Linear system assembles valves precisely at speed

To achieve total reliability at 200 items/min a linear assembly system was especially developed to assemble six tiny components of a medical non-return check valve with 100% reliability.

Guaranteed reliability in the manufacture of medical equipment can literally mean the difference between life and death.

The slightest error in medicine can have tragic consequences.

British manufacturer Bespak needed high-speed production, but demanded 100% reliability.

Mikron Assembly Technology provided the solution.

Bespak is one of the world's leading manufacturers of medical equipment for the administration of drugs, in both liquid and powder form.

One of the company's products, a non-return check valve, is a device used in medical equipment such as catheters and tracheotomy tubes.

The valve comprises six elements, and the manufacturing process must guarantee 100% reliability.

Cleanliness is vital; any of the assembly systems parts that come into contact with the valve's components must be made of stainless steel, and the machine must not produce any trace of dust, or particulate.

Total reliability at 200 items/min - Mikron's Flexcell linear assembly system was especially developed to cope with the intricate task of assembling the tiny components, precisely, at high speed.

Some of the items have to be inserted into the body of the valve within a tolerance of only 0.05mm.

The Flexcell is equipped with six vibrating bowls of different sizes that feed the valve's components onto pallets containing four sets of nests.

With an operating speed of 50 cycles/min the system is capable of assembling 200 items per minute.

Despite this high rate of production the valves produced are of the highest quality, and display none of the superficial faults (damage to the plastic components) that would consign them irredeemably to the scrap heap.

Reducing the amount of production wastage was one of the improvement initiatives tackled by the team headed by Claude Maitre, project manager at Mikron's factory in Boudry Switzerland.

The team was able to draw on the experience gained as a result of using an earlier Mikron machine, the Polyfactor, which was installed in Bespak's King's Lynn factory in the mid '90s.

Versitility - the Flexcell developed for Bespak has been configured to produce four different versions of the product.

Changes in the types of material used and differences in the diameter of the caps that seal the valves can therefore be accommodated.

The assembly line comprises 21 stations and the system allows the operator to select random samples for inspection from each of the four nests.

This makes it possible to quickly trace any irregularities to the particular line involved.

Less than one defect per million - Bespak aims for zero defects and demands a minimum defect rate of less than one valve per million.

This underlines the importance of the checks that have been built-in to the Flexcell system to stringently reject any item which does not conform to the company's exacting standards.

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