In today’s world of medical device manufacturing, cost pressures are very real. At the same time, cost savings can be just as real, especially when companies examine their manufacturing processes for greater efficiencies. One area that is gaining particular attention is metal stamping of previously machined, metal injection-molded, or laser-cut parts.
Finding Cost Efficiencies
A major medical device company recently discussed its plans to realize $550 million in cost savings over the next five years. At the same time, many other companies are having similar conversations in order to realize 3–5 percent in cost reductions year over year. Those are just two examples of what contract manufacturers and the production floor are hearing from the device industry as original equipment manufacturers face year-over- year price reduction pressures that are passed on to the supply chain.
Opportunities for greater cost efficiencies in medical device manufacturing can be found anywhere, but one area that is gaining attention is metal part stamping. The successful conversion of a machined, metal injection-molded or laser-cut part to a stamped part relies on a number of key factors. Cost savings can average about 30–40 percent. In one example, a laser-cut and formed hypo tube cost five times as much as its equivalent stamped part. In another instance, when converted to a stamped part, oval extruded tubing with additional secondary processes and a total lead time of 16 weeks cost three times less and lead time was eight times less.
Four Critical Questions for Stamping Success
The successful conversion of a machined part to a stamped part involves hitting specific geometry, quality, delivery, and price point requirements. Companies understandably have concerns around the risk involved in converting a part within a life-saving medical device, along with any new qualifications that would be necessary, additional costs, lead time, and more.
Can My Part Be Stamped? In many cases, customers may be unaware that their complex part can be stamped, when in fact any part that is made out of any type of metal is a potential candidate for stamping, including steel, titanium, nickel, kovar, moly, bi-metal, brass, copper, and many others.
A variety of tooling types (phase 1, phase 2, matrix, modular, or full progressive) with progressive dies plus other processes (such as drawing or hemming) are available that can enable tubular parts, biopsy jaws, and other rolled or formed parts to be stamped. These tools can be used successfully to meet complex geometries as well as tight tolerances. In other words, parts do not have to be flat or simple in order to be converted to stamping.
While it is preferable to work with the contract manufacturer during early device development stages, it is not necessary. The right partner will work closely with a customer in order to understand the form, fit, and function of the part and ensure that the design of the stamped part is fully equivalent to that of the machined, metal injection-molded or laser-cut part.
Depending on the regulatory flexibilities, the contract manufacturer’s design and engineering team might be able to recommend material or dimensioning modifications. If a current component has multiple thicknesses or is a clad material, the manufacturer could discuss options such as using a dual-gauge material that is either electron-beam (EB) welded or skived, or using dual-alloy materials that are EB welded. Or, if a machined part uses a bar stock that is not available in a strip form, the manufacturer might explore whether an alternate material could be used. Certain radii might also need to be met, and sharp corners also need to be addressed. It’s helpful if a concept design can be created using a CAD model. If approved, the part will go into prototyping and multiple phases of testing before it enters production.
What Factors Can Impact a Greater Return on Investment? During the initial phase, the manufacturer should provide a review of potential costs as well as return on investment (ROI). Converting to stamping may require greater up-front costs to build the tooling and for validation, but the ROI is often very short. ROI can be dependent on a number of factors, but the two most significant are production volume and production process:
Higher volume = greater cost savings. Say it takes a full minute to machine a part, but when converted to stamping, a die can produce 150 parts in one minute. Also, say that the machined part costs $1 to produce, compared to 15 cents for the stamped part. So, the larger the production quantity, the greater the return and shorter the payback.
Translating multiple operations to a progressive die. Stamping a part using a progressive die may provide immediate cost savings compared to that same part having to go through several machining processes.
It is also important to remember that quality tools make quality products. Investing in the right tool — one designed and built precisely using innovative, modern technologies and with the flexibility to allow for design changes down the road — can help save time and money in the long run.
What Will the Qualification Process Involve? It is important to choose a contract manufacturer that adheres to global quality standards such as ISO 9001 and ISO 13485; is committed to zero defects and continual improvement; and provides engineering, design, and tool build expertise in-house. That expertise — most often correlating to a company’s longevity — will help provide assurance that the part will meet quality standards during the process of designing for manufacturability, which should save time and expense during development and production.
Other important numbers that a customer should ask about are a manufacturer’s lot acceptance rate and its parts per million (PPM) defective rate. The highest-performing companies will have a 99 percent or higher lot acceptance rate, and its PPM should be at six sigma.
Customers should anticipate a robust qualification process from their manufacturer to ensure the stamped part is equivalent to its predecessor. Manufacturers should follow an APQP (advanced product quality planning) process during tool design, and they should apply a failure modes and effects analysis for development of the tool.
As first articles are run, a manufacturer should examine manufacturability and reliability of the stamped parts. Next comes operational qualification, which involves defining the parameters within which a product can be successfully produced, such as defining the target speed ranges at which the tool can run (strokes per minute) to produce an accurate part. A process capability assessment then examines the ongoing capability of the process in producing parts at a determined quantity.
The final performance qualification runs ensure that the parts can be produced with the same results each and every time. Other assessments include functionality testing to ensure that a product functions as it always did with the new stamped part. Biocompatibility testing may also be important to assess the safety of any lubricants used during the production process.
Customers will also likely be performing their own inspections parallel to their manufacturer. While various systems and inspection methodologies do not need to be exactly the same, those systems do need to correlate and speak the same language to ensure that the customer and manufacturer are making accurate comparisons of results.
What Does an Ideal Prototype Timeline Include? The prototype development timeline should include four phases:
Phase 1: Prototype development — Two tool build-outs, two customer reviews, and sample part runs.
Phase 2: Production development: Design and build — Design and build-out of the actual tool, including prequality planning.
Phase 3: Production development: Tool development and operational qualification (OQ) and process capability assessment (PCA) — Full setup and tool documentation, inspections and assessments, OQ, and PCA.
Phase 4: Production development: Performance qualification (PQ) — Development of the PQ plan, PQ run, data collection, and report, with final customer approval.
During these phases, the customer will concurrently perform its own design and product build verification, validation and OQ/PQ, followed by submission to the regulatory body.
The Bottom Line
No industry is immune to the pressure of cost savings. The medical device industry is under greater pressure than most, considering the life-saving value of its products. As customers consider stamping as one solution for greater cost efficiencies, it’s important to ask the right questions to ensure that the manufacturing partner can provide the confidence that a part can be stamped successfully, while maintaining equivalent quality and function.
This article was written by Rommel DelSol, Engineering Manager at Meier, a Cretex Medical company, Anoka, MN. For more information, visit here .