Z axis error woes

[HankMcSpank]

This would have probably been good Info to tell us at the start don't ya think Hank. :rofl:.

Which bit?!! (there's nothing confirmed about the driver board - just an inkling only that it might be the problem ....it's certainly caused me no end of problems & googling reveals that A3977s should never be socketed blah blah). The significant part for me was that one remaining A3977 on my board is still fully working & therefoe allows microstepping, so yesterday I dropped that particular chip into my stepper board's Z axis position ....my probed errors became less (about 0.1mm vs 0.350mm over the same 10mm Y0->Y10 probing run ...now if it was mechanical or bed levelling, I reckon the error would be the same no matter what the resolution of the steppers.

I wasn't keeping this a secret - my 'post 11' on this thread yesterday alluded to this!

the thing is I'm likely to be coughing up for a better machine (which will come with very good stepper drivers), so just need to limp on investigating as best I can ...probably until the chap I'm buying off has more machines in stock (22nd feb)


oh...btw - All your jokes are falling ahem 'flat' :heehee:

[JAZZCNC]

LMAO . . .Can't come back at that one Poz. . :clap:

[Swarfing]

Hank what about just lifting the holders and soldering the QFP's directly to board?

Thanks Jazz at least it was us not STEPPING out of line here.......:naughty:.....My last one promise

[JAZZCNC]

I wasn't keeping this a secret - my 'post 11' on this thread yesterday alluded to this!

Ye but you should know by now Hank I only read the first and last post's. . .:heehee:

[Swarfing]

Jazz your as bad as me not reading it all as well! Apologies to Hank:whistling:

[HankMcSpank]

Hank what about just lifting the holders and soldering the QFP's directly to board?

Well I have 3 '(likely fake) A3977s winging their way to me from china ...once they arrive, I'll look at doing something like this.....

[HankMcSpank]

Ok...solved!

It was my stepper board after all. This mnorning I managed to wire in a nasty Chinese TB6560 based stepper board (in place of my easy-cnc 3 axis board).....selected 1/8 microstepping, calibrated my axises -BINGO! (so as suspected a combination of low axis resolution & then missed steps which was causing large errors on my Z axis (& likely the other axises too)

I'm now quite content with the results, certainly the SOT23-5 (which only has 0.4mm of space inbetween the pins!) is fine by me....
(the pic below is massively magnified - that main IC toward the middle of the photo is an SOIC-14 package ...which is just about 8mm long)


(the stray islands of copper you see randomly peppered about the board - eg just above & below the SOT23-5 pads - I'm not worried about them, so it's not in my g-code to remove them)

Thanks for all your input....it's nice to put this one behind me!

[Jonathan]

Result looks great from here. What V-cutter did you use (angle, flat width)?

[HankMcSpank]

That was a cheap carbide V cutter from China - 20 degree angle, 7500rpm (ie the fastest my spindle goes), about 0.15mm depth)

[Swarfing]

Grand job Hank and good to see you are on your way again. Well done