Pattern carving above surface

[shadowcarve]

Am carving a photograph, something I regularly do. This time, although pattern shows correctly in the software, it is actually carving a bit above the surface. Bit only touches down into the wood intermittently when actually it should be in the wood all the time.
Any ideas?

[RayTrek]

Welcome Shadowcarve,

I am sure there will be many ho can help you get threw this, I have two jobs today so I will only be able to get you started with trouble shooting,
1) With the power off check your Z truck for a nice smooth up and down motion, if it is rough or sticky it may have thought it touched the board and is carving where it thinks the board surface is.
2) Watch to see if when the machine is going threw its measurement that the bit touches the board.
3) If this does not work post the mpc so others can see your layout
4) Also, check that your Z motor encoder is free of dust (3 screws 2 with little nuts that you do not want to fall into the machine) pull the dust cover on the back of the Z motor and check.
Hope this helps ~ Ray

[Digitalwoodshop]

The most common thing that does this is when the bit is going down to touch the bit flag it stops before actually touching the bit flag giving a false length.

You must always watch the bit flag hit, it is an indicator of machine health...

A lump of dust on the Z Rails, a wood chip in the cogs of the Z Belt.... All cause the Z to HIT SOMETHING and that is what the computer is looking for... A increase in current in the Z Motor.....

Clean the rails and belt...

I bow air into the z belt EVERY bit change....

AL