Losing steps

[Edendale]

My first attempt at 3D carving on my Chinese 6040 router came out really well and so did the next one, but now when I start the Z axis is getting higher the longer it runs, on a file that is 200 x 150mm after a quarter of the way through it ends up being 8mm above zero, I’ve checked to make sure everything is tight and running freely, not sure what is going wrong. Regards, Mike.

[JAZZCNC]

If it was working correctly and you have changed nothing regards settings etc then it can only really be a mechanical issue. It will either be a slipping motor coupling or the Axis is binding up causing the lost steps.
If it's a different file with different settings then you could just be pushing the machine too hard. To test just lower the feed rate and see if it happens.

It could possibly be electrical noise but It would be random and would have happened all the time.

If not settings etc then I would start by marking the motor coupling and motor shaft to see if you got any slippage.

[NordicCnc]

I had a similar problem when using parallel port on windows 10 and Mach3, while running 3d g-codes (X,Y and Z simultaneously). I swapped to a ethernet smoothstepper (ESS ) control board and have not any issues since!

Was the first carving program also 3D or was it 2D? Becuase 2D worked fine for me, but not XYX movements at the same time.

[Neale]

I'm wondering how complex your first "3D" carvings were? There is a not-uncommon problem where the polarity of the "direction" pulse is reversed. The effect is to lose one step every time there is a direction change on that axis. If there aren't many direction changes it might not show at all but where there are many changes you see exactly this effect. With a commercial machine this should all be set up correctly - but I've met one Chinese machine where the target for a proximity switch was a broken tap. And it would have worked fine except that it hadn't been adjusted correctly even though it did have a correctly fitted locknut! So you can't take anything for granted until proven. Slipping coupler or similar has to be the first place to look - mechanical issues are the most likely if it was working fine - but the dir signal polarity thing is not impossible and very easy to fix.

But if this is a repeat of a carving that has already worked fine a couple of times, then forget I said anything!

[JAZZCNC]

Was the first carving program also 3D or was it 2D? Becuase 2D worked fine for me, but not XYX movements at the same time.

I'm wondering how complex your first "3D" carvings were?

But if this is a repeat of a carving that has already worked fine a couple of times, then forget I said anything!

Look at the picture he posted up you can clearly see it's 2.5D so it's lots of Z moves. I think it's probably pushing the machine too far regards feeds n speeds. If it's not slippage.

[Edendale]

When I levelled the waste board it didn’t lose steps at all, I’ll try and do an engraving and see it it’s the same,

[Edendale]

When I stripped it down it was sticking at the bottom of travel on Z axis, I lowed the spindle so as to miss out the bottom of screw, I try and do it slower and see if that works ��

[Edendale]

When I stripped it down it was sticking at the bottom of travel on Z axis, I lowed the spindle so as to miss out the bottom of screw, I try and do it slower and see if that works ��

[Edendale]

Hi Dean, you were right, I ran a file and lowered speeds & feed and it didn’t lose any steps, guess I’m just going to have to be more patient, I contacted the seller in China about the wiring fault and they sent me a replacement breakout board & stepper driver in case I have problems,
Regards Mike.

[JAZZCNC]

Hi Dean, you were right, I ran a file and lowered speeds & feed and it didn’t lose any steps, guess I’m just going to have to be more patient,

Hi Mike, yes, unfortunately, that's the problem with these cheaper machines, they are great for learning on but they are slow and limit the quality of what can be done. However, if your patient can still give very rewarding results.