Making light work of medical grinding

Part of the Rollomatic cell at Smithstown Light Engineering
Part of the Rollomatic cell at Smithstown Light Engineering

Coventry-based Advanced Grinding Solutions (AGS) has announced the sale of several additional grinding machines and Comat filtration systems to Smithstown Light Engineering in Ireland. PES reports.

Smithstown Light Engineering (SLE), has grown rapidly in recent years as the larger OEM medical manufacturing companies have sought to use specialist outside providers for higher value machining processes including grinding and surface finishing.

Today, SLE offers its medical customers a true one-stop-shop for all kinds of medical component manufacture and has mastered a wide variety of processes including internal and external grinding, jig grinding, turning, milling, electro polishing, EDM, laser cutting and welding, 3D printing and heat treatment.

Brian King founded SLE in 1974 as a machine shop, quickly growing into the design and supply of plastic injection moulds and press tools for the electronics industry. Later it moved into contract manufacturing for the medical device sector and in 2011 was taken over by Brian’s son, Gerard King. From there it has gained international recognition and has more than doubled in size in the last two years.

The Rollomatic at SLE
The Rollomatic at SLE

The new machines from AGS will mean the Coventry company will have supplied £3.75m worth of grinding machines to Smithstown since the two businesses started working together in 2021.

The latest grinding cell comprises an additional Tschudin centreless grinder and a 6-axis Rollomatic grinding machine for processing specialist medical parts along with a large Comat filtration system.

Gerard King comments: “We’ve got to get faster, more accurate and more cost-competitive, and the only way to do that is to increase automation levels and be upfront with the latest machining technologies as they hit the market.

“While a lot of companies in our sector are concentrating on traditional milling and turning, we also take on higher risk processes that aren’t as commonplace to give a wide service offering. Having a broad array of grinding disciplines is just one of our processes that separates us from the crowd.

“You have to embrace the latest technology that’s why we are using the latest, very fast linear axis drive type grinding machines from Tschudin and Rollomatic. We’re trying to reduce the endpiece price to our customers and of course that’s what they like to see.

“And we are growing rapidly. We’ve purchased another 10 acres of land next to our main production units here in Eire and have also opened up a facility in Poland for specific machining tasks such as 5-axis machining and mill-turning. The grinding machines from AGS typify the kind of very high level of production machining that we do.”

He continues: “Although we manufacture parts in small volumes, we also get involved in true mass manufacture for certain components which is why our Tschudin and Rollomatic machines were specified with robot loaders for 24/7 running.”

Sixth axis capability

The Rollomatic 630XW machine ordered by SLE is designed for grinding many kinds of cutting tools with a more complex geometry whereby its additional sixth A-axis, which is claimed to be unique within the industry, provides improved accuracy on special tools with a possibility to incline the grinding wheels by up to 45⁰.

This avoids collisions, allows for easier programming, and ensures demanding and highly precise geometric forms, such as those found on special medical tools, can be machined in a single operation.

Typical medical parts ground on Rollomatic machines
Typical medical parts ground on Rollomatic machines

The Rollomatic 630XW grinding machine has a general working range of grinding tools from 0.1mm to 20mm in diameter, has a high-speed multi-pallet pick and place loader with positions for up to 1,360 tools as standard, and also as standard a six-position grinding wheel changer holding up to 24 wheels.

The efficient synchronous grinding spindle motor provides constant rotation speed and torque regardless of the load on the motor and is combined with the latest linear motor technology providing enhanced surface finish and reduced maintenance costs. The oil used for cooling the linear motors is the same as the coolant oil which ensures constant thermal stability during production.

The machine is also equipped with a touch probe that determines the exact location of the insert blank after clamping so that the software can grind the tool geometry according to the virtual centreline of the blank. This ensures that a run-out of just 2µm can be achieved. As with all Rollomatic grinding machines it comes with a three-year parts and labour warranty at no additional cost and free of charge software updates for life.

Cube capacity

The Tschudin Cube centreless grinding machines enable end users such as SLE to achieve significant productivity gains and the quick changeover times help minimise downtime.

The Cubes use Tschudin’s patented W-axis which has the work-rest blade mounted onto its own CNC axis that allows for parts to be loaded outside of the grinding area making loading efficient, fast, and safe. Traditional centreless grinding machines require parts to be loaded to a fixed work-rest blade that sits inside the machine between the grinding wheel and control wheel making loading difficult, more expensive, and sometimes unsafe.

Another benefit from Tschudin’s CNC work-rest blade axis is that it allows multiple parts to firstly move to an initial position for a rough grinding and large stock removal, before automatically being transferred to a second position for final finish grinding. For example, it is possible to load five parts to the work-rest blade and have a machine with 10 grinding wheels: five rough grinding wheels and five finishing wheels, with the parts being automatically transferred between the two.

Another optional feature – also reported to be unique to Tschudin centreless grinding machines – allows the work-rest blade to move or oscillate backwards and forwards on its own CNC axis during the actual grinding process. This allows finer finishes to be obtained from a relatively rough grinding wheel enabling high accuracy at the best possible cycle times.

Urs Tschudin, board member and director at Tschudin (right) with Gerard King at SLE
Urs Tschudin, board member and director at Tschudin (right) with Gerard King at SLE

The Cube’s simple and low-maintenance machine design helps to reduce operating costs. The natural granite machine base and upper structure guarantee the best possible thermal stability, high-precision and safe grinding processes. Areas of application include plunge-cut grinding, grinding of several parts in a single cycle, oscillation of the component during grinding and through-feed grinding. This versatility means that the Cube is suitable for a wide range of applications.

It can be specified with a grinding wheel of 150mm wide (option of 205mm) with a 12kW grinding spindle for grinding up to 63m/second and is ideal for the production grinding of parts from 0.1mm in diameter up to 20mm, bringing true sub-micron grinding capability to a large variety of parts.

The Tschudin machines at SLE are equipped with FANUC robots for loading and unloading during unmanned shifts.

Filtered system solution

The Comat super-filtration systems in use at SLE were specified and supplied by Advanced Grinding Solutions, along with the machines, and will keep the Rollomatic and Tschudin grinders in a perfect condition for years to come. Comat manufactures super-filtration systems that deliver ≤ 2-3μm filtration quality (making oil cleaner than unused oil as supplied new) and importantly do so throughout the entire working cycle while minimising lifetime running costs and maintaining maximum coolant consistency.

Chris Boraston, managing director at Advanced Grinding Solution’s comments: “We have long been involved as a major supplier of grinding and finishing machines to the medical industry and apart from selling many machines to the large OEMs we have now progressed onto supplying solutions to their major subcontract suppliers such as Smithstown Light Engineering as well.

“We see this trend continuing as the demand for machinery from forward-thinking and highly flexible companies such as SLE offering one stop, all-encompassing services increases. We very much look forward to a developing a close working relationship with SLE in the future.”

Advanced Grinding Solutions

Smithstown Light Engineering

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