Challenge

Week 9 - Attachment Feature Creation - Challenge 2

Ex-01:

Aim:

To create a Coin holder with screw boss,Dog House,Ribs and Draft Analysis.

Tools Used:

Draft Analysis:

Normally on the injection molding the parts which are getting ejected will have some defects and very difficult to remove from the cavity, So to make easier and reduce the defects this draft analysis is used.

The above pic shows that the parts on the cavity with normal in shape and another is drafted.
Basically the plastic components should be drafted at 3deg and for a sheetmetal components the draft angle should be 7 deg.

Tooling Axis:

This axis represent the tooling direction of the mould part.so that the part can travel on the axis to achieve the draft angle.

The above fig Blue line represented as tooling axis by bisecting the two lines with respect to the surfaces the tooling axis will be provided.
Creating the tooling axis we need to intersect the class A surface.

Screw Boss,Dog House:

Screw boss are used for locating,holding the screw with the parts or provide a location for a fixing position of the screws.
There are some manufacturing factors are considered for making this screw boss.
Draft angle should be min or equal to 0.5 deg.
Optional radius = 0.25mm
Height of the screw boss = 3:1 ratio of thickness.

Dog house are used as an prevention of the defects like shrinkages,breakages which are not visible outside the surfaces and act as an guide.
Lets consider a 10mm screw which as to join with other plastic part but max limit is considered as 5mm it is not acceptable,so they provide dog house and above the dog house the screw boss is provided.
Here too some manufacturing factors are considered.
Wall thickness (c) should be 40% less than thickness of the part (T)
Height (B) should lie b/w 3mm-6mm.

Procedure:

After creating the Tooling axis extract the surfaces to create Class B surface and trim the excess surface that are intersecting with Class A surfaces and offset it to 2.5mm and provide edge fillets accordingly.

Create a Class C surface by extracting the boundry of the class A surface and extrapolate to certain length and sweep it and join with Class A surface.

Draft Analysis:

Create Ribs for support and apply draft,trims and fillets to get good finish.Extract the class A surface and sketch the rib and extrude it.

Create a screw boss by sketching it on the top surface provide two circles and extrude it.

Create a Dog house by Extracting class A surface and create a sketch and sweep it to Particular height.

Draft Analysis for Dog House:

Views:(Isometric,Top,Front,Side)

Feature Tree Manager:

Ship work like this
in your own course.