Week 8 - Challenge 1 - Draft Analysis on a Fan Cover

DRAFT ANALYSIS

Draft analysis technique is used to analyze whether our part model created in CAD is manufacturable or not. The part should get easily removed from the mould or die. No part can be ejected from the tool if it is having straight 90 degree angle from its base surface. A small draft angle is provided to each and every area of the component and we are providing a direction in which components should eject in order to easily remove the component from the tool.

Draft Angle is the amount of taper given to the molded parts perpendicular to the parting line. As the plastic cools it shrinks and sticks to the mould surface and therefore need draft angle while ejecting and to avoid damage. Normal draft angle is 3 degree. Increasing draft value will increase manufacturing cost.

TOOLING AXIS

In order to perform analysis, we need to create tooling axis and in order to do that we need to check class A surface first. We need to check whether all the surfaces are closed or not using boundary option. Once inspection is complete, we need to create separate geometrical set for tooling axis. We need to choose the axis in such a way that all the pockets, holes, sections etc. should get covered. For example, once inspection is completed, we concluded that Z axis is the tooling axis. Now we take reference point to create dummy tooling axis.

Next step is to create clearing axis for two axis X & Y. For this create axis system with reference point in dummy tool axis. Once axis system is formed select plane with respect to the surface (XZ & YZ). Use intersect tool to create the profile. Then we need to create two reference lines in the profile using point to point option in order to create the bisecting line. Rename the bisecting line as tooling clearing X direction. Follow the same procedure to create bisecting line for other axis. Rename the bisecting line as tooling clearing Y direction. Now use this both bisecting lines to create tooling axis. Publish this tooling axis using publication command.

DRAFT ANALYSIS

Now we need to check whether material mode of class A surface is in customize view parameters. Now go to Insert – Analysis - Feature draft analysis. Select the compass mode and drag the compass to the tooling axis of class A surface . Now select the surface to activate the surface and lock it using lock button. You can also do analysis during running point and move mouse all over the surface to check degree and draft angle. You can do analysis on full scale mode or quick scale mode. The color change shows change in draft angle.