Ten years ago, Hopwood Gears Ltd invested in an Oxy-Propane gas cutting machine from Kerf Developments. Owning a profiling machine that runs like a dream with exemplary service support for over a decade was two of the key reasons why the Oldham based subcontractor went back to Kerf Developments for its latest machine, a twin-head water jet machine.
Founded in 1974, Hopwood Gears immediately set its stall out as a subcontract manufacturer with a niche for producing gears, gear sets and all associated components.
Now with 40 years of gear manufacturing under its belt, Hopwood Gears is a true specialist, manufacturing gears from 4mm diameter up to 3m - and everything in between.
The 33 employee company serves the defence, aerospace, automotive, white goods and consumer markets with bespoke gears for anything from a tank or submarine through to the everyday watch or washing machine.
To manufacture its gears and meet the demands of its wider subcontract business, Hopwood Gears has a machine shop stacked with CNC EDM, turning and machining centres from Agie, Haas, DMG and Mazak as well as a multitude of specialised gear production machines.
However, the issue for Hopwood was the upstream issue of profiling its gears and the consequent subcontract costs and lead-times. Discussing the issue, Hopwood Gear Managing Director, Mr Cory Hopwood says: "Ten years ago we were either buying steel plates for £500, or to save time we were paying upward of £1000 for the plates to be pre-cut into blanks. We invested in a twin-head Kerf Scorpion gas cutting machine to cut the cost and gain control over the process."
The 4m by 2m machine immediately cut costs by 50% when processing steel plates up to 150mm thick. Additionally, the Scorpion cutting head allowed the Manchester company to 'semi-finish' large gears with its impressive precision levels. Still in operation after a decade, the Scorpion is still well used today. Nowadays, the company has a need for a more flexible machine for processing a wider range of materials at even greater precision levels - enter the Kerf Optima 420 waterjet machine.
Commenting on this, Mr Hopwood continues: “We were spending a lot of money getting gear profiles cut prior to entering our machine shop for secondary processing. However, the quality of gears was indifferent. The supply was regularly outside our tolerance band and the gears were often tapered where the waterjet wasn’t cutting at 90 degrees.
As soon as we heard Kerf had waterjet cutting machines, we spoke to Dan at Kerf Developments and gave him some of our externally processed gear profiles. Dan was confident the cut quality and precision of the Kerf Optima would solve all our issues. We trust Kerf implicitly, so we bought the Optima 420 waterjet machine. We haven’t looked back since.”
By installing the Kerf Optima waterjet machine, Hopwood Gears immediately improved the precision of its profiles, attaining a precision level of +/-0.05mm as opposed to +/-0.3mm on subcontract supplied profiles. This precision is credit to the highly acclaimed BFT high-pressure pump on the Optima 420.
The enhanced precision reduced returns and it also cut the internal re-working of gears. These factors reduced lead-times, improved precision and edge finishes and also prevented labour and machine time from being unnecessarily absorbed in the machine shop.
From an economic standpoint, Hopwood Gear estimates that £2000 of the £5000 monthly cost of profile cutting was actually material cost. So, by purchasing the Kerf Optima and acquiring the material direct from the stockholder, Hopwood Gear has reduced its subcontract costs by £3000 each month. The flexibility of the water jet cutter means that Hopwood has also eliminated an additional £500 per month in subcontract costs for laser cutting of thin plates and discs.
With the easy-to-use IGEMS CAD/CAM system on the Optima waterjet machine, Hopwood’s staff were comprehensively trained on the machine in one-day. The unparalleled ease-of-use and the automated running of abrasive waterjets allows one operator to simultaneously run a number of machines, avoiding the cost of additional staff. Furthermore, the twin-head configuration permits fast dual-cutting production. This is ideal for a company producing anything from one-off and batch work in the region 50 through to production runs up to 200,000 off.
Whilst the Kerf Optima 420 high pressure product line has cut costs, improved quality and precision for the subcontractor, the benefits reach much further. As Mr Hopwood concludes: “The lead-time for external waterjet profiles was 4-6 weeks, now we can get the material next day and often turn work around in less than a week. By eliminating the 4-6 week supply chain, we can get gears into the machine shop for secondary machining a lot faster. This gives us more production capacity, better scheduling and it means our machine shop is always busy, as nobody is waiting on a third-party to deliver profiles to the machine shop.”
“Furthermore, the profiles are more precise and this means fewer set-ups and operations in the machine shop. With fewer down-stream operations, there is more machine and labour capacity and even our cutting tool consumption has been reduced. To put it simply, our entire cutting systems production facility would struggle to keep up with demand if we didn’t have the Kerf Optima waterjet cutting machines on the shop-floor.”
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