Loooong Swarf becomes a ratsnest -- how to avoid it?

[ttrikalin]

Your Graces,

Whenever I turn aluminium, I get long strings of swarf that becomes a real safety hazard as it spins and spins and spins... For example, see in the following short video time interval from 00:01:30 to 00:01:37... Although it has been sped up, you can still see that the swarf gets entangled in the chuck jaws and spins around like crazy... I have to stop the machine, take the swarf out using a set of pliers, and then on to the next pass...

[ame]http://www.youtube.com/watch?v=R57OGbXMAjA[/ame]

Apart from being a health hazard, it is not efficient... Stopping and starting all the time is annoying...

I understand that I have to grind a chipbreaker groove, but for the life of me, I do not know how to do this... Do people grind chipbreakers on the bench grinder (I have a 6" el cheapo one -- but with good new, trued wheels)... Or with a rotary tool?

I should take a closeup of the ground tool... tomorrow... Any pointers, or closeups of tools with chipbreakers, comments, or advice welcome...

take care,
tom in MA.

PS. The periodic squeal you here 00:00:30 onwards is the serpentine auto belt I have spliced... Thanks to the guys from Good News Garage (yes, Click and Clack's shop) for donating the belt to the cause...

 

[mhh]

Is it toolbit or brazed carbide?

 

[Tin Falcon]

when I think chip breaker I think of a small groove ground just behind the cutting edge of a tool. I would use my Dremel tool. No product placement that is just the rotary tool brand I have and use. I would use abrasive cutting disk for HSS and a diamond cutting wheel for carbide.
there are actually several ways of cutting and placing a chip breaker
found this on the NEMES web site.
http://www.neme-s.org/Shaper%20Books/Norton%20Tool%20Room%20Grinding/Norton%20Tool%20Room%20Grinding%20Chapter%205.pdf

army TC 9-524 mentions and shows grinding a chip breaker on a regular grinding wheel but in my opinion the Dremel would offer more control and better results.
The idea here is to bend the chip so it breaks.
Hope this helps
Tin

 

[Dave G]

Hi Tom, Tin 's chipbreaker is a good way to go. It also helps to increase the feed abit, makes the chip thicker so it will break easier. Also the cutter position relative to the workpiece has an effect, try repositioning the cutter so it will roll the chip away from the workpiece. We all deal with stringy swarf with aluminium, sometimes just fiddling with the tool alignment gets the desired effect. When I have alot of stock to remove I will use a carbide insert with a chipbreaker for roughing and then finish with HS. I was always taught that if you are getting stringy swarf you are not being aggressive enough. This has its limitations though, machine size, rigidity, small part, or finish cut. Taking light cuts will produce a stringy chip unless you can get the chip to roll into a curl with a chipbreaker. When I rough aluminum, it looks like it is raining chips in my shop because I keep the rpms up and I feed aggressively. If you ever have the opportunity to watch a CNC turning center turn aluminum you would be amazed at the speed at which the stock is removed. This is hard for us with small machines to duplicate but I only use a slow feed when finishing and yes I get a stringy chip when doing so. Dave

 

[Tin Falcon]

A lot of the commercial inserts have built in chip breakers. Even my tiny 1/4 indexable tool set from harbor freight has CB inserts.
Also if you have not read the Army TC 9-24 chapter 7 lathes it gives a pretty good picture of the basics.
http://www.metalwebnews.com/machine-tools/ch7.pdf
Tin

 

[steamer]

I've never had great luck with chip breakers , but I think it's me.

I'll make it a goal to be good at using them though!

Dave

PS....and who's Grace? ;D

 

[ttrikalin]

dave and Tin,
thank you very much for your input and the pointers.

mhh,
these are 1/4 HSS hand ground bits, not brazed carbide.

thanks once more,
tom in MA

 

[ttrikalin]

I've never had great luck with chip breakers , but I think it's me.
I'll make it a goal to be good at using them though!
Dave
PS....and who's Grace? ;D

but there is an explanation... I'm rereading John LeCarre's "the honourable schoolboy"... An Australian character opens his lines addressing people as such... your graces... oh:

The first part of LeCarre's trilogy on George Smiley's adventures, "Tinker, Tailor, Soldier, Spy", is coming to a theater near me this December... The expected phenomenal commercial success will make them film "the honourable schoolboy", and my favorite third part of the trilogy, "Smiley's People". :hDe:

I now feel for the teenage girls who are waiting for the next part of Twilight (the one with the vampires that sparkle... )

take care,

Tom in MA

 

[purpleknif]

There are carbide inserts designed for aluminum. They resist "build up" and have chip breakers specifically designed for aluminum. Took a while to convince my boss to get some but the difference is night and day.

 

[Swede]

Long dangerous ribbon chip is very common with aluminum. I think the answer is to be more aggressive. A thick chip cannot curl and remain intact as easily as a thin one. And honestly, I am not convinced a ground chipbreaker will work in all circumstances, but it'd help.

I like the advice given. Change SOMETHING - angle, feed, speed, to eliminate the ribbon.

Sometimes you get the many feet long "spring chip", and these aren't as bad. Sometimes under power feed, I'll guide that spring out and away, to the floor, and by the end of the cut, I'll have a 6 foot "slinky" that goes right into the trash! ;D

 

[maverick]

The aluminum alloy being machined makes a big difference on the chip. Screw machine bar ends of 2011 alloy make nice small curls.
This alloy is sometimes hard to find but I got lucky and was able to raid the scrap bin at an auction.

 

[lee9966]

I was told that pausing the cut every second or so breaks the string swarf coming off. Good for roughing, not for finish cuts.

Lee

 

[purpleknif]

Yes, indeed a "peck feed" on all but semi & finish cuts will solve a lot of problems.

 

[student_Machinist]

Just wait till this happens with stainless Shreds up your hands real nice ;D But yea "peck feed" works but ive also seen people make a hacksaw cut through the material that needs to be removed to break up the swarf

 

[shred]

If it makes sense I'll run the compound parallel to the lathe ways, so when you're power-feeding along and a nasty long chip starts to form, you can quickly back a half a turn off the compound and it'll interrupt the chip.