Cutting metal round the clock

11 Sep 2019

Engineering capacity news posted by Andy Sandford

Stoneswood Precision Components has automated its Hermle 5-axis machining centre with a multi-pallet storage and retrieval system to allow unattended subcontract production overnight and at weekends.

The C 400 5-axis vertical machining centre (VMC), supplied by sole agent Kingsbury, has now been operating around the clock at the Duckinfield company, a member of the Hyde Group.

Stoneswood Precision's managing director Charles Day said: "We looked at four options before deciding to buy the Hermle cell. Its major differentiator is the ability to stop automatic production quickly and use the machine in manual mode to manufacture a one-off part. The other solutions we looked at could not achieve that easily.

"The flexibility it provides is already proving useful, as it is allowing us to machine fixtures during the day and simultaneously set up the HS Flex for lights-out running overnight. The cell's connectivity also fits well within the Industry 4.0 environment that we are creating in our factory."

Stoneswood Precision's current facility was set up in 2004 to produce 450 different aluminium and titanium parts for a military aircraft, involving machining of mainly wing details. Already a user of several multi-pallet production systems based on horizontal machining centres (HMCs), the subcontractor needed an additional system to fulfil a different contract for the manufacture of aluminium control boxes.

Mr Day continued, "Apart from the control box work dictating the use of a 5-axis VMC, there are parts of other aerospace contracts that lend themselves to a vertical-spindle production platform and many new enquiries we receive also require such capacity.”

The specification of the Hermle cell includes an 18,000 rpm / 20 kW spindle, extended tool capacity from the standard 38 pockets by the addition of an 88-position magazine for HSK-A63 tools with breakage monitoring and measuring included, a Heidenhain TNC 640 control, 850 x 700 x 500 mm working area, +91 / -139 degrees trunnion swivel, 500 x 400 mm pallet size and capacity for 12 of them on two levels in the HS Flex store, which is served by a three-axis pallet handling unit with rotary, lift and linear motions.

Currently, the Hermle C 400 HS Flex is devoted to the control box contract, which entails supplying 300 assembled housings annually. All components are machined either individually on a pallet or four at a time on a tombstone, depending on size, from solid aluminium billet in two operations involving milling, drilling and thread milling cycles lasting up to two hours per side. True position of the holes is now well within tolerance.