LMS 3990 cnc conversion

miffyfoof

Registered
Registered
Joined
Sep 30, 2019
Messages
2
Hi everyone this is my first post here

I'm supposed to get my LMS 3990 soon. I ordered the heavy metal CNC conversion kit. Having used the mini mill in the past there are some things that I want to address. Firstly there's the rigidity of the column, even though its a solid column there is still a significant amount of chatter and flex due to the light weight nature of the machine and the thin walls of the cast iron. To fix this the column is going to be filled with something (the exact material is tbd, lead shot, sand epoxy ... etc) and stiffened with a beefy aluminum brace and column riser. The column brace has raised sections where the bolt holes are for shimming. The purpose of the column riser is actually not predominantly to increase Z travel but to increase stiffness because the less stiff column is raised on top of a stiff cast iron block. Attached below is also my electronics test board, the system is using linuxcnc through a parallel port. The motors turn but the exact microsteps and holding current are still a mystery to me since I don't have the mill yet. Additional planned upgrades include an enclosure, flood coolant, and a power drawbar.
 

Attachments

  • Annotation 2019-09-30 212616.png
    Annotation 2019-09-30 212616.png
    154 KB · Views: 26
  • Annotation 2019-09-30 212759.png
    Annotation 2019-09-30 212759.png
    980.2 KB · Views: 27
  • Annotation 2019-09-30 213805.png
    Annotation 2019-09-30 213805.png
    58.8 KB · Views: 24
in the meantime I've also been 3d printing motor wire housings and wire strain reliefs. Currently I'm using db9 connectors and cables for the stepper motors but will likely change in the future.
 

Attachments

  • Annotation 2019-09-30 214411.png
    Annotation 2019-09-30 214411.png
    66.9 KB · Views: 23
  • Annotation 2019-09-30 214502.png
    Annotation 2019-09-30 214502.png
    479.9 KB · Views: 22
Back
Top