At Astley Diamond Tools swarf problems totally controlled the business of machining silver steel blanks to which the firm then electro-plates diamond finishes for sale direct to customers around the world.
Astley Diamond Tools is a small two people business based in Witton, Birmingham that took the plunge and made a significant investment in the latest Low Frequency Vibration (LFV) turn-mill technology on a Cincom L20-VIII LFV from Citizen Machinery UK. Within just three months of installation, proprietor Ben Astley has been able to transform the firm’s blank turning operations for its diamond tool production while opening a new operational door by using his very competitive sliding head machining platform to provide a sub-contract small part turn-milling service.
Said Mr Astley: “A recent batch of 500 rotary diamond burrs that are used to fettle cast iron by a regular Polish customer. This normally meant I had to almost stand by my previous aging Citizen sliding head machine and stop it every five or so parts to clear the tangled bird’s nest of swarf. It would take at least 70 hours to produce the batch and now with LFV I can complete the same order well inside 16 hours.”
He followed on: “As swarf is chipped so finely, the only attention required now is to change over the short bar feed and remove completed parts from the outfeed conveyor. Even size and surface finish is totally consistent which gives total confidence.” He then describes a sub-contract order just completed for hundreds of small collets out of EN24T. “I turn the outer form and drill through and the customer now collects them for slitting and finish grinding,” he said.
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 the routine action of the cutting tool through the servo axes of the drive system in the direction of feed. This happens 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 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.
Ben’s Astley Diamond Tools produces electro-plated tools in natural diamond, cubic boron nitride (CBN) and synthetic diamond between 3 mm and 20 mmm diameter plus made-to-order internal grinding wheels between 3 mm and 20 mm diameter, routers for opening out gaskets and existing holes, diamond needle files plus electro-plated grinding wheels.
On making the purchase decision he said; “What really impressed me was Citizen’s understanding of my needs as a really small turning operation and my concerns over the outlay and returns. They spent time with me and put together a finance package specifically to suit my needs which clinched the deal. Having the precision of LFV chip control meant I could reduce some of the outlay. For instance, we do not generate smoke in the cycles so we saved on the smoke hood, and did not need high pressure coolant.”
He is still discovering advantages to the business such as the capability to turn in one cycle direct-to-depth. He said: “We use a lot of 20 mm material and can run LFV with 6 mm depth-of-cut using standard carbide tooling without a murmur from the machine.”
He opted for Citizen’s Alkart CNC Wizard programming aid which he maintains is absolutely tailor-made for his needs especially as sometimes he has to support orders for just five tools. This he said: “Means set, run machine, then reset.” Most changeovers take 20 to 30 minutes and his time cycles now vary between 20 secs for a dowel type component to 65 secs for a more complex blank.