Wave goodbye to distortion

Aerospace specialists, Produmax was having to leave components ‘to rest’ for a week after roughing, as the process led to them bending. But managing director, Jeremy Ridyard says that when they started using Waveform milling to speed up cycle times and provide better swarf control, they discovered an added benefit: the components were being subjected to considerably less stress.

“Waveform generates only minimal heat, so we’re getting far less distortion, and the parts don’t bend anywhere near as much as they did - which is especially valuable, as high precision is our major USP.”

Vero Software’s Edgecam drives its Mori Seiki, DMG and Nakamuura CNC machine tools, creating toolpaths for a wide range of components made from titanium, inconel and aluminium, mainly for the working area of aircraft wings. This includes flaps, leading edge, steering mechanisms, rudders, and thrust reversers, along with bearings and bushes, complete assemblies and a number of fuselage components.

“We always work to extremely tight tolerances, and produce some large gearbox casings with a one-thousandth of an inch total run-out from milled surfaces to turned bores. Before we started using Waveform, we hand lapped the gearbox faces to get them in position where we could go back and finish machine, because of the distortion. With Waveform, we’ve been able to remove all the lapping processes because we’re getting much better stability.”

The company also utilises the Waveform turning strategy, and plunge milling. Ridyard says Waveform turning is particularly important for swarf evacuation on components with deep grooves.

“It allows the swarf to break readily, so the coolant can easily wash it out of the groove. Previously, the swarf was stringy and could clog the cutting tool, sometimes even breaking it. Using Waveform turning with button tools and double-sided grooving tools we can push it harder, improving the cycle time.”

He adds that the turning strategy has been particularly successful in producing PH steel components around three-quarters of a metre long, requiring nearly 80% metal removal.

“Waveform speeds up both milling and turning roughing operations by at least 30%, and also gives us first rate swarf control, which is very important to us.”

And working with the Advanced Manufacturing Research Centre (AMRC), it came up with plunge milling as being the best process for producing PH steel thrust reverser door mechanisms. “Plunge milling profiles with a lot of stock, on a Mori Seiki MH40, rather than machining round profiles, gives us 40% faster metal removal rates.”

Ridyard says the Mori Seiki’s sturdy Meehanite bed construction makes it the ideal machine tool for plunge milling: “Just working in the Z axis, drilling the material out with an indexable insert, means we’re taking large radial stepover cuts, which remove the material much faster. The swarf chips are smaller, and the process puts all the heat into the swarf instead of the component, so again, there’s less stress on the parts.”

Produmax uses Waveform mainly on internal cutting, with plunge milling largely reserved for external profiles. According to Ridyard, Waveform is also a critical part of its automation process.

“We’ve recently installed a DMG NMV 3000 with 34 pallets, and we also run Laing Automation Eco towers. Using Waveform for swarf control, we’re currently hitting 60 hours of unmanned production on Saturday, Sunday and Sunday night. We just load it up with pallets and it runs right through the weekend.”

Produmax carried out trials at Mapal in Germany to prove out the Edgecam programs for the operation. “Mapal tested six different software programs for the roughing strategy, but the Waveform strategy beat their best cycle time.”

Working with the Government-backed Sharing In Growth scheme in the early days of its ongoing expansion has seen the company move out of its premises at Otley and Leeds Bradford Airport into a £3.1m purpose-built 28,000ft² factory at Shipley, West Yorkshire.

“We have a culture where we’ll try anything – we learn through designated experiments to push the boundaries in our production cells, and we’ve designed the factory with a separate division purely to practice new operations which can then be rolled out into the full manufacturing process.”

www.verosoftware.com

www.produmax.co.uk