Super Precision & Productivity Magazine - Volume 2, Issue 2 - (Page 19)

do. Just as in producing an injection mold, hand polishing is always the last step. We massage the data into the machine tool program, machine the part and then hand polish. What we do is match the fit of the part from the original injection mold. Sure, we can hold 0.00003” or 0.00004” on most of our contours with a surface finish of 8 or 10 Ra, but then when it’s all polished, any marking is eliminated completely. That’s why the finer the finish, the less polishing.” The finish may in fact be closer than described above, says Powers. He notes that when they used Japanese machines the amount of polishing in finishing might take 60 to 90 minutes. With the Bridgeports, polishing takes 30 to 40 minutes to get the same results — about half the time of the old process. “As a matter of fact,” Powers says, “the results are better because there’s less marking on the parts. With the Bridgeports we’re getting a far superior finish — before polishing. This again is due to more accurate transmission of data. What we transmit and what we see at the machine tool spindle are much more accurate with the Bridgeports.” material availability and the design of the tool and machine time, he’ll probably do. But there are times that he won’t be able to meet the deadline because there’s more machining in the part than can be done in three to four days. Some tools may take three to four weeks to obtain, and when the part requires outside finishing to allow certain carbides sprayed on and ground, that may take another week or so. “Some of these tools last for years,” Powers says, “depending on the stress put on the tool and the application. We make four varieties of tools: 15 kHz, 20 kHz, 30 kHz and 40 kHz. Most of the applications we see are 20 kHz jobs. What a 20 kHz tool does is vibrate back and forth 20,000 times a second. That’s what creates the energy when it contacts the part. The friction melts the plastic and welds the part. Welding cycles are typically less than a second. There can be times when the weld cycle is longer, but a well-designed plastic joint would weld in between 300 and 500 milliseconds. It’s a very fast, very quick process. There’s no contamination. It’s very environmentally friendly. It’s also pretty unforgiving. We have to produce perfect tooling, which means we must rely on the precision, accuracy, repeatability and data crunching speed of the Bridgeports.” Ultrasonic welding Powers reminds us that Branson is a time-to-market business and builds to customer order. In some cases he might get an order that’s due in three to four days, which depending upon “We have to produce perfect tooling, which means we must rely on the precision, accuracy, repeatability and data crunching speed of the Bridgeports.”, states Powers S.P & P Magazine . . 19

Table of Contents Feed for the Digital Edition of Super Precision & Productivity Magazine - Volume 2, Issue 2

Super Precision & Performance - Volume 2, Issue 2 Contents Corner View Worth Noting World View Jig Grinding From Farm Branson-Tooling Radical Sportscar Creating The Impression Hardinge QUEST GT 27 S Hardinge ELITE 27 MS Propelling Productivity Bridgeport FGC 2

Super Precision & Productivity Magazine - Volume 2, Issue 2

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