Tooling decisions for medical products play a major role in the cost per part and turnaround time

In the medical industry, metal parts play an integral role in a vast array of diagnostic, testing, medical instruments and equipment. Although certain complex metal parts can only be machined, thinner gauge parts and enclosures are typically stamped using hard tooling or fabricated using lasers, turret presses or press brakes.

This includes carts, cabinets, enclosures and user workstations that safeguard sensitive controls, electronics, or hardware. While not as high tech as the diagnostic equipment itself, these structural components are still critical to the products function and longevity.

In addition, medical instruments and surgical tools are often comprised of metal parts that must be stamped to meet stringent tolerances. This ensures a tight fit for mating parts, for example, in a surgical stapler used to close incisions. Given the critical nature of these types of medical tools, it is also important that back-up or replacement parts hold the same tolerances as well.

In order to meet these requirements, medical device OEMs frequently turn to contract metal fabricators and stampers for assistance to reduce the price-per-part. This typically requires a careful evaluation of production volume requirements as well as decisions about the type and investing in tooling utilized. In some cases, completely finished, assembled products can even be produced, allowing OEMs to focus on critical design aspects of the technology and less on manufacturing.

The Tooling Dilemma
One challenge for manufacturers that outsource metal parts is in estimating the initial production requirements for new products. As a consequence, forecasts are often conservative or the complete opposite - unrealistically high.

With this inevitable uncertainty, OEMs are hesitant to invest significant dollars in hard tooling, which can cost tens of thousands of dollars upfront. Instead, less expensive soft tooling options may be selected initially even if it increases the price-per-part.

However, as production demands increase soft tooling options quickly slow production. At the appropriate "tipping point" in demand, medical equipment and instrument manufacturers ideally should transition to hybrid tooling, staged tooling and even progressive dies that speed turnaround time and drive down the price.

This "laddering up" of the range of tooling options requires assessing at each plateau whether or not greater upfront investment in tooling will pay off with a relatively quick ROI. Since tooling plays such a key role in this equation, it also means working closely with OEMs willing to evaluate the best available tooling options at any time.

"As production requirements increase, transitioning to a more efficient type of tooling can save some medical equipment manufacturers tens of thousands of dollars a year with a ROI measured in weeks or a few months," says Bob Denholtz, president of DureX Inc., an ISO 9001 registered contract metal manufacturing facility of 120,000 square feet based in New Jersey. "Any good metal parts supplier should be able to help the OEM determine the most cost-effective tooling for their situation."

Although, tool selection for the medical industry involves various factors, including part size, metal thickness, complexity, and finish, the cost per part is often related to the type of tooling utilized, says Denholtz.

This progression generally ranges from soft to hard tooling; hybrid approaches, staged tooling and fully progressive dies.

Soft Tooling
Low volume part manufacturing for the medical industry often involves soft tooling for sheet metal fabrication. Usually this entails having a flat or slightly formed part that has holes, slots, or tabs punched in it by a CNC laser or turret punch press, followed by bending using a press brake.

"Soft tooling typically costs $75 to $500, but can cost up to $2,000-3,000 for more complex parts," says Denholtz. "This can work for medical part prototyping and low volume production orders. However, it can take several minutes of machine time to make each part, depending on its complexity, so the cost per part is higher."

One strategy for medical equipment manufacturers to lower or even eliminate soft tooling cost is to borrow the tooling from a suppliers "library of tools." Because DureX has been serving a variety of markets for over 30 years, they have built up an impressive inventory of soft tools in many sizes and shapes. When appropriate, these tools can be put back in service. If that is the case, DureX does not charge for the item.

Hard Tooling
When critical tolerances are required and/or volumes increase to 15,000 units or more annually, OEMs often benefit from moving from soft tooling to hard tooling to reduce costs. According to Denholtz, the cost of hard tooling can vary from $5,000 to $300,000 depending on size, complexity, and whether it is designed to produce a finished part.

"One OEM started at 500 parts per month with soft tooling," says Denholtz. "However, when production requirements increased to 4,000 parts a month, we suggested they move to hard tooling to reduce the price from $22 to $15 a part. With a hard tooling cost of about $85,000, they achieved ROI in about four months."

Hybrid Tooling
As the name implies, hybrid tooling is a combination of soft and hard tooling. Depending on the part, it might begin as a flat piece of metal that is punched or formed with a soft tool, with further forming by a hard tool.

For example, an enclosure could be started in a turret that punches all the holes and slots before it is moved to a hard die that forms up the sides into a box in one operation.

"Instead of putting a flat piece of metal in a brake and hitting it four times to bend the two sides and two ends, we could use a die and hit it once. So it only takes 30 seconds or less to make the entire part instead of 2 minutes," explains Denholtz.

Staged Tooling
To create metal parts for medical equipment manufacturers at even greater speed and volume as well as lower price per part, staged tooling can be used. This basically involves moving a metal part between multiple stage tools, so the work is performed in unlimited processes that utilize hard tooling.

"For example, instead of taking 5 minutes in a machine to punch all the features individually using a soft tool, we could make a blanking die and punch everything in one hit in seconds," says Denholtz. "Then we could put it into a forming die and form it into shape."

Progressive Dies
The fastest, highest volume part production can be achieved by a progressive die. This accomplishes multiple operations in a single process using hard tooling. Depending on the part, a progressive die utilizes metal coil and can often produce a finished part with every machine cycle.

Denholtz gives an example of a customer that was spending about $125 for a metal card cage that held circuit boards. "When volume rose to 1,000 parts a week, we reduced the cost to $55 per cage by switching to multiple staged tools," explains Denholtz. "Although the hard tooling cost was substantial - about $350,000 - the OEM achieved ROI in only 5 to 6 weeks."

Value Added
Finally, medical equipment manufacturers may benefit from working with a contract manufacturer with added valued services such as finishing and assembly to further streamline the process.

"The ability for a contract manufacturer to take a medical part from cradle-to-grave from design through prototype, into full production of a fully assembled, finished product - even including fulfillment - can further reduce costs and allow the OEM to focus more on core competencies," says Denholtz.

Whatever the scope of manufacturing, medical equipment manufacturers can benefit by working closely with metal part suppliers to optimize the tooling for the job. In doing so, they can significantly reduce per-part costs with a surprisingly fast ROI.

For more information contact DureX, Inc. at 5 Stahuber Ave, Union, NJ 07083, visit www.durexinc.com or call 908-688-0800.