PCE Automation has developed a high-speed machine for testing medical inflation check valves. The one-way valves are used by the medical device industry to inflate or deflate balloons or cuffs, which are built into critical airway management devices such as endotracheal tubes, tracheostomy tubes and urology catheters. The valve testing machine - which forms part of a modular production system - makes extensive use of Festo parallel grippers to help accelerate the manufacturing process, and achieves a very high throughput of 240 valves per minute.
PCE Automation developed the valve testing machine for Bespak, one of the UK's leading manufacturers of drug delivery devices. Bespak has been at the forefront of this market for more than 40 years, working in partnership with pharmaceutical and healthcare organisations, and is renowned for supplying the medical industry with innovative, high-quality devices and components. PCE Automation has a similarly prestigious heritage; the company was formed in 1961, and is now regarded as one of the UK's leading suppliers of automated handling, assembling and testing systems.
The valve testing machine is a fully integrated standalone system comprising ten separate stages, or stations, on a rotary indexer, each of which features independent control. Because the machine forms part of a medical device manufacturing line, with rigidly-controlled process quality, all testing must be 100% accurate and both the test procedures and the control software need to be fully compliant with Failure Modes and Effects Analysis (FMEA) criteria.
According to Julian Tarratt, PCE Automation's Sales Manager, "We are exceptionally pleased with the performance of the Festo HGP series parallel grippers that we chose to employ on this machine. These low-cost pneumatic grippers are ideal for applications like this, combining cleanliness of operation with reliable, high-speed actuation."
Bespak operates four valve assembly lanes concurrently, to maximise manufacturing throughput. The plastic valves are fed straight from all four assembly lines to the testing station, in batches of two valves per lane - i.e. 8 valves at a time - thereby preserving the same lane flow path to ensure process traceability. The machine's first two stations handle product loading and air-blast cleaning, while the next two handle tensile strength pull tests to check that the caps have been securely welded to the valves' bodies. Station 5 initially checks the valves for the presence of adaptors, and then performs functional testing of valve operation.
Stations 6 and 7 perform high speed leak tests on the valves, checking that the valve seal is both present and working correctly. PCE Automation has developed highly innovative leak detection hardware and result processing software to dramatically accelerate this aspect of valve testing, with the result that the machine can accurately detect leaks with flow rates as low as 2cc/min in less than 1 second. Station 7 also checks that the valve spring has been correctly fitted, and that there is no extrusion flash on the valve cap.
Valves are off-loaded from the testing machine by station 8, which discharges the tested devices into 'passed' or 'failed' tubes. This station also accommodates product sampling, enabling a complete table of valves to be discharged for further inspection. Station 9 carries out air blast and vacuum cleaning, and station 10 conducts an inspection of the valve nests to ensure that they are empty before the rotary table indexes round to the assembly feed area again, ready for the next valve on-load and test cycle.