Incorrect casting product design is one of the
reasons why you end up producing faulty casting components. The communication
language between casting product design engineer and casting component
manufacturer is casting drawing.
The
following five tips will help you in designing a good casting product and in
preparing a correct casting drawing:
● 1. Deciding parting line: The parting line is the line around a casting component where
two molds meet
each other. The parting line should be decided by the casting component design
engineer and should be shown in the casting drawing. Ideally, the position of
the parting line should be such that the height of the mold box should be
minimum, or, in other words, the draw distance of the mold box should be
minimum.
● 2. Draft Angle: The draft angle of the casting component should
be designed in such a way that easy removal of the pattern will be possible
without disturbing the sand mold cavity. Giving 1 to 2 degrees of draft
angle is standard practice for sand casting.
● 3. Uniform section thickness: A uniformly thick casting surface cools uniformly, and uniform
cooling is the utmost requirement for getting a sound casting. Uniform cooling
leads to stress-free and distortion-free casting. So, while designing casting
components, all the sections should be kept as uniform as possible.
● 4. Gradual change in section: In case it is not at all possible to maintain uniform thickness at
any area of your casting design, then make the change gradual rather than
abrupt. Refer to the picture below:
● 5. Designing the junctions of uniform sections: Although the individual sections may be of uniform cross sections,
the meeting points of these sections may become bulky in nature. You should
take special care while designing such areas. One method of keeping the area
similar to the remaining area is by creating a hole at centre like below:
The casting design tips discussed here will be handy for
both sand casting as well as die casting design.