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Rapid Tooling
Sir:
I work for a big automotive glass company, and I research new technologies to build our
molds for car-window glass encapsulation in RIM (polyurethane) and/or PVC.
For the RIM injection, we use a low pressure and for our prototype, we use epoxy mold
or aluminum mold.
I would like to know if some process like SLS or spray metal tool, will be better for
cost and accuracy than the classical milling or high speed milling process. Please, can
you inform me?
MO
Dear MO:
When you say "encapsulation," are speaking about molding the glass material itself into
the shape of the window, or does your process add a plastic component to the glass part
such as connections to the mechanism or something like that? Or are you speaking about
something completely different, for example encapsulating the entire window in plastic?
Please describe more about the application, and also how big are the parts?
Rapid Tooling is not likely to be more accurate, but depending on the application it
may be faster to get prototype parts and it might also be cheaper depending on your
requirements.
Please let me know a little more so that I can advise you better.
Thanks and best regards,
Ed
Ed Grenda
Castle Island Co.
The Worldwide Guide to Rapid Prototyping
Ed,
We manufacture glass, especially windows for cars, and afterwards we overmold these
windows with RIM or PVC material through an injection process.
We put the window inside the mold, this window is maintained by a vacuum system, and
then we clamp the mold with a press, and we inject material(PVC or RIM) inside the mold
all around the window.
For the RIM process, we use prototype mold in epoxy or aluminum. These molds are
machined by CNC milling machines. We would like to find new mold makers using different
technologies than CNC milling, to build our mold.
The size of molds is usually about 1400x800x500 for one side of the mold.
So, I would like to know if you are able to build this type of mold through a newer
technology like SLS, SLA or spray mold ...
Thanks again for your interest.
Sincerely
MO
Hi MO:
The choices for rapid tooling that produce parts this big are fairly limited. First,
I'd say you have to define what you mean by "better." For some people this means faster to
market, for others more accuracy, for yet others, faster cycle times.
In general, direct CNC tooling is going to provide the best accuracy out of the box.
However, some RT methods might provide equal accuracies, because they often need CNC
finishing steps - while providing the other benefits.
I would start by looking at the technology from POM-Group and Ford's Spraymetal system.
Both can do big parts and both companies are heavily involved in automotive applications.
You can find a description in our tooling section:
http://home.att.net/~castleisland/tl_c.htm
Look at the tables in that section for a comparison and web page references. Ford is
licensing a number of companies to provide SprayForm tooling in different market segments,
so you'll have to contact them to ask what company might cover your application area. They
may send you to someone else or be able to help you directly.
Most of these technologies are still in an early stage of development. I don't think
we're talking about orders of magnitude of improvement, but the benefits can still be
substantial because these tools are expensive.
There are other approaches to the problem, but look at these first.
Best regards,
Ed
Ed Grenda
Castle Island Co.
The Worldwide Guide to Rapid Prototyping
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