Prototype for product made of molded plastic

I have designed a plastic product that is supposed to be made by injection molding. I would like to make a prototype for it but I understand that injection molding can only be done in the industry and can be very expensive. Does anyone know of any process and material that can be used to make the prototype that would be a good substitute for an injection molded plastic product? Thank you.

Cast urethane…it uses a two part urethane that isn’t the same as the plastic…but they can get pretty similar in material properties.

Any decent proto shop can tell you all about it.

Thanks, I was wondering if there is a method that can be done at home? I do not know of any prototype shops in my area and I have a bit of a budget. Any idea how much this method would cost?

Price is dependent on size and quantity. Size most rtv houses will utilize sla’s for the master, you would also need the digital file.

Just check out quick parts, usually a one off rtv and sla master will run $300+…but dependent on the size

I’m going to assume you’re a novice:

Can the prototype be a solid block? Or is it important to show it as a hollow shell?

Typically Industrial Design “appearance models” are solid, carved from blocks of high density urathane foam. This can easily be done at home with hand-tools. You can also use wood like balsa. In order to achieve the final finish, paint the finished model with automotive Laquer (not enamel) primer that can be wet sanded with 1000-grit sandpaper.

If it’s important to show it as a shell, you could do a home-made “rotational molding.” Take a plaster cast of your solid model, insert some resin and swirl it around.

But I don’t recommend doing any of that unless you have a good reason for keeping it cheap. Typically if you need a shell, you’d have an SLA or SLS prototype made from a CAD model, and bill your client for the cost. You’ll get high quality, and your CAD model can eventually be used in the final injection molding tooling.

CNC’d abs…then painted the color you want…cheap and still plastic

Yes, the prototype is a solid. Thanks for all the suggestions. I think I will try the polyurethane foam or balsa wood approach, as the product is not being developed for any client yet.