Scotland-based
Northern Tool and Gear Ltd (NTG) has a long history of producing high-quality gears since 1945 at its facility in Arbroath. Nowadays, the company uses a wide range of high-end machine tools to manufacture everything from one-off to high-volume production of gears and transmission components.
Employing over 50 people, NTG manufactures spur, helical, straight and spiral bevel gears, hypoid bevel gears, precision ground gears, specialist bespoke gears, shafts and bevels on the latest CNC machinery to achieve the highest-quality standards.
Supplying customers in a diverse range of industrial sectors, including renewables, mining, marine, oil and gas, 3-D printing and motorsport sectors, NTG has full CNC gear-checking technology as well as an on-site heat treatment facility to guarantee complete quality control of all projects.
However, when it came to EDM machining particular features, the Scottish manufacturer was sub-contracting work to external vendors. This led to the arrival of the company’s first wire EDM machine in March 2024 — a Mitsubishi MV4800S wire EDM machine supplied by Wellesbourne-based
Engineering Technology Group).
NTG’s managing director Gordon Strachan said: “Before the arrival of the new Mitsubishi wire EDM, to produce things like keyways, we would use a broach which is a high-volume process or we would use an old-fashioned slotting machine, which was slow, laborious and it would have quality issues at times. Internal splines, external splines and external gears have dedicated machines for cutting the internal or external splines - these are fast and efficient but they require a lot of tooling and considerable set-up times. In fact, sometimes the tooling would cost more than the job. Now, if the customer needs something in a hurry, we can cut it on the new wire EDM.”
Looking at the diversity of the gear components that NTG is manufacturing, he continued: “We get approached by major motorsport companies that require specific gears, diff pinions or diff gears for the start of the season with designs that are a change from the previous season. If we are lucky, we have the tooling already and if we are not, we have to source it. Sometimes, the time it takes to procure tooling is more than the time that we have to deliver the job.
Prototypes and small batches“So, going down the wire-cutting road allows us to meet customers' expectations and it forewarns us of larger batch volumes that may be in the pipeline. This gives us time to manufacture the tooling in preparation for the pending work. This makes the wire EDM perfect for prototypes and small batches as it helps to get customers up and running quickly.”
Discussing why the Mitsubishi MV4800S wire EDM machine was chosen, Mr Strachan added: “When we first started looking at wire cutting, we were looking at four or five main manufacturers. I cut this list down to two, and we eventually with the help of Ross from
RAM Engineering and Tooling, the Scottish distribution partner for ETG – we selected the Mitsubishi.
“I had been impressed with the Mitsubishi machines from the start and from visiting machines on manufacturers’ sites, I could see the quality of the product and the technology involved. Everything is ‘state of the art’ and the control system is very user-friendly. I have had exceptional backup and support from Ross at RAM and the team at ETG from the very beginning, it has been second-to-none.”
The particularly large MV4800S machine was selected for its 1,080 x 780mm table that can accommodate parts up to 1,250 x 1,020 x 505mm, with a maximum weight of up to 3,000kg. This is perfect for the Scottish company that manufactures hobbed gear components from 50 to 1,200mm. Additionally, the new arrival incorporates technology like automatic wire threading, linear shaft motors and an optical drive system for unparalleled precision and circular accuracy within 1µm. From a user-friendly perspective, the 19in screen and the ability for functions to be used in just one touch from the ‘home’ screen helps to reduce operations performed in the navigation menu from setup to machining by almost 40%.
Looking to the future and the potential opportunities for the Mitsubishi MV4800S to make an impact at NTG, Mr Strachan explained: “With the technology and the Mitsubishi control system, we have a very powerful and user-friendly machine. Anything we can program on the control system, we can also wire on the part. It gives us immense flexibility, especially if there is a change in specification in any splines and gearing, which is very common.”
He concluded: “If you don’t have the correct standard of cutter, you can’t use it. You may have the correct pitch and the right size, but it may not have the right profile and this makes it a redundant cutter as far as that job is concerned. However, if we can wire cut it on the Mitsubishi machine, we then have a huge level of flexibility that can also help us to compress lead times.”