Ask The Search Engineer 12552

Dear Search Engineer: I'm looking for a source for small plastic nails. My company currently uses steel nails that are held in a close-array format for the purpose of snagging small parts as they move down a vibratory track. Individual nails are about 1.3 to 1.5 mm in diameter with a small head. The nails don't have to be strong, just light and no special environmental properties are called for. I will need a lot of them. -C.M. in CA

Dear C.M.: One possible answer is to have the nails custom injection molded. You could then pick the precise diameter, length, surface finish, head size, material, etc. You could also mold an array of nails if nail-to-nail tolerance is critical or handling individual nails is a problem. The obvious disadvantage is paying for a mold up front. If you can use a plastic cylinder with no point or head, an extrusion die could be made for several hundred to a couple thousand dollars and the parts cut to length on the extruder.

Dear Search Engineer: I am looking for electrically controlled fiber optic devices, components, etc. that allow several fiber optic inputs (up to 12) to a single output fiber. The input photon signals (very low level) need to be electronically selected via TTL control. Both multiplexer and demultiplexer devices are needed. -D.O. in WA

Hey there guy: Both Lucent and TI make micro-mirror arrays that are digitally controlled. The Lucent Lambda router is an array of 256 mirrors, and the TI digital Micro-mirror device goes up to 1024 x 768. Or check out Weed Instrument (www.weedinstrument.com) for their fiber optic MUX.

Dear Search Engineer: We are looking for co-mold materials to make soft-touch power tool parts having a durable chemical resistant substrate. We have worked with Soft-Flex, Santoprene, and TecBond ... any other recommendations? -P.D. in Cleveland

Dear P.D.: Alcryn Melt Processible Rubber from Advanced Polymer Alloys (www.APAinfo.com) bonds well to ABSA, PC/ABS alloys, ASA, and SAN. It offers chemical resistance, UV stability, abrasion resistance, and a soft, secure grip.

Hi Search Engineer:We need to source a woven or non-woven, natural or synthetic fabric with the following properties as a component of a disposable medical device: multi-directional stretch with memory, non-fraying, breathable, latex-free with wicking properties. -P.H. from MA

Dear P.H.: Try W.L. Gore as they have a medical division that provides a variety of products made from GoreTex^(R) at www.wlgore.com.

Advice from a reader about a past question:

D.J. in GA reminded us that the answer in the nut and bolt combination question (DN 04.21.03) failed to mention that the torque is supposed to be applied to the nut. "When a tapped hole is used," he points out, "a screw is used. And the size of a hex head cap screw is larger than the size of a hex head bolt of the same thread size." Thanks guy.