A new sliding head turning centre gives PES Engineering the capability, productivity and flexibility it needs to serve its customers.
Owner Martin Lock believes that it is difficult to justify using a fixed-headstock CNC lathe on turned and milled components under 38mm diameter.
Underlining this, he recently invested in a Cincom L32-XLFV sliding hear machine supplied by Citizen Machinery UK.
He said, "We held off investing in this technology before, as up to about five years ago sliding-head lathes were not as flexible as their fixed-head counterparts in terms of their power or the number of tools in the working area. Consequently they could not produce such a wide variety of components, but that is no longer the case.
"Modern sliding-head lathes are able to produce anything a fixed-head equivalent can, and on average completes the same cycles in two-thirds of the time. It is down to the speed of movement of the gang tooling and the wealth of static and live cutters that can be deployed."
Materials machined include stainless steels, which account for half of throughput and plastics, which make up another 20%. Both tend to generate stringy swarf when machined on the subcontractor's fixed-head lathes. This can lead to reduced tool life and productivity.
The Cincom slider overcomes these swarf problems by using Citizen’s low frequency vibration (LFV) software that breaks the swarf into smaller chips.
Mr Lock continued, "LFV has removed much of the aggravation of turning stainless steels, which gives us a much easier life. We can machine efficiently everything from 304, which is billed as free-cutting but really is not, through to highly alloyed marine grades.
"We have LFV switched on permanently when machining plastics and it works perfectly, even on nylon. When processing stainless steel, for nine out of 10 components we produce it is engaged for typically half of the cycle and always for parting-off. "
At the end of last year, two 40 mm capacity fixed-head lathes producing 304 stainless steel medical parts broke down on the same afternoon, prompting Mr Lock to look for a replacement. As sliding-head technology had advanced sufficiently to consider it, he decided to go down this route.
He therefore ordered an L32-XLFV with a conversion kit that allows stock up to 38 mm in diameter to be fed from an Iemca three-metre bar magazine.
The speed of the machine means that many parts are coming off more than twice as quickly compared with the output from one of the ageing fixed-head lathes. In one extreme case when turning a plastic part unattended, 400-off were produced in two hours instead of over a full manned shift.
In the first three months of operation, the slider produced 20,000 parts of around three dozen varieties, all but one of which were in length less than 2.5 times the diameter. The majority were therefore not classical sliding-head work, so Mr Lock plans to take advantage of the ability on most Cincoms, including the L32, to remove the guide bush. The main advantages are the ability to use less expensive bar, as straightness and dimensional variation are not so much an issue, and a four-fold reduction in remnant length at the end of each bar, leading to significant material savings.
Established in 1967 by Mr Lock's father Clifford and a partner who subsequently left, PES Engineering derives its turnover from milling and turning in approximately equal measure. Industries served are mainly aerospace, automotive, medical, hydraulic, rail and electronic connectors, and customers are to be found throughout the UK as well as in the US and Germany.
A particular skill is in redesigning components to simplify their manufacture and reduce the cost of production. In one recent case, an injection moulded plastic component that was proving difficult for a US customer to assemble with other parts was re-engineered so that it could be turned from plastic bar at an acceptable price.