Where is the fountain of knowledge for learning about CNC setups / understanding them

**Doddy** · 14-02-2018

Originally Posted by m_c

Just checked, and I should of said get TB6600 drivers if you do replace them.
TB6560 is the older chip, whereas the TB6600 is newer, far more resilient, and has better performance.

Which has also reminded me that the TB6560 has quite a large pulse width requirement. It needs a 10uS minimum pulse width, which limits it to 15KHz step rate. Some where in the Mach settings (think it's the motor tuning screen), there is a box for setting the pulse width. Make sure you have it set long enough.

The attached chart shows the key differences between the chips.

I was about to dismiss this - the controllers I've seen (and modded) have had a 74-series monostable oscillator to pulse-extend the clock signal - however the image of the board (and various clones thereof) don't appear to have this luxury, unless it's rear-mounted on the board? If not, this board is seriously junk. The 10us minimum pulse width is actually dependent on a capacitor value, and can be significantly longer than 10us dependent on value. Mach3 advertises a limit of 1-5us for step/dir pulses, but appears to let you enter a larger value (I can't test as my motion controller is hard-limited to 2.5us). I'd agree - experiment with larger pulse widths (and reducing the micro step to 1 will also help to limit the PRF to a sensible value)

EDIT: My bad - just checked, and the controllers I did modify are TB6600s, not 6560s.

**Palletlad** · 14-02-2018

Just a quick update, I have confirmed that there is no issue with the frame alignment or ball screw.
I tested the motors when not connected to anything and even on low settings (320,1000,150,0,0)=motor settings.
And they still jam/jar.
so definitely something to do with the electrics/settings.

**Palletlad** · 14-02-2018

Ooh just remembered to ask I saw the TB6600 stepper motor drivers via amazon and ticked them for a purchase later idea, however when looking for a standard BoB (I know so little on them) I found https://www.ebay.co.uk/i/25208589694...4960578&crdt=0 and I kept having this one pop up https://www.newfrog.com/product/elec...waAsFpEALw_wcB everywhere I looked but not many others? I would have thought there would be all sorts of brands, low, medium, high spec etc

**Clive S** · 15-02-2018

I would not go with the drives all on one board for the same price you could have :- https://www.ebay.co.uk/itm/5pcs-CNC-....c100677.m4598

or

3 of these:- https://www.ebay.co.uk/itm/20KHZ-CNC....c100677.m4598

The bob you linked to is OK if you want a cheap one. I have used them a few times

**Doddy** · 15-02-2018

What's the

Originally Posted by Palletlad

low settings (320,1000,150,0,0)=motor settings

part?, have you not tried larger pulse widths on step/direction?

**A_Camera** · 15-02-2018

Originally Posted by Palletlad

Just a quick update, I have confirmed that there is no issue with the frame alignment or ball screw.
I tested the motors when not connected to anything and even on low settings (320,1000,150,0,0)=motor settings.
And they still jam/jar.
so definitely something to do with the electrics/settings.

Good. At least we know that the mechanics are OK. Now change the pulse width to 10. If that doesn't help KEEP it there and change speed to something really low, like 500. If that is still an issue then you probably have a faulty driver card, or a faulty PSU, or both.

I started off with a 3 axis 6560 (blue card). Fixed all the electronic design issues but still managed to fry two before I gave up. In the end I bought a $5 BoB and a handful of DQ542MA drivers and never looked back. My CNC immediately became more quiet, more powerful, faster and with much better acceleration, even though at that time I still had a crappy 24V switched PSU. Changing the driver was the key to success in my case because it solved a lot of issues. That's the route I'd advice you to walk through even if you manage to sort out the current issues. I am still using the same drivers but upgraded the PSU and the CNC in many other ways...

**Palletlad** · 15-02-2018

Doddy I did attempt with pulses as well but no difference it was the same result what ever setting I attempted.

**Palletlad** · 15-02-2018

Is this a good BoB? https://www.amazon.co.uk/Motion-Cont...breakout+board as I am unsure what I am looking for other than how many axis, connector type (USB/Parallel) would this be a good card to have https://www.amazon.co.uk/gp/product/...9I2AQIQH&psc=1 also https://www.amazon.co.uk/Switching-P...ywords=psu+48v.
I wont be buying straight away if need be as I still want to check the PSU 1st before any buying but I understand my currant card cant handle a 48v only 36v but is the one I linked good for the above linked items?
Would the setup I have linked be a good idea or are they not a good combination?
Cheers guys for your time.

**Clive S** · 15-02-2018

Did you not read post #54 as the drive above is very similar and nearly double the price

**Doddy** · 15-02-2018

Originally Posted by Clive S

Did you not read post #54 as the drive above is very similar and nearly double the price

I think I have 5 of the ones that you linked to sitting in a corner collecting dust... will check tonight and if they are, and my memory serves me correctly, will post a photo or two. There might be justifiable caution to buying from our Chinese friends.