The measure of things

Its speciality is providing manufacturers of soft contact lenses with instruments for checking critical dimensions and features using optical and projection systems. However, its latest development has seen a switch to laser-based measurement and, as the component parts of these units have had to be engineered to even higher standards, its recently installed XYZ turning and machining centre are playing a central role.

The upgrading of Optimec’s in-house machining began following a review of its existing machine tools and its reliance on subcontractors by director Colin Richards: “At the time we had some old manual machines at our disposal, but much of the more intricate work was being subcontracted,” he recalls. “We looked at the costs of bringing this in-house by investing in new machinery against continuing to rely on subcontract, where, as a relatively low volume customer, we were an easy target for our production to be pushed back down the schedule.

“The calculations showed that with our existing products we could justify the investment, while at the same time use the improved machine capability to redesign many of our components in order to streamline production by eliminating some manual alignment of assembled parts. Bringing this work back in-house also gave us much greater control over lead times and quality.”

With the purchase of the XYZ CT52LTY Y-axis turning centre and an XYZ Mini Mill 560 vertical machining centre being Optimec’s first step in to CNC machining there were challenges, but machine shop supervisor Mark Noden quickly came to terms with the programing of the Siemens 828D ShopTurn/ShopMill controls.

This early induction into CNC programming was to prove to be a good foundation as Optimec began to develop its latest generation of metrology instruments, the Optimec is830. With this new system the company is moving from optics and projection methods, to laser technology to carry out detailed non-contact measurement of soft contact lenses that are inspected while they are submersed in a saline solution.

This meant that the main body of the Optimec is830 had to be designed as a single component in order to provide the highly stable and repeatable platform that the system would require. “Without the upgrading of our machining facilities with the XYZ machines, in particular the Mini Mill 560, we simply couldn’t have produced the parts we needed,” says Mr Richards.

“Even with this technology we were pushing the limits of what could be achieved. The package that XYZ put together for us was perfect and in combination with our enthusiasm and determination we have achieved our goals with the successful launch of the Optimec is830. There was simply no way that we could have machined these parts with our old equipment.”

One of the keys to the success of the Optimec is830 is its main body component which is machined from a solid aluminium billet. To machine the complex forms Optimec specified the optional fourth axis on the XYZ Mini Mill 560. “We had to create a highly stable and accurate platform to seat the laser in to ensure consistency of measurement,” says Ben Coldrick, head of technical development at Optimec.

“Stability is everything when you consider what we are achieving with this new system. It will measure contact lens thickness at any point (lens thickness does intentionally vary for technical reasons and needs to be accurately measured), all elements of the curvature of the lens, the overall diameter and even the sagittal depths of the lens. To achieve the degree of accuracy that lens manufacturers demand, we need the initial starting point of the system’s construction to be exceptionally rigid and accurate.”

The complexity of this key component pushed Optimec’s machining knowledge and capability to the limit and required some outside assistance from XYZ and an engineering consultant to assist with the creation of the CAD/CAM file.

However, having taken on and overcome this challenge, the process of re-engineering and transferring all of the other machined parts it produces to the XYZ machines continues. “What we have achieved in a relatively short space of time, with limited initial CNC knowledge has been remarkable,” Mr Richards concludes. “We couldn’t have achieved it without the excellent package of machines and support that we received from XYZ.”

XYZ Machine Tools www.xyzmachinetools.com

Optimec www.optimec.com