Harland Medical Systems uses EFD's precision spray valves to apply a UV-curable coating to urinary catheters without the risk of clogging two small openings at the tip.
Medical coating processes require a high degree of precision and process control. As today’s hydrophilic, antimicrobial, and other biocompatible coating chemistries become increasingly sophisticated, the challenge becomes finding the most efficient and cost-effective ways to apply them.
Harland Medical Systems (Eden Prairie, MN; www.harlandmedical.com) specializes in developing automated modules that can be linked together in different configurations to handle a wide variety of coating applications. The company says this modular approach gives device makers a cost-effective alternative to outsourcing a custom coating system or fabricating one in-house. “We can essentially provide device makers with the performance of a custom coating system, but without the high cost or long lead time, which can be a huge advantage when building products with short life cycles or introducing a new product when time-to-market is critical,” says Drew Summerville, Harland’s vice president of marketing.
Harland recently assembled one of its modular coating systems for a manufacturer of urinary catheters. Because the UV-cure coating specified in the process had a tendency to “bridge” over the two small openings at the tip of the catheter, Harland needed to find an alternative to the dip coating process often used for high-volume catheter production. “With dipping, the sheer volume of fluid can plug small openings, especially on devices with complex geometries,” Summerville explains.
Harland found the solution in the 781-series spray valves from EFD Inc. (East Providence, RI; www.efd-inc.com). Unlike traditional spray valves, the units feature a low-volume, low-pressure (LVLP) design that uses extremely low nozzle pressure to apply a fine, even surface coating with very little overspray.
With the Harland system, a pallet of 48 catheters moves into the spray module on an overhead conveyor that stops above a rectangular opening that has four EFD valves fixed on each of the longer sides. As the module’s software actuates the valves and they begin to spray, the catheters are lowered and raised at a controlled rate while the coating is applied. At the same time, the catheters are rotated to ensure a uniform coating thickness.
Harland’s system allows the customers to clean, coat, and cure a batch of 48 catheters every 3 minutes, and the EFD valves have virtually eliminated the possibility of the UV-curable material bridging over the small openings. Another advantage is that the coating material is supplied to the valves from closed tanks, which simplifies changeovers and eliminates the downtime and waste involved with emptying static dip tubes.
“The EFD valves have proven extremely effective for this application, and they produce a coating as good as or better than dipping—but without the risk of blocking openings or getting material inside the catheter,” Summerville concludes.