Help needed

[Clive S]

So I repented my error and got the Z axis within 0.02mm left to right. Just don't know how to correct the 1mm drop over 400m on the Y axis. Good job `i am commissioning a new machine. Problem is I am asking my little machine to do tough work. Thanks for shaming me to get out the allen keys and dial gauge.

Is it out by 0.5mm over 200mm ? if so the steps per might be wrong

[cropwell]

Is it out by 0.5mm over 200mm ? if so the steps per might be wrong

Clive, I don't think this will be the case. More likely the frame geometry.

Peter, If it is cutting squarely on the X-Y plane, then the easiest thing to do is put an MDF sacrificial bed on and machine it flat with a largish cutter. IF that produces a rippled surface, then your Z axis is not going squarely up and down, again geometry!

You are a lucky bugger to be in a position to order a new machine from Dean. I would if I could, but only so he would not be able to criticise it (not that I would expect it to have any flaws )

[AndyUK]

Peter, If it is cutting squarely on the X-Y plane, then the easiest thing to do is put an MDF sacrificial bed on and machine it flat with a largish cutter. IF that produces a rippled surface, then your Z axis is not going squarely up and down, again geometry!

Can we deviate slightly from topic and discuss this? As a rather inexperienced user, I'd have thought that ripples here would indicate that the spindle isn't trammed - I wouldn't have thought a misaligned Z axis will show when the cut is at a constant Z.

[cropwell]

Can we deviate slightly from topic and discuss this? As a rather inexperienced user, I'd have thought that ripples here would indicate that the spindle isn't trammed - I wouldn't have thought a misaligned Z axis will show when the cut is at a constant Z.

If the cutter face isn't square to the bed, when you cut it will do an angled cut. The larger diameter cutter you use, the more the effect. This will make a sawtooth wave ripple on the bed and it is quite noticeable. the distance between the ridges will depend on stepover. I am assuming that you use a raster or spiral pattern, trochoidal will be less noticeable.

This error will also be noticed on the side walls of a deep cut.

[Clive S]

Clive, I don't think this will be the case. More likely the frame geometry.

Is it out by 0.5mm over 200mm ? if so the steps per might be wrong

So I repented my error and got the Z axis within 0.02mm left to right. Just don't know how to correct the 1mm drop over 400m on the Y axis.

Yes you are correct Rob I was reading it as it was out from 400mm to 399mm and not the drop in Z