low volume molding RP ?

Hey guys,

for once I have a sincere question concerning a manufacturing process:

Some time ago I read about a new rapid prototyping process (probably here on the board).
Now we need to do about 10 Prototypes of a part that later would be done as injection molded
ABS.

It is a rather large and heavy part. About 30 inches high and 12,5 inches diameter.
800 x 300mm, weight: 15 kg =33 pounds.

If anyone could lead me to a process that is able to cast 10 to 20 prototypes that have the
same characteristics as the later serial part this would be of great help!

What I have in mind:

Doing a one off as a CNC milled part. Casting that in silicone. Doing low pressure injection molded
ABS parts out of the silicone molding. Would that be viable? Any contacts/ leads in central Europe?

Your help would be very appreciated.

yours mo-i

Sounds like you’re looking for urethane castings. They are not ABS, but the hardness is adjusted to simulate ABS (or other thermoplastics). I’m not familiar with European service bureaus but you might find them here:

Yea I think Urethane Casting is probably your best bet. SLAing in an “ABS like” material is also an option, though its going to be expensive to do that large of a part.

I have done a lot of work with the company Quick Parts and they have always been great. There website also has a lot of good information, so hopefully this could help.

http://quickparts.com/Home.aspx

best of luck

Urethane casting, definitely.

The only caveat is that while the mechanical properties of the urethane can be made similar to ABS, the chemical properties and thermal properties can be fairly off, so if you are doing functional testing of those properties, cast urethanes won’t be representative.

Depending on the geometry, you might want to look at prototype thermoforming.

I doubt you could find an FDM (SLA-type machine) that is that big, and it would be expensive, but at least then you would have real ABS>

Hey guys,

thanks a lot for your timely responses and useful hints. While I asked these questions here I also
stirred up the process within our company a little which lead to one of the owners calling me back
about it. Looks like one of our certified suppliers is familiar with this kind of process. Today they
tell me they can do it. Last week that looked quiet different…

Sometimes it makes a difference, if one of the big guys makes the splash…

Nevertheless your help and the info given was most useful and is very appreciated. I am almost
sure we will encounter further obstacles within the process.

Thank you very much.

yours mo-i

Yep, definitely UC. If you need additional help with material selection or questions about lead times/costs, feel free to PM me.

Hi mo-i . As a matter of fact, it’s hard for you to get a good quanlity prototype via silicone molding (RTV tooling and urethane casting). because it’s a big part. Low pressure perfusion process (somebody call RIM tooling) is suitable for your project. How to make the bumper prototype of car/truck? That’s this method. Usually, we make the low pressure perfusion tooling via wood outside and gypsum inside. This is the answer you want? Any other question, don’t hesitate to contact with me.
David Chen

David,

thank you for your interesting addition to this thread. As stated above we have found a
solution for that project in the meantime. Nevertheless it could be interesting for other
ventures to know more about your process. I tried to look up “perfusion tooling” but
couldn’t find anything beyond your post. Please, could you shed some more light on this?

PM me, if you want. But as I am on vacation right now, getting back to you might take
some time.

Yours mo-i

Hi Mo-i

It’s not " perfusion tooling", it’s low pressure perfusion process. You can also try " RIM tooling" to search.
Working theory at attachment.
low preessure perfusion.jpg
Typically leadtime: 30 working days.
Lifetime of tooling: around 100 pcs
tooling cost level: save 50% comparing to injection molding mould

If you have more question, you can PM to me.
We can discuss more about it.

David Chen