Week 9 - Attachment Feature Creation - Challenge 2
Aim: To create boss and Dog House for the Centre console coin holder.
Boss: Bosses are typically used to assist in assembly, as a receptacle for a screw or threaded insert or as the locator for a mating pin on another part. Because of its function, a boss must have sufficient strength to do its job.
Designe considerations for creating Screw Boss:
D is the diameter of the hole
t is the mai thickness
To reduce stress bosses should have blended radius rather than sharp edge at their base. To avoid sink marks bosses should not merg with the side walls by forming a thick surfaces as shown below. If needed we can use connecting robs for support.
- If t is thickness of component one wall should be of thickness W=(0.6*t).
- Optimum fillet radius is 0.25mm.
- Draft can be 0.5 degrees on each side for inside and outside walls of the boss.
Dig House: The mai pourpose oddog house is to avoid sink marks and overcome the length issue.
- C is where doghouse contacts bacjoff surface.
- Dog house wall thickness at c should be 40% or less then the main wall thickness.
- B should be between 3-6mm
- Width of dog house should be 12mm
- 3:1 is the height and width ratio for steel and 2:1 is preffered fot other materials.
- Minimum draft should be of1.5 degrees for each side.
Draft analysis for doghouse:
- We should perform draft analysis for dog house by taking tooling axis created for the main part.
- To clear the side walls we should create a side core tooling axis.
- to create side toolong axis we have to draw a line on through the point created for main tooling axis in Z direction as shown below.
- After getting side tooling axis now we can perfore draft analysis for the dog house for other surface clerances.
After performing draft analysis now have to assemble to the main part and perform draf anlysis.
