A partnership in full flow

Running through Northern Ireland’s verdant Ulster countryside, the flow of the river Moyola is constantly affected by the course of change. Moyola Precision Engineering’s Raymond Semple has seen it all during his tenure as chairman of the precision engineering subcontractor and like the river that wends and winds its way close by, understands when change is required to ensure his company remains competitive in the fast-flowing world of aerospace manufacturing.

In Moyola’s case, this change has manifested itself in the need to acquire more productive and agile CNC machine tools – purchases of which, in recent times have comprised two universal machining centres from Grob Machine Tools UK, adding to the one first installed back in November 2015.

As a supplier of 5-axis aerostructure components, kits and assemblies, Moyola holds full assembly approvals from both Bombardier and Airbus. The Grob G550 5-axis machine installed in 2015 was acquired after winning a substantial Airbus package that includes the production of sub-1m 5-axis components. It is equipped with a 30,000rpm HSK63 spindle, 120-pocket on-board tool magazine, twin-pallet changer and 80bar through-tool coolant. Such has been the success of the machine that Moyola purchased a second G550, along with a smaller G350 that offers 600mm diameter workpiece capacity.

[caption id="attachment_12329" align="aligncenter" width="1024"] The Grob G550 5-axis with rotary pallet storage system[/caption]

Down with swarf

A major differentiating feature of the G550 is its horizontal spindle configuration. Here, the ability to machine overhead provides free-fall swarf evacuation directly on to the chip conveyor. Compare this with a vertical machining centre when producing pockets, for example, and the benefit becomes very clear. On a VMC, the pocket simply fills up with chips, introducing heat into the tool and the workpiece. Grob says that the aerospace industry is now latching on to this fundamental advantage.

The company also points out that a horizontal configuration promotes high machine rigidity and fast metal removal rates. Indeed, meeting the aggressive cycle time targets was a huge factor in Moyola’s purchase decision. The G350 has helped open up job shop capacity at Moyola. With its 16,000rpm spindle offering 206Nm of torque, it is used to machine materials ranging from aluminium to titanium, thus introducing high levels of flexibility.

“In my 40 years’ experience as an established family-owned business, Grob has really stood out as being a solid and reliable partner and I’ve been very impressed,” begins Semple. “When I first began looking to purchase new machining centres, I performed a desktop analysis – initially looking at a range of different CNC machines – before breaking it down to four defined choices. I then collaborated with my engineering team to further down-select to a final choice of two.

“Based on the visits to the two suppliers involved, we were able to see the technology and experience the relationships first-hand. Grob stood out the best in three areas: its reliability based on their family-owned ethos, the agility of its machines, and the machine tool trials we performed. Grob was up for it and really demonstrated the will to make it happen. We will definitely be adding to our capabilities with new machine tools, and depending on our requirements, I’m sure Grob will be on my radar.”

In terms of the types of performance demands placed on Grob by Moyola, whilst price, quality and delivery are a given, I’m keen to learn whether there was anything else that really stood out?

“Horizontal machining was a key requirement for Moyola, particularly the overhead, ‘upside down’ machining capabilities for machining their parts,” states Grob’s managing director, Louis Hill. Semple agrees: “I wanted to buy a horizontal machine because of the amount of swarf the machines would be generating. We’re removing up to 95% of the material to produce the deep pocket features of a finished aerospace part. We never cut the same chip twice as this could damage parts or break our cutting tools – even a small surface indent could see a part being rejected as scrap. The Grob machines have the ability to drive 80bar through-tool coolant pressure into deep pockets to wash the swarf away.”

The automation station

A key difference with the new G550 is the inclusion of Grob’s PSS-R10 rotary pallet storage system. The PSS-R10 offers 10 pallet storage slots on two levels accommodating 630 by 630mm pallets. It represents the first step into a multi-pallet platform for Moyola; currently the company deploys a twin-pallet approach to its production of aluminium aerostructure components.

“The automation of the twin-pallet system and the 10-pallet system on the second machine was another key requirement for Moyola,” Hill explains. “From the drawing board onward, the G550 has been designed with automation in mind. The flexibility of its construction and the options available means that customers can specify the machine tool with or without an automated pallet changer, or the option of direct load onto the table.

“We’d never profess to be just a ‘out of the box’ seller of universal machine tools, because it’s far more important for us to offer customers our full technical support and maintenance for the lifecycle of the machine. Looking ahead, we’re working towards building much larger machine tools. At present, our G750 goes up to 1,280mm diameter, but we now offer the G800, which goes up to 1,600mm diameter. Size matters, and our aim is to go bigger and bigger.”

For any potential purchaser of a CNC machine tool, attributes such as fast cycle times, fast speeds, low-down ‘machined from solid’ grunt, accuracy and ‘done in one’ ability will always remain high on the proverbial shopping list. The parts Moyola manufacture on its shopfloor are exclusively made from aluminium, so for Raymond Semple, the Grob machines must possess a first-class, solid bed construction.

“It is an absolute ‘must’ that these machines do the work they’ve been designed for with the exceptional agility of precise movement,” he concludes. “We cannot afford any vibration or a CNC machine tool with jerky movements, because the quality of the aerospace components we produce is paramount. We’re machining very complex parts, as well as deburring the parts in-cycle – all of which requires a high degree of agility and precision. Grob is a company that I feel confident enough to run any ideas past and they can be relied upon to be honest with me.”

www.grobgroup.com/en

www.moyola.com