Wear parts

18
Tolerance table
Blank tolerances
Compact formed parts are manufactured through pressing and subsequent sintering which implies a
volume shrinkage of around 20%. It is therefore a special challenge for the production specialists to
obtain tight blank tolerances.
Apart from the composition and the geometrical shape the type of machining operation is mainly decisive
for the result achieved.
For standard parts, tolerances are also specified in the ISO standards (e.g.: ISO 2768).
Examples for blank tolerances depending on the manufacturing method:
Manufacturing method
Directly pressed parts
Extrusion pressed parts
Formed parts
Preform
Dimensions
(example)
[mm]
d s
12,7 x 12,7 x 4,76
15,88 x 15,88 x 6,35
19,05 x 11,05 x 7,15
d L
3,25 330
6,2 330
16,2 330
L B
40–50 50–50
100–120 80–120
200–225 > 120
Tolerances
[mm]
d s
± 0,10 ± 0,05
± 0,12 ± 0,06
± 0,15 ± 0,07
d
+ 0,1 0,25
+ 0,25 0,25
+ 0,3 0,25
± 0,45
± 1,1
± 1,25
Sintered part
Grinding
allowance
[mm]
0,2 – 0,5/page
+ 50% of the sintering
tolerance
0,25
0,20
0,20
0,4
0,5
0,5