[Galane]

I've a need to put together an "idiot proof" manually controlled XY gantry for making straight cuts in plate steel with a plasma cutter. The client just wants it dead simple. Something to set the direction along the X or Y axis, a speed control and (such luxury) possibly movable auto stops.

He has a large CNC Torchmate table but that takes longer to boot the PC than it would to run a straight cut on a machine built to do nothing but make straight cuts. It would also be easy to train employees on so that when he tells them to cut a 2 foot strip off the edge of a sheet of 1/4" plate they can simply load it on the table, shove it up against a fence, manually move the Y axis to 2 feet (using the control buttons or switches), set the speed for the material then fire up the torch and hit the go button.

What I'm thinking it will need is a stepper motor and driver for each axis, same as a regular CNC system. Then it will need a control that generates a variable step pulse. Changing direction should be as simple as using a DPDT switch to invert the direction polarity.

Won't need automatic torch height control since it will only be used to cut steel that's heavy enough not to be warping. The shop already has a single axis, 4 foot long straight cutter with a torch carriage which is manually pushed or pulled. Works good but cut quality depends on the operator keeping the right and steady speed.

I have a simple breakout board I can use on this. If the control system could be made to output signals like a PC parallel port, then it could be built for a later upgrade to CNC.

[aarggh]

If all you want is to make a cut along one axis, wouldn't this be easily achieved with a couple of limit switches, some sort of height detector possibly, (maybe a cheap PLC for a modicum of safety control), and a constant speed motor geared down?

Seems to me a stepper controlled system being an open loop system possibly isn't the best for this scenario?

cheers, Ian
cheers, Ian

[Galane]

The speed needs to be variable. Height can be manually set by moving the torch head. Will most likely build a mount with a piece of threaded rod, a big knob and some type of lock so it can't move.

Needs to be simple and rugged enough to withstand use by people who don't know electronic stuff, yet versatile enough to be able to cut a range of thicknesses of steel.

I found this Stepper Motor Controller with speed control and forward reverse - YouTube Note the fast and slow switch. That would be ideal for lining up the torch to a mark.

Looks like it should be simple to modify to be able to set the speed pot then flip a switch to start it instead of having it move as soon at the pot is turned. Should then be able to connect end stop switches in series with the start switch. Could get real fancy and also connect that into the plasma cutter trigger.

3 amp motor coil current capability, that'll more than handle the motors. The Torchmate table uses some little NEMA 17's but that's an aluminum gantry. The shop has (literally) tons of steel laying about to build things with. Will most likely use the Torchmate table to cut the parts for this straight cutter.

[ger21]

I'd use Mach3 with a custom screen that only has the controls you need, with macros to create the g-code based on user entered data (length, feedrate, ...).

[techrat]

I've a need to put together an "idiot proof" manually controlled XY gantry for making straight cuts in plate steel with a plasma cutter. The client just wants it dead simple.

If I read your requirements correctly, I think that the most "Idiot Proof, Dead Simple" solution would be to replace stepper motors in your plan with appropriately sized dc gear motors with simple movable limit switches. Direction, speed and limits are easily handled without the need for any special controllers or computers. It really would take an un-needed layer of complexity out of the design. I envision each axis having the folowing controls FWD (to limit switch) REV (to home/limit switch) and Speed (A simple potentiometer speed control). Simple to operate and maintain.

HTH
Jeff

[datac]

I'm with Jeff.... If you want "simple", why bother at all with any stepper based anything ? There is nothing to "keep track of" per say if you just make the limit switches Relocatable.

This is a straight DC project if you ask me. A simple DC gear motor with a variable DC power supply gives you all the control you need when it comes to speed. Your DPDT is not going to be beneficial to any stepper drive... you'll likely blow the drive when you switch it, but that same DPDT fits perfectly into a plain DC project.

I'd put a pinion gear on the motor, run it directly onto the rack. I'd use proximity switches and various relays to control automatic travel stops and perhaps auto torch shut off.

Sounds like simple and fun project. I wish someone gave me a project that fun.

[Oleksii_Kyslyi]

Hi, Galane,

Just want to mention, that it would be better to use servo motor, which has feedback feature, for your purposes. Yes, it is more expensive, than stepper motor, but in comparison with cost of time, which can be spent for troubleshooting using stepper motor(which has no feedback feature), it is better to use servo motor.

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Oleksii Kyslyi Solutions for CNC machines Website: http://ww-cnc.com

[dram]

I've a need to put together an "idiot proof" manually controlled XY gantry for making straight cuts in plate steel with a plasma cutter. The client just wants it dead simple. .

GALANE, I know exactly what you want, because, I am looking for exactly the same thing. A fast and Slow, Fwd/Rev manual drive, that us numnuts can't destroy, well, easily.

Those in the know, tell me, I need a DC motor, speed control direction set up. Well, I've tried that, and what I want is "What You Have Described" the other is just not able to do the job.
So here it is a few years later. How did you go. were you lucky enough to get there??????

I would like to be able to just drive a stepper motor, with a fair amount of torque, (an X axis on a Hobby mill, tail stock on a Lathe

APF 500 Power Feed Drill 110V mill Machine Power table Feed Easy control auto feeder machine free shipping-in Other Machinery from Industry & Business on Aliexpress.com | Alibaba Group
Exactly like this beasty., but is over AU$400.00 at to-days play money time. and NO, I do not have shares with this company.

Galane, I really hope you had a win, mate.
Cheers, Mark Needham

[rowbare]

Search eBay for "stepper motor pulse controller". There are all kinds of boards available that will get you going. Some can drive a small motor directly though I would avoid those in favour of one that simply provides the pulse stream.

bob

[dram]

Search eBay for "stepper motor pulse controller". There are all kinds of boards available that will get you going. Some can drive a small motor directly though I would avoid those in favour of one that simply provides the pulse stream.

bob

rowbare, Bloody Bottler. Thank You. I have just bought/ordered 2. One to use, one for smoke.
DC12V Stepper Motor Speed Pulse Controller Speed Direction ON OFF Control | eBay

Galane. this module has buttons for direction, Like you, I also will use a "Lever" type switch. It is more intuitive.
That is the reason I bought 2. Once I can prove the setup, I will modify the buttons/direction to a 3 position centre OFF switch.
Will let you know, how I go.

[Galane]

Are those buttons press and release and it'll keep going or do you have to hold the button? If they're momentary it'll get complicated to have a three position toggle where flipping it one way makes it go and center cuts input power. Would either need a latching or one shot circuit - with a limit switch input to stop it.

[dram]

Are those buttons press and release and it'll keep going or do you have to hold the button? If they're momentary it'll get complicated to have a three position toggle where flipping it one way makes it go and center cuts input power. Would either need a latching or one shot circuit - with a limit switch input to stop it.

Mate, they are latching buttons.
I'll just lift the 2 buttons and solder some leads from the board to a toggle switch.

Further to the normal motor type control, the reason I want to use a stepper, is that I need a feed rate from about .001"/sec to say 2"/sec.
The higher speed to move the table/cutter/pointy bit to get to a new start position or whatever.
ie, cutting a gear, like watching paint dry,doing it manually. With a milling cutter in a small hobby mill,
New HAFCO METALMASTER HM-32 Vertical Mills in Melbourne, Brisbane, Perth & Sydney, NSW Price: $1,490 <7046>
slowly hand feeding and then a Quick return, index and start a new cut.
Or cutting a slot with a 2mm slot drill feeding by hand. the feed rate is all over the place, and slot drills break. I currently buy small sizes, by the carton, lol
An automatic feed should at least eliminate/minimise breakages.
On my mill, only the Right to left axis, which is the X Axis????? But that one anyhow.

The Chinese link, in an earlier post, I think, will actually bolt straight on unit to my Machine., which is a square thread screw. If I can get the Stepper bit working, I will lash out and buy a ball screw and nut also.
All the best,
Mark Needham

[rowbare]

I found and ordered one of these on the weekend. It has provisions for limit switches. 9 24V Input Stepper Motor Controller Speed Regulator Pulse Signal Generator | eBay

I am sure it will come in handy some day.

bob

[cstmwrks]

I found and ordered one of these on the weekend. It has provisions for limit switches. 9 24V Input Stepper Motor Controller Speed Regulator Pulse Signal Generator | eBay

I am sure it will come in handy some day.

bob

I've been looking for a simple solution for single axis control as well. Just ordered mine last night. Looking forward to dumping the bulk of a PC to control one motor.

[dram]

Mate. I ordered one of them also, on the 30th May. Still not arrived.
I manage to keep letting all the Smoke out of Stuff, that's why I have about 3 different models to "Cook".
Nothing has turned up to date.
I'll keep in the loop and let you all know how I'm going.
Cheers,
Mark Needham

[cstmwrks]

Mate. I ordered one of them also, on the 30th May. Still not arrived.
I manage to keep letting all the Smoke out of Stuff, that's why I have about 3 different models to "Cook".
Nothing has turned up to date.
I'll keep in the loop and let you all know how I'm going.
Cheers,
Mark Needham

Sounds good to me. Was tempted to buy a few other models but went with the seller that had the highest eBay rating. I have a test driver and stepper waiting to plug it into. These things prove out I think it's worth a sticky on the forum subject.

[dram]

9 24V Input Stepper Motor Controller Speed Regulator Pulse Signal Generator | eBay

Mine turned up today, will get at it in the next couple of days.
Looks Good.
Mark Needham.

[cstmwrks]

9 24V Input Stepper Motor Controller Speed Regulator Pulse Signal Generator | eBay

Mine turned up today, will get at it in the next couple of days.
Looks Good.
Mark Needham.

Any update? Have two in the mail now. Soonest I can hope to see one is the 20th.

[dram]

I'll try and get at it to-night.

Got some issues with my TB6600, DIP sw settings.

Also the other 2 ebay units have turned up

[cstmwrks]

One of two just showed up today. Nice surprise that it came with a 10K pot.. did not see that in the listing.
Am studying the info on it now. The power, pot, step and direction hook ups all look simple enough.
Looking at N1 to N4 they show each as a switch to ground. So my take is you pair up run/ stop with one single pole double throw switch and the same with the CW / CCW with another. Getting extra fancy a guy could add a NC limit switch to each CW and CCW. Then you would stop travel in that direction if they get hit.
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