Optical encoders with DC motors

tommylight wrote: Your motors are rated at 50W, probably 100 to 120 in short bursts and that is plenty for a light gantry plasma cnc. A while ago i had build a 2X1.25 meters plasma cutter with nema 17 motors and it ran fine, never skipped a beat. Had to change the motors as whoever took a look at it started complaining that the motors are to small.
Use small pulleys on the motors and try to get the ratio from 1:7 to 1:10, you would be surprised at what can those tinny motors do.
Or just mail them to me, and i will name the machine i use them on "the RodW" !!!

Tommy, you are full of great ideas so thanks. With a bit of luck I will have forgotten your mailing idea by the time I find where I put them!

Have you seen: emergent.unpythonic.net/projects/01142347802

(CNC Etch-a-sketch)

cptX wrote: Guys, here is the result of my work over optical encoders and PID control in LinuxCNC the last days:

That looks like a pretty good basis for a pick-and-place machine for PCB assembly. (and you could also use it to apply etch resist to PCBs, ordinary OHP marker pens work just fine as etch-resist.

Hi andypugh, yes I know the etch-servo project. I was based on it to create mine.
pick-and-place looks very complicated.To apply etch resist looks more feasible.
From my experience on the machine you saw in my video, I can say that if the forces are great then when approaching to final positions you have some delays. I trimmed the PIDs when the heads were alone. I didn't retrim it after the final assembly. Also the speed you see in the video maybe the 1/10 of what is possible with these motors. But the whole assembly has a lot elasticity and backlash, so I cannot run it much faster. Actually these printer heads are very cheap quality...
Good quality heads have metal bearings on the guides. This had only plastic and not fitting very well. I 3D printed afterwards some bearings to reduce some plays.

rodw wrote:

tommylight wrote: Your motors are rated at 50W, probably 100 to 120 in short bursts and that is plenty for a light gantry plasma cnc. A while ago i had build a 2X1.25 meters plasma cutter with nema 17 motors and it ran fine, never skipped a beat. Had to change the motors as whoever took a look at it started complaining that the motors are to small.
Use small pulleys on the motors and try to get the ratio from 1:7 to 1:10, you would be surprised at what can those tinny motors do.
Or just mail them to me, and i will name the machine i use them on "the RodW" !!!

Tommy, you are full of great ideas so thanks. With a bit of luck I will have forgotten your mailing idea by the time I find where I put them!

Or something like this :






They can etch on any hard surface so very useful.

Very interesting Tommy. I had thought of doing a CoreXY something or other. So this is ideal as there is no need to build a Z axis.
How fast would those spindles be?
What software is needed to generate the gcode?