Rebuilding gantry type Suregrave engraver - advice needed!

I have been given a non-funcional Surgrave Rotation S engraver, a well constructed commercial machine, but the controller boards were always a touch flakey and it simply doesn't work any longer. Suregrave as a company have long since disappeared so no help there and as I'm just a hobbyist I'm looking for a low cost solution to getting it working again. I have absolutey no experience with CNC machines but I do have a very good workshop, experience with putting electronics together and a great deal of patience and persistance!

Having tried Cut2D Desktop I'm certain that this is the design software for me, especially as it generates toolpaths and G Code from within the package, I'm now assuming that a Mach3 based controller system is the way to go to control the machine but am open to alternatives. However, I want this build to be as simple as possible, so I don't want to have learn any programming languages, I just want to be able to design an engraving in Cut2D, produce the code, send it to the machine and engrave.

The engraver uses ECMotion SECM264-2.0A stepper motors and a GEFEG 24V 17.4A 12000rpm spindle. The steppers are rated at 2.8A in bipolar parallel mode. Details of the stepper specs are shown below. I'll be running the system via a Windows 7 laptop with USB2.

As I'm so new to CNC I'm still uncertain as to exactly what I need and how the whole system should go together, so please be patient with me. My thoughts so far are that I need the following;
Software to design the engraving job and produce the relevant toolpaths and G Code (Cut2D Desktop?)
Software to run the motion controller (Mach3?)
A motion controller board to match the software above (Mach3 board? Which one? Recommendations? Must be cheap and available in the UK)
Stepper motor drivers to match the SECM steppers already installed (Recommendations?)
A spindle speed control board (Recommendations?)

I appreciate this is quite a long and complex list but I'd be grateful for any help. I'm based in Suffolk, near Ipswich if there's anyone local who reads this I'm very happy to meet at an appropriate social distance!

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Photo of engraver, it's fairly dirty, haven't got round to cleaning it yet!
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Hi Gordon,

Ok well first off let me explain the Controller side and what your options are. Because your using Win7 which I assume will be 64bit version, if so then you can't use the parallel port driver for mach3 as it's not compatible with 64bit win7. So this rules out the cheap option if you do want to use Mach3.

This means you need an external motion control board or some adapter like the UC100 from CNC drive which lets you use USB and converts it to same pin out as a parallel port. This would be the cheapest option for Mach3, it also allows you to use there own UCCNC software which is actually better than Mach3 now.
http://cncdrive.com/UC100.html

However, I wouldn't advise this approach as I'm not a fan of USB for a CNC machine. Ethernet-based motion controllers are much more reliable so in this case, I'd suggest using an AXBB from the same company. This will do everything you want and provides a speed reference voltage for the spindle controller (which I'll come to soon)
http://cncdrive.com/AXBB.html

Then a third option and by far the cheapest but will require another PC ideally, which you can pick up a refurb PC for like £50. This is called Linux CNC.
It's free and it will allow you to run from the parallel port. However, it does have a bit of a learning curve to install and not something I'd recommend to a new user unless they have help from someone with experience. Thou it is do-able by a new user with just maybe a bit more head-scratching.!

The actual working of the control software regard using the machine and cutting parts is simple enough and it works just like Mach3 and all the other control software. Don't be intimidated by the control software, any of them, as it's very simple to use in practice. It's the setup of the machine that requires a deeper knowledge of the inner workings and we can help with that.

Regards the Drives then most drives will run those steppers but you will need to decide on the voltage you intend to run them on. These would be a good choice for those motors and run them on 40-44Vdc. The PSU in your existing controller may be usable but without seeing it then can't say. Many of these types of bespoke control systems use AC transformers and then Rectify to DC on the control board it's self. You may be able to re-use the transformer and just add a bridge rectifier and Caps to give the DC voltage you require.
https://www.cnc4you.co.uk/Microstepp...tepping-CW5045

Now comes the potential fly in the ointment.!! . . . . That spindle motor looks like a brushed DC motor so it will have a Brushed DC speed control drive. You need to identify the control board and see if it can be re-used and what type of reference voltage it requires. Many of these types of drive require an Isolated speed reference voltage and if you get it wrong will easily damage any board supplying the reference voltage not mention they often working at mains potential so can be lethal if you are not sure what you are doing and stick your fingers in the wrong places.!!

This needs careful examination and it may mean either a new BDC drive or replacing the whole spindle and drive with something different.

Now regards the current machine then if it's working or in need of just a few parts then it may be worth contacting these people because they know everything about these types of machines and may possibly have the spares you require. They are family-run super helpful people and the old man as forgot more about engraving machines than most so-called experts know.
http://www.pantograph.co.uk/

I hope this helps and if you do continue down the conversion route then posting a little more info about what's in the control box and good pics will help.

Just a quick response to JAZZCNC, thanks very much indeed, plenty to digest there but I think I'd go for the AXBB board, looks like it would do what I want and the cost is offset by the lower cost of the software, about £80 less than Mach 3 I think. For stepper drivers I was considering these, partly for cost, partly because they have decent reviews, and they will easily cope with 36V 2.8A/phase supply to the steppers, which is what they are rated at.
https://www.amazon.co.uk/TB6600-Step...p_pl_dp_2&th=1

The power supply within the existing engraver controller is a large toroidal transformer with a rectification and smoothing circuit board. I've checked the outputs and it provides 36V for the steppers, 5V for controllers etc, and 24V for the spindle. All works fine and I don't see any need to use anything else. I'll post a photo tomorrow.

The spindle spec sheet is shown below, the one installed is 24V brushed dc, but it's rated at 17.4A. Needs a PWM controller I presume but I'm not sure what to go for. There might be a PWM circuit in the existing controller but I think it's part of the stepper driver board, which is completely unmarked as to what each connection is, which is a bit of a bummer as I might have been able to use it. From my discussions with Mervyn White at Microwhite (he's a Suregrave guru) the main controller boards were somewhat unreliable and not capable of being repaired. More tomorrow!

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Originally Posted by GordonB

For stepper drivers I was considering these, partly for cost, partly because they have decent reviews, and they will easily cope with 36V 2.8A/phase supply to the steppers, which is what they are rated at.

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Complete and utter junk I wouldn't use them on a printer let alone a CNC machine. If you run them at 36v, even thou rated at 42V they won't last long.
If you buy those you will regret it take my word for it. Even if they stay alive long enough the difference is motor smoothness and performance alone is worth paying the extra.

Don't make the classic mistake made by many new CNC users and buy cheap electronics, they are cheap for a reason none of which make for a good or reliable machine.

Regards the speed controller then you will need something that can accept 0-5 or 0-10v analog input for the speed reference because I don't think the Axbb provides a PWM output, I could be wrong so ask CNC drive first or go to there forum and ask.

You can also get BDC controllers that have stand-alone PWM built into them and control the spindle speed with a Pot.!

To be honest I don't do a lot with BDC controllers as Brushed spindle motors are not common on CNC machines these days.

I've been using these drivers on my CNC router at 36V for a couple of years now without any problems.

Kit

https://www.omc-stepperonline.com/di...or-dm542t.html

Here's some photos of the electronics inside the control box for the Suregarve Rotation S, there are no electronics as such in the rest of the machine, just wiring to the steppers and spindle.

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I've decided to go for the AXBB-E from CNCDrives, looks as though it will do what I want, and for the drives I think I'll go for the Stepperonline ones recommended by Kitwn, they appear to be the correct spec and are a reasonable price. I'll be buying the UCCNC software to run the controller, CNCDrives have an offer of the AXBB plus UCCNC for £178, saves a few quid.

That leaves the issue of controlling the spindle. I have two options, the simple one would be to use an external controller such as this one
https://gimsonrobotics.co.uk/categor...th-lcd-display

or go far a PWM controller that it should be possible to control using the AXBB and UCCNC, this one appears to fit the specs
https://www.4qd.co.uk/product/sst/

I'll be using either Cut2D desktop, Fusion 360, or VCarve desktop to produce the GCode and toolpath, possibly Rhino as my daughter is a jewellery designer and is fully familiar with Rhino (I'll cheat and get her to do the designs...)

Anyone got any comments on this lot before I press the buy buttons next week? Thanks for the hlep so far!

I bought the DM542T digital drivers to replace the TB6600 based ones I had been using before. The reduction in noise was a real surprise and the motors run cooler as well.

Kit