I’m still having issues with my machine

(George Allen) #1

I’ve been having problems with my controller settings or mechanical issues as my machine is not making smooth moves and messing up cuts. I tried the v-carve trial cut “Bullshead” with a 60 degree v bit and got these. The bottom one (I assume) was cut with Z-0 being too low. I was guessing at the height it should be on the top one and it did better but you can still see how the router moves were not smooth. Any ideas??

(Michael K Johnson) #2

You’ll probably want to provide a lot more detail for folks here to be able to help. Machine and controller to start with (you might put them in your profile so they are available without having to add the to every post). Also, the speeds and feeds you attempted here. What depth of cut? What spindle speed? How many inches or mm per minute in X and Y? What fixturing did you use with this board? Clamped to spoilboard? Screwed? Taped?

I don’t know how much experience you’ve had with CNC, but you might want to start with something more consistent than the pine board you are using. MDF is probably better. If you’ve used a hand router in pine, you probably know that it can “grab” as you go through the grain. That still happens with CNC.

(George Allen) #3

Apologies. I built my own machine. It has an ESS ((Smooth Stepper) motion controller connected to a PMDX-126 BOB. I’m running a three axis machine using Mach 4 controller software. The external drivers are all DM542T stepper drivers with dual 425 oz-in NEMA 23 steppers driving 2010 Ballscrews on linear rails. The X axis is a smaller torque NEMA 23 driving a 1605 ballscrew on linear rails and the Z axis is a NEMA 34 driving a 1204 ballscrew on linear rails. The frame is made of 80/20 aluminum extrusion (profile 3030). I’ll include a photo:

(George Allen) #4

I no longer use the pulley for my Z axis, it’s direct drive.

(George Allen) #5

When I ran the trial cut, I didn’t see anywhere in the vectric software to enter feeds and it seemed to ignore the relatively slow speed I use. I’ve had to lower my max velocity in Mach to 1800 mm/ min as well as lowering the acceleration. When the gcode was entered into Mach the controller sounded like it initially missed some steps, but not on the top cut.

I’ve actually had better luck cutting pine and cedar than MDF. I tried to limit the depth of cut to.2 inches. I think that’s what I entered into the vectric software system. I’m not too familiar with v-carve so I tried to use mostly the values they had. The issues I’ve been having, though occurred on the other programs as well. I’ve been experiencing shuddering and staggering with some motors and have tried all technical functions I know of to remedy it (extending look ahead lines from 20 to 190. I have switched from exact stop mode to constant velocity, but I’m not necessarily sure it’s just around arcs.

(George Allen) #6

Made a little bit better cut today on plywood. I switched micro stepping from 1600 steps per rev to 3200. Slowed the feed to super slow.