On 04/04/2013 02:54 AM, Gregg Eshelman wrote: > Anyone using LinuxCNC with a CandCNC Dragon Cut system? That hardware > looks like the perfect setup for a large plasma table, provided I can > keep the gantry weight down. Would definitely save a lot of time > making bits and pieces from various sources work together. > > I still want to make a few pennies scream by using free software > instead of Mach3. ;-) > > What bugs me about it, and many other kits for plasma tables, is the > motor for the Z axis is waaaayyyyy overpowered. 620 oz-in for moving > the gantry, but for raising and lowering a torch head that only > weighs a few pounds? > > The only other motor option they show is all motors at 300 oz-in. > That's still using a sledgehammer to crack eggs for the Z axis. > > Now if I could come up with a way to use all that excess power, > perhaps a second head fitting with a drill chuck and its own spindle > motor, use the 620 oz-in grunt to push it down.
Don't be so sure it's excess power! The biggest thing is that you need to be able to accelerate the Z quickly for direction changes. The faster the X/Y axes move, the faster the Z has to accelerate. In order to get the best cut on thinner metal (which is mainly where you need a THC), you have to move the gantry quite fast, and so the Z has to be able to keep up. For instance, the Hypertherm manual calls for a rate of 350 in/min in 16 guage mild steel with a 45A shielded tip for best quality, and 400 in/min for production. I have seen tables that were able to move at the speeds required for the material thickness, but the Z limited it so the whole thing had to be slowed down. Moses ------------------------------------------------------------------------------ Minimize network downtime and maximize team effectiveness. Reduce network management and security costs.Learn how to hire the most talented Cisco Certified professionals. Visit the Employer Resources Portal http://www.cisco.com/web/learning/employer_resources/index.html _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
