Spark and wire erosion Creating a spark: Toolmaker makes its mark with Mitsubishi EDM
Due to considerable business growth, UK toolmaker Denmark Products has added a Mitsubishi wire EDM and a spark erosion machine to its shop floor. With features such as precision automatic wire rethreading, IoT technology, next-generation drive systems and a user-friendly control system, the new machines significantly reduced lead times.
With four generations of toolmakers in the family, Denmark Products has been manufacturing injection mould tools since its inception in 1993. Started by father and son team Dennis and Mark Rowlands with a 15,000 pound investment that stretched to the purchase of a mill, sparker and surface grinder — the company has come a long way since the 1990s. Testament to the journey travelled is the recent investment in a high-end Mitsubishi spark erosion machine from the Engineering Technology Group (ETG).
The small start-up that operated out of a 900 sq/ft unit has moved to a 4,500 sq/ft facility in Donnington on the outskirts of Telford where it manufactures precision injection mould tools for the automotive, medical and white goods industries. With considerable business growth, the company has added both a Mitsubishi wire EDM and a spark erosion machine to its plant list in a little over twelve months. As a company with everything from 3 to 5-axis machining centres, milling machines and lathes through to surface grinders, spark erosion machines and more, the interest in Mitsubishi machines started just over a year ago.
The seven-employee company was using an external supplier for its wire EDM requirements. This wasn’t an ideal situation with costs and process control being surrendered to the subcontract supplier. Recalling the situation, Company Co-Founder and Managing Director Mark Rowlands says: “With the demise of so many companies through Covid, we had an opportunity to buy a used Mitsubishi MV1200S wire erosion machine. As the UK supplier of Mitsubishi machines, we went straight to ETG for installation and commissioning support. In the 12 months since the machine has been installed, we have eliminated our subcontract wire EDM costs, and the lead times associated with a subcontractor turning work around, and we have complete process control. Additionally, when it comes to wire EDM, we 100 percent know if we want a loose or interference fit between our components — an external supplier would not know this, so our quality and surface finishes have improved too.”
With next-generation technology such as precision automatic wire rethreading, IoT technology, next-generation drive systems and a user-friendly control system, the high-performance Mitsubishi MV1200S has significantly reduced lead times and improved throughput for Denmark Products. Furthermore, the acquisition exposed the subcontract manufacturer to the impeccable service levels provided by ETG.
Service makes the difference
With customers in the high-end automotive and medical industries ramping-up production post-Covid, Denmark needed to invest in a larger capacity spark erosion machine. With three ageing spark erosion machines already on site, Denmark needed a machine with a larger bed and tank capacity for processing the increasingly larger dimensions of automotive interior trim parts and large white goods injection mould tools. Despite having spark erosion machines from several different vendors on-site, the service provided by ETG with the MV1200S was a major factor in why the company invested in a second Mitsubishi machine.
As Mark continues: “We did our due diligence and looked at spark erosion machines from a few leading suppliers. Once we identified our capacity needs, it was the technology, capability, reputation for quality and impeccable service levels from ETG that were the main factors in our decision to buy a Mitsubishi EA28V Advance spark erosion machine.”
The Mitsubishi EA28V Advance can accommodate maximum workpiece dimensions up to 1350 by 850 by 450 mm in its 390 litre capacity tank that utilises an automatic elevation method. Capable of accommodating electrodes up to 200 kg and workpieces up to 2,000 kg, the Mitsubishi EA28V is a powerful workhorse with technology that delivers finesse for the highly productive processing of components of unsurpassed precision and quality. Discussing this spacious work area, Mark adds: “We’ve been increasingly receiving requests for larger components that had to be externally produced, as our spark erosion machines were not big enough. This resulted in external subcontract costs that were a drain on our business and extended our lead times. With the arrival of the Mitsubishi EA28V, we have brought all of this work in-house - reducing both our costs and lead times.”
Modernised machine shop
Investment in spark and wire EDM technology turned a business around
However, the Mitsubishi EA28V Advance has given Denmark so much more, as Mark continues: “The extra capacity not only allows us to process larger parts, it also enables us to put two or three different smaller jobs on the bed and run them consecutively. This means we can undertake lights-out machining, and in many instances, we can set the machine up on a Friday night to run all weekend unmanned. This is a huge saving for our business. The ability to run up to three different components on the machine consecutively is a credit to the 20 electrode tool change facility an intuitive programming technology on the Mitsubishi EA28V.”
Setting of up to 20 electrodes
“Our existing spark erosion machines only have single-electrode capacity, which means that we would continually change electrodes for every operation and part. With the Mitsubishi EA28V, we can set up to 20 electrodes, and program several parts — and the machine will run for a couple of days unmanned. This is a huge saving for our business. From a productivity perspective, the technology in the Mitsubishi EA28V means that we can adjust our settings to erode components at higher speeds and feeds or we can similarly slow the speeds to extend the life of electrodes or improve surface finishes. Regardless of the multitude of settings, the machine can process parts far faster and to a higher level of quality and precision than any of our other spark erosion machines,” says Mark.
This is reducing energy consumption and costs for Denmark whilst simultaneously reducing consumable costs. Another advantage for the small business is the reduction in hand polishing, as Mark adds: “Our existing spark erosion machines are typically generating a surface finish in the region of 24VDI (1.6Ra), which often requires considerable post-machining hand polishing. This is particularly the case for injection mould tools for interior vehicle trim components that are used in marque vehicle brands and medical mould tools for containers and spoons. With the new Mitsubishi EA28V, we are easily achieving surface finishes of 12VDI (0.4Ra), which has drastically reduced our hand finishing. On some parts such as ribs and cavities, the high level of surface quality has eliminated hand finishing, which is a necessity for sensitive features. Overall, bench finishing has massively reduced, freeing up hours for our machinists every week.”
Looking at the level of service from ETG, Mark concludes: “The service from ETG has been exemplary. The knowledge and understanding of Scott at ETG are unfathomable. We initially did four days of training on how to programme and operate the machine, and Scott was giving us tips and tricks to enhance our processes further. Whilst the capability and productivity of the machine are impressive, the tips on process improvements from Scott were the icing on the cake. We have another day of ‘advanced training’ to schedule with ETG and we can’t wait to see what else we can learn from this training.”