Can you fix a piece of steel just behind the cutting edge, to force the ribbon sharply upwards, so that it breaks? That might be a piece of steel taped to the toolpost, or it could be clamped in place along with the tool, by the screws that secure the tool in the tool post. Mind you; I use a polished carbide tip designed specifically for aluminium, and it is just as good at filling the place with long strips of swarf. That tip has a built-in chip breaker, but its tiny. I'm thinking of something much larger.

Marcus

You could try cutting back in sections then finish off the required profile in one go. For example cut just 1/2" (or other suitable small fraction of an inch) at a time up to 1.9" and down Ø1.6" to keep the swarf ribbons shorter then finally finish off the last 0.1", when the material removal rate will be lower due to the smaller diameter, in single passes.

Martin

I find that the carbide inserts for aluminium break up the swarf if you use them with decent feed rates. I normally run from 4 thou to 16 thou per rev depending upon the nose radius. The bigger the radius the higher the feedrate.

Andrew

Thermal effects considerably influence chip coiling and breaking. Obviously if the chip is to roll up the outside of the bend needs to be longer than the inside of the bend. The outside of the bend is the just cut surface and will be hot due to the energy imparted during cutting and will expand. So if it is sufficiently more hot than the inside the chip will naturally tend to curl up. Problem with aluminium is that it conducts heat so well that the chip cools to near enough even temperature before the chip can bend. Feeding harder, as Andrew suggests, puts more heat into the chip which increases the thermal gradient and helps it bend. Mist or air blast cooling on the outside of the work can help too. Flood cooling not so much as it cools the cut area and lubricates the top of the tool so making it easier for the chip to flow over the tool top and round the chip breaker. If the chip has to work harder to flow over the tool it stays hotter due to the extra energy needed. I imagine this sort of effect is why a straight chip will suddenly start to curl when a large built up edge forms on the tool. Cutting and chip flow being less efficient everything stays hotter. Under the right conditions built up edges can get pretty big. I've had them up over 1/8" thick during rough cutting. Finish is awesome but coming back for the next cut with the built up edge still on makes it ploughed field time.

When the chip cools the locked in thermal stresses weaken it so it snaps much easier too. The ductile nature of aluminium doesn't help here.

Chip breaking is pretty complicated as there are several effects involved and its a matter of finding a set-up and style of working that gives a reliable balance which works well over a decent range of situations for your machines, and materials. Good luck. The insert manufacturers have labs full of people working on this and they haven't come up with a simple one size fits all approach. Yet!

Clive

Unfortunately no tool ever made will chip break 6082 I work with it every day for 20 odd years. Other grades chip breakers may work.

That means rakes, type of tool in fact everything will come off continuous. Manually break it up by stopping feed rate momentarily as in interrupted cuts.

6082 is a bad one for stiction constantly clogging up tools with or without coolant. Put something behind in an attempt to break up the continuous chip will only deflect and or aid clogging. It has a spring like quality in T6 whereas others can be brittle or gummy, then of course theres the free machining gorgeous any tool works.

Heres an old action shot 14 years ago, 5 1/4" dia facing off 1/2" one pass 1000rpm on power cross feed, just keep an eye on whats happening and listen for tonal change. Will have to interrupt the cut to break the chip.

Current lathe has a lot bigger hold so don't need to stop so often and keep emptying.

Two hours in compressed, longest strand around 6ft mostly 2ft.

Wire cutters and pliers come in handy.

Can turn back wards towards tail stock pushing the built up or wrapped around chip off the round being turned, just need to move tool out the way to clear the debris.

Clive – you have reminded me of my last place of work. I used to machine rubber's, polyurethanes and pretty much every high-tech plastic there is. We used a vacuum system to suck the swarf into a hoover. When the machines indexed their turrets it dragged the swarf back out of the hoover and generally made a mess. The machine I worked on did up to 700mm and you can imagine the lengths of swarf, especially when your doing upwards of 10mm cuts, 0.3 feed. My machine had a swarf cutter, so pieces were atmost 6" long. It was two blades shaped like an X, so they self sharpened themselves, driven by a motor, worked quite well. I'm sure it could be done with aluminium.

Edited By Joe Page on 06/12/2015 21:20:10

The chipbreaker shape seems to be rather critical but there seem to be several out there claiming to work eg Becker:

Lach:

Edited By Muzzer on 07/12/2015 17:57:39