first of all sorry, if this topic does not belong here, yet I struggled to find a proper category for my issue.
My CNC machine has issues to create straight lines, whenever I try to engrave a letter. Cutting out the material is absolutely no issue. Kindly see the image attached.
Holes also seem to be not exactly round.
Specs:
Machine:
HGR-15 rails on all axis (1200mm X & Y; 300mm Z)
Closed-Loop Nema 23 steppers with 3Nm and HSS57 drivers (2x600W 48V power supplies)
2.2kW air cooled chinese spindle
T12 rods on X- and Y-axis(8mm pitch) (1200mm)
SFU1204 for Z-axis(300mm)
MKS DLC V2.1 as controller
EstlCAM V11
All wires are shielded
These forums focus on the machines designed by V1Engineering. So random makes sense to me. Most of know these machines and the common failure modes well. But not your custom CNC.
It looks like something is loose. Or there is a cracked part somewhere. It may also be significant chatter. I was scared away from the chinese spindles a long time ago because they used rubber bushings that had a ton of runout under significant load. I haven’t seen anyone complain about it in years though.
You can try cutting in HD purple foam. That will be zero load and if you still see the waves, then you can narrow down the scope. You can also try putting a dial indicator on the bit or collet and add a load to different sides. I attached a 5kg water bottle on a string and hung it over the side of the table. You can think of similar ideas to try to measure some deflection. If something is moving, then you can move the dial indicator (or just watch with an error that large) and see where it is moving/flexing.
You can also preview the gcode in an online gcode preview. To make sure it isn’t in the gcode somewhere (but I doubt it).
Lastly, make sure you bit is sharp and has the right geometry for CNC/side cutting. If your bit was working hard and got dull in the middle of the cut, it will flop around instead of cutting and that could explain that wave pattern. The bit is skinny in one direction, so it can kind of squeeze through if it ended up dull.
