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Automatic tool withdrawal for threading.

I don't have my ELS yet so I have to ask someone who knows: when threading, at the end of the cut, does the tool automatically withdraw in X to avoid cutting a groove immediately under the bolt head?

Many thanks!

 

Dumitru

 

 

Threading with X-Axis enabled is done in several passes. But it cuts to the end, and then retracts.

So a bit of a groove is cut on the end, which is not really a problem. It secures that the thread is really till the end of the bolt.

Ok thank you Louis, I understand. I'm not a fan of how that groove looks right under the screw head, and I think an argument can be made that the screw would be stronger without the groove (a 1.2mm screw).

Is there a technical reason why ELS cannot auto-retract to avoid cutting that groove?

Cheers and thanks,

Dumitru

 

 

 

?

You can't cut a thread on a lathe without cutting a groove at its end. That's because the workpiece is turning, not the tool. If you dont want a groove, you have to mill or grind the thread.

But i don't understand the problem with the groove...

There is no real reason, the thread cutting function is just currently this way.

The Problem is how to set it up. It should be possible to switch it on or off, and we should be able to set it up somehow, how long the way of the retract is, for example. That make things more complicated, therefore I left it how it is.

It is not really a problem, and it ensures that you can use the thread till the end of the bolt, which is not the case when you retract before the end of the thread.

But to make things perfect there is the "undercut"-mode, which is also available in the ELS 3.

Zitat von Louis Schreyer am 3. März 2019, 12:26 Uhr

There is no real reason, the thread cutting function is just currently this way.

I'm very glad to hear that, I was preparing to build a quick-retract toolholder and add some Rube Goldberg device to trip it at the end of the thread!

The Problem is how to set it up. It should be possible to switch it on or off, and we should be able to set it up somehow, how long the way of the retract is, for example. That make things more complicated, therefore I left it how it is.

I think this is something that a lot of users would set up when they initially configure the device, i.e. some users will always cut the groove, some will always retract, so the setting for it can be left somewhere deeper in a menu.

As to the length of retraction, I think retracting all the way back to the starting X position is the most logical.

Do you mean how many threads before the end of the operation the retract should begin? If so, I think the ELS should calculate to retract as late as possible depending on the rpm and the maximum X stepper acceleration capability.

It is not really a problem, and it ensures that you can use the thread till the end of the bolt, which is not the case when you retract before the end of the thread.

I've thought about this, but how often does this come up? I mean, usually you have something being clamped between the nut and the head of the bolt.

But to make things perfect there is the "undercut"-mode, which is also available in the ELS 3.

Excellent! Is there a video somewhere of the "undercut" mode in action?

At any rate it'll be a while before my lathe hardware is ready to receive the ELS, and hopefully the manual will be ready by then. It's just nice to be able to plan ahead and anticipate what things will be like with it installed 🙂

 

Cheers and thanks again!

Dumitru

 

 

 

 

Do you mean how many threads before the end of the operation the retract should begin? If so, I think the ELS should calculate to retract as late as possible depending on the rpm and the maximum X stepper acceleration capability.

I've thought about it some more. Let us assume it is difficult to synchronize Z and X motions so that X is retracted to zero just as Z reaches zero. A simpler way to do it (at least I assume it is simpler) is to simply cut the thread as usual and as soon as the end of the thread is reached (Z=0), X can retract at max acceleration while Z continues.  Obviously, the thread will be longer than specified and this may lead to a crash if done extremely close to the shoulder, but I think most users will anticipate that and do a few test runs on scrap pieces first.

Cheers,

Dumitru

 

 

Your last idea is not possible, it would crash in some cases.  A retract on the end should be possible in the software, but comes to the cost of more settings needed, something I always want to prevent as much as I can to keep it as simple as it is.

This not a full scale lathe cnc controller, it is designed as an easy to use device, fast, simple, sleak. There are many options which I could add, which are common in cycle controllers known from industrial manufacturers (Siem ens, Haid enhein etc. ) But have a look at their usermanuals, and you understand why it is not desirable to enable every idea possible. It would just overload the user interface.  I will eventually build a larger ELS controller in the future allowing more options for the Pros, but the current ELS 3 is already cramped with options, and I am very cautious to add more as I do not want it to become too complicated to use.

I would recommend using the ELS with threading, and then see if you still have a problem with the groove.
Until today, no user complained about the threading mode. I am sure this is a more theoretical problem, not practical.
The undercut video is at https://www.youtube.com/watch?v=6HXqYgFdyeU&t=158s

or here:

https://youtu.be/VGIDWsFqCwA at 7:30

Please do not misunderstand me, I always listen to ideas and suggestions, and try to make things possible. But I often have users on the telephone asking things they think is a problem, in advance of using the ELS in real life. After they have it up and running most of these "problems" are gone.

 

You're probably right Louis. Groove or no groove, the lathe will be far more capable with ELS than before, so I'll do the conversion and we'll see. It's not as if the manual lathe doesn't leave a groove when threading.

I've got my work cut out for me with the conversion so we'll see how that goes first.

Cheers!

 

Dumitru