Swarf build-up

[gerry maddenParticipant @gerrymadden53711]

I enjoy boring, generally, but today was doing this to a workpiece approx. 50mm deep. I had to enlarge the hole in it from a drilled 16mm, out to 45mm. I use a 12mm bar fitted with the 6mm CCMT tips and the material was 6028 aluminium.

The cut always starts beautifully, but by the time I’m halfway in, the swarf gets wrapped around the bar and you have to repeatedly extract the tool, clean it and re-enter. The problem is that progress is just SO slow and with a lot of material to remove, the job can get very tedious.

I have tried boring in a series of wide diameter steps on the entry side, to help the swarf make an easier escape but that’s of limited help. I have also tried angling the bar when the hole gets to a diameter that allows me to do this. But again, this is only partially successful.

High speeds and low speeds change the texture of the swarf, but don’t stop the wrapping-around-the-bar tendency. I was hoping that the highest speed of 2600RPM might produce chips instead of wire, but it doesn’t.

One real frustration is that even when making a final very light finishing pass, I don’t seem to be able to do this in one go to avoid getting a ‘stop line’. If I try to, by pushing on ignoring the squeals and vibration, the finish is damaged by the swarf instead.

Anyone have any thoughts ideas or suggestions as to how to minimise this swarf buildup issue?

Gerry

 

 

[Ian PParticipant @ianp]

My suggestion would be to use a say 12mm diameter endmill (a long series might be best) to rough out the bulk of material and use your boring bar for the final finishing. Clamp endmill just like the boring bar, rotate/adjust endmill to get the best ‘tip’ position.

Ian P

[FulmenParticipant @fulmen]

Coolant?

[David SeniorParticipant @davidsenior29320]

Try a more aggressive feed to see whether you can get it to chip.

If you are feeding by hand then feed in short bursts. At least the swarf is shorter, and the interrupted cut won’t matter until you need to do the finishing cuts.

6026 can be better at chipping. You say you are using 6028 which I am not familiar with. I know 6082 is bad for this.

It is a recognised problem in industry, especially where machines are running unmanned. The swarf build-up can mean that running overnight is a problem.

Dave

[Mark RandParticipant @markrand96270]

High speeds and low feeds mean the swarf is thin and flexible. it’ll be stringy because it’s to flexible to snap and the insert’s chip breaker groove isn’t fully engaged.

Lower speeds (if absolutely needed by available hp and/or reaction time) and (much) heavier feed rate and depth of feed will allow the insert to break the swarf into chips.

Yes. It is quite scary! but once you get an insert into making chips instead of strings in aluminium you’ll be amazed.

[Author]

Posts