Parting off alluminium

This topic has 30 replies, 16 voices, and was last updated 7 January 2017 at 17:38 by petro1head.

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6 January 2017 at 16:40 #276127
petro1head
Participant
@petro1head
Getting frustrated when parting off aluminium.

I use a Glanze parting off tool with carbide tip, however the problem I have is half way through the alloy welds itself to the tip and if I am not quick enough the lathe jams and buggers the tip and the holder

Any suggestion as to how to avoid this?
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6 January 2017 at 16:40 #8483
petro1head
Participant
@petro1head
6 January 2017 at 16:45 #276128
Ex contributor
Participant
@mgnbuk
WD40 or similar liberally applied.

Nigel B
6 January 2017 at 16:49 #276130
JasonB
Moderator
@jasonb
Paraffin works for me
6 January 2017 at 16:50 #276131
Howi
Participant
@howi
Some aluminium can be stickier than other grades, as Nigel B suggests, WD40 or parafin, you can also tell things not happy by watching the award and listening, back the tool out, clear the tip and get back in.
6 January 2017 at 16:52 #276132
Howi
Participant
@howi
Some aluminium can be stickier than other grades, as Nigel B suggests, WD40 or parafin, you can also tell things not happy by watching the swarf and listening, back the tool out, clear the tip and get back in.

Edited By Howi on 06/01/2017 16:52:54
6 January 2017 at 16:59 #276134
Chris Evans 6
Participant
@chrisevans6
Plus one for plenty of lube. I use paraffin of neat soluble oil.
6 January 2017 at 16:59 #276135
Anonymous
For parting off aluminium alloy with insert tooling I always use flood coolant (soluble oil) and a decent feedrate, at least 6 thou/rev. The topslide and saddle are locked.

I don't have a Glanze parting holder, but the Glanze boring bars I use are fine, once the supplied inserts were binned and replaced by a decent industrial brand.

Andrew
6 January 2017 at 17:00 #276137
Ajohnw
Participant
@ajohnw51620
Let the material and tip cool now and again which can also be done via a slower feed and speed variations.

Micropolished inserts are almost bound to help too.

John

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6 January 2017 at 17:03 #276139
petro1head
Participant
@petro1head
Ok, so some coolant will help.

Andrew, you mention using better inserts, which ones

John, Micropolished inserts???
6 January 2017 at 17:23 #276142
Allan B
Participant
@allanb
as others have said ally can be sticky, and also has a low melting point, and even though you shouldn't get to the point of melting, you can get it to a point where it more of a soft solid, so I use a good flow of coolant, and light pressure backing out to clear the swarf regulally
6 January 2017 at 17:31 #276145
Ajohnw
Participant
@ajohnw51620
Posted by petro1head on 06/01/2017 17:03:50:

John, Micropolished inserts???

Aluminium is very abrasive stuff so they produce various micropolished tips – the coating can't get rubbed of those. The coated tips start to deteriorate before the coating is completely worn off as well.

Ordinary turning tips are available micropolished. So far I haven't found any for parting off. Somebody some where may have them though. My usual source ( ATP ) has turning tips like this but none for parting off. Just general or stainless.

John

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6 January 2017 at 18:29 #276155
Muzzer
Participant
@muzzer
Korloy actually sell an uncoated parting insert in grade H01. This is sold as being suitable for aluminium and other nonferrous metals. I have some that I bought from Cutwel but tantalisingly I haven't been able to test them here in my armchair workshop. AFAIK, these are the GTN-style inserts that are compatible with many other holders.

These are the uncoated (for loominum) and yellow coated (for steel) inserts, side by side. Note that the uncoated inserts are not polished…..

Murray
6 January 2017 at 18:38 #276160
Carl Wilson 4
Participant
@carlwilson4
Plus one for shed loads of lube.
6 January 2017 at 18:44 #276163
JasonB
Moderator
@jasonb
If you use the MGEH type grooving and parting holders then APT do an insert for Ali that fits them. I have taken to using this holder more than the GTN holder (Glanze etc) for parting since one arrived from ARC Euro.

Edited By JasonB on 06/01/2017 19:53:01
6 January 2017 at 18:59 #276167
petro1head
Participant
@petro1head
Posted by JasonB on 06/01/2017 18:44:44:

If you use the MGEH type grooving and parting holders then APT do a polished insert for Ali that fits them. I have taken to using this holder more than the GTN holder (Glanze etc) for parting since one arrived from ARC Euro.

I was just looking a the Chronos site and Glanze also do something similar. Is this system better than the blade type?
6 January 2017 at 19:15 #276172
JasonB
Moderator
@jasonb
They seem more rigid when you start using them sideways for profiling or widening a groove but generally won't go as deep as the blade type and that depth is dependant on shank size so you are limited on max dia you can part off.
6 January 2017 at 19:18 #276173
Anonymous
Posted by petro1head on 06/01/2017 17:03:50:

Andrew, you mention using better inserts, which ones

I've used assorted brands over the years but I've settled on Korloy inserts from Cutwel. I use CCMT inserts for everything except aluminium, where I use CCGT polished inserts.

For parting I use an Interstate blade system and whatever insert came with it. I use the same insert for all materials, including aluminium. Flood coolant is used for all materials except those which are short chipping, ie, brass and cast iron. The single most important factor is feedrate. Below 4 thou/rev the insert chatters. At higher feedrates 6-8 thou/rev the chips curl properly, are folded inwards and break into relatively short chips. The system seems to work fine on deep grooving too:

Andrew
6 January 2017 at 19:19 #276174
Ajohnw
Participant
@ajohnw51620
Posted by JasonB on 06/01/2017 18:44:44:

If you use the MGEH type grooving and parting holders then APT do a polished insert for Ali that fits them. I have taken to using this holder more than the GTN holder (Glanze etc) for parting since one arrived from ARC Euro.

Do these fit any of the 25mm / 1" deep holders that are available Jason?

I can only see one polished insert on there for grooving / profiling – 6mm wide. The others are just uncoated

John

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6 January 2017 at 19:52 #276184
JasonB
Moderator
@jasonb
No

Yes think you are right they are uncoated but geometry for ali
6 January 2017 at 20:09 #276190
John Haine
Participant
@johnhaine32865
May work better if you also increase the speed.
6 January 2017 at 21:21 #276211
Neil Wyatt
Moderator
@neilwyatt
+1 for faster, with a big lump of ally you ideally want to speed up as you go in AND increase the feedrate to match.
6 January 2017 at 23:21 #276243
Ajohnw
Participant
@ajohnw51620
Posted by Neil Wyatt on 06/01/2017 21:21:33:

+1 for faster, with a big lump of ally you ideally want to speed up as you go in AND increase the feedrate to match.

A sure fired way to get more friction = more heat = melts the al and it sticks. That's the problem.

Also not keeping and even feed, more or less stopping which causes the tool to rub. So just like more speed = more heat.

John

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Edited By Ajohnw on 06/01/2017 23:35:36
6 January 2017 at 23:42 #276250
vintagengineer
Participant
@vintagengineer
Since I was given a demonstration of Iscar insert parting tools when they first came out, I use them in rear toolpost upside down and engage the crossfeed at a reason speed with plenty of suds. This clears the swarf which cause the heat build up and the sticking.
6 January 2017 at 23:50 #276252
Ajohnw
Participant
@ajohnw51620
Posted by vintagengineer on 06/01/2017 23:42:32:

Since I was given a demonstration of Iscar insert parting tools when they first came out, I use them in rear toolpost upside down and engage the crossfeed at a reason speed with plenty of suds. This clears the swarf which cause the heat build up and the sticking.

The suds don't cool it all then. I thought that was why suds was regarded as a coolant.

John

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