Subcontractor has ‘steely determination’ to succeed.

Formagrind is a subcontractor that is certainly playing its part in supporting the local manufacturing community. The company has recently won a significant order that has led to the delivery of two Hurco machining centers and new tooling innovations from Mitsubishi Materials.

Tooled up for production
Like many subcontractors, Formagrind was primarily using the services of a local distributor that sold multiple tooling brands without the required expertise to best service the end user. The frequency with which Formagrind was processing materials such as molybdenum, tantalum, titanium, inconel and other difficult-to-cut materials was increasing and made the situation more prominent. At this point, the company called upon the expertise of Mitsubishi’s local application engineer Jason Gardner, for support. The expertise and the consequent results have seen the Formagrind tooling spend on Mitsubishi products rise from 10% to beyond 80% of the total spend in just over five years.

A 0.5mm diameter tool machining apertures on base plates

“Our tooling spend wasn’t truly measured or qualified and we set about using the experience Mitsubishi offered to set performance parameters and structures. Initially we trialed Mitsubishi’s face mills with huge success. Jason from Mitsubishi then recognised that our existing aluminium roughing end mills were also under-performing compared to the potential of Mitsubishi tools. He implemented the Alimaster aluminium roughing end mill range on a long-term satellite project for a major aerospace customer, and the material removal rates were nothing short of brutal. The success of the face mills and the Alimaster cutters gave us complete confidence in both Mitsubishi tools and the local engineer,” said Formagrind’s shop floor manager Mike John.

The confidence that Formagrind has in Mitsubishi products has seen the subcontractor evolve from an occasional purchaser of Mitsubishi tools to a consignment stock customer with a complete range of solid carbide end mills, indexable end and face mills, plus high quality back-end tooling. Additionally, in April, an Autocrib vending system to store and automatically re-order tools was installed.

Mitsubishi guarantees ‘lights-out’ production
The base plate and corresponding top plate cover units that clamp the automotive electronic assemblies were initially required in a batch size of 105 bases and 160 cover plates. With over 14 hours of machining for each base and one hour 50 minutes of machining for each cover plate, Formagrind realised that it needed to run its new Hurco VMX30Mi machines 24 hours a day, seven days a week for almost two months. With iMachining optimising the process and the Hurco machines purchased for the project, the key factor for unmanned lights-out production was the cutting tools.

Andrew Probert on the left with Robert Owen on the right discussing tooling in front of the new Hurco VMC

Formagrind developed a fixture to clamp and subsequently machine two 300mm by 200mm by 9.5mm thick base plates at a time. The grade two titanium plates are firstly machined with a Mitsubishi 8mm diameter solid carbide four flute VQ Series end mill at a 4.5mm depth of cut with a 1.2mm step-over and a feed rate of 1400mm/min. After almost two hours of non-stop machining, the 8mm tool is followed by a 4mm and a 3mm diameter VQ end mill for the remaining machining of the finite details. Once the surface and the respective details are complete, Formagrind uses the 2, 3.5 and 4mm diameter VQ end mills for rough and finish machining the pockets that are waterjet cut prior to machining as this reduces on-machine times. For the smallest details, a 0.5mm diameter MS2-XLB end mill is used. With a total machining time of 9 hours for the top-face of the two parts, tool life is critical.

“We consulted with Mitsubishi at the very start of the project and they recommended the VQ end mills for the majority of base plate operations. For us, the ability to confidently run unmanned for prolonged periods was crucial. Tool life is an essential aspect of this. We couldn’t afford to have a tool breakage mid-cycle, as this would potentially scrap the parts and impact on the tooling in the following sequences. To this end, we change the tools after each pair of bases even though tool wear is hardly noticeable after 14 hours of machining,” said John.

As for the smaller top guide clamps, Formagrind created a fixture to machine 10 guides in a single set-up. On the top guides, the first stage machining is done with a 6mm diameter VQ Series end mill at a 4.5mm depth of cut for a total machining time of 1 hour 50 minutes. Again, this is followed by 3, 3.5 and 4mm diameter VQ end mills for the other machining and pocket milling whilst a 2mm diameter VFH long neck series with a 0.5mm radius and a variable helix is applied to finishing the detailed features. During this process, the 3.5mm VQ end mill has a run-time of 55 minutes and it hasn’t been changed through the complete project, demonstrating a staggering tool life of 550 minutes on titanium. Additionally, the 6mm roughing tool has conducted 4.5mm deep roughing throughout the complete batch – returning over 20 hours of machining even at these testing parameters.

“Mitsubishi have an excellent reputation for their solid carbide end mills and we can clearly see why. Without the truly impressive VQ range and the support from the Mitsubishi engineer, meeting the deadline of this project would have been more of a challenge. The final base plates and top plate covers have now been delivered with a total machining time of 2 400 hours. The customer is now moving to the next generation electrical assembly and we will once again be providing the clamping bases and guides for this project. Luckily, we have Mitsubishi tools in our corner,” concluded Mike John.

The Mitsubishi VQ series are vibration control end mills for difficult to cut materials. There are nine types in the series used for square corner, ball nose, corner radius and roughing operations and range in diameter from 0.2 to 25mm.

For further information contact Multitrade Distributors on TEL: 087 803 2377 or visit www.multicarb.com