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 ProtoCAM offers urethane casting and urethane
mold making for short-run production. There are many
urethane casting materials, making urethane molding ideal
when your production material is going to be a plastic injection
molded resin. After your stereolithography (SLA) prototype
has design has been approved, the SLA part can be prepared
for use as a molding pattern. Urethane molding is another
phrase to describe Room Temperature
Vulcanization (RTV) molding. Urethane
is the commonly used shortened form of polyurethane, so urethane casting is the same process as polyurethane casting, urethane molding is the same process as polyurethane molding, and urethane castings are the same items as polyurethane moldings.
Urethane Casting Process
To start the mold making process, a master pattern is needed;
it can be a part you supply, or a stereolithography prototype
that has been given a "finishes" Level
4 finish. The master pattern is coated in a silicone-based
liquid rubber. Once the liquid hardens, the master pattern
is removed, and the void left behind is injected with a urethane
casting material that best fits your material requirements.
Using this process, several copies, or urethane castings,
can be made of the initial prototype.
Download
an animated video demonstrating the Urethane casting
/ RTV mold making process.
Key Benefits
- Fast
turn-around (up to several parts per shift)
- High degree
of accuracy is maintained in the copy, including surface
finish
- Parts without draft, or with undercuts, can be
reproduced
- Different materials can be used for each casting,
making it possible to test your design with a variety
of material
properties
Urethane Casting Materials
- Liquid silicone rubber
- Urethane / polyurethane
Urethane Casting FAQ
- What materials can ProtoCAM cast?
- Please let us know the production thermoplastic
for your part and we will pick the urethane / polyurethane
that most
closely matches its mechanical properties.
- How large
a part can you mold?
- Virtually any size. Through cutting and gluing,
stereolithography master patterns can be made that exceed
the size of any
single SLA machine. In this manner, ProtoCAM has successfully
molded
parts over 3' x 3' x 3' in size.
- What colors can be created?
- ProtoCAM can exactly match any color using a
swatch or paint identification number. The lead time for
an exact
color
match is three weeks; however, ProtoCAM can approximate
colors with no additional lead time.
- Can urethane castings
be painted?
- Yes, ProtoCAM recommends painting the parts after
over-curing the part in a specific color. This will yield
a better
quality part finish.
- What type of surface finish can
a part have?
- The common finishes are gloss, textured and matte.
- What temperatures can urethanes withstand?
- There is no standard answer to this question.
Urethane casting materials have individual heat deflection
temperatures,
the maximum of which is 225°F. ProtoCAM has experience
in fire-retardant urethane casting materials.
- Can ProtoCAM
produce prototypes with living hinges?
- Yes, please contact
our sales team for specifics.
- How many parts can
be produced per day?
- A single cavity mold can be "shot" from 1 to
3 times per day, depending on material selection. (The phrase "shoot
a mold" refers to the pouring of urethane into an
empty mold.) If you need castings more quickly, a multiple
cavity
urethane mold can be produced. The number of cavities in
a single mold depends greatly on the part complexity and
size, with 10 being a reasonable upper limit.
Post curing a urethane casting, and thereby strengthening
it, will also reduce the number of castings that can be
produced per day.
- How does a urethane casting cost?
- Piece price varies from project to project depending
on the size and complexity of the part, as well as the
number
of castings. Many parts are $15 to $49 per piece, but please contact
us for an exact quote.
- How much does a Urethane casting
/ RTV mold cost?
- The price for RTV molds varies depending on part
complexity and size, but typical molds cost from $145 to
$495. Please
contact
us for the cost for your design.
- How long after I order
are urethane molds retained?
- ProtoCAM retains molds for a year. If you plan to order
additional pieces off of an existing mold after a year,
please let us know.
- How many castings can I expect to
receive out of a mold?
- Typically, around 15-25 shots. This figure depends
on the part size, complexity, and material selection. For
very complex molds expect 10-15 shots; while for simple
molds
expect 30-50 shots.
- How accurate are urethane molds?
- As accurate as the stereolithography prototype (+/-0.005");
however, tolerances of +/-0.002" have been achieved.
- Can you produce wax castings?
- Yes, we use the urethane mold making process to produce
a mold suitable for wax castings. Such castings are ideal
for use as investment patterns for metal
casting. Care must be taken to produce the master pattern
with the appropriate shrink factor for the target metal.
Please contact
us for a quote.
- Can you produce castings out of
silicone rubber?
- Yes. We have low durometer urethanes that can be very
soft, but we can also make stereolithography molds and
inject silicone rubber into it. Please contact us for additional
details, and we will be happy to provide
you a quote.
Contact ProtoCAM for Urethane Castings / Urethane Mold
Making
Please contact us to discuss
your urethane casting and urethane mold
making needs or to request a quotation.
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