Electronic Lead Screw (ELS) Introduction.

[jcdammeyer]

Hi Everyone,

This forum has been set up to serve as a support location for the ELS product.

Unlike the Yahoo E-Leadscrew group which deals with all different kinds of methods for controlling a lathe lead screw I'd like this forum to concentrate specifically on the ELS design and be the place were specific support questions and photos can be posted.

I won't be ignoring the E-Leadscrew group but I think this forum is a bit more user friendly.

Thanks

John Dammeyer
http://www.autoartisans.com/ELS/

[Bread_O]

Hi,

I want to build a backguage controller for my guillotine.
The back guage is currently controlled by a motor connected to a leadscrew and has backward and forward motion.

I basically want a controller whereby i key in the measurement i require and the back guage must move to the correct position.

The maximun travel of the backguage is 1020mm

any ideas

[jcdammeyer]

You bet that's possible. It's the next project on my do list for the ELS for my own shear and bender. I have already made up the sprocket hubs and cast one carrier block.

The attached photo shows what the guide assembly would look like. The motor would sit in the middle attached to both screws with chain and sprockets. For bending metal I'd include the K factor, thickness and bend depth. For shearing just the cut depth. The motor would move the fence to position.

The spindle sensor input will be used to calibrate the fence location although it may be possible to use stock ELS software and just set a measured position. Something like shearing a piece, measuring it and then entering that value into the ELS. At that point while power is applied it would remember where it is.

John

[Bread_O]

Brilliant,

I want to use it on a paper guillotine but it works the same way as in your application.

i had a look at my machine today and noticed it has a single lead screw in the centre and two slides on both sides of the leadscrew. The motor is 3 phase and connected via a small gearbox to the leadscrew. i have two buttons up front for backward and forward.

would I have to remove the current motor and gearbox? What else would I need to get the whole setup running?

Say i have a sheet that's 500mm in length and i want to cut different sizes out of it. Would I be able to enter 500mm first and just press (-) and the size i need? instead of calculating and entering measurements

My machine is about 25 years old and works 100%. Its a german product and built very accuratley. With a computer controlled back guage it would reduce my cutting labour time by 60%.

Comercially available systems cost about USD$5000.00 which is more than what the machine cost so I am seriously considering your product. However I want to get all the info I can before I buy it.

[jcdammeyer]

I would replace the motor and gear box with a Stepper Motor. It's difficult to say how large it needs to be. You might have to do some experiments by attaching a lever and hanging a weight to see how much torque is required to turn the screw. Or just take a chance on the motor.

The ELS can drive a stepper motor up to 3 amps. So you would need a power supply of about 24VDC to 45VDC. Ultimately some sort of switch for a Predefined position. It doesn't have to be HOME for 0.000.

As to how to use it, that's hard to say at the moment since I haven't written software for a backfence yet.

The only automated motion available is a move to HOME. (0.000" or 00.00mm) so if you could program in the current position (which isn't possible at the moment) you could then tell the ELS to take the Z axis to HOME.

Stay tuned. I do want to have something like this working soon. Meanwhile, start figuring out how to connect a size 23 or size 34 stepper motor.

[Bread_O]

What I have learnt from the other systems available.

One you install the setup you just move your back guage to the min and max positions and enter the measuremnts. This is stored in the system and will not change

You can load a full sheet into the machine by inputing the size of the sheet and work backward by minus the size you need.

Sound quite simple but guess its not when you building a standalone controller to do this

please keep me informed on ang progress

[jcdammeyer]

Originally Posted by Bread_O What I have learnt from the other systems available. One you install the setup you just move your back guage to the min and max positions and enter the measuremnts. This is stored in the system and will not change You can load a full sheet into the machine by inputing the size of the sheet and work backward by minus the size you need. Sound quite simple but guess its not when you building a standalone controller to do this please keep me informed on ang progress

There's no guarantee that the unit won't be turned off. At that point, it's unknown exactly where the fence is. So on power up I would (on request from user) move the fence until it reached a home switch. At this point the system knows where the fence is because the operator has already calibrated the system that the home switch is at X.

The operator has also told the system what the maximum and minimum distances are relative to X.

To me working backwards from the sheet size is odd but I can understand why a system might work that way. The cut off pieces are in front and haven't dropped down into a bin.

Seems more logical for most non-production line applications to ask for a specific size and then have the fence move to that location. That's because the size of the piece of metal picked as raw material is unknown or hard to measure accurately (to the nearest 0.001").

For fixed size paper products I can see why it's done the other way. No reason the software couldn't address both.

John

OTOH

[Ryobiguy]

Hello,
I know exactly what you're talking about - paper cutters. I worked at a shop when they bought a new expensive, really nice cutter.

It had an air table - little check-valve balls on the table surface every 5" or so that opened when pressed down by the paper. Anyways...

The ELS as an electronics kit would be well suited for this application.
It would ideally need different firmware unless you want to key in each distance (which you don't since you mentioned production time.)

What you want is a set of user "programs". Each program is a series of back-fence distances, advanced after each cut. Each program is a specific pattern of cuts to start with a standard parent sheet size and end up at whatever is needed.

I visited that shop a few years back and checked out the fence positioning motor setup. It looked like maybe some kind of DC or 3ph brushless motor and a separate rotary encoder off a timing belt from the single leadscrew. Motor size was surprisingly small.

Encoder is pretty important - there is some back-driving going on when jogging the lift of paper against the backstop. That machine would detect that and reposition in that case: increase distance then sneak up to the exact distance.

Another thing I remember is that sometimes it was useful to have the backfence push the paper out, but now that I think about it, that sounds a little weird.

-Matt

[jcdammeyer]

The backfence I'm building for my 3:1 metal brake/shear is going to be pretty crude I think. Two lengths of 10TPI acme all-thread with nylon nuts to reduce backlash. Each lead screw will sit under the guide rod and they will be connected with a chain which is driven inbetween the two with a stepper motor.

The fence brackets will use bronze oilite bearings although I should probably use linear bears or rails with cars. Attached pictures should give you the idea of what I'm trying to do.

However, work-work has been so busy lately I haven't found myself in the shop now for several months.

John

[40fordcoupe]

OK I'm very interested in this one. My question is;
Does the design have the ability to "map" the leadscrew? That is, can it add a correction factor for any given point along the leadscrew. I would like to be able to get ball-screw accuracy from all-thread rod.
Thanks,
Bob B.

[jcdammeyer]

Originally Posted by 40fordcoupe OK I'm very interested in this one. My question is; Does the design have the ability to "map" the leadscrew? That is, can it add a correction factor for any given point along the leadscrew. I would like to be able to get ball-screw accuracy from all-thread rod. Thanks, Bob B.

Alas not. This would only be possible if there were an encoder or some sort of index pulse off the leadscrew too so the computer could keep track of where the lead screw is from a cold power up start. It doesn't. And then even mapping it would be difficult.

A more advanced unit would probably work better to have a linear encoder on the carriage and use the position as feedback. But the ELS isn't that powerful.

Sorry.

John

[peterb33]

I would also like to make the back fence on my paper guillotine automated. At present it is hand operated and one turn of the handle moves it 10mm.

What I want it to do is add a stepper motor to move the leadscrew which is fairly simple but what about a controller? I see reference to an ELS, or is it easier to go the PC route, has anyone done this before?

Thanks Peter