Such has been the impact of installing a Citizen Cincom sliding head turn-mill centre with low frequency vibration (LFV) cutting technology that Roscomac immediately increased its installed base to three machines, a further L20-VIII LFV and a smaller capacity L12-VII LFV.
Said Cell Leader of the Worthing-based sub-contractor, Sean Keet: “We had been experiencing constant problems with swarf when machining certain difficult components made from high grade alloy and some stainless steels plus copper, plastics and even some difficult specification aluminiums. Despite constant monitoring, we often faced significant levels of scrap or re-working, in particular due to swarf marks.”
He now maintains that production of parts has been totally transformed following the initial installation of the Citizen Cincom L20-VIII LFV turn-mill centre in July. He said: “Such was the level of realisation that within weeks Managing Director Joe Martello insisted we bring forward 2018 investment plans and immediately ordered two further machines with LFV.”
What is LFV?
LFV is based on initiating selectable sequences programmed at the machine control through ‘G-codes’ to impart the size of chip to be produced. This introduces oscillation to action of the cutting tool through the servo axes of the drive system in the direction of feed. This occurs in phases of tens of microns which are precisely synchronised with the rotation of the machine spindle.
The resulting controlled ‘air-cutting’ breaks the swarf into a designated chip size which prevents ‘bird-nesting’ and can be applied to turning, drilling and even threading cycles. LFV can be switched in or out of the programmed cycle as required and helps reduce the on-set of built-up edge on the tool tip, extending its in-cut life. It also allows deeper depths-of-cut and enhances the achievement of improved surface quality through a wiping action of the tool.
Not the Same:
Mr Keet outlines from his investigations of the market that you cannot get the same results from utilising, for instance, a macro in the control. He said: “The machine has to be built to obtain the level of rigidity, control over vibration and create process stability which we are achieving across each component we have run through the machines.”
Roscomac’s adopted benefits due to LFV:
- Special lever production: Immediate savings made tool life from two changes a day and just 100 parts to a tool change every two days and 400 parts when machining 174PH stainless steel. Workpieces are 7 mm diameter by 44 mm long with milled flats, a slot across one end, a turned waist 2.8 mm diameter by 20 mm long and a drilled and tapped M3 hole in one end.
- Tolerances are typically 0.05, but 0.008 mm has to be maintained over a 4.10 mm length at one end of the component.
- Surface finishes held to Ra 1.6.
- Non-ground bar can now be used slashing projected material costs by £2,000 a year.
- The ability to run the Cincom LFV machines without its interchangeable guide bush feature relieves any need for frequent adjustments.
- Eliminated possible problems with swarf carried over into collets.
- Neat oil savings. Now being topped up once a month due to controlled chip size. Previously, due to stringy swarf carry-over, oil was topped up every two days
- Manning levels downsized from one operator per machine to one between three machines over three shifts, creating significant leap in productivity levels
- Stability of production is of benefit to quality systems and customers.
- Once the LFV machine installed, Roscomac so confident in the performance agreed to stock customer parts for immediate call-off and run a year’s supply in single batches without interruption.
- Another customer required 2,000 difficult parts a month now agreed single batch run stockholding 10,000 parts giving faster on-demand delivery.
- Currently, most cycle times are maintained the same as on the existing non-LFV Cincom machines and using same programs. Progressive methods investigations being made to improve cycle times and capitalise further on LFV.
- Aluminium is being machined at much faster rates with increased depths-of-cut. Plan to run one L20 LFV with guidebush and the other without for shorter parts to improve downtime eliminating guidebush resetting.
The future at Roscomac: Now with such a positive feedback and the resulting impact of LFV in the production processes of the Citizen Cincom machines, the engineering team has been charged to look back over enquiries. They are looking at work that was recorded as ‘declined to quote’ due to not being suitable, or may have caused problems in maintaining the normal level of service with customers.
Said Mr Keet: “Our production team are now insisting that further sliding head or fixed-head machine installations must involve LFV technology as it is such a game changer.”