Lecture/Homework 4: Casting

What is a riser?

A reservoir in the mold that acts as a source of liquid metal to compensate for shrinkage

What are the advantages of casting?

* Less machining due to being near net shape
* Can create complex part geometries
* Can create very large parts with internal features

Which casting method can achieve the very best surface finish?

Investment casting

Which methods can cast parts that do not require a taper, and can even handle regions with undercut?

* Expanded polystyrene casting
* Investment casting

True statements about metal casting include:

* Metal alloys that do not segregate during cooling can be cast
* Parts are near net-shaped, which reduces post-processing requirements
* Scrap metal can often be reused in future castings

Which are true of permanent mold casting?

* Can be used for only a few metals
* Higher throughput than all expendable mold casting methods

Which of the following are true statements?

(Everything except the ones below):

* Metal shrinking without a riser can lead to trapped air in the middle of the cast part