried out if the machine is fitted with the required spindles

M2 is a follow-on test after M1

Diagram l 1 is the length of the table l 2 is the distance between extreme faces of test pieces mounted in successive order l 1 − l 2 = 600; or l 1 − l 2 is defined by agreement between user and manufacturer

Nominal dimensions of test piece are the same as for test M1

The supplier or manufacturer must specify all testing conditions, including tool quality and dimensions, cutting speed, feed rate, depth of cut, and material of test pieces, to ensure consistent and reliable testing results.

All test pieces shall have the same hardness

Squareness between side face C and face B

Squareness deviations of all test pieces: within 0,02 for a measuring length of 300

Observations and references to ISO 230-1:1996, 3.1, 3.22, 4.1, 4.2, 5.321 and 5.412.2

Orient block(s) parallel to X-axis

9 Accuracy and repeatability of positioning of numerically controlled axes

Linear axes

Checking of accuracy and repeatability of the X-axis movement of the column

(Measured deviation) Axes up to 2 000 mm

Unidirectional repeatability of positioning, R ↑ or R ↓ 0,008 0,010 0,013

Reversal value of the axis, B 0,010 0,013 0,016

Bidirectional systematic deviation of positioning, E 0,016 0,020 0,025

Range of the mean bidirectional positional deviation of the axis, M

Bidirectional systematic deviation, E 0,025 + 0,005 for each additional 1 000

Range of the mean bidirectional positioning deviation of the axis, M

Reversal value of the axis, B 0,016 + 0,003 for each additional 1 000

Linear scale or laser measurement equipment

Observations and references to ISO 230-2

For accurate measurement, it is essential to compare the tool position relative to the workpiece position When using a linear scale, ensure it is mounted parallel to the X-axis on the table, with the scale reader positioned at the tool If laser measurement equipment is employed, place the reflector on the vertical milling head at the tool position and position the interferometer on the table for precise readings.

Concerning the test conditions, test programme and presentation of results, ISO 230-2:2006, Clauses 3, 4 and 7 shall be referred to

Checking of accuracy and repeatability of the Y-axis movement of the vertical milling-head saddle

Tolerance u 500 u 1 000 u 2 000 (Measured deviation) Axes up to 2 000 mm

Range of the mean bidirectional positional deviation of the axis, M 0,010 0,013 0,016

Range of the mean bidirectional positional deviation of the axis, M 0,016 + 0,003 for each additional 1 000

For accurate measurement, the relative position between the tool and workpiece is essential A linear scale should be installed parallel to the Y-axis on the table, with the scale reader positioned at the tool When using laser equipment, the reflector must be mounted on the vertical milling head, while the interferometer should be positioned on the table or its extension to ensure precise alignment.

Concerning the test conditions, test programme and presentation of results, ISO 230-2:2006, Clauses 3, 4 and 7 shall be referred to The starting point of measurement shall be stated

Checking of accuracy and repeatability of the Z-axis movement of the vertical milling head or quill

Unidirectional repeatability of positioning, R ↑ or R ↓ 0,008 0,010

Reversal value of the axis, B 0,010 0,013

Bidirectional systematic deviation of positioning, E 0,016 0,020

Range of the mean bidirectional positioning deviation of the axis, M

For precise measurement, it's essential to assess the relative position between the tool and the workpiece When using a linear scale, ensure it is aligned parallel to the Z-axis on the table, with the scale reader positioned at the tool Alternatively, if laser equipment is utilized, place the reflector on the vertical milling head and position the interferometer on the table to achieve accurate measurements.

Checking of accuracy and repeatability of the W-axis movement of the horizontal milling head

Range of the mean bidirectional positional deviation of the axis, M 0,010 0,013 0,016

For accurate measurements, it is essential to determine the relative position between the tool and the workpiece When using a linear scale, ensure it is installed parallel to the Z-axis on the table, with the scale reader positioned at the tool If laser equipment is employed, the reflector should be mounted on the horizontal milling head, while the interferometer is placed on the table Proper setup of these measurement tools guarantees precise alignment and optimal machining accuracy.

Concerning the test conditions, test programme and presentation of results, ISO 230-2:2006, Clauses 3, 4 and 7 shall be referred to The starting point of measurement shall be stated

Checking of accuracy and repeatability of the V-axis movement of the horizontal milling head or quill

Unidirectional repeatability of positioning, R ↑ or R ↓ 0,008 0,010

Reversal value of the axis, B 0,010 0,013

Bidirectional systematic deviation of positioning, E 0,016 0,020

Range of the mean bidirectional positional deviation of the axis, M 0,010 0,013

For accurate measurements, it is essential to establish the relative position between the tool and work-piece When using a linear scale, ensure it is aligned parallel to the Y-axis on the table, with the scale reader positioned at the tool location For laser measurement systems, position the reflector on the horizontal milling head and the interferometer on the table to obtain precise results.

Checking of accuracy and repeatability of the R-axis movement of the cross-rail when numerically controlled.

Range of the mean bidirectional positioning deviation of the axis, M 0,010 0,013 0,016

For accurate measurement, it is essential to establish the relative position between the tool and the workpiece When using a linear scale, ensure it is mounted parallel to the Z-axis on the table, with the scale reader positioned at the tool location In laser measurement systems, place the reflector on the vertical milling head and position the interferometer on the table for precise alignment Proper setup of measurement tools enhances machining accuracy and ensures reliable results.

Rotary axes

Checking of accuracy and repeatability of the A-axis movement of the vertical milling head

Unidirectional repeatability of positioning, R ↑ or R ↓ 5 6

Bidirectional systematic deviation of positioning, E 10 13

Reversal value of the axis, B 6 8

Polygon with autocollimator or master index table with mirror and autocollimator or master index table with angle interferometer

When using a master index table, position it on the swiveling head so that its rotation axis is parallel and close to the head's rotation axis Rotate the head by a specific indexable angle [a)] and then return the index table to its original position to ensure precise alignment and efficient machining.

[b)] so that the mirror comes back to its original position, and check the angular deviation

10 Geometric accuracy of axes of rotation of toolholding spindles

Axis of rotation error motion for toolholding spindle (C1): a) radial error motion (ERC); b) axial error motion (EZC); c) tilt error motion (ETC)

1 to 5 linear displacement sensors (probes) (See Observations)

Tolerance at percentage of maximum speed

10 % 50 % 100 % a) total radial error motion value ERC 0,010 0,014 0,020 b) total axial error motion value EZC 0,010 0,014 0,020 c) total tilt error motion value ETC 0,040/1 000 0,060/1 000 0,080/1 000

If the minimum speed is larger than 10 % of the maximum speed, then the spindle should be operated at minimum speed

Test mandrel, non-contacting probes and angular measuring device; or two precision spheres located slightly eccentric to spindle average line and non-contacting probes

Observations and references to ISO 230-7:2006

This test is a spindle test with rotating sensitive direction (5.4 of ISO 230-7:2006)

After setting up the measuring instrument, the spindle should be warmed up at 50% of its maximum speed for 10 minutes, unless otherwise specified by the manufacturer or user Proper warming-up ensures optimal instrument performance and measurement accuracy Following standard procedures for spindle warm-up helps maintain calibration and prolongs the lifespan of the equipment.

Total error motion is defined in section 3.2.4 of ISO 230-7:2006, with the total error motion value specified in figure F.3.4 of the same standard Accurate measurement of total error motion is essential and should be carried out by assessing the total radial error motion value (ERC) using probes 1 and 2, ensuring compliance with ISO 230-7:2006 guidelines for precision and reliability.

Radial error motion measurement is detailed in section 5.4.2 of ISO 230-7:2006, emphasizing the importance of measuring as close as possible to the spindle nose This ensures accurate assessment of spindle performance, with sensors 1 and 2 positioned near the spindle nose as illustrated in the test diagram Proper measurement of radial error motion is crucial for maintaining precision in machine tool operations and quality control.

For assessing radial error motion ERC, a comprehensive polar plot of total error motion should be provided in accordance with ISO 230-7:2006 section 3.3.1, including a least squares circle (LSC) center as outlined in section 3.4.3 Additionally, the total axial error motion value EZC should be determined using probe 3, ensuring accurate measurement of axial deviations.

Axial error motion measurement is described in 5.4.4 of ISO 230-7:2006

To analyze the axial error motion EZC, a comprehensive total error motion polar plot must be provided in accordance with ISO 230-7:2006 section 3.3.1, featuring a polar chart centered as specified in section 3.4.1 of the standard Additionally, total tilt error motion values (ETC) should be measured and reported using probes 1, 2, 4, and 5 to ensure accurate assessment of tilt deviations.

Tilt error motion measurement is described in 5.4.3 of ISO 230-7:2006 The tilt error motion can also be checked with just two non-contacting probes (see 5.4.2.1 and 5.4.2.2 of ISO 230-7:2006)

For the tilt error motion ETC, a total error motion polar plot (3.3.1 of ISO 230-7:2006) with a PC centre (3.4.1 of ISO 230-7:2006) shall be provided

For these tests the following parameters shall be stated:

⎯ radial, axial or face locations at which the measurements are made;

⎯ identification of all artifacts, targets and fixtures used;

⎯ location of the measurement set-up;

⎯ position of any linear or rotary positioning stages that are connected to the device under test;

⎯ direction angle of the sensitive direction, e.g axial, radial or intermediate angles as appropriate;

⎯ presentation of the measurement result, for example error motion value, polar plot, time-based plot, frequency content plot;

⎯ rotational speed of the spindle (zero for static error motion);

⎯ time duration, expressed in seconds or number of spindle rotations;

⎯ appropriate warm-up or break-in procedure;

The frequency response of the instrumentation, measured in hertz or cycles per revolution, includes the roll-off characteristics of electronic filters to ensure accurate signal transmission For digital instrumentation, it is essential to specify the displacement resolution and sampling rate, which directly impact measurement precision and data quality These specifications are critical for evaluating instrument performance and ensuring reliable, high-quality measurements in various applications.

The structural loop describes the placement and orientation of sensors relative to the spindle housing, which is essential for accurately reporting error motion It specifies the objects concerning the spindle axes and reference coordinate axes, ensuring precise measurement Additionally, the loop details the elements connecting these objects to maintain proper alignment and system integrity This comprehensive understanding of the structural loop is critical for optimizing spindle performance and ensuring accurate error detection in machining processes.

⎯ time and date of measurement;

⎯ type and calibration status of all measurement instrumentation;

⎯ other operating conditions which may influence the measurement, such as ambient temperature

[1] ISO 841:2001, Industrial automation systems and integration — Numerical control of machines — Coordinate system and motion nomenclature

Tiêu đề	Test conditions for bridge-type milling machines — Testing of the accuracy — Part 2: Travelling bridge (gantry-type) machines
Trường học	ISO
Chuyên ngành	Machine tools
Thể loại	International standard
Năm xuất bản	2007
Thành phố	Geneva

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