Chip breaking while turning/boring

[Brian Pallas]

Hello,

 

Where I work we do a lot of 6061 aluminum barstock.  I started working there two months ago, so am still getting the feel for what problems are holding up production, where improvements need to be made.  One thing I have been seeing frequently is while turning the 6061 getting birdsnest around tools, that either stop the automatic machines (barfed, dual spindle lathes) from running unattended after hours, or on the 2 axis lathes having birdsnest cause accuracy/finish problems that make it so that a cycle can't be completed without operator intervention.

 

One thing the setup guys will do at the machine is add a "chip break" into the turning or boring.  AKA turn .100" to .200", then back off .015, turn some more...etc.  I was asking my boss if I should be writing the programs to do that out of the box and he said don't worry about it because it isn't always needed and the guys will take care of it if it is needed.

 

But it did get me thinking- Is there a way to accomplish something like this, without manually creating the toolpaths, in MasterCam?   

 

I have done things like this frequently for boring, where I break the geometry every so often, and then do a toolpath for each segment to rough.

 

Or any other suggestions on how to get the chips to break?  The boss said he has spent a bunch of time in the past with different insert shapes/chipbreakers/feeds/doc etc and some stuff just doesn't want to break.  One thing I was thinking about on the live tool lathes is drilling some holes in the face, so that there is always an interrupted cut while turning. Anybody doing anything like that with success to break chips?

 

I appreciate any input anybody has on chipbreaking.

 

Thanks,

Brian

 

 

[Guest]

Faster feed or slower RPM or a combination thereof

[Hertz]

^^^What he said. Push the feed hard. Test different DOC's as well. 

[Guest MTB Technical Services]

All of the above but also get the correct insert.

if you're getting a rat's nest in 6061 then you don't have the right insert for chipbreaking.

[Sticky]

It would be helpful if you told us which inserts you have used, along with doc and feed rate.

 

If you are turning Chinese aluminum it's just plain hard to break.

 

Different inserts are designed to break chips at different doc's. Get some aluminum specific inserts and start with the maximum feed/rev on the box, and about middle of the range on doc, and play with your sfm to get your desired mrr or tool life. You might have to try a few to get it preferred results. We just trialed 17 different cnmg inserts for roughing 304 last month, there wasn't a clear winner, it can be tiring.

 

Also we use Sandviks "high precision coolant" stick holders, add some high pressure coolant to these and they make a pretty big difference in chip breaking ability.

[Mike@Lustre]

^{I turn a fair amount of 6061-t6 , it is only a 1" dia item but I was dealing with bird nesting around the tooling and such . one of the fixes I did from the obvious increase the feed rate and adjust the rpm was to use high speed peck drilling . I also played with the coolant nozzles on the tool blocks as well .  we run 99% of our parts on the "B" spindle so on certain items I kept the thru coolant on the "B" on till the turret has returned to it's g28/g30 position , I also kept the coolant on the turret till it reaches it's g28/g30 position . These changes have allowed us to run around the clock with little to no bird nesting around the spindles or the tooling blocks in the turret .}

 

^{We also run Aluminum grade inserts on all the tooling , this has helped stop build-up on the tool edge and also helped break the chips up , ISCAR  from my experience makes some really good grades  that work very well with Aluminum and the likes .}

[Mr. Wizzard]

I've had pretty good luck with Horizon inserts when i had issues breaking a chip in aluminum. Don't be scared, though, you have to push them! The right coolant helps so it doesn't stick to the insert also.

Also, depending on the machine/control, some canned cycles (G74 i think) can peck turn, but only straight geo, no arcs/curves.

[Mike@Lustre]

It would be helpful if you told us which inserts you have used, along with doc and feed rate.

 

If you are turning Chinese aluminum it's just plain hard to break.

 

Different inserts are designed to break chips at different doc's. Get some aluminum specific inserts and start with the maximum feed/rev on the box, and about middle of the range on doc, and play with your sfm to get your desired mrr or tool life. You might have to try a few to get it preferred results. We just trialed 17 different cnmg inserts for roughing 304 last month, there wasn't a clear winner, it can be tiring.

 

Also we use Sandviks "high precision coolant" stick holders, add some high pressure coolant to these and they make a pretty big difference in chip breaking ability.

 

 

try the ISCAR CNMG 432 M3M IC6025 and for lighter cuts the F3M version in the IC6025 , we turn 304 daily and get really good tool life .