Emco unimat pc cnc

[Trevor SmithParticipant @trevorsmith36244]

Hi I’m new to here and recently picked up a Emco unimat pc .Which I hope will be my first adventure into cnc machine’s.It has stepper motors which have plugs on them with yellow brown white and green wires going into them but I’m not sure what is needed from these onwards . I would be grateful of any advice on offer.Many thanks in anticipation. Ps I’ve been very impressed by such a compact machine working it as a normal lathe so far .

[Trevor SmithParticipant @trevorsmith36244]

Setting up for cnc

[Joseph Noci 1Participant @josephnoci1]

Hello Trevor. Welcome to the clan….

Do you have only the mechanics? Or do you have the controller/pc as well?

If only the lathe with steppers, then if you really want to get it working as a cnc learner, you have some effort ahead!

This links to a PDF that gives all the info how that machine was in its heyday – you need the electronic interface and a DOS pc and the EMCo software if you want to try run it as original and I think that is impossible…

Emco PC CNC PDF

The only practical way I could suggest is to go the MACH 3 or 4 route – Window PC, MACH3 or 4 software plus its hardware interface, 2 x stepper driver modules with a power supply….

Someone else may be able to suggest something simpler – maybe GRBL type system ( I am not familiar with that so cannot comment) .

There is of course Linux CNC, but don't get me started on that…

What is your modelling/work background? Mech eng/Electronic..???

It is a 'small' challenge to make this work if it is out of your comfort zone!

Regards

Joe

[sam sokolikParticipant @samsokolik60334]

I have never heard of this.. (I have a compact 5 pc – which uses the printer port..) I have a config that works with the stock compact 5 pc (plug and play) with linuxcnc.

Looks like a cool little machine. Have to know a little more about it! Did you get any of the electronics?

sam

[John HaineParticipant @johnhaine32865]

Probably the simplest route is to use Mach3 which will run on a Win10 PC using a motion controller connected by USB or Ethernet. In my case I use a Dell mini-PC with Win10 and a CNCDrive UC100. Then you need a "breakout board" to isolate the stepper drivers from the UC100; two stepper drivers; and a power supply. Depending on your comfort with electronics you could buy all this on eBay for probably less than £250 and wire it up yourself.

GRBL is a "motion controller" that can run on an Arduino, but it also needs something to send it g-code commands and as far as I know there isn't anything that supports turning. In any case GRBL couldn't support threading.

Having made CNC controls for my Super 7 and Denford Novamill (which I got without the electronics) I am pretty familiar with this process so happy to help.

[sam sokolikParticipant @samsokolik60334]

If you want to just get going the least expensive – $10 break out board, couple stepper drives and a computer with a parallel port would get you cutting.

You could also make really nice threads with a 25 to 100 line encoder + index. (parallel port would handle that too)

sam

[Joseph Noci 1Participant @josephnoci1]

Posted by sam sokolik on 21/07/2022 21:45:42:

If you want to just get going the least expensive – $10 break out board, couple stepper drives and a computer with a parallel port would get you cutting.

You could also make really nice threads with a 25 to 100 line encoder + index. (parallel port would handle that too)

sam

With what software and what OS Sam? I also believe the steppers on the unimat pc cnc are uni-polar connection only – drivers for such are not as common as bi-polar stuff.

Joe

[sam sokolikParticipant @samsokolik60334]

Posted by Joseph Noci 1 on 22/07/2022 07:48:13:

Posted by sam sokolik on 21/07/2022 21:45:42:

If you want to just get going the least expensive – $10 break out board, couple stepper drives and a computer with a parallel port would get you cutting.

You could also make really nice threads with a 25 to 100 line encoder + index. (parallel port would handle that too)

sam

With what software and what OS Sam? I also believe the steppers on the unimat pc cnc are uni-polar connection only – drivers for such are not as common as bi-polar stuff.

Joe

stepper motors which have plugs on them with yellow brown white and green wires going into them…

That sounds like bipolar to me… 4 wire?

[John HaineParticipant @johnhaine32865]

The instruction book linked to above shows the old pancake-style steppers which are generally unipolar and would have 3 wires per winding, so 6 wires, or 5 if the centre taps are commoned. So there's a puzzle here.

Trevor, please could you post some photos of your lathe, especially of the stepper motors, cables and plugs? Does it have any signs of sensors on the headstock spindle as would be needed for threading?

Thinking again, I doubt that a Unimat would do successful threading using Mach3 as the latter only accommodates one pulse per headstock rev. This works well on a lathe with lots of torque and moment of inertia but on a light Unimat type lathe you would need both a 1ppr sensor and encoder. Mach4 would as would UCCNC and LinuxCNC.

Unless you happen to have an old XP PC with parallel port lying around I think using the latter might be best avoided as only Mach3 supports the latter properly. Starting out anew a motion controller is a better.

I've just discovered CNCL which is an App on the Microsoft store, presumably running on a PC, that can drive a lathe using GRBL as a motion controller. I assume that it does threading by driving the spindle from a third (beefy) stepper motor, which would be an easy mod to a Unimat. Trial version free, £12.99 to get the licence. Also Google "GRBL threading" and "GRBL lathe".

GRBL is free software to run on an Arduino (also other small processors now) to which you feed g-code commands via a serial link (can be over USB or even Bluetooth) and it generates pulses to drive steppers via additional drivers. It expects to see bipolar stepper drivers so if your lathe still has pancake-style motors that's a problem to solve. GRBL can drive 3 axes so can handle driving the spindle plus 2 feed screws.

[sam sokolikParticipant @samsokolik60334]

I don't know – If I wanted to learn cnc – I would want a control that uses normal gcode and threads without the need of a stepper on the spindle. Things like FPR and CSS also.. Linuxcnc can do single index threading – but also supports multi line encoder + index (single channel or dual). Even through the printer port. Ie index only, a+index and a+b+index. a+b+index allows linuxcnc to see the spindles direction too – so things like rigid tapping works.

computers with printer ports are not hard to find. You can even get new systems with at least the printer port header on the motherboard. I have been liking the HP 8300 sff – it is a 3rd gen i5 with a printer port header on the motherboard. So you can plug in their pig tail..

https://photos.app.goo.gl/hUSrNBj8fDstekWE7

It also has really good latency… (linuxcnc uses a real-time os)

https://electronicsam.com/images/KandT/testing/8300/Screenshot_2019-04-25_21-25-12.png

More than powerful enough.

And – if you want to move up from the printer port to an external interface (not motion controller – linuxcnc is the motion controller in the computer) you can. Something like a 7i92 for $89us is like 2 printer ports on steroids. So you could use your exiting 10 dollar bob,,, (and you can expand it with daughter boards) Sky is the limit.

I have used linuxcnc for over 15 years. It has never left me wondering WTF it did. Rock solid machine control. (and we have machines with 8 tons of cutting force..)

Linuxcnc is actively being developed. I have been playing with turning cycles that have been added to development. Pretty cool. (plus – with the real time in the computer – you have access to motion and HAL unlike other system)

Turning cycles.

 

Fun with math… (also css and fpr)

 

 

sam

Edited By sam sokolik on 22/07/2022 21:11:03

Edited By sam sokolik on 22/07/2022 21:12:41

[Trevor SmithParticipant @trevorsmith36244]

Thanks for all the replies I see I have plenty of food for thought.I’m in hospital just now so thank you all

[Michael CallaghanParticipant @michaelcallaghan68621]

Here is my 2 pence worth. I have converted two lathes for cnc. One a Denford orac and the one I am fooling with now a Wabeco lathe. People keep going on about screw cutting on a lathe. To be honest in all my years I have never cut a tread on a lathe, just dies. So that’s sorted. If you are looking at software. There are a few to pick from. Mach3 is the most common, lots of information on the net etc, and most breakout boards will run mach3 or 4. Linux is a sort of build your own sort of thing and needs breakout boards that can run this program which makes it more expensive in equipment over mach3. Then you have acorncnc which is very good but also expensive being only available from the USA. As for equipment needed. Stepper motors and drivers x2. For the price now I would go with what’s called a closed loop system this means that the stepper motor can inform the driver if it starts to loss steps and adjust as needed. There is around a £20 increase in price over open loop but worth the money all day long. Then you need a breakout board, this is the board that works like a car ECU it informs the motors what to do. A power supply is not much to buy. If you go Mach 3 get a usb fitted breakout board which will allow a newer pc to be used. Linuxcnc you are stuck with the printer port. Acorn allows use of the Lang cable. Cost wise, it’s mach3, linuxcnc, acorncnc. It all depends on what you want from the lathe. Me I went with mach3, but will swap to acorncnc when the exchange rate is better. Or I can my mate to send it to me.

[Joseph Noci 1Participant @josephnoci1]

From Michael Callaghan

There are a few to pick from. Mach3 is the most common, lots of information on the net etc, and most breakout boards will run mach3 or 4. Linux is a sort of build your own sort of thing and needs breakout boards that can run this program which makes it more expensive in equipment over mach3.

Not quite true – Both Mach3 and Linuxcnc will run on basic PC's, with only a printer port. Both Mach3 and Linuxcnc via printer ports 'should' use breakout boards – those boards keep the noisy voltages and spikes from getting into the computers works. Do not confuse 'breakout boards' with Motion Controller boards. Most other setups ( Acorn and the like) have motion control in outboard hardware – those are NOT breakout boards, although many of them have breakout connections built onto the same motion control board.

So, Linuxcnc is FREE, costs nothing, while MACH 3 you pay for. And I believe Sam has got the small lathe working on Linuxcnc with just a printer port as I/O…

I also think you need to become more familiar with Linxcnc's hardware world before saying that you are 'stuck' with the printer port on linuxcnc…

You propose using an external USB 'breakout' board for Mach3 to be more 'modern' and to be more modern, even a LAN interface to Acorn…placing Linuxcnc in the geriatric realm – well for similar money to the MACH3 USB board, a 7i92 will give you the best possible, LAN, fast I/O, lots of I/O for steppers, closed loop, works on 'old' and new PC's, etc.

I started with MACH3 on my DIY CNC lathe – Mach3 was lacking, so moved to Linuxcnc, fought tooth and nail with it, gave up, bought Acorn CNC modules and software, fought even more. My requirements were not the 'basic' plug and play so that annoyed the Acorn folks and so support was abysmal. After a long fight, they found it easier to give my money back – did not even want the hardware back! I went back to Linuxcnc, and eventually it all clicked and I am comfortable with it now. I did get the basic lathe with threading working within a few days the during the first attempt, but my lathe has a C axis with live tooling, and that was a mission with Linuxcnc. However, NO other diy cnc system would do this!

[sam sokolikParticipant @samsokolik60334]

Posted by Michael Callaghan on 25/08/2022 14:28:46:

If you go Mach 3 get a usb fitted breakout board which will allow a newer pc to be used. Linuxcnc you are stuck with the printer port. Acorn allows use of the Lang cable. Cost wise, it’s mach3, linuxcnc, acorncnc. It all depends on what you want from the lathe. Me I went with mach3, but will swap to acorncnc when the exchange rate is better. Or I can my mate to send it to me.

Linuxcnc doesn't just use the printer port. There are pci, Ethernet and even SPI for the RPI. Price wise you can get something like a mesa 7i92 ($89us) which out of the box acts like 2 printer ports on steroids.. (and expandable). Linuxcnc is the motion controller. This means that it does the trajectory planning and everything in the computer in realtime. Not a buffered setup like mach or most other hobby controls. This means you will not find a usb solution for linuxcnc. Usb isn't deterministic enough (realtime enough) for linuxcnc.

You also don't have to make sure a feature you want is available in the external motion hardware you buy. Want rigid tapping? lathe threading? make sure it is in your mach hardware or it won't work. You can rigid tap and encoder thread with the printer port and linuxcnc if you want. (because the motion controller is in the computer – all features are available to all hardware interfaces)

And – the printer port is still available if you want to experiment. I bought a few off newegg (pci and pci-e) They work great for an inexpensive option.. (<$15 dollars in most cases)

I actually did an experiment to show how flexible linuxcnc is with just printer port hardware.. Using the printer port to run pwm to a servo drive and reading encoder position. (closing the position loop within linuxcnc)

Linuxcnc and the printer port

Acorn seems like a good controller too. It is one of the few hobby controllers that has encoder threading and rigid tapping. (plus the interface has been around forever so people like it) Mach3 hasn't been updated for 10 years. Mach4 – I don't know enough about to say other than it has the exact same trajectory planner as mach 3 (at least when I did some testing and Brian confirmed.)

In conclusion…

Linuxcnc is constantly being updated and features being added. It runs on a realtime OS. It is feature rich and very very flexible. It will run anything from a basic desktop mill/lathe to a large machining center with pallets.

sam

[sam sokolikParticipant @samsokolik60334]

Posted by Joseph Noci 1 on 25/08/2022 15:09:55:

I went back to Linuxcnc, and eventually it all clicked and I am comfortable with it now. I did get the basic lathe with threading working within a few days the during the first attempt, but my lathe has a C axis with live tooling, and that was a mission with Linuxcnc. However, NO other diy cnc system would do this!

Wow – glad you stuck with it! The last I read I thought you had given up with linuxcnc. Yes – it certainly is different and takes a bit to get used to and learn.. Once you do though – most everything looks like a linuxcnc solution.

[Michael CallaghanParticipant @michaelcallaghan68621]

I know that you can purchase breakout boards for Linux, but at a price if usb. The biggest problem with Linux for me is the time you need to invest in getting to know the ins and outs. Really all one wants is a program that talks to the machine be it a lathe or milling machine. I was not knocking Linux, but I think that the OP just wants the lathe up and running. Not sure what a C axis is. or what you mean by live tooling. Can you please explain. Thanks

[Joseph Noci 1Participant @josephnoci1]

Michael:

C axis is the lathe's main spindle, with the ability to be positioned to accurate specific angles, ie, not just a rotary spindle, but a servo position controlled spindle as well.

Live tooling is for example a milling head radial or tangential to the workpiece in the lathe spindle. You could mill flats on a shaft, keyways in the shaft, a hex on the shaft end, or hexagonal holes in the end, etc. The lathe I made has a servo spindle and an auto-tool changer with 8 tools, and a central milling spindle, able to mill only in line with the lathe spindle – Hex on the end of the shaft type work

Don't wish to hijack this thread more than it has been, so if interested, take a look at these posts…

Joe's CNC lathe

 

Edited By Joseph Noci 1 on 25/08/2022 16:59:44

[Ex contributorParticipant @mgnbuk]

I've just discovered CNCL which is an App on the Microsoft store, presumably running on a PC, that can drive a lathe using GRBL as a motion controller. I assume that it does threading by driving the spindle from a third (beefy) stepper motor,

Thanks for pointing out that a screwcutting version of GRBL (GRBL-L) is now available John – it wasn't last time I looked.

Seems like the early attempts at screwcutting with GRBL did use a stepper motor on the spindle, but things appear to have moved on. Now it uses an index pulse + an optional "syncronisation" pulse for more accurate tracking of spindle speed changes under load. More info here & a video of it working here

The test machine appears rather pedestrian (particularly the X axis) , though in the Wiki the author does say that it is a low cost conversion on a mini-lathe using small motors and basic drives & he doesn't appear to be controlling the spindle speed from GRBL either (so no CSS ? ). It is possible to hear the Z stepper changing the feed when the spindle slows under load to keep synchronised. I have not yet found a GRBL "front end" other than the author's CNCL to drive the turning version of GRBL.

The same author also has CNCR for controlling a stepper driven rotary table.

While it is nothing like as snappy as Sam's Emco, it does appear to be working non the less. The lack of an X axis retraction at the end of the pass rather makes me cringe, though !

While no fingers were lost in that particular video Sam, it will only be a matter of time if you keep removing ribbon swarf from the vicinity of a moving spindle ! A simple swarf hook is much safer – at least you can let go of one of those if it gets caught up & keep your fingers. I have seen some nasty cuts on others clearing swarf nests from static spindles with bare hands, let alone moving ones.

Nigel B.

[sam sokolikParticipant @samsokolik60334]

While it is nothing like as snappy as Sam's Emco, it does appear to be working non the less. The lack of an X axis retraction at the end of the pass rather makes me cringe, though !

While no fingers were lost in that particular video Sam, it will only be a matter of time if you keep removing ribbon swarf from the vicinity of a moving spindle ! A simple swarf hook is much safer – at least you can let go of one of those if it gets caught up & keep your fingers. I have seen some nasty cuts on others clearing swarf nests from static spindles with bare hands, let alone moving ones.

Nigel B.

Yes – this is stuff that works in linuxcnc.. CSS, FPR.. Lead in and out of threading.. It is cool that it works on an arduino but you give up so much. That is why I did the printer port example – you get all of that.

I agree – stupid. I really am suprised I have all my fingers. (I am mostly safe – really I am)

[Peter EggingtonParticipant @petereggington83966]

Trevor, did you manage to get any further with yours? I’m in exactly the same boat, have the lathe but no interface box etc. my motors have 6 pin terminals which need to go somewhere, although I assume I could run it as a manual lathe if needed I guess.

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