Frequently Asked Questions
Thank you for your inquiry into Unicast. We have compiled the following list of questions and answers from the inquiries we have received over the years. These are the most popular questions asked. We hope this helps you aquire a better understanding of the process, but if you still have questions, please feel free to ask your representative anything else.
Q) Does the process generate any heat?
A) No, there is no exothermic reaction during curing.
Q) Is there any shrinkage or expansion
to allow for?
A) No, the mold does not shrink or expand during cure. However, you
still must allow for shrinkage of the metal you are casting.
Q) What temperature is the
high-temperature cure done at?
A) High temperature cure is a minimum of 1000 C (~1850 F). It can
not be lower.
Q) How long must the ceramic cure?
A) As a general rule, we allow for 1½ hours of soak time for each
inch of cross section molded.
Q) What temperature does the mold need
to be before casting the metal?
A) The mold may be either hot or cold when casting. You can not
thermally shock the cured ceramic.
Q) Are the ceramics re-usable?
A) Generally not. The various ceramic blends we produce are a
delicate balance of various particle sizes that create a mold to
provide for a very fine surface finish while allowing for the
required permeability to prevent cracking of the molds. Used
ceramics do not allow for that balance to be maintained. The used
can be used as a backing however.
Q) Is the material hazardous to the
environment?
A) Once a ceramic mold has been fired, it is completely inert. This
is one reason it can accept such a wide range of alloys. Being
inert, it is environmentally safe and can be deposited in landfills.
Q) How many times can a mold be used?
A) Generally, a mold is used one time and broken away from the
casting after cooling.
Q) Is there any outgassing of the
material during casting?
A) No, because the ceramics are completely fired prior to casting,
and fully inert – there is no outgassing.
Q) Why do you require training?
A) Training is required because there are basic steps to the process
that must be understood before trying to apply the process to your
specific application. Training allows us to ensure those basics are
understood and to be able to work along side of you while actually
making molds. Training greatly reduces the time it takes to learn
the process and apply it. It also gives us the opportunity to review
shop layouts and how your equipment can be adapted to the process.
Most importantly it makes discussions over the phone and email much
more productive later – saving time and trouble.
Q) Is there special equipment required?
A) Generally, most shops already have what is needed to get started.
The largest piece of equipment would be the furnace for the high
temperature cure. In most cases, a foundry will already have a heat
treat furnace that can be used for this purpose. Mixing of the
ceramics can be accomplished by hand for most applications and is
the best way to get started. When larger molds are required or a
higher rate of production is needed, more sophisticated mixing
equipment may be acquired.
Q: [FAQ Question]
A: [FAQ Answer]