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

[Doddy]

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.

Ah yes, I have a number of these, advertised as TB6600s but which are, in fact, TB67S109AFTG drivers.



Taking one apart...



No TB6600, but on the rear....



A tiny QFN package, pasted to a bit of a heatsink that is then coupled to a secondary heatsink.

After you've been caught once with these, spotting them is pretty easy. For one thing - they advertise a 32 micro step, which isn't supported by the TB6600 (only 16 micro steps).

There's some discussion online that supports these as a reasonable alternative to the TB6600s, but you need to read the data sheets and understand each on their own merits. Personally, I think the thermal solution on these is poor - you could end up with the chip shutting down under load. The R(on) is 20% higher than a 6600 (that's a bad thing that exacerbates the thermal solution). The max clock is 100kHz - doesn't sound bad unless your using 32 micro steps (then it's 100,000 / 32 microsteps / 200 steps/revolution stepper = 15.625 revs/sec, or 937.5RPM max out of the stepper (the 6600 is rated at 200kHz, and only supports 16 micro steps). Lower working voltage and lower drive current (4A vs 5A). Although rated upto 50V worryingly the 67S109 data sheet gives typical characteristics at 24V.

I bought them, and they didn't work well for me (missing steps), but my replacements (TB6600s) also had similar problems that needed the optoisolators updating. I'm not saying they're good, or bad, but different to that advertised.