The new Sigma 8 turning centre from Tornos since acquired by Dalau is the first to be installed in the UK and is capable of machining extremely small parts to very tight tolerances. This tight tolerance capability has been perfected by Tornos over decades of manufacture for the watchmaking and medical industries.
Dalau typically produces components for the electronics, telecommunications, aerospace and medical industries, making over 100 million PTFE and plastic components a year. All turning centres reviewed were incapable of meeting such demands; however the Sigma 8 with its ability to machine to a 1 micron tolerance has little difficulty meeting the needs of Dalau.
Naturally to meet such tolerances the machine shop at Dalau is a temperature-controlled environment, as PTFE components are subject to expansion at elevated temperatures making it difficult to hold tolerances in the realm of +_0.015mm. “Many subcontract machinists will not touch PTFE, but with the help of the Tornos machines we have gained the experience to make us a leader in our field. The reliability of the Tornos machines is first class, which is exactly what we require for rapid throughput parts,” says Philip Alston, production and QA manager for Dalau.
Commenting upon the ability of the Sigma 8 to meet the tight tolerances, Mr Alston continues: “The tooling on the Sigma 8 is positioned very closely to the workpiece and it results in the tools travelling a shorter distance to the part. This reduced tool travel increases rigidity and most importantly takes away any potential deviation in cutting tool accuracy.’
The close positioning of the cutting tools and drills not only improves accuracy and rigidity but also enhances surface finish and tool life.
“As a general rule of thumb, straightforward single operation components are loaded to the cam-driven autos, while anything more complex, perhaps involving PCD drilling, milling or second operations of any kind, will be put on the Deco CNCs to come off complete. However, the latest order is taking precision to a new level and this called for new technology,” explains Mr Alston.
Quality is a key issue at Dalau and the company has developed its own SPC system as part of its TQM system that is linked to the CNC control of the Tornos machines. The innovative system allows operators at the ISO 9001:2000 and AS9100 accredited company to monitor every dimension and characteristic on every drawing in real time.
Maximum Ø Capacity
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up to 0.3 inch (8mm) / up to 0.4 inch (10mm)
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Part Length
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0.8 inch (20mm)
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Simultaneous Axes Control
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5 or 7
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Tool Positions
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8 (4 front, 4 back)
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Axis Z1 Sliding Headstock (+C1 optional)
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100-15,000rpm
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Axis X1/Y1 & X2/Y2 Guide Bush
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100-15,000rpm 12 x 12mm tool shank flexible combination of fixed or live tooling
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Axis X4/Y4/Z4 (+C4 optional) Counter Spindle & Back Operation
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100-15000rpm 4 end working tools 2 OD turning tools
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Axis_EndUnit
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NA
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Indexing
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0.001°
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Control
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Fanuc 32i
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Programming
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ISO
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Simultaneous axes
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yes, all axes up to 2 tools in the cut
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