3D Rubber Rapid Prototyping

First question is: what do you mean by rubber? You say exactly rubber. To me that would mean natural rubber which is a natural material from a tree which has been polymerized. It is not used much in industry anymore. Everything else is synthetic usually called an elastomer. Examples would be silicone, neoprene, latex, polyurethane, polyvinyl chloride ( with a high percentage of plasticizer ), Etc.. I don't believe any of the rapid prototyping processes such as stereo lithography (SLA) can produce an elastomer. The normal process is to have a rigid model made either by SLA or machining. You then make a flexible mold from the model and can then cast your prototype using any of the above elastomers. Most any company that does rapid prototyping can do this for you. Low cost prototype molds can be also be made of rigid plastic or aluminum. This is my specialty. I have made many molds for industrial foams and elastomers. If you would like help contact me via my website at: www.gacampbelleng.com .

You can use the conventional CAD>CAM>CNC route for rapid prototyping, if the chunk of natural rubber that you plan to machine is maintained below its brittle point @ -57°C (-70°F). You may pre-chill the rubber and maintain a chill-stream of cold gas at the cutting point.

An alternative, somewhat less predictable though feasible at room temperature, is laser ablation, exactly as used in rubber stamp manufacture. Here, the material removal is dependent upon the local laser energy density. If your RP application is 2.5D rather than 3D this could be very applicable.

These two subtractive methods are both practical.

Mark
http://www.fourth-axis.com

I have used a resin from Objet to prototype keypads and other soft-touch parts I have designed in the past. For thin walled parts, the robustness leaves something to be desired though. Lead-times are similar to SLA (< week).

What is the purpose of this question? Is it just curiosity, an answer for a class, or do you actually have a product you are trying to develop?