Draft angles makes it easier to release castings from their molds. If you look at a cupcake, the diameter of the bottom is smaller than the top. This is the same for cake pans and industrial molds. The slope on these molds is the draft angle. According to Kinetic Die Casting, a draft angle of 2 degrees per side is common for aluminum die casting molds. One simple way to measure the draft angle is to use a protractor, which is a tool for measuring angles used in math class.
Things You'll Need
Observe the casting from a mold from its side to view the draft angles. Most castings are created from two-part molds for easy release of the casting.
Lay the casting down on its side if it is large. This allows for easier measuring.
Place the protractor onto the middle of the casting. This is where the two parts of the mold met and where the draft angle is most prominent. Often you can see a line where the two parts met. Hold the protractor with its bottom edge along this line.
Look for the protractor's center hole. Shift the hole to the right or left edge of the casting.
Observe the intersecting line on the edge of the casting from its middle. The intersecting line is the angle. Look at the number on the curved top of the protractor to measure the angle.
Move the protractor to the other edge. Look for the intersecting line from this side. The number on the curved top of the protractor is this side's draft angle.
Tips & Warnings
- Measure the draft angle from the mold also.
- Wait until the casting is completely cooled before handling and measuring. Some materials contract or shrink in the cooling process.
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