PDC Enhances Medical Micromachining Capabilities

For a company started by accident, Plastic Design Corporation (PDC)—a business that provides engineering services, tool design, and product design to OEMs—has come a long way.

PDC, of Scottsdale, Arizona, began as a pure engineering service company and relied on outside partners for prototype work. Not satisfied with the quality of prototypes they were receiving, the company started a small in-house tool room to make their own. This evolved into an in-house molding operation, and today the prototype mold making and prototype molding represent the lion’s share of PDC’s business.

With business on the rise, the 14-person company recently turned to Makino to enhance its micro-machining capabilities in order to satisfy its customers’ growing demand for medical molds.

Branching Out[back to top]
PDC didn’t begin as many other companies do; its inception was by accident. “The company started out when I worked for the Tech Group, and several of our customers were asking if we provided engineering services,” recalls Mark Kinder, PDC’s president. “Although we had the talent within the Tech Group, we were not organized in a way to easily sell engineering services to our clients.”

Kinder approached the Tech Group management with a business plan to market and sell engineering services, but the company had just heavily invested in a Puerto Rico facility and was unable to make the financial commitment. With the company’s blessing, Kinder took his business plan and started PDC.

In the early ’90s, PDC mainly supported the electronics industry because of the large demand for intricate development work. As the company’s prototype capabilities evolved, it waded into the medical market, which forced it into clean molding.

“Initially we were using portable clean rooms,” says Kinder. “In 1996 we built a class 100,000 clean room, which opened up several additional medical markets for us.”

MicroMachining for the Medical Market [back to top]
Today, medical and lab-ware design and molding represent about 90 percent of PDC’s business. The company also handles a great deal of low-volume production and prototype work for manufacturers of invasive medical devices and implantables.

PDC primarily focuses on lab-ware with small configurations, such as micro-titre plates with lab wells less than a millimeter in diameter and micro-fluidic circuits with channels measuring 100 microns or smaller.

“We are working with several OEMs to develop micro-fluidic circuits that can be injection molded,” explains Kinder. “We are also focusing on implantables, such as those used in neurological and cardiac surgery. These devices, and the instruments used to implant them, must be small and extremely precise.”

Increasing Speed without Sacrificing Quality [back to top]
PDC turned to Makino for the tools required to machine the molds for these very small components. “We wanted to enhance our capabilities but also improve quality,” says Kinder. “Since we are in the development market, speed is critical, but we didn’t want to sacrifice accuracy. We often need to create several iterations of a design, have our customers test these, come back with subsequent versions and then test those. As a result, we are constantly trying to get tools completed in a short amount of time.”

PDC added a Makino V22 vertical machining center and Edge 2 Ram EDM with a fine-hole attachment to meet its speed and quality demands. “In addition to increasing our production speed, versatility was another factor in our decision to add the Makino machines,” continues Kinder. “Because we are a small company, we’ve got a lot of vertical integration. That works well for us because it allows us to keep everything in-house, under our control. But, by the same token, that means everything that we have in here has to be versatile.”

New Technology [back to top]
Experience and relationship were critical factors in PDC’s selection process. “When you are looking at new technology, looking to expand your own capabilities, you need somebody who has been there and done that,” says Kinder. “We wanted someone who could lead us through the minefield.”

Local tech support was also a critical factor in Kinder’s decision. “Arizona has a small but strong tool and die community, but the machine tool distribution mostly comes from the West Coast,” continues Kinder. “We found over the years that if we purchased a piece of equipment that is serviced out of California, we were always the last guy on the list to get attention, so we wanted somebody who had local service in the Phoenix area.”

While local tech support was important, quality improvement was also a priority for the company. Kinder wanted a machine that cut more accurately than what they currently had. He also wanted to relieve his work bottleneck.

PDC is unique in that its manufacturing philosophy is constraint management, which is contrary to most shops. “Other shops look at individual machines or groups of machines as a profit center, and they base their purchase justification on how productive that particular machine is,” says Kinder. “We look at the shop as an organization and are more concerned with how productive we are as a whole. We also measure productivity not just in man-hours, but in delivery dates. So if it usually takes us four weeks to deliver a prototype and we want to shorten that to three weeks, we look at what machine we need to do that.”

By applying constraint management, PDC identifies its bottlenecks and can then purchase the equipment to relieve them. Prior to purchasing the Makino machines, PDC looked at what was keeping them from producing a job faster and what was slowing them down. Kinder explained that as PDC took on jobs that required smaller and smaller parts, the ability to blend cutters was a main concern.

“We could do this with our old machine, but it was difficult and painful,” explains Kinder. “We wanted to reduce the time we were spending measuring blends and tweaking tools to get the blends to match the way we wanted. This was one of the reasons we landed on the V22.”

Paying Off Before It Was Paid Off [back to top]
PDC immediately realized the benefits of the V22. “We built a prototype on our old machine, and the customer came back and asked for more precision because they were trying to do finer fluidic circuits,” says Kinder. “Our old machine wasn’t precise enough, but we told the customer that we had a new machine on order [the V22] and as soon as it came in, we would cut them a new cavity. We just got the order and are working on the new prototype now.”

Before PDC added the Makino V22 machining center, it operated a machine with a 15,000-rpm spindle, which was good for the axis control, but not good enough for the parts they were trying to produce.

“Typically with the micro-fluidic plates, it’s important that we are able to hold our Z-depth on the cutter to 0.0001 of an inch or less,” explains Kinder. “With the previous machine, we’d rough out a plate, or the cavity for a plate, and would have to come back and pick corners out with a smaller cutter. Any variation between the cutters on the Z and we’d have to scrap the fluidic circuit. That was a significant struggle with the old machine.

“We have now built eight microfluidic molds, three micro-titre plate molds and numerous micro molds on the V22. Most were cut in pre-hard or fully hardened 420 stainless steel. Blends between cutters are less than 0.00005 inches.

“The V22 has a 40,000-rpm spindle and lends itself better to the small cutters. It’s got an HSK tool holder so we get better control on the Z-axis. We also ordered the machine with a hybrid tool length measurement system, so we’ve got better control over the Z-height on the cutters and tool-to-tool blends.”

By adding the Edge 2 with a fine-hole attachment, PDC simplified the machining of micro-titre plates, which are used by drug discovery companies in testing compounds.

“While the actual part measures three-by-five inches, the features are very small,” says Kinder. “It’s a challenging job creating a core insert with 3,456 active wells spaced that close together. We are one of only two companies in the world that is manufacturing this type of well plate, so we need to be as precise as possible.”

When PDC first began machining these parts, they experimented on short prototypes to learn what their clearance would be between the core pin and the hole it strips through. “The window was only .0002 of an inch and when you’ve got one-tenth variation on your core pins, you’ve just really tightened your window,” continues Kinder.

In the past, PDC manufactured these parts with conventional drilling and reaming, which was difficult with holes less than one millimeter in diameter going through 0.700 inches of hardened stainless steel.

“We were looking for options and really hadn’t found anything that met our goal until we came across the Edge 2,” says Kinder. “The machine’s capabilities were just what we were looking for. Plus, Makino had a fair amount of small-hole experience. They worked with our technical staff on some demo cuts. The quality, depth, and location of holes were very impressive. We pretty much made up our mind right there.”

A Tremendous Difference [back to top]
PDC can also attest to improved cutter life, which Kinder believes is the best indicator of value, as well as an indication of machine rigidity and minimal spindle runout.

“We’ve seen a tremendous difference with the Makino machines,” explains Kinder. “Simply put, they are allowing us to do things at a much higher quality than we could before. Our relationship with Makino goes beyond machines, though. Makino has a lot of experience with these machines, and they passed that experience on to our staff. We learned a lot from them, and I believe we are operating more efficiently than we were before.”

While PDC began as an engineering service company, today the prototype mold making and prototype molding represent the majority of its business, although it also still does product design work. Kinder is excited to see what the future holds for his company.

“Our business is an evolutionary process,” says Kinder. “If you look at the types of parts we are doing today compared to what we were doing five years ago, what used to be a challenge could be done in our sleep now.”

Kinder will be the first to admit that the company’s beginnings may have been somewhat of an accident, but its success and its relationship with Makino were anything but that.

Plastic Design Corporation (PDC)
Mark Kinder
Scottsdale, Arizona
Phone: (480) 596-9380
Web: www.plasticdesigncorporation.com

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