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Objectives :
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Need for Acceptance Testing ?
What is Acceptance Testing ?
How do I perform the test ?
What is checked during Geometrical Tests ?
What are the Equipments for Geometrical Testing ?
How to perform Geometrical testing of a Lathe Machine ?
What is done during Performance tests or Practical tests ?
What have we learnt today ?
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Need for Acceptance Testing ?
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What is Acceptance Testing ?
Acceptance Testing of a Machine Tool can be defined as checking
alignment of a component relative to the other component.
It includes:
1. Geometrical tests or alignment tests,
2. Performance tests or practical tests.
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How do I perform the test ?
Tests for Acceptance Testing of a wire EDM
1. Checking of principal, horizontal and
vertical planes and axes.
2. Tests of straightness, parallelism and
quality.
3. Concentricity of main spindle.
4. Movements of all the working
components
5. Practical tests are conducted.
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What is checked during Geometrical Tests or
Alignment Tests?
1. Straightness.
2. Flatness.
3. Parallelism, equidistance and coincidence.
a. Parallelism of lines and planes.
b. Parallel motion.
4. Rectilinear movements or Squareness of straight lines and planes. Quality of the guiding and bearing surfaces
of beds, upright and base plates are also tested.
5. Rotation.
a. Out of round.
b. Eccentricity.
c. Radical throw of an axis at a given point.
d. Out of true running (run-out).
e. Periodical axial slip.
6. Movement of all working components
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Equipment for Geometrical Tests:
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Dial Gauges
Test Mandrels
Straight edges and Squares
Spirit Levels
Autocollimator
Optical Alignment telescope
Waviness-Meter
Water level
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Geometrical testing of a Lathe Machine
Example
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Leveling of Machine bed.
Parallelism of spindle axis to bed.
Straightness of carriage movement in horizontal plane.
Parallelism of tailstock quill movement to the carriage movement.
Parallelism of spindle axis to the carriage movement.
Difference in the height between headstock and tailstock.
Parallelism of longitudinal movements of tool slide to the spindle axis.
Run –out of spindle nose - centering sieve or cone.
True running of the taper bore of the spindle.
Squareness of the transverse movement of the cross-slide to the spindle axis.
Axial slip of lead screw.
Parallelism of tailstock guideways with the movement of carriage.
Axial slip of main spindle and true running of shoulder face of spindle nose.
True running of headstock center.
Accuracy of pitch of lead screw.
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Test / Test Item
Picture of the set-up
Measuring Instruments
Permissible Error (mm)
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1. Leveling of Machine bed
a) Longitudinal direction b) In transverse direction.
Y
X
Spirit level or any optical instruments
0.01 to 0.02
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2. Parallelism of spindle axis to bed.
Test mandrel and dial gauge.
0.08 per meter.
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3. Straightness of carriage movement in
horizontal plane
Dial gauge and test mandrel.
0.015 to 0.02
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4. Parallelism of tailstock quill
movement to the carriage movement
Dial gauge.
0.02 to 0.04
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5. Parallelism of spindle axis to the carriage
movement
(a) in horizontal plane (b) in vertical plane
Dial gauge and test mandrel
0.05 to 0.02
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6. Difference in the height between
headstock and tailstock
Dial gauge and test mandrel.
0.03
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7. Parallelism of longitudinal movements of
tool slide to the spindle axis.
Dial gauge and test mandrel
0.04/300 & 0.03
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8. Run –out of spindle nose - centering sieve
or cone.
Dial gauge
0.01
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9. True running of the taper bore of the
spindle
(a) near to spindle nose, (b) at a distance L
(a) 0.01
(b) 0.02 for L = 300
Dial gauge and test mandrel
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10. Squareness of the transverse movement
of the cross-slide to the spindle axis
Dial gauge and flat ground disc or straight edge.
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0.02
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11. Axial slip of lead screw.
Dial gauge.
0.015
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12. Parallelism of tailstock guideways
with the movement of carriage.
Dial gauge and a block
0.015 to 0.02
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13. Axial slip of main spindle and true
running of shoulder face of spindle nose.
Dial gauge
0.01
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14. True running of headstock centre
Dial gauge
0.01
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15. Accuracy of pitch of lead screw.
Dial gauge, pin P, piece A, Block B and length bar.
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0.08 per metre.
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What is done during Performance tests or
Practical tests ?
According to approved general specifications,
acceptance tests of machine tools should include:
 Idle run tests, operation checks of
mechanisms, certificate data checks,
 Load tests and productive output tests,
 Checks of the geometrical accuracy, surface roughness, and accuracy of
the work-pieces being machined,
 Rigidity tests of machine tools,
 Tests for vibration proof properties of machine tools in cutting.
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Summery
We have seen general procedure for Acceptance Testing and also the
procedure for alignment test for lathe in detail.
This procedure can be implemented for any of the machine tool required
in any workshop or to be installed in a lab.
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