Pros and Cons of the ER collet system

[Mark CParticipant @markc]

Murray, my training does not extend to that level of analysis software – you would need to be a simulation engineer for that. I chose to ignore the friction for this as it was just to get an insight – i could add the friction contact in the system but there did not seem much point as I would need to know about surface finish, material properties lubrication etc. I did set the materials for a reasonable approximation to the real stuff but again, it is hard to know exactly what the real thing is made from and what HT was done.

Mark

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mark C on 19/09/2016 10:59:01:

i tried saving the report as a pdf but there does not seem to be any way to up-load it, sorry.

.

Mark,

Depending on the content and size of the report; I could convert it to jpeg quite easily.

eMail it to me & I will have a go.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

Here is Mark's FE Report, as a set of 14 images

**LINK**

http://www.model-engineer.co.uk/albums/member_album.asp?a=42201

MichaelG.

[Raymond AndersonParticipant @raymondanderson34407]

Thanks Michael G for putting up Mark's pdf. If I was almost "lost" at page 1 by the time I got to 14 I was completely lost !! This is the kind of tests that real engineers would understand and the type of tests that yield valuable data for those that understand them. Well done to Mark for taking the time and trouble to perform the FEA.

Mark, I notice the bulge in the collet, so that must be why there is only point contact [not even line contact ] and why the collet does not grip at all in the middle, only at the ends. and thus why the test bar was only showing contact at the ends. That may be why they are unsuited to High feed High performance milling. I have a stand alone FEA for Siemens Solidedge but I should NEVER have bought it because it is far too complex for me to understand, so in effect it was a shed load of dough [even with a good discount ] wasted . Ahh well we live and learn. and often at great expense. So Mark well done with the FEA. Thanks.

Neil That looks very much like a SAUTER VDI turret on the lathe is that the case?. Also what make is the lathe DMG Mori , Mazak, Doosan or some other. The ER 40 to ER 11 reducers are very neat , good thinking.

CHEERS.

[Michael GilliganParticipant @michaelgilligan61133]

Converting to jpg has inevitably reduced image quality, so; I have added a couple of details of the mesh.

.

MichaelG.

[Neil LickfoldParticipant @neillickfold44316]

The lathe is a 19 year old Nakamura lathe ,71mm spindle bore, with their LucBei software on a Fanuc control. I also have made ER16 to ER11 for my cnc router at home. I really like the ER system, especially the ease at making special sized collets. On the smaller ones, I ruf them out and drill/bore /ream the holes and for the final finishing, do that between centres on the hole that was created to finish the outer front 30deg and rear 8 deg tapers. I do this on the collet sizes smaller than 4mm. I always slit them last if they are collets.

Neil

Edited By Neil Lickfold on 19/09/2016 20:24:02

[John HinkleyParticipant @johnhinkley26699]

I don't pretend to understand a blind word of any of this, but is there something different with ER11 closing nuts compared with the larger sizes? The two pictures in Neil Lickfold's post seem to show the collet not seated properly in the nut. I have ER25 and ER32 collet systems for the lathe and mill and all my collets are flush with the nut front face when fitted.

John

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Mark C on 19/09/2016 10:33:07:

I will attach an image of the whole thing in a moment < etc >

.

Reference ^^^

It seems to have gone rather quiet

Has Mark frightened everyone off ?

or is this the calm before the storm ?

MichaelG.

 

Edited By Michael Gilligan on 21/09/2016 12:04:32

[Raymond AndersonParticipant @raymondanderson34407]

[Raymond AndersonParticipant @raymondanderson34407]

Above is the e-mail received earlier. I think it is the same chap who sent me the er details for a previous thread on the er's.

I have enjoyed the [sometimes heated ] confab on the subject. I and I think a few others have found it interesting.

and thanks to Mark for doing the FEA.

I will reiterate once more that as a toolholding system for our [hobbyist ] needs it can't be beat. I wouldn't say otherwise.

cheers

[Nick HulmeParticipant @nickhulme30114]

Proof of intent is not proof of function or fact, in Law or in Engineering, Engineers know this  

————————————————————————————————————————————————

Dear Sirs,

Can you confirm that the key features and many systems utilised in the Saturn 5 Rocket were initially and primarily designed for the Terrestrial delivery of weapons systems?

Thanks,

Nick

————————————————————————————————————————————————

Dear Sirs,

Can you confirm that your track based, steam powered mass transit system is designed for a maximum speed of 15mph because greater speeds will prove fatal to the human body? 

Thanks,

Nick

———————————————————————————————————————————————–

Most innovative systems have evolved from something designed for an alternate purpose or to operate under other parameters, to suggest that proof of design intention is proof of limits of functional capability is instead proof of massive misunderstanding and complete failure of engineering conceptualisation on the part of the author, 

– Nick

Edited By Nick Hulme on 22/09/2016 00:27:33

[Raymond AndersonParticipant @raymondanderson34407]

Point 1 I said they were designed for drilling and reaming , outcome correct.
Point 2 That they are weakest at heavy radial forces ie heavy milling
Outcome, correct.
Point 3 that there are better workholding systems ,Outcome correct.
You would have us believe that you know more about this than the originators. Ive got news for you
” big fail ”
Do like the attempted side step though. You executed that move like a ” natural “
Still haxent seen any of this extensive machinibg experience that you have ???

[david williams 14Participant @davidwilliams14]

recognise the limitations and work within them

[Michael Smith 15Participant @michaelsmith15]

A friend of mine has several 5 axis Huron machines making parts for the areospace industry to limits that most people could only dream about . They use ER collets for everthing and recon there is nothing to beat them . Good enough for , good enough for me

[Raymond AndersonParticipant @raymondanderson34407]

At the start of this thread a member simply stated that the er system was not designed for work holding only for toolholding, he was met with the reply "utter tosh" . I replied that he was correct. I also stated that they were originally designed for holding Drills / Reamers. again proved correct . I also stated that they were not the best toolholders, I never specified in which scenario that was in. I will concede that I should have specified in an industrial setting. they lack the clamping power for High feed milling. and in our "environment and many industrial scenarios, they are great.

I have proven what I stated in all 3 areas. ie their original design intent , Torque / Rigidity at HPC, and the workholding scenario. As far as I am concerned the case is closed. I have no interest or need to argue this "Ad Infinitum".

[John Stevenson 1Participant @johnstevenson1]

Meanwhile the people that can do, do
And the people who can’t, waffle on.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Raymond Anderson on 22/09/2016 09:30:53:

At the start of this thread a member simply stated that the er system was not designed for work holding only for toolholding, he was met with the reply "utter tosh" . I replied that he was correct.

…

I have no interest or need to argue this "Ad Infinitum".

.

Well said, Raymond

The system 'works' for work-holding, to the extent required by many; and the cheap stuff is very cheap .. So it's a 'no-brainer' that it will be adopted [and, using the word literally; abused] by this community. There is therefore no argument to be had.

What interests me however, is the matter of understanding what goes on inside; so that, on the rare occasions when it matters, we can say "ah, I know why it's doing that … perhaps I should use this instead"

To that end; the questions to manufacturers; the practical tests; and the Finite Element Analysis, are very welcome,.

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

Meanwhile the people that can do, do
And the people who can't, waffle on.

[SillyOldDufferModerator @sillyoldduffer]

Posted by John Stevenson on 22/09/2016 10:11:45:

Meanwhile the people that can do, do
And the people who can't, waffle on.

But don't forget the poor beginner trying to learn their trade. If no-one explained I'd be left in the dark. To that end I'm prepared to forgive a certain amount of willy-waving.

I'm off to the workshop for some 'doing' now, I promise!

Cheers,

Dave

[Michael GilliganParticipant @michaelgilligan61133]

John,

Is this ^^^ really necessary ?

You and I have different 'interests' and different motivations … But surely there is room for both.

I have great respect for what you do, and for the 'bodges' that you share with us … But I also happen to have an enquiring mind.

Could you perhaps manage a little respect [or at least patience] for those of us who are interested in the 'hows and whys' ?

MichaelG.

.

Edit: Dave posted before me … My comment refers to John Stevenson's post.

Edited By Michael Gilligan on 22/09/2016 10:44:49

[Raymond AndersonParticipant @raymondanderson34407]

Thank you Michael and Dave, If people never tried to understand what causes this or that, then nothing would progress. It is about understanding cause and effect [ or at least trying to ] Marks fine work with the FEA has shown what happens, even though I could'nt even pretend to understand the figures But I certainly understood the graphics. This has proved very interesting for me and I hope you and a few others also.

At the end of the day if certain folks have no interest in the topic then fine, they can ignore it but, there are folks who ARE interested in it..

cheers.

[Martin KyteParticipant @martinkyte99762]

Perhaps the "practical" results from all of this is when using ER collets for workholding make some attempt at using the things close to their original design mode. That being, when practicable, grip diameters close to the nominal size of the collet and ensure that the part is neither tapered to any great extent or off round and that the full length of the collet is filled. Many other collet systems really should be used with ground stock but they probably hardly ever are in our workshops.

regards Martin

[FarmboyParticipant @farmboy]

Well, I've read the whole 10 pages of this thread and I'm still not sure how the Bank of Scotland figures in all this

but I'm looking forward to the comparative tests of all the other collet systems available . . .

[alan frostParticipant @alanfrost17805]

Oh dear,after a couple or so years of grown up discussion I felt encouraged to use the site occasionally but I see that handbags have again been procured. What do you mean we don't have to read it.? Who could resist it ? Now can we get down to something useful ? What is recommended as giving the firmest grip on a handbag strap?

Oh, a useful addition. I intend to use the bag ,speaking technically as a tool.

 

 

Edited By alan frost on 22/09/2016 13:19:55

Edited By alan frost on 22/09/2016 13:23:35

[alan frostParticipant @alanfrost17805]

But only in self defence,officer

[Author]

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