[dbsharp]

Machining FSAE Bellcranks On My CNC - YouTube

[СССР]

Hello dbsharp,
Thank you for sharing your design. Looks fantastic. I'm new to CNC design. Could you please share photos or just just explain how did you design your X (long) axis movement ? Did you use some kind of a rail or just use an aluminum as a surface ?

Thank you in advance.

[dbsharp]

Ball screw in the center with thk linear rails on the underside of the bed.

[Sesh]

Ball screw in the center with thk linear rails on the underside of the bed.

dbsharp, you also said you used epoxy to hold the rails in place. I'm also trying to build a machine using tslot sections, and am concerned about the friction hold of the rails with tnuts in the sections. Though the flexibility to adjust individual t nuts to achieve parallelism is useful. Did you align your rails, and then pour the epoxy? Did you use any additives? Any details on this process will be greatly appreciated.

Regards,
Seshadri

[dbsharp]

dbsharp, you also said you used epoxy to hold the rails in place. I'm also trying to build a machine using tslot sections, and am concerned about the friction hold of the rails with tnuts in the sections. Though the flexibility to adjust individual t nuts to achieve parallelism is useful. Did you align your rails, and then pour the epoxy? Did you use any additives? Any details on this process will be greatly appreciated.

Regards,
Seshadri

I just poured it and tightened down the rails too the epoxy bed. Its a "precision" leveling epoxy and as far as I can tell it lays down pretty flat if its is tick enough. I have indicated off of a large precision square and the axis seems to run straight to ±.001". Considering its a weldment that got no stress relieving thats not too bad.

[dbsharp]

I have uploaded models to Grabcad for this machine. Good luck to anyone who wants to make one. I also posted my 4th axis. https://grabcad.com/library/sharp-s-cnc-asy-1

[dbsharp]

I have occasional issues with this machine on rapids where the motors just dont want to keep up. Being closed loop steppers, they get there but you can tell they lose position. I have done some analysis and will share this. The automationtechnologies (leadshine) closed loop steppers seem to get bogged down from the drag in the ball nut when they are dirty. Even with this they are light years better than the steppes I used to run.

I have decided to gear them down, and I have charted the force and speed with the gear reduction, and this seems like a no brainer now that I can see the data.

I also measured current draw on my machine to determine the power supply needed for my Lathe project https://www.cnczone.com/forums/verti...6-cnc-cad.html.

Max sustained amps were measured at motor speeds of 750-1000 rpm with me pushing hard enough against the machine to make the motors have some positional error. This is where this drive kicks on higher holding torque to catch back up. I'm 6ft3in and 300 lbs and this was actually pretty hard to do on the bigger motor.

KL-8082H with KL-34-8N-1000 at 72V: Max sustained 4.2 amps with around 1-2 under normal circumstances

KL-5080H with KL-23-2N-1000 at 40V: Max sustained 2.2 amps with around .5-1 under normal circumstances

[CarveOne]

Glad that you got that issue sorted out.

I'm still using the heck out of my standard step motors, but haven't had any problems with them so far. Have to keep the mechanics lightly lubed and clean off any dust and debris. All of my work since building the last two machines in this forum is shown on the Vectric Aspire or Vcarve Pro forums.

Carry on sir, the rifle stocks look superb.

CarveOne