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QUALITY CONTROL |
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Quality Control
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Quality control of all products, incorporating :
> hardness measurement > crushing strength measurement > material analysis > roundness & surface inspection
E & R is extremely proud of its quality control laboratory, containing some of the most sophisticated inspection equipment available. All quality control members undergo extensive training to ensure that the required skill levels are achieved and maintained.
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Ball Class and Tolerances to DIN 5401
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DIN class |
Nominal diameter mm |
Nominal diameter tolerance µ |
Dia tolerance per unit container µ |
Spherical deviation µm |
Description |
I |
Up to 10 |
± 10,25 |
0,5 |
0,25 |
Super Precision |
II |
Up to 25 |
± 10,5 |
1 |
0,5 |
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III |
Up to 25 over 25 to 50 over 50 to 75 over 75 to 100 over 100 to 125 over 125 to 150 |
± 11 ± 13,5 ± 14 ± 17,5 ± 21 ± 24,5 |
2 3 4 5 6 7 |
1 1,5 2 2,5 3 3,5 |
Bearing Grade |
IV |
Up to 10 |
± 14 |
4 |
2 |
Cycle Grade |
V |
Up to 25 over 25 to 50 over 50 to 75 over 75 to 100 over 100 to 125 over 125 to 150 |
± 75 ± 113 ± 150 ± 188 ± 225 ± 263 |
50 75 100 125 150 175 |
25 38 50 63 75 88 |
Castor Grade |
VI |
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± 200 |
400 |
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Burnishing Grade |
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Definitions of DIN 5401
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Nominal diameter the diameter value that is used for the identification of all ball size (eg 1/8”, 4mm, etc)
Nominal diameter tolerance The maximum allowable deviation of any ball lot diameter from the Nominal Diameter
Diameter tolerance per unit container The permissible difference between the average diameter of the largest and smallest ball within any unit container
Diameter Tolerance Per Ball The permissible difference between the largest and the smallest diameter measurable on a ball
Surface roughness Surface roughness consists of all those irregularities which form surface relief and which are conventionally defined within the area where deviations of form and waviness are eliminated
Spherical Deviation The difference between the largest and the smallest indication of the V-block out of round in 60° angle
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