CAD/CAM Tips Thread...

GSPBASSES

Gizmo said:

So, one small tip if your going to self build and config a home CNC...DO NOT USE the TB6600 Stepper drivers

After cutting all the inner body routes on this Ash sc 5 string bass without issue they lost stepping while 18mm down in the outside body pass (step over was 1mm so the bit wasn't rubbing/tight at all) and locked up the machine scary!.

I can recover/fix this piece by altering the profile for that aera by a few mm (i dont think it will look that bad or the other option is to fill and paint...)

I have some DM556 driver's coming as replacements,which now i look on YT for the problem loads of people have had issues like this with the TB6600 ir seems.....humm.

I haven't been a CNC operator for over 30 years, I used to do most of the programming line by line, the software we had back then didn't do very much for you. But one of the things I always did after the machine had done major cut I program the machine to send everything back to 0, then the machine would start running the program again. If it had lost any steps it will put itself right again, then carry on with the program. I should add I was machine in stainless steel not wood. the company eventually converted all the CNC's to servomotors and stop using stepper all together. 

Misterg

Gizmo said:

So, one small tip if your going to self build and config a home CNC...DO NOT USE the TB6600 Stepper drivers

I've also had one of them fail on me. Stopped working halfway through a job (and cost me a cutter), but seemed to be working OK after a power cycle. The construction inside is pretty poor as regards to thermal management. I though I had fixed mine by cleaning things up and adding some more heatsink compound, but it failed again shortly after (I was watching it like a hawk, so no damage). Power cycled it and it worked again. Now in the bin.

I replaced them with 'DIV268' ones. They're really crude and noisy, but cheap and hopefully more reliable.

Incidentally, the 'TB6600' branded drives as in the photo don't use the TB6600 chip (good for 4.5 amps) - they seem to use a different chip that's only rated at 3 amps (despite the settings on the case). The TB6600 chip only goes up to 16X microstepping, but those 'TB6600' drives offer 32X microstepping...

Sporky

The heatsink on those does look minimal. Each of my Gecko drives has a big (40mm deep) heatsink, plus a fan.

Misterg

Sporky said:

The heatsink on those does look minimal. Each of my Gecko drives has a big (40mm deep) heatsink, plus a fan.

It's not the heatsink so much as the thermal path from the chip to the heatsink (I had my drives mounted on an external heatsink, anyway).

The silver square is a piece of guillotine cut aluminium sheet (i.e. not flat) that's stuck to the (surface mounted) chip with a dab of thermal paste. The screws holding the PCB in place press this gently onto the completely dry heatsink (the black thing) - you can just about make out a witness mark where it's been. I had thought that adding some thermal paste there would help, but it didn't.

Sporky

Oof. That's not going to do a lot of good! 

Gizmo

Hey Guys

Thanks for the feedback, since doing some more digging on these "maybe" TB6600's it seems a lot of folk have had a whole host of problems with these drivers so mine are just going in the bin.. i don't even feel good about giving them away!.

the DM556 replacements i purchased have arrived

And these have a much much better build qualitiy, won't get chance to install them till monday as im a bit flu'ed up atm

While im in the groove for chanhing the Drivers i've decided to jump from GRBL/UGS to Fluid NC/Gsender

(i know,i know when trouble shooting dont add extra things to the mix )

the great thing with FluidNC is that you can switch the pinout's with a simple Yaml/config file and not have to recomplie/upload to alter settings, it also has it's own built in Gcode sender which runs directly from the board which should be handy.