Glenn Poleykett began his career in 2006 at his uncle’s firm, making components for darts on Cincom sliding-head and Miyano fixed-head centres from Citizen Machinery UK. He quickly realised that sliding-head lathes with driven tooling were capable of producing virtually any part 32mm diameter or smaller.
When Glenn started Stellar Precision Components 12 years later in Bishops Stortford, he remembered that lesson. He purchased two Cincoms, an L32-VIIILFV and an A20-VII. They have since been joined by an L20-VIIILFV.
Mr Poleykett said: “I worked at several subcontractors on various sliders, but I always regarded Citizen as the best. My opinion was reinforced when they introduced the LFV (low-frequency vibration) operating system software. It is programmable via G-codes to start and stop during any program, breaking what would normally be stringy swarf into smaller chips that cannot wrap around the tool or component.”
He witnessed LFV in action at Citizen’s technical centre in Bushey before he bought the first two lathes and described it as ‘incredible’. When machining short-chipping metals such as mild steel, 303 stainless and brass, it is not needed and the extremely short periods of air cutting slightly lengthen cutting cycles.
However, when turning and drilling 304 or 316 stainless, aluminium, copper and plastics, he always turns on LFV. It greatly improves production output by not having to stop the lathe to clear the swarf and it allows the machine to run unattended. LFV oscillation of the tool by tens of microns not only breaks the swarf but also allows coolant to penetrate the cut more efficiently, reducing heat and prolonging tool life. Depth of cut may be increased substantially, even when processing tough materials.
Swapping between the two modes of LFV is simple according to Mr Poleykett. If a more vigorous chip-breaking action is required, for example when cutting plastics, and the other mode has been inserted in a program by Citizen’s Alkart CNC Wizard off-line part programming software, manual insertion of a single line of code at the start and finish is all that is necessary.
The most recent L20-VIIILFV delivered has the chip-breaking functionality on both the main and sub-spindle, whereas on earlier models it is applied to the main spindle only. The latest machine at Stellar was purchased for ventilator parts for the NHS. Funding through Citizen UK Finance and a six-month payment holiday smoothed the acquisition process at a difficult time.
Much of the throughput is destined for the aerospace, medical, electrical connector and pneumatics industries and batch size ranges from 10 to 40,000 pieces at the site that operates 24/7. Many of the components produced are of very high accuracy with a tolerance of ± 0.1mm down to ±5 microns.
Components up to the maximum bar size can be produced on both L-series lathes either when the guide bush is in place or guide bush-less mode, the latter being a standard feature of the machines. The L32 was installed with an optional extension kit that allows bar up to 38mm diameter to be accommodated, higher than the lathe’s nominal capacity of 32mm. This additional capability is regularly used and has allowed new business to be won.
