Challenge

Week 9 - Attachment Feature Creation - Challenge 2

Aim : - To create a bose and dog house upon coin holder component and check the draft analysis for the component.

General Guidelines for Bosses:

"C" is where the doghouse contacts the backside of the surface

Introduction : -

A boss feature finds use in many part designs as a point of attachment and assembly. The most common variety consists of cylindrical

projections with holes designed to receive screws, threaded inserts, or other types of fastening hardware. Under service conditions, bosses are

often subjected to loadings not encountered in other sections of a component. Provide a generous radius at the base of the boss for strength

and ample draft for easy part removal from the mold.

Procedure : -

To create a Bose component, Draw the sketch lines upon the coin holder component.
The construction begins with extracting the base and then drawing the two concentric circles.
Considering the diameter value of 5, the outer circle will be 5+(2* 0.6*2.5)= 8.
To create the rib, go to the surface design layout and extrude the lines in y direction.
Then, Go to the part design layout to insert the solid body, with the help of thickness surface command.
Give the value of a solid body to create the body with given measurement.
Draft the solid body, Giving the values of 0.25mm to the surface.
Give the fillets values for the drafted body.

Then, these circles are padded along the tooling direction to a height of 15. Using the 3:1 height to diameter ratio.
The thickened ribs later on are drafted by 0.5 degrees and the pulling direction is taken as the upper face of the ribs.

The screw boss is not made alone, they are coupled with the stiffener or ribs to provide structural stability.
The ribs sketch is drawn considering the boss center in a cross shape.
Then, they are extruded to a height of 12.5 and thickened to 1 mm.

Later, ribs are also drafted to 0.5 degrees.
The screw boss and ribs are then union trimmed to form a single part.
Now, the final screw boss is assembled to the main coin holder component and provided with the fillets or 0.25mm radius.

Dog house : -

It is a ‘doghouse’ looking embossment for screws to attach one piece of plastic to another one.
For example, you have a bumper cover, and you want to add a garnish to it.
The shaded oval is where the screw comes in and in this example, these dog houses are on the back of an a-surface bumper cover.
Now the reason it's a doghouse is that you want to keep the legs of the doghouse thin so that there are no sink marks on the a-surface.
If a plastic component is too thick as in where the a-surface thickness of 3mm and the doghouse thickness of say 3mm comes together, you would have a sink mark.
First, the screw boss is translated to someplace, and keeping a reference of this, the dog house is created on the base extracted and a C shape.

That sketch is swept with a drafting direction of 1.5 degrees and a height of 22 mm.
This box needs to be packed from the top, so the base surface is offset to a height that intersects with the top, and then they are trimmed to close the top of the box.
Then the extended portion is again trimmed with the surface to form the proper box and the edges are given the fillets of 1 mm.
The above surface is then thickened to 2mm in the part workbench.
For the lower part of the dog house, the inner walls of the box are extracted and offset by 1mm to the outer side in a shape generative workbench.
C= 0.4*2.5 = 1mm
The offset face is then extrapolated by point continuity by 10mm and another face from the base is offset by a distance of 6.5 mm such that the distance B should be around 4-5 mm as per the design rule.
The two offset faces are trimmed together to get the lower cut section of the house and later they are trimmed with the solid box to form the final dog house.
Lastly, the dog house is assembled with the main coin holder body and the screw bode is translated and positioned on the top of the dog house.

Draft analysis : -

It’s important to perform the draft analysis for the final attachment features to see if the tooling axis will be able to capture all the features properly or if there is a need for the side core.

So the feature draft analysis is performed on the dog house since an inside portion of the dog house is questionable to capture in the current vertical tooling axis.
So the above draft analysis shows the negative draft for the inside feature, we need to create the side core tooling axis to properly extract the dog house properly.

Final Solid body : -

Result : -

The Screw Boss and Dog House for the Centre console coin holder has been successfully created considering the design rules and the draft

Analysis for the final component has also been performed.

Ship work like this
in your own course.