Casting Part

Maximum???????????????????????????????????????A flat plate.

Minimum, 1°.

Your question is not very clear and indicates that you know little about the process.

What's the real question?

I am designing a die casting part.i want to give draft for a face of lenth 40mm.so what is the maximum and minimum draft angle i can give so that the surface texture is smooth.

Thanks

Talk to the toolmakers.

Now I convinced that you are in over your head here, technically.

Surface finish has nothing to do with draft angle, unless you are molding a textured finish and have no draft. Then you must rely on shrinkage.

We can't help you, you don't know enough about the process to design a part. GET HELP! At least do as Del suggests and talk to a molder or tool maker.

Once again, minimum normal draft angle is 1° per side. There is no maximum! Think about this. This also depends on several other factors you probably aren't aware of, most notably, the material you're molding since metals and plastics act differently and even different metals and plastics behave differently. Have you even considered material shrinkage?

You're doomed to fail unless you get help. And not from total strangers on an anonymous forum.

I would suggest that you obtain a copy of the NADCA (North American Die Casting Association) Product Specification Standards for Die Castings. There is probably a similar publication for the Plastic Industry.

Section S-4A-7-06 gives the Draft Requirements: Standard Tolerances. The calculation for draft is a formula D=sq. root of L/C where C is a Constant derived from a table(Table S-4A-7) Aluminum has C=6.00mm for an inside wall, C=12.00mm for an outside wall and C=4.68 for a hole (total draft for dimension in mm.)

Since it varies for the area of the part you have to do more than one calculation. Also I would recommend that you discuss it with the Die Caster first before the mold maker. After all, that's who has to make the part itself and he has much more experience in what he needs to make the part itself. You could ask 3 different mold makers that question about the amount of draft and come up with at least 5 different answers. Many pattern makers would try to tell me how they should make my sand casting patterns because it was less costly to do it this way or that way.

My stock answer was that "You only have to make the pattern once. I have to make the castings over and over for my customers so I want it my way since I know what has to be done to them before I can ship them out".