A Subcontractor’s Guide to Tool Presetting
Why Should I Be Presetting?
By setting tools offline using a presetter, previous sequential methods of preparing for machining operations are replaced with a more efficient, simultaneous process that releases significant amounts of latent production time. And yet, despite this very clear and proven benefit for subcontract machine shops, tool presetting remains a process that is not fully appreciated or totally understood.
Many ask why there is a need for a dedicated presetter when cutters can be set on the machine tool itself. The simple answer is that machine tools should be cutting parts as much as possible in order to ensure an efficient process. As an alternative to using feeler gages and test cuts to determine tool offsets at the machine, deploying an offline system to perform independent tool presetting offers up significant benefits.
Consider a typical machining operation where each tool change takes 3 minutes when presetting is performed on a machine tool. If there are 20 tool changes in an 8-hour shift, the result is a whole hour of manufacturing lost because of tool setting – on every machine. However, if that tool setting was performed on an offline presetter, then manufacturing would be improved by 12.5% – where else can that level of gain be found in modern production operations without investing in an additional, expensive CNC machine tool and another operator?Calculate Your ROI
Based on three machine tools, it is estimated that a subcontract machine shop can save up to £12,000 per shift over the course of a year through the use of a presetter. Furthermore, unlike on-machine probing, the technique ensures that the tool becomes productive the instant it is loaded into the machine, while the guaranteed accuracy of tools reduces scrap levels and adheres to ‘right first time’ manufacturing philosophies. Improved tool setting precision also means lower costs for replacement carbide inserts and better component surface finish.
Despite these numerous advantages, it’s fair to say that many subcontract machine shops assume they are not good candidates for presetters because their production quantities are small. However, subcontractors often represent the very best applications for presetters, simply because they change tooling not only because of wear, but also because of new jobs. The more frequently a shop has to load a fresh tool into a machining centre, the more savings offline presetters can deliver.
Similarly, those thinking that presetting requires high capital investment should also think again. A general purpose presetter such as the Zoller Smile Pilot1 offers first generation users a high quality system for less than £12,000, thus achieving ROI within a year in most applications. Moreover, a machine such as this not only offers guaranteed accuracy and repeatability, but auto-focus capabilities and seamless transfer of data to machine tools thanks to control specific output, which eradicates operator intervention.
Among a growing number of subcontractors to take advantage is TEG, a specialist in the provision of bespoke engineered solutions to fully accredited specifications, which has installed a Zoller Smile 600 at its headquarters in Mullingar, Ireland. The investment has seen the company witness “significant improvements in quality”, with “over 98% of parts” now coming off the company’s machine tools “right-first-time”.
“We knew we had to invest in consistent technology so that we could control that part of the process, and this is what the Zoller enables us to do,” says John Hunt, TEG’s CEO. “We need our customers to feel confident in our ability as we want their repeat business. And, in many ways, that’s what it boils down to – repeatability.”
Elsewhere, Southampton-based Benham Engineering, an established subcontract supplier to aerospace and defence customers, is also using a Zoller Smile presetter to help the company reduce set-up times on its range of Mazak machine tools by an average of 15%.
“There’s hardly any tools we don’t preset on the Zoller, including face mills, end mills, reamers, turning tools, parting and grooving tools, and gun drills – over a huge size range,” says Production Engineer, Neil Griggs. “When you consider the work type, the frequency of setting and the number of machines here – we have eight Mazak Integrex and six Mazak Variaxis machines, plus numerous VMCs, HMCs and turning centres – that’s a lot of savings.”