Second nature

Completely sold on the benefits gained from four years of almost continuous successful production with a 7-axis Miyano BNJ-42SY fixed head turn/mill centre, precision aerospace contractor Rodford Engineering...

Completely sold on the benefits gained from four years of almost continuous successful production with a 7-axis Miyano BNJ-42SY fixed head turn/mill centre, precision aerospace contractor Rodford Engineering trusted its instincts with the installation of another Miyano – this time a larger 51mm capacity BNE-51SY5. Solutions reports.

Rodford Engineering, based in Wimborne, Dorset, has been in business for 26 years specialising in subcontract turning and milling of components up to 150mm cube in aluminium, stainless steel, Inconel, titanium and plastics which are supplied to leading aerospace and tier 1 customers.

When it came to purchasing a second machine, director Rod Dallyn did not even attempt to check out possible competing machines when the time came to upgrade.

“We have built very close relationships with our customers that include leading aircraft manufacturers and tier 1 suppliers,” he says. “This means much of our business is generated from repeat orders and customers know the quality to expect, that the delivery will be on time and the price competitive. We like to work the same way with our suppliers and will only change if we are let down or, for some reason, something is not available and we are forced to look elsewhere.”

The original BNJ-42SY was added to the plant list to enable Rodford to meet a growing order book of challenging, complex and demanding aerospace parts. As Mr Dallyn explains, his company had been progressively building a production strategy of combining as many operations as possible on existing components into a single machine setting. “We have applied these methods to 4- and 5-axis vertical machining centres and five multi-axis lathes,” he explains. “However, when it comes to making significant savings the methods being used have really reached a plateau.”

Not so the installation of the BNJ-42SY which he maintains proved to be a complete step change to the business. “It totally altered our way of thinking, seriously upgraded our machining capability and dramatically reduced our leadtimes on the 42 different parts we have produced from up to 42mm bar,” he says.

Expansion decisions

Through the back end of 2009 and into 2010 Rodford Engineering was again facing a growing order book and Mr Dallyn knew he had to maintain competitiveness, absorb cost down regimes and preserve the level of service to customers. He knew he needed to expand his machining capacity but wanted to be able to achieve the same advantages by applying the proven Miyano technology to larger parts from bar and to machine billets of material up to 125mm diameter.

He affirms: “Talking to Miyano Machinery UK, we agreed the BNE-51SY5 would fit the bill and indeed, the moment it was installed and set on existing work, it had an immediate effect. Within just a month we were combining two and three previous operations into one cycle and immediately cut both our machining and leadtimes.”

“It's the overlapping capability of machining cycles at both spindles that is saving us 30 to 50% on floor to floor times and with combined operations we immediately cut at least two weeks from our lead times,” adds Mr Dallyn's son Neil who is works manager and largely responsible for production.”

While the Dallyns have created a close working relationship over the years with customers, they attribute their success to being focused on the type of work they undertake and the development of operator skill levels. “This also applies to the equipment we buy – over £300,000 was spent in 2009 – and each machine has to be very capable as we look very carefully at maintaining high spindle utilisation.”

Rod Dallyn maintains: “We try to buy forward on specification so we know we can meet future requirements and as almost 90% of our work is from repeat orders, this is a big help when choosing capacity and options, and in the end feeds back to the customer.”

Totally driven

Like the BNJ, the new BNE-51SY5 features the same configuration of spindles and turrets but each of the 12 positions are now driven as against six before. It also has the advantage of a Y-axis cross feed. However, for Rodford's setters the ability to hold billets of material in the six inch chuck as well as accommodating bar up to 51mm diameter made it ideal for producing larger components in one cycle that previously required turning and milling as separate operations.

Mr Dallyn is already appreciating the additional power of 15kW at the spindle and the added flexibility of the driven tooling at each turret position. Some components produced require up to 16 tools and with ±40mm of Y-axis cross feed travel to the top turret that services the main spindle, this feature has significantly improved the flexibility giving more options to the tool layout.
As part of the new machine specification, Rodford also ordered an angled driven tool head for use in conjunction with the Y-axis which is able to accommodate the drilling of angle holes that would normally have to be produced as an additional operation on a drill spindle.

Component quantities vary from a few orders for spares to batch sizes of 500 with cycle times tending to be between three and six minutes. The company runs a long day shift between 6am and 10pm then, providing the right component is ready to run, will often be left in unmanned production mode through the night.

As Mr Dallyn divulges, the Miyano is excellent to produce simple parts as well as the more complex. “We can program a simple part with a deburring sequence as part of the cycle, run overnight and the whole batch is ready for despatch in the morning. Billet work however is machined with an operator to load and unload but the job comes off the machine complete so we are still cost-effective in our methods.”

By example

A case in point is a jet adaptor component produced on the BNJ from 1.5 inch aluminium bar that involves turning, drilling, grooving, screw cutting, boring and the production of a seal groove, a slot and a scallop milled in the end. Two cross holes are also drilled into the bore before it is parted off and automatically transferred to the second spindle. The component is then faced, a 25mm A/F hexagon milled, and two 2mm diameter holes produced off centre, prior to the main bore being finished to size.

This part is now produced on the new machine which can also incorporate two 1.6mm diameter angle holes through the milled hexagon by combining Y-, X- and C-axes. The inclusion of these holes avoids a previous need to separately produce the holes on a drill spindle.

Another fuel system body produced from an aluminium billet is initially milled to produce four 60mm square flats. It is then drilled, bored and counterbored, an M56 thread is screw cut and four holes drilled and countersunk in each corner.

Transferred to the second spindle the part is faced, grooved, eight holes of 10mm diameter are drilled on a 30mm PCD then chamfered and four further holes drilled and tapped. Again, the angle head is used to produce four holes of 1mm diameter on each flat to provide a wire locking facility.

Previously this part was produced in four separate operations involving turning followed by milling, drilling/tapping and drilling of the wire holes. “This part is easily produced on the BNE-51SY5 in a single cycle so we are saving lots of manual intervention and work held between machines – and as we are producing the part in a single operation, we are more confident of the precise geometric positioning of features that are required,” Mr Dallyn concludes.

Miyano
www.miyano.co.uk

Rodford Engineering
www.rodfordengineering.co.uk

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