Re-Building Suregrave CNC

[dazp1976]

Word of caution with using 48V with drives rated at 50V, esp the DM542 clones which don't tolerate over-voltage well..

Im with Jazz on this.
I'd rather get a 48v that's adjustable and drop it to 45v.
I'd never go back to the 50v drives since using the DM860T.

[PeterC]

Many thanks for the advice, it is appreciated!

Would I be better off to swap out the old 48v PSU (the only thing still left of the original electronics) for a new 36v one (the cheap option), or upgrade the drivers to somthing like these DM680C (https://www.amazon.co.uk/2-Phase-2-4...2&sr=8-14&th=1) which are 24-100V input with 48-60v Typical then continue to run them at 48v? Upgrading the drivers at £70 quid each is a fair hit on the wallet but if this was the better route it's worthwhile. I'm sure I'll find uses for the current drivers, or I'll stick them on ebay.

I'm not too worried about slowing the speeds down while I play / learn. I just want it to be vaguely usable to begin with!!
The steppers are rated at 84V. and are pretty beefy.

For the moment I'm hoping the current setup will at least allow me to get the thing fully wired up and moving without blowing up. I have the current limits on the drivers set to 1A while i'm testing and will only up this when the machine is electrically complete. To begin with I'll probably start test cutting on MDF or florists foam while I get my head around the CAM software (think of this as training wheels for a CNC!).

Sorry for the questions...

1) Would I completely kill the stepper motor performance by lowering the supply voltage to 36V for now and use the existing drivers. Any idea if the stepper would even function?

2) If I buy new drivers, should I keep the supply at 48v or go higher (60v) or lower (36v). What are the pro' and cons?

Many Thanks

Peter

[PeterC]

Thought I'd post a couple of pics vids about adapting the Surecraft to accept a 500w Air cooled spindle. I had to 'mill' a block of Aluminium - without a mill. I managed to cut it with a metal blade in my table saw (very sketchy!) then alot of sanding, drilling and tapping!

Overall I'm really happy with the result, it fits well and is a rock solid mount for the spindle.

Here's a couple of videos, one of me fitting it and the other of the final result.





Hope you enjoy

[Kitwn]

I can't say how those particular motors will behave at 36V, but I'm using DM452 drivers with 36V switch mode supplies to drive 3NM NEMA 23 motors with no difficulty. My gantry is way heavier than yours, has a 2.2kW spindle riding on it but it will rapid at over 10m/min and acceleration is fine for me.

Your 48V supplies may well be adjustable, look for a small trimmer near the terminals, so you might be able to reduce he voltage to somewhere near 45V to give the driver a bit more headroom.

[Sam C]

The electronics / control board was completely dead. This machine was built ~2005 so I figured the chances of getting any spare parts were next to none. Luckily the machine itself is in excellent condition and seems to have had very little use.
Peter

Hi Peter,

If you are still working on this project, can I pick your brain a bit. At the college I go to, we have the exact same router with the same problem and are looking into replacing the controller with the same one you have. The issue that we are having is that we don't know exactly which components to get and what wiring goes where in some cases and then we stumbled across this post.

We were wondering if you have any more info or pictures of the build to help us with ours?

If not, don't worry about it but we thought it was worth a go.

Thanks,

Sam Clark and the team at The College Of Richard Collyer's.

[PeterC]

Hi Sam,

Happy to help. If I get a chance I'll try and do a high level schematic, it is fairly straight forward. I suppose the most complex part was the Emergency stop system. I was not happy with the idea of just using the e.stop on the controller pendant - which is basically a software halt. I've added added Full E.stop system in that kills the power to the motor drivers and spindle, and it also sticks the controller into e.stop as well.

90% of the parts came from Amazon or Ebay. The spindle and motor drives are the cheap clones, I always planned to upgrade these later if required however they have been as good as gold so far.

The DDCS controller is basic bit does exactly what I need. I didn't want the hassle of PC's and dust etc in the workshop so opted for a dedicated controller. I use Fusion 360 to do my design work, there are post processors for the DDCS controller you can download and install, they work well for me.

One modification I'd recommend was to the X-axis gantry rail. If you look the only support the Z axis carriage has is the linear rail itself. I got a piece of angle iron and bolted it to the back of the linear rail and to the two side supports. This stiffened up the X axis massively, and I now get a lot less chatter, and deeper cuts! It's a £5 mod!

I can cut plastic, plywood, MDF and Aluminium (slowly!),

I'm going to fit a larger spindle in the new year, I'll post some updates when it's done.

Peter

[PeterC]

Quick video of E.Stop in action.

[Lee Roberts]

Nice work Peter, cant beat a latching relay for an estop situation, good to see, have you got everything sorted out with it now ready to start using it?

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