How to Calculate Draft Angle for Die Casting

What is Draft Angle for Die Casting?

Draft angle, or the taper for the walls of a die cast part, is an important metric to consider for die cast design. Draft angle runs perpendicular to the parting line, or the line on the die cast object where two molds meet. Engineers know that a proper draft angle will make the ejection of the die cast metal part from the mold much easier. And good designers know that a smooth ejection from the die ensures a better surface on the finished product and requires less secondary machining.

What is the Proper Draft Angle for My Die Cast Part?

Double the draft angle is usually required for inside walls of a die casting vs. the outside surfaces. In general, draft decreases as depth increases. According to the NADCA, calculation for draft and draft angle are as specified below:

There are various draft angle calculators online that automatically calculate your needed draft angle. However, hiring a professional die casting company with experienced designers is the recommended way to calculate this metric. A proper draft angle calculation requires the surface type, depth of the surface and the metal alloy being used to be taken into account.