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Designing for Permanent Mold

design

comp3

Designing for the Permold process is very intuitive. As in most casting processes, draft, radius, and wall thickness are the main design elements critical to good castability. Our engineering staff is available around the clock to help you get the most out of your investment. Gupta Permold always meets and/or exceeds the Aluminum Association Standards for Permanent Mold Castings which are outlined in the table below for your convenience.

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design standards summary

Linear Tolerance
Range (in.)
From To Base Tolerance Each Add'l In.
One Side of Parting Line (Basic): 0 1 +/-.015 +/-.002
Across Parting Line (Add'l): Tolerance is added as a function of projected parting face surface area.
0 in2 10 in2 +/-.010
10 in2 50 in2 +/-.015
50 in2 100 in2 +/-.020
Flatness
Greatest Dimension (in.)
From To Base Tolerance Each Add'l In.
0 6 +/-.020 +/-.002
Concentricity
Range (in.)
From To Base Tolerance Each Add'l In.
Same Plane: 0 5 +/-.025 +/-.003
Across Parting Line: 0 10 +/-.040 +/-.003
Machine Stock Allowance
Greatest Dimension (in.)
From To Stock Amount
0 12 1/16
12 18 3/32
18 24 1/8
Wall Thickness
walltk
*Note: Wall thickness values represented are minimums for castings of minimal complexity. Thickness values need to be increased as part complexity rises. Please consult Gupta Permold Engineering for specific job analysis.
Draft Requirements

Draft decreases inversely with length of draw. Note; the below amounts are simply industry guidelines and can be tightened in many cases. Also, additional draft extends mold life and makes better, cleaner castings. Contact us for details

Draft Requirements for Inside & Outside Walls Depth (in.) Inside Draft (degrees) Outside Draft (degrees)
04-536X388 0.03 - 0.125 20 10
0.126 - 0.5 15 7
0.501 - 1 10 5
1.01 - 6 5 3
6-12 1.5 1.5
Fillets & Radii

Razor sharp corners not possible (in all foundry). For two wall of thickness "t," designer should consider optimal radius of R=t. For Radii Between 2 non-uniform walls, designer should use the average wall thicknesses being connected, i.e. R= (T + t)/2.

rccmd_fllt
Cored Hole Diameter vs. Depth Draft
Diameter (in.) Max. Depth (in.) Draft / Side (degrees)
coredhole 0.25 0.125 15
0.25-0.5 0.25 8
0.5 - 1 1 5
1 - 2 3 3
2-4 6 2