LK Metrology automated inspection “transforms” medical manufacturer’s quality control
Alltrista Plastics, a plastic injection moulding service based in Christchurch, England, has installed two new Altera S 10.7.6 CMMs manufactured by LK Metrology. The supplier’s CAMIO 3-axis scanning and reporting software was also provided along with a Renishaw SP25M scanning probe and PH10M motorised indexing head.
The company says the scanner is in effect two sensors in one, and that it enables continuous path tactile scanning as well as touch-trigger probing of discrete points.
LK Metrology says that together with a Renishaw matrix plate to allow accurate placement of parts for inspection, the set-up has resulted in a vast improvement in metrology productivity for Alltrista by facilitating fixturing of samples, speeding measuring cycles and ‘virtually eliminating’ human intervention and the attendant risk of errors.
The supplier says that it would not have been feasible to retrofit scanning capability to the older CMM’s, as the cost would have been prohibitive, and claims the machines were becoming obsolete.
“I operated LK CMM’s for several years when working for an aerospace manufacturer, which had standardised on their use. When Alltrista decided to upgrade its quality room, we approached four potential machine providers including the incumbent supplier. LK’s response was by far the most comprehensive,” said Alltrista’s Quality Manager Peter Makosa.
The Christchurch site is one of the five Alltrista manufacturing locations, and is notable for being the first facility within the holding Jadex group to be powered entirely by renewable electricity according to the company.
The ISO13485-accredited firm specialises in plastic injection moulding of devices such as drug delivery systems, and packaging such as contact lens blisters, for the medical, pharmaceutical, and nutraceutical industries.
Alltrista says that typically at the outset of a new production run, 30 shots containing 15 components each will be run off and checked, with customers requesting a process capability of at least Cpk 1.33 and often 1.67 or 2. The company says that tolerances are generally fairly open on plastic items, normally in the 50 to 100 microns range, but any inaccuracy of measurement is undesirable as it would consume part of the tolerance band.
When the CMMs were installed, LK wrote core programs for inspecting components for four major Alltrista customers and devised a PC screen dashboard so the whole process is menu-driven.
The first screen displays an icon for each customer, which when clicked reveals every part that is injection moulded for that company. Clicking on the appropriate icon automatically sends the program to the CMM, whereupon the operator keys in their name, whether it is a standard or first article inspection report that is needed and clicks start.
The Altera S controllers and CAMIO software were supplied to accept data input form a laser scanning sensor in the future should Alltrista decide that the increasing complexity of its plastic devices requires this further upgrade.