CASTING PROCESS AND MATERIALS:
What type of casting does APC do?
Precision, close tolerance castings produced in an air-set sand, green sand, or plaster mold process.
What materials do you cast?
Aluminum, magnesium, zinc, brass, and bronze.
How long does the process take?
Typically 3 to 5 weeks from order placement to first part in your hand. This time includes construction of tooling, sampling, and first article inspection.
How does the casting process work?
First, we construct a positive tool similar to the eventual casting, only larger to allow for material shrinkage during solidification. After the establishment of parting lines (the same parting lines used by the die casting process), the mold material is poured onto the tooling halves, allowed to solidify, extracted, dried, rejoined and molten material is introduced. After solidification of the cast metal, the mold material is broken off. The result is a simulation of a die cast part.
Are the molds reusable?
The molds cannot be reused but are rather recycled.
At what rate can they be produced?
A single cavity tool can produce approximately 9 parts per day. This means that a 2-cavity tool can produce 18 parts per day, a 3-cavity tool 27 per day, etc.
How is the tooling constructed?
From your dimensional data, we machine a negative the same way one would machine a die-casting die. After locating the negative halves on a ground aluminum tooling plate, we pour aluminum or iron-filled epoxy into them. This produces a rigid tool that offers dimensional integrity.
How long do the tools last?
Almost indefinitely. In low volume production situations, we have tools on the floor that are more than 20 years old.
Can you core holes like you can with die casting?
Yes. But depending on casting size, location, hole size and positional tolerance, they can often be introduced to the part more effectively via secondary operations.
What about drill points
Yes, bearing in mind that cast drill points will carry cast tolerances. You may or may not want these to be the only guide to hole location.
Can you provide secondary operations?
Yes, we can supply the parts with secondary machining and finishing operations. However, we like to quote them separately. This gives you the option of handling these operations yourself or contracting them out to a vendor of your choice. If the latter is the case, we can "drop ship" for you.
What is the average cost?
On average, our tooling is 10 to 20 times cheaper than a production die. However, the labor intensity of the process dictates a per part cost about 20 times higher than the cost of the part when produced as a production die casting.
What is the cost compared to investment casting?
This is a more difficult question to answer in that two processes are geared to different types of parts and circumstances. Generally, the investment casting process is utilized for much smaller castings in much larger volumes. Since it is more geared to larger quantities, it is allowed to operate with much longer lead times both for initial samples and subsequent production. This long lead time situation (14 weeks) does not allow it to actually compete in quick turnaround prototyping situations. From a strictly cost type of comparison, the larger the part becomes, the more attractive our processes will be. On average, our air-set sand, green sand, and plaster mold processes should be more cost effective for castings larger than a cigarette pack.
USING COMPUTER AIDED DESIGN (CAD):
Can APC accept CAD data?
Yes. We can work with any CAD system that will allow an IGES translation. We can work with either 2D or 3D data.
In working with CAD, can you utilize data if the part is designed in solids?
Yes.
How should I send my CAD data to APC?
Please e-mail all drawings and cad data to info@apcast.com.
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