Automate Paper Guillotine Back Fence

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Automate Paper Guillotine Back Fence

This topic has 6 replies, 3 voices, and was last updated 4 May 2010 at 08:19 by Peter Bell.

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2 May 2010 at 20:59 #14929
Peter Bell
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@peterbell11509
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2 May 2010 at 20:59 #51352
Peter Bell
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@peterbell11509
Hi

I would 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 have seen references to an ELS, or is it easier to go the PC route, has anyone done this before?

Thanks Peter
3 May 2010 at 18:38 #51387
Les Jones 1
Participant
@lesjones1
Hi Peter,

I do not think the electronic leadscrew would serve your requirements. I works like an electronic gearbox. It senses one pulse per revolution from the headstock spindle and generates a string of pulses to drive the stepper motor at speed which is a set ratio to the spindle speed. For example if the leadscrew has 10 threads per inch and you want to cut a 26 TPI thread then the lesdcrew needs to be rotated 10 times for every 26 revolutions of the spindle. So if the stepper was coupled directly to the leadscrew and the stepper requires 200 steps per revolution (Which is a fairly common value.) 2000 step pulses would be required for every 26 revolutions of the spindle. It also needs to be kept in phase so that the thread is cut accurately. I imagine that you want to be able to key in the required distance between the blade and the fence and the stepper motor to move the fence to the required position. This could be done with a PC or a microcontroller. If this is what you require each time the equipment was switched on it would have to set its zero position using a sensor or driving to a mechanical stop. The “DivisionMaster” rotary table controller could probably be adapted for your purpose. Here is a link to some information on the DivisionMaster. DivisionMaster

Les.
3 May 2010 at 21:42 #51402
Peter Bell
Participant
@peterbell11509
Hi Les,

Thanks for the reply, you are right with what I want to do, it is fairly simple really but I am not really sure which way to go so I was looking for suggestions and thought perhaps someone had already done something similar.

The guillotine has a fairly good scale but I can see mistakes creeping in due to the amount of repetive moves needed.

After some googling I thought ELS was probably not suitable but found a post on a forum asking the same question about a guillotine backstop, added a post and received the following reply

The ELS can even do it now although there’s no distinct home switch to automate things. On power up you’d have to move the fence to the zero position and zero the scale. After that you can key in a BEGIN position and press START. With the X axis disabled, the ELS will always stop and ask you to move the tool into the workpiece. At that point you’d shear what you wanted. Press the BEGIN button again and enter a new position, press OK. Press TURN and START and the fence moves to the next position. It’s kludgy but it would work.

Thanks for the link for the Divisionmaster, I see they also sell kits for the ELS which are slightly cheaper and was also hoping to keep it simple as possible.

Peter
3 May 2010 at 22:26 #51404
Gone Away
Participant
@goneaway
Peter, if you want to check out John Dammeyer’s E-Leadscrew group and perhaps ask John himself whether he thinks it would be suitable for your purposes, you can join the group at:

http://tech.groups.yahoo.com/group/E-LeadScrew/
3 May 2010 at 22:42 #51406
Les Jones 1
Participant
@lesjones1
Hi Peter,

After making the suggestion about the “DivisionMaster” I had a look at the web site of the designer. I found that the source code was not available so it could not easily be adapted. To use it you would have to write the code from scratch. I did not realise the ELS was so versatile. All of the hardware you require is in both devices. The advantage the ELS has is that the source code is available so you could modify it to do exactly what you want. I cannot offer any help to modify the ELS code as it is written in “C” and I have not yet learned to program PIC’s in “C” (I work in assembler.)

Les.
4 May 2010 at 08:19 #51409
Peter Bell
Participant
@peterbell11509
Hi,

Thanks for the suggestion, joined the groupE-Leadscrew group but it does not seem terribly active so have not posted anything yet.

What would help would be a reply from a user of the ELS confirming how it would fit my use. Difficult for me to evaluate it’s versatility, perhaps the answer is to build one and try it?

Not a code man at all but if it could be fine tuned for my application that sounds interesting but would need someone to do that. Perhaps Lester Caine knows more, will give him a ring as he offers the kit.

Peter
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