Investment casting design standards
１、Cast linearity dimension tolerance
The cast steel, generally CT4-6; High-precision can be CT3; Common sandsellmolding, CT8-12.
２、Cast Circular arc dimension tolerance
| Diameter |
＜3 |
≥3-6 |
≥6-10 |
≥10-16 |
≥16-25 |
≥25-40 |
≥40-63 |
≥63-100 |
Tolerance |
CT3-CT5 |
0.6 |
0.7 |
0.8 |
1.0 |
1.2 |
1.5 |
1.8 |
—— |
CT6-CT8 |
1.2 |
1.3 |
1.5 |
1.6 |
1.7 |
1.8 |
2.0 |
2.2 |
３、Cast thickness tolerance
| Fundamental Dimensions |
Cast Thickness |
1-3 |
≥3-6 |
≥6-10 |
≥10-18 |
≥18-30 |
30 |
0.4 |
0.75 |
1.5 |
—— |
—— |
30-80 |
0.4 |
0.75 |
1.5 |
1.8 |
—— |
80-120 |
0.6 |
1.2 |
1.5 |
1.8 |
2.1 |
120-250 |
0.6 |
1.2 |
1.5 |
1.8 |
2.1 |
250-400 |
1.0 |
1.6 |
2.0 |
2.2 |
2.5 |
400-500 |
|
1.6 |
2.0 |
2.2 |
2.5 |
４、Cast Hole Reference Tolerance
Pore Diameter |
12.5 |
25 |
38 |
50 |
64 |
125 |
200 |
250 |
Tolerance |
±0.13 |
±0.13 |
±0.23 |
±0.25 |
±0.3 |
±0.64 |
±1 |
±1.3 |
５、Cast Machining Allowance
Generally Reference
| Top Size |
40 |
40-63 |
63-100 |
100-160 |
160-250 |
250-400 |
400-630 |
630-1000 |
1000-1600 |
Machining allowance |
0.5 |
0.5 |
1 |
1.5 |
2 |
2.5 |
3 |
3.5 |
4 |
６、Minimum Pore Diameter
The minimum pore diameter of investment cast is generally 2mm.
7、 Maximum Cast hole depth
Investment casted hole depth and pore diameter are relevant with the hole types. General reference is listed in the below table:
| Through Hole |
Blind Hole |
|
D≤7mm: H≤2D |
|
D≤7mm: L≤1D |
D>7mm: H≤3D |
D>7mm: L≤1.5D |
D>13mm: H≤4D |
D>13mm: L≤2D |
8、 Minimum cast round corners
Generally the inner round corner should be beyond 0.5mm and the external fillet should be beyond 0.3mm.
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