The Injection Molding Prototype And Sterolithography

The injection molding prototype serves many purposes. The most obvious is that of providing an actual, physical example of the design. From a mold makers perpective, this is immensely helpful.

Often the engineering department has a plastic prototype just sitting on the desk, but not in the hands of the mold maker. How much better would it be if the guy who was about to actually make the mold could see what he is making!

One look at various details can make the job so much easier. Instead of struggling to visualize from a drawing or wire-frame on the CAD program, he can hold it in his hand and see the difficult areas at a glance.

Plastic prototypes from sterolithography-SLA

Many custom injection molders use stereolithography to produce plastic prototypes. Also known as SLA, this process seems almost magical at first glance.

 It is claimed that SLA offers the most accurate and precise rapid prototyping available. From concept to holding a plastic prototype in hand, it is also one of the fastest methods.

By using a CAD model, a sample part can be produced in a matter of hours. Of course, size and complexity determine the length of time required.  To find the form and fit of a concept part SLA can provide quick and accurate models, relatively inexpensively.

Some manufacturers are even using stereolithography for limited production of complex parts.  By using finishing techniques, such as pad printing, texturing, and color matching paints, it is possible to achieve that high end production look and feel.

SLA and plastic materials

Rather than build injection molding tooling for a very limited number of parts, SLA can use various materials to give similar properties to your plastic prototype that an injection molded part would have.

There are materials that closely resemble ABS, for example. Other commonly used plastics can be imitated as well. This can be very useful for demonstration purposes or shows.

Conclusion

Using the injection molding prototype vs. the additive prototype is a decision based on several factors. Time, expense, accuracy, volume, complexity and finish all weigh into the equation.

For highly complex, low volume plastic prototypes, stereolithography offers some unique advantages over the injection molding prototype. It is possible to produce high quality, accurate plastic prototypes very quickly using both SLA and injection molding.