Didn't know my parting tool could do this...

dksoba · Jul 9, 2014

I roughed most of the outside with a CCGT insert, and roughed the undercut/finished with my 2.2mm parting tool (Korloy, Sawman, from Exkenna). Turns out if you go slow enough, you can actually do turning with this thing (other than the occasional back chamfer). Of course the finish isn't as nice as if I had used another tool, but it is acceptable until I get something better. The finish was certainly way better than I expected.

I basically held this part from the inside and machined the outside (the part was mounted such that the taper diameter decreases as Z increases). I thought about using a left hand 35 degree holder, which could work, but I would need a really tall set of softjaws to have enough clearance. So I decided to buy an Iscar Cut-Grip holder (ISCAR Cutting Tools - Metal Working Tools - GHDR/L (short pocket) : 2800146 - GHDR 16-3) and related inserts. I need this holder for another set of parts I'm working on as well. Hopefully this is the right tool for the part pictured below.

Cheers,
Matt

mecheng10 · Jul 9, 2014

I also use a parting insert to take some light turning cuts in tough to reach areas - mainly because I only have a 8 tool turret and I always have the cutoff tool loaded so it saves a position for another tool I need.

jkruger · Jul 9, 2014

It's actually pretty common to to get decent finishes and good tolerances with a parting tool. Pay attention to the parts, you can scrap a lot of parts fast when you are not watching.

dksoba · Jul 9, 2014

jkruger said:
It's actually pretty common to to get decent finishes and good tolerances with a parting tool. Pay attention to the parts, you can scrap a lot of parts fast when you are not watching.

Because the insert falls out?

Matt

SeymourDumore · Jul 10, 2014

dksoba said:
Because the insert falls out?

Matt

Matt

Not as much as because the inserts fall out, rather that the inserts are not positively held and located.

For what you're doing there, a GTN might be sufficient ... 'till the pocket wears out.
It is held in ( and located in X/Z ) by the grace of god and the guys who molded the insert as well as the guys who machined the blade.
You've gotten away with it, good for you.

Try the same in something a little tougher and you'll be looking at a new blade, insert and new idea ..

For the next time, I'd suggest a DGN insert in a DGTR holder from Iscar.

Your Z is still iffy to some degree ( upper and lower groove ), but the X is likely consistent w/in a thou or so, but more importantly the insert is positively
clamped with a screw and will not move.
Next step is to go to a full radius insert in the same DGTR holder, and after the first part you will hold +/-.0002 in not only a single profile, but full
spherical profile such as a ball.

JP Machining · Jul 10, 2014

I use a Seco MDT (Multi Directional Tool) for that type of stuff, works great and can get full radius inserts for profiling as well as double ended square groove/turn bits.

i_r_machinist · Jul 10, 2014

Call your local Iscar distributor and get a visit from a sales guy. They will work with you to find the best tool for the job, no matter what size operation you have.
have fun
i_r_machinist

dksoba · Jul 10, 2014

i_r_machinist said:
Call your local Iscar distributor and get a visit from a sales guy. They will work with you to find the best tool for the job, no matter what size operation you have.
have fun
i_r_machinist

Did this when I first bought my machine. Great advice. Also did the same with Sandvick. Even went to one of their seminars. At the end of the day I ended up with 90% of my tooling from Iscar, 10% from exkenna. Finding tooling on Iscars website is super easy, and ordering and getting quotes is also very fast and easy.

I don't want to mention names, but the vendor I use for iscar tooling was much more responsive than the one I use for Sandvick.

dksoba · Jul 10, 2014

SeymourDumore said:
Matt

Not as much as because the inserts fall out, rather that the inserts are not positively held and located.

For what you're doing there, a GTN might be sufficient ... 'till the pocket wears out.
It is held in ( and located in X/Z ) by the grace of god and the guys who molded the insert as well as the guys who machined the blade.
You've gotten away with it, good for you.

Try the same in something a little tougher and you'll be looking at a new blade, insert and new idea ..

For the next time, I'd suggest a DGN insert in a DGTR holder from Iscar.

Your Z is still iffy to some degree ( upper and lower groove ), but the X is likely consistent w/in a thou or so, but more importantly the insert is positively
clamped with a screw and will not move.
Next step is to go to a full radius insert in the same DGTR holder, and after the first part you will hold +/-.0002 in not only a single profile, but full
spherical profile such as a ball.

What's the difference between a DGN insert and a GIPA insert?

Matt

SeymourDumore · Jul 10, 2014

dksoba said:
What's the difference between a DGN insert and a GIPA insert?

Matt

That is one helluva good question Matt!

From what I can see, they just might fit ....
But then again, Iscar has more different varieties of grooving inserts and it's respective holders than all other manufacturers combined.

I bet the entrance fee to the pickle jar for each newcomer engineer in Israel is the design of a new and improved grooving tool and the accompanying silly name ...
I mean GIMY, GIPY, GIPA ....

adama · Jul 11, 2014

I would certainly look to changing that to one of the mechanically clamped parting insert styles, as others said, its iffy doing that with a GTN or similar friction fit insert long term, it will catch up with you.

sable · Jul 11, 2014

My biggest concern with turning with a parting tool is uneven wear of the tip ,eventually causing the blade to wander while actually parting off ,another reason to keep a close eye on it.

yardbird · Jul 11, 2014

Doug said:
Usually I use a grooving cycle to rough down then clean up passes with the insert.

Maybe a bit OT but curiosity has the best of me. Do you mean you use a groove canned cycle with corner rounding/chamfering at the top and bottom of the groove? Or a G75 just for material removal? If not G75 would you mind posting the code to get a look? What control? Fanuc?

I do a lot of small parts that I finish the left side of the part with a cutoff blade like the OP before I part it off. Yes it does wiggle around and walk to the side your not using but you can fool around with the program to rough then take light finish passes and it looks actually pretty good. As others have stated the tool holders with the clamp do a better job from keeping the insert from walking on you. This is what I use if I am doing more than just using the tool as a cutoff blade.

Its a Manchester cutoff blade .1875 wide tool. It will walk on you if your not careful. It is kinda old school but thats all I have access to on a regular basis. The part in the pictures the OP posted doesn't look too bad but inspection will be the deciding factor.

Brent

dksoba · Jul 11, 2014

yardbird said:
Maybe a bit OT but curiosity has the best of me. Do you mean you use a groove canned cycle with corner rounding/chamfering at the top and bottom of the groove? Or a G75 just for material removal? If not G75 would you mind posting the code to get a look? What control? Fanuc?

Curiosity always gets the best of me as well. Pays off though. Regarding your question, the code for my whole program is here:

% O0003 (Z Height @ stock height, 2.0) (Front of part @ Z1.8504 ) (T1, 2.2mm - Pastebin.com

Explanation of grooving/parting tool operations:

N1003 (GROOVE ROUGH 1) - Use G75 to rough cut some grooves for clearance for the next two roughing cycles.
N1004 (GROOVE ROUGH 2) - Use G72 to rough the left side of the groove.
N1005 (GROOVE ROUGH 3) - Use G72 to rough the right side of the groove.
N1006 (GROOVEFINISH1) - Finish pass on the left side of the groove.
N1007 (GROOVEFINISH2) - Finish pass on the right side of the groove.

Let me know if you have any questions or criticisms. Explaining myself is usually a productive thing, and getting constructive criticism is always a bonus. Destructive criticism sometimes makes me stronger in the end, sometimes not. Some people hinted that I'd kill myself if I got a CNC lathe before learning on a manual, that's made me extremely cautious. "G50 S500" has helped a lot.

Terrible Juan · Jul 11, 2014

GTN, GFN, DGN, etc, are not meant to do any side turning whatsoever. You can use it to do small chamfers and stuff like that, but it is definitely not the correct tool for doing side turning.

GRIP, GIP, GIF, GIP-E, GIF-E, GDMY, GIPA, GIDA, etc, are meant to do side turning.

It has less to do with how the insert mounts into the pocket as it does the "edge prep" and clearance on the side of it.

SeymourDumore · Jul 11, 2014

Terrible Juan said:
GRIP, GIP, GIF, GIP-E, GIF-E, GDMY, GIPA, GIDA, etc, are meant to do side turning.

See what I mean by silly naming of umpteenth varieties?

Future iterations of new inserts will be named as GIMP, GUMP, GRUMP, GRAB, GRUB and the likes....

yardbird · Jul 11, 2014

dksoba said:
Curiosity always gets the best of me as well. Pays off though. Regarding your question, the code for my whole program is here:

% O0003 (Z Height @ stock height, 2.0) (Front of part @ Z1.8504 ) (T1, 2.2mm - Pastebin.com

Explanation of grooving/parting tool operations:

N1003 (GROOVE ROUGH 1) - Use G75 to rough cut some grooves for clearance for the next two roughing cycles.
N1004 (GROOVE ROUGH 2) - Use G72 to rough the left side of the groove.
N1005 (GROOVE ROUGH 3) - Use G72 to rough the right side of the groove.
N1006 (GROOVEFINISH1) - Finish pass on the left side of the groove.
N1007 (GROOVEFINISH2) - Finish pass on the right side of the groove.

Let me know if you have any questions or criticisms. Explaining myself is usually a productive thing, and getting constructive criticism is always a bonus. Destructive criticism sometimes makes me stronger in the end, sometimes not. Some people hinted that I'd kill myself if I got a CNC lathe before learning on a manual, that's made me extremely cautious. "G50 S500" has helped a lot.

Thanks for your explanation. Were pretty much are on the same page for a “groove cycle” or lack of. This is what i came up with, its the same just different.

http://www.practicalmachinist.com/vb/cnc-machining/grooving-looking-better-way-283260/

I only finish with a cutoff tool if I have no other option. I have no criticisms but maybe a question (without seeing the print) gripping on the ID (if clearance permitted) couldn’t have used a used a left & right hand 55deg or 35deg diamond? less likey to walk on you. The part looks very nice the way you did it. Good job!

"G50 S500" has helped a lot." that's pretty funny.

Cheers Brent

dksoba · Jul 11, 2014

yardbird said:
I have no criticisms but maybe a question (without seeing the print) gripping on the ID (if clearance permitted) couldn’t have used a used a left & right hand 55deg or 35deg diamond? less likey to walk on you.

55 degree in a left hand, middle, and right hand holders just wouldn't work. Almost, but it wouldn't. 35 degree in a left hand holder would work, but I'd need a 3" high softjaw to cut enough chuck clearance behind the part to make it work. I think in the "production run", roughly 100 pieces per batch, 1000 pieces per year, I'll likely run the cut-grip iscar tool I ordered (see post #1).

Terrible Juan · Jul 11, 2014

seymourdumore said:
see what i mean by silly naming of umpteenth varieties?

future iterations of new inserts will be named as gimp, gump, grump, grab, grub and the likes....

There's also GDMF, GDMN, (goddamn?), GDMU (goddamn you?), GIA-K, GIM, GIMY (gimme?), GIPA, GITM (git 'em!), GIMM, TAG, HGN...

Didn't know my parting tool could do this...

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