Needle manufacturing gets a in the arm shot

Oct. 1, 2001
EDM lowers the cost and improves the quality of hypodermic needles.

EDM lowers the cost and improves the quality of hypodermic needles.

Using wire EDMs, Peridot produces complex point geometries on these minimally invasive surgical needles.

This Mitsubishi FA10 wire EDM, along with two FX10Ks, let Peridot take on jobs ranging from surgical needles to self-configuring robots.

With wire EDM, Peridot fabricates accurate bend tooling for producing the beryllium copper emi gaskets installed in this supercomputer cable-dock assembly.

Not just any shop can develop and manufacture 0.012-in.-diameter curved and straight hypodermic needles for minimally invasive surgical procedures. But one in particular has been doing it for almost five years, and just recently, it improved the process, making needles less expensive and easier to handle. Because of this accomplishment, and others, the company has gone from a 20-person shop that hadn't yet completed its medical trials to a well-established surgical-products developer.

Besides surgical components, Peridot Corp. of Pleasanton, Calif., specializes in EMI/RFI shielding, springs and wireforms, battery contacts, PCI/ISA brackets, and subminiatures. When it comes to shop-floor equipment, the company is committed to staying ahead of the new-technology curve, and EDM not only keeps it there but also makes the surgical-needle job possible.

As originally designed, needles were made from nitonal, an expensive nickel-titanium memory wire. By incorporating EDM into its production process, Peridot makes the same quality needle using stainless steel, which is much easier to handle and less expensive than nitonal. In addition, EDM cuts the parts without leaving burrs.

According to Patrick Pickerell, president of Peridot, needle surface quality is excellent and has no rough or pitted areas. This, he adds, makes sterilization more effective because nothing can hide in the pits.

The shop cuts 10 wires at a time. While one set is running, operators load or unload another. The company uses three EDMs, all of which are from Mitsubishi EDM/Laser, Wood Dale, Ill. — two FX10K wire machines and a FA10 wire machine.

The FX10Ks have X, Y, and Z-axis travels of 13.8 9.88.7 in. and handle workpieces measuring up to 31.5 22.68.5 in. Each machine's usable wire diameter is 0.008 to 0.012 in. with a maximum taper angle of 15° at 4 in. The machines' fully automated Power Master 2 feature speeds machining by detecting changes in a workpiece and automatically adjusting the power for optimum performance and speed. For the needle job, the machines' Smart AC servomotors provide a resolution accuracy of 0.000004 in. Peridot's newest addition is its FA10 submerged wire EDM that boasts an anti-electrolysis power supply called the AE3-HS. It reaches speeds of 30 in. 2 /hr. Complimenting the FA10's cutting speed is a quick wire-threading system. For a standard 2-in. workpiece, it threads 0.008 to 0.010-in.-diameter brass wire in 10 sec.

Cross training
At Peridot, jobs can change every two weeks. This kind of turnaround, says Debra VanSickle, company vice president, requires a dependable staff capable on multiple levels. Therefore, Peridot has implemented an aggressive internal training program.

The company pays for all of its employees to take classes with the National Tooling and Machining Association. Based on how these employees perform in school, Peridot determines whether or not to advance them to high-level journeyman status. Peridot has one employee currently in journeyman training and several employees on the apprentice level.

It is mandatory that Peridot's journeymen pass their knowledge on to other employees. This policy stems from personal experience. Both Pickerell and VanSickle have been involved in companies that have literally died off because the journeymen were resistant to passing on their knowledge.

Employees are not compartmentalized and segregated but, instead, cross-trained in several areas. This provides Peridot with a market advantage over companies that only train employ-ees to operate in one arena.

What makes Peridot's university-style operating structure possible, says Pickerell, is equipment that is user-friendly and moves the company away from the old, chips-on-the-floor machine shop operating style and toward the computer-driven end of the business. A good example of this type of equipment is the Mitsubishi EDMs, he adds.

"As far as the Mitsubishis are concerned," says Pickerell, "operators punch a couple of buttons and know exactly what's going to happen. One person can run two or three machines."

At Peridot, it doesn't matter who runs the Mitsubishis. "The repeatability and control are amazing. You don't have to be an EDM expert to operate the machines," comments Pickerell.

What makes this possible on the FA10, for example, is a 64-bit PC control combined with a 0.000002-in.-resolution digital AC servo system and special high-speed power control that prevents wire breakage during machining. In addition to the machine's control, other features such as E.S.P.E.R. and AI make job setup and technology selection simple.

The FA10 also features several self-cleaning functions designed to address normally high-maintenance areas, such as the auto threader, seal plate, and wire-transfer system. These self-cleaning systems automatically remove or prevent dirt buildup that could cause inaccuracy and downtime.

Beyond surgical needles

Making surgical needles is just one of the consistent jobs that gives Peridot the grounding it needs to work on other projects like the Polybot. It is a prototype that Peridot helped manufacture for Xerox Palo Alto Research Center.

Polybot is the first self-configuring, modular, segmented, and morphing robot that moves like a caterpillar, a four-legged spider, or a snake. It also climbs stairs and rolls like a tractor tread.

As Polybot crosses over different terrain, it reconfigures itself, adapting to each new environment. Applications for the robot include search-and-rescue operations, space exploration, or even exploratory surgery.

Xerox has an interest in this kind of reconfigurative technology on many levels. Perhaps the most interesting is the prospect of creating modules that are as small as a grain of sand, but still operate like the Polybot. These small modules could lead to systems that are self-repairable.

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