Overmolded needles demonstrate growing automation

German automation and moldmaking specialist ZAHORANSKY (Freiberg, Germany) will demonstrate an interesting, fully automated system for the glueless production of disposable syringes at Medtec Europe next month in Stuttgart.

Founded in 1902 in a garage in the Black Forest, ZAHORANSKY has leveraged expertise in tooth brush manufacturing into other areas such as medical manufacturing.

Working with Engel, ZAHORANSKY developed a system capable of separating as many as 400 needles per minute. Once separated, a custom servo-driven linear robot lines up and then places individual needles into an injection mold where they are overmolded with cyclo olefin copolymer (COC).

During the insertion phase, previously injected parts are removed at the nozzle-side mold half by a 6-axis articulated robot. COC is then injected via an Ewikon hot runner system with needle valve nozzles. Inserts are thermally separated from the mold to minimize loss of energy and to accomplish a rapid thermal equilibrium in the system.

Laser units check the needle in-feed and the sheathed needles for quality control. The finished syringe bodies can then be coated with silicon on a downstream station to improve their sliding ability. Finally, the overmolded and inspected needles are automatically packaged to minimize contamination risk.

The line will be operating in a clean room  at the Engel stand 4415 in Hall 4 running on an Engel Emotion 200-100T injection machine. The Engel easix robot is based on a TX 90 by Stäubli Tec-Systems (Bayreuth, Germany). Transcoject (Neumünster, Germany) is involved in the project as the plastics processor.

ZAHORANSKY says that more than 95% of all cannulas are still assembled with glue, mostly in countries abroad using manual labor.

"Process integration is becoming increasingly important in medical technology", says Christoph Lhota, who heads medical business at Engel Austria. "The automotive industry, which has been exposed to continuously increasing cost pressure for many years, is the role model for this. It demonstrates the great potential that is waiting to be leveraged in medical technology."

The demonstration shows two other trends in medical molding.

One is the increasing use of large-scale, electric machines which are also increasingly being used for multiple component technologies. Driving this trend is the use of large, multi-cavity molds for small precision components.

Another trend is the increasing use of materials with very low extractables. COCs, which are very high in purity, are increasingly important for that reason. They are produced in a high polymerization process. Any remaining catalyst is then removed through a filtration process. As a result COC has purity levels of glass. It costs $4 to $5 per pound.

Engel will also demonstrate automated production of medical components in its exhibit at NPE2012.