Medical Manufacturing Machine Producing Reagent Covers

Case Study


Comar Medical utilizes materials science expertise and automation to solve a unique challenge in manufacturing a diagnostic consumable.



  • Pursue a new manufacturing approach without altering FDA-approved materials.
  • Reduce scrap and production waste.
  • Improve capacity and material performance.

"Our goal was to adopt a new method of producing elastomeric covers, one that eliminated resin scrap, improved throughput and provided greater performance and consistency."

Senior process engineer for the diagnostics company


Trust. That word is taken very seriously at a leading global clinical diagnostics company that manufacturers immunoassay reagent packs.

Their reagent packs contain the antibodies needed for the quantitative testing of medical samples. Lab technicians, preparing to run an analysis trust that the reagents are stable and have not been contaminated or altered in any way as the packs move through the supply chain. A flexible elastomeric cover on top of the pack seals the contents of the reagent wells until time of use.

For such a simple component, the reagent covers have been surprisingly challenging to cost-effectively manufacture. The prior process required that a sheet of thinly extruded elastomer be attached to a multilayer adhesive film. The desired elliptical shape was then punched out using a flatbed die-cutting machine, resulting in covers that could adhere to the packs.

According to a senior manufacturing process engineer at the diagnostics company, the existing manufacturing approach had problems that could not be overcome.

“All of the excess resin material — more than 50% of what was extruded — was peeled away and scrapped after die cutting,” he says. “Besides costly waste, this process led to quality issues, such as the extruded layer peeling off the adhesive film. Our goal was to adopt a new method of producing the elastomeric covers, one that eliminated resin scrap, improved throughput, and provided greater performance and consistency.”

As the incumbent manufacturer was not equipped to implement a new production process, the diagnostics company began searching for a new contract manufacturer better suited for the difficult task. They found a truly collaborative partner in Comar Medical, which had extensive expertise in plastic injection molding for the diagnostics and medical/surgical device markets.

"From a manufacturing perspective, there’s a lot of excitement to move our customers to this new part. I think there’s going to be much better consistency. We have a high degree of confidence in this product and have already run 30,000 parts through our facility since production began at Comar."

Manufacturing Process Engineer for the diagnostics company


Comar’s proposed solution was logical and straightforward— replace extrusion and die-cutting with medical injection molding. However, the FDA-approved status of the existing commercial reagent pack and associated cover made it cost-prohibitive to entertain a resin switch from the extrusion-grade thermoplastic elastomer to a molding grade or even another resin. Any change in materials would require extensive requalification. So the initial challenge was to work with a polymer whose material properties (such as melt flow) were less than ideal for molding.

In addition, Comar saw an opportunity to dramatically increase capacity by using automation to bring together the molded shapes with the multilayer adhesive film at high line speeds. Comar envisioned scaling up the proof-of-concept to production volumes using a high-cavitation, 16-cavity mold integrated with complex, high-speed automation in a dedicated work cell.

Executing this vision required close collaboration between the two companies. At high speeds, new obstacles emerged in processing the material, and overcoming them took a great deal of dedication and persistence by the combined project team.

To address these challenges, the diagnostic company’s engineers partnered with Comar to create new specifications for the placement of the molded elastomer onto the liners, intentionally offsetting the parts a few degrees in every direction. Comar engineers then developed an in-line vision system that could locate the molded components and the precut adhesive footprints on the multilayer roll and precisely bring them together at high speeds before heat activation. The vision system would then verify placement accuracy. Test parts were sent to the production line to ensure they met all performance criteria before final validation.


Comar is now producing elastomeric covers for the diagnostics company that are visually identical to the original but with improved performance characteristics. While injection molding delivers immediate savings by avoiding die-cutting scrap wastes, it also provides a more consistent product due to the highly repeatable surface finish achievable with this process. In addition, the extra steps of extruding and shipping elastomer rolls have been eliminated from the supply chain, as resin is now processed directly onsite.

Benefits of the New Process Include:

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Reduction in material waste
cost savings icon

Per-unit cost savings
downtime reduction icon

Reduction in equipment downtime
enhanced performance icon

Enhanced performance on the reagent filling line
higher throughput icon

Higher throughput with increased quality
Medical Manufacturing Engineer working on machine in cleanroom


“It never felt like it was ‘us versus them.’ It has always been ‘us,’ and how are ‘we’ going to solve this issue together,” he says. “Anyone would expect this level of commitment on both sides when things are going well, but you find out who your true partners are when multiple technical issues arise and cause project delays. I was impressed to see the collaboration between the two companies and the way we were able to keep on working through and solving the issues as true partners.”


– Manufacturing Process Engineer for the diagnostics company

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