Muffett gets in gear With Kellenberger

There are very few manufacturers with the heritage of Muffett Engineering Solutions, a company founded in 1920 by Stanley Herbert Muffett.

Operating as a general machine shop, it wasn’t until the 1950s that the business turned its attention to the production of precision gears. Now, the modern face of the business is very different to the company that started over 100 years ago, and evidence of this can be seen with the latest acquisition the company has made in a Kellenberger 100 grinding centre with a Wenger autoloader from DF Precision Machinery.

Muffett manufactures and assembles special gears, mechanisms and gearboxes that are produced to the exacting requirements of its high-profile clients in industries as diverse as aerospace, marine, medical and automotive through to construction and the offshore sector.

Producing gears from 4 to 400mm PCD with a module from 0.25 to 5, the Tunbridge Wells company required ground gear components with a specific dimensional range and output rate and it was the Kellenberger 100 with Wenger autoloader that fitted the bill perfectly.

Recalling the scenario, Mark Jagelman from Muffett Engineering says: “Mike Duignan, managing director of DF Precision Machinery, was given a brief of what we expected and what we were looking for. Automation was a primary requirement, so Mike took us to several end users of Kellenberger machines with automated solutions. We also had trial parts manufactured before taking receipt of the machine.”

Looking at specific parts and the challenges facing Muffett with its existing machines, Mark Jagelman adds: “With a small part, you can be grinding three diameters with two journals on the end and with the previous process we had to drive the part with a carrier which resulted in two operations. With the new Kellenberger machine, we have synchronous drives, so we can grind the part complete in one operation – and we also have the automation factor as well.”

Considering the two-op process of grinding precision gears, parts had to be re-set to exact dimensions to complete the second operation – a time-consuming and laborious process that had the potential for error. Alluding to this, and how the new Kellenberger machine has helped, Mr Jagelman adds: “You have one loading and one datum, so you have no issues with concentricity or run out.

“This is where the driven tailstock that is fully synchronised with the main spindle supports the process. It is driven purely by friction through the centres and you have full alignment through the datum. In addition to this, we have in-process gauging where the machine makes any necessary alterations to any offsets if there are any size changes and deviations through production. However, we are only seeing around 1µm of movement in a full day of production.”

The Kellenberger 100 universal CNC OD/ID grinding machine is a new, high-performance and economical grinder for use across medium to large-scale universal grinding applications. The Swiss-made machine is highly configurable and offers a plethora of options to accommodate the widest range of universal grinding operations across a variety of industry sectors.

From a specification perspective, the machine has the choice of a universal work head, a work head with direct drive and C-axis, chuck loading, power clamping or the option of loading between centres.

The machine also incorporates a 19-inch LCD touchscreen monitor with the FANUC 31i CNC system, FEM optimised cast machine bed and mechanical separation of machine and peripherals for thermal stability and vibration damping.

There is a range of tailstock options, a modular wheelhead configuration that allows 10 different wheel head variants with up to three tool positions and a host of other solutions that can be specified by the end user to create the most suitable solution for their business.  

Taking a closer look at the Wenger automation system, Mr Jagelman says: “This is our first grinder with automation; before that, each part was manually loaded. This means we are now starting to trial unmanned lights-out running, and the most success we have had so far is that we have run the machine for 14 hours without any manual intervention.”

In the early days of installation, this is an impressive result that will undoubtedly continue to evolve and improve as the company gains familiarity with its new automation capabilities.

Discussing the benefits of the machine, Mark Jagelman affirms: “The new machine has improved our throughput, our capacity and has enhanced our ability to run unmanned without any labour input.”

Looking at the learning curve and implementation of the new Kellenberger 100 with Wenger autoloader, Theo Marks from Muffett Engineering says: “In principle, it is similar to before where we have the same tools doing the same process.

“The programming was a little bit more challenging than the old grinding machines, but the training we received from Kellenberger made it all quite straightforward. We went over to Kellenberger’s headquarters in St Gallen, Switzerland and we had excellent training from the staff there.

“After that, we had training on the physical machine when it was delivered. We had about a week of the actual programming of the machine while we were in Switzerland and we learnt a lot more than we are likely to use here. This is because there is so much you can do on this machine.”

DF Precision Machinery

Muffett Engineering Solutions

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