It's often a good idea to invest in prototype parts to confirm that a design meets its functional requirements before committing to steel molds for production plastics. That's because permanent tooling is expensive, can take several months to develop and manufacture, and once the tooling has been completed only limited modifications will be possible. Two primary techniques for making prototype parts are molding and machining. A few guidelines can help in choosing the best method.

Molded prototypes make sense when lower temperature materials are involved. These allow using less expensive prototype-mold materials like aluminum. Such molds work well for short runs (100 to 1,000 parts) but design changes to the part typically require starting all over with a new prototype mold.

In contrast, high temperature materials, such as PEEK, will deform an aluminum mold. Also, a complex design involving compound angles and curves is not practical for prototype molding. In such cases it is usually better to CNC machine prototypes out of the same plastic that will be used in production. This “machine-before-molding” approach allows design changes with relatively inexpensive adjustments to machine tooling. Medical device components that make good candidates for machining first include spinal, cardiac, orthopedic, and neurological implants, as well as biopsy, radiology, and bone-cement delivery instruments.

After testing prototype parts made by either method, a typical procedure “freezes” designs that meet all requirements. Future increases in production volumes over short runs can then warrant investing in permanent tooling.

It is helpful to work with a company capable of development, machining, tool design and production, and production molding. Working with this kind of one-stop firm speeds time to market, avoids the risk and confusion of working with multiple companies, and simplifies optimal decision-making.

IDEX Corp. forms IDEX Medical

IDEX Corp. formed a new company called IDEX Medical. It provides development and manufacturing services for medical-device components including machining, molding, extrusion, and assembly and tooling. The company has facilities in Oak Harbor, Wash. (Upchurch Medical), Bristol, Conn. (Eastern Plastics), and Pocasset, Mass. (Sapphire Engineering). Contact IDEX Medical at (800) 679-8718 or visit www.idexmedical.com.