Novamill update, spindle control

[mad_tunes]

Hi ladies and gents,

A friend aquired a Novamill and it's black electronics box months ago now and we've finally been able to spend a bit of time plumming in a USB 'motion control card' and Mach3.
We're both completely new to this, but so far we've got the three axis' up and moving (without any kind of calibration or limits). Manually nudging them them around is working fine. It was great to get some life out of it, felt like good progress.

We're having a mare trying to get anything out of the spindle though. TBH, I've read so much on here and tried so much now that I can't write it out.. and if I keep trying on my own I'm liable to blow something up before too long.

Would anyone be kind enough to help two guys start making stuff in a garage and point us in the right direction please?

Pics so people can see what we've got:






Huge thanks in advance,

'tunes

[Alastair]

Hi Tunes,

You need a 0-10v output from somewhere to drive the spindle drive card to get the variable speed. You don't mention what type of "motion card"/breakout board you have - often these have a 0-10v output on them which you would connect to the spindle drive where the [un-numbered] red and blue wires are in your photo.

If you don't have a 0-10v output from your breakout board, it's a pretty simple thing to make for probably less than £1 - tons of circuits on Google.

You may also have a problem with the Spindle Go Relay (SGR) not activating - does the little red LED come on? You need to take the other side of its coil down to 0v to activate it - have you checked that the lid safety interlock switch is not preventing the machine running (for safety reasons)?

Alastair.

[mad_tunes]

Hi Alastair.

I think I was on the right track with the basics..

Lid safety interlock: The big red lock on the hood? We took the catch apart and left that in the red box as if the hoods always shut. Probably the opposite to the right approach, but we wanted to exclude it entirely just for now.

With the blue spindle board powered up (red LED lit), I'd read that putting a pot. over the three corner connections (the two un-numbered ones and the 10v next to them) should make the spindle motor spin.. it didn't.

As long as I've understood correctly, that'd suggest an issue with the spindle board, connections between it and the motor or the motor. My only reservation is that I'd used an old audio pot. we had knocking around which was of a larger resistance than what I'd read should be used.. but the the resistance I'd read (10k, I think?) should have been within it's range.

Does that suggest something's not working as it should?


On a related note, I'm not sure I understand what the original green coloured card actually did.. am I right in thinking that the original controller board supplied spindle step commands, which that green board converted to an analogue 0-10v? (so, it's now not needed at all, with the new board having a PWM output?)

The bob we have handy can be seen here: https://www.ebay.co.uk/itm/261163689018. The manual's here in case it's of any use: https://www.dropbox.com/s/fp6py40dn6vcl ... Manual.pdf (9.5mb).

Thanks for any/all help!

'tunes

[Martin]

Yes that's correct. It converts a digital signal in to the spindle analogue. (0-10 volts DC)

[Alastair]

'tunes,

Sounds like you're nearly there!

From what I see of the eBay ad for your BoB it doesn't appear to offer a 0-10v output - I couldn't face ploughing through the full instructions though.

This means you will need to find a way to convert PWM to 0-10v. As mentioned in my previous reply, you can build a converter easily and cheaply (you're obviously a practical person, or you wouldn't be here), try searching:
https://www.google.co.uk/search?q=pwm+0 ... 37&bih=911

You should be able to junk the green card (I don't know how it works and was unable to find much info about it)

Your 10K pot should do the job just fine. Make sure it is connected up correctly, though. The spindle will not start unless the safety interlock circuit through the SGR relay is complete. The red LED is a good clue but not an absolute guarantee.

Good luck
Alastair

[mad_tunes]

Thanks a lot both of you.

Re 0-10v from the bob: It'll output 0-5v, but its manual says a resistor between its PWM output and the spindle boards 10v output will do the trick. I guess it must pull the signal up to 10v when the bobs not pulling it to ground.. but that seems too easy somehow.
I might try doing that, and knock up what you kindly linked to if I suspect a problem with it. What are your thoughts?

It all lives at the friends’ place which is a couple of hours away from mine, so it might be a while before I get back to it to have round 2. I'll post how it goes when I do.

I'll get to work finding how to get models of things into mach3 in the meantime. My closest experience so far is using Sketchup while mucking about with Arduino based bots (https://dl.dropboxusercontent.com/u/171 ... exapod.png), but I hope Google’s going to be friendly.

Also, I like the idea of cobbling together a 3D printer extruder head-thingy that could be fitted as a tool. I’m not sure of how this mills physical capabilities stack up against those of 3D printers though, anyone know of a place/way I could find out? It might well be a non-starter.

'tunes