Just for Fun

[msimpson99]

I have been working on one of the prototypes for my first plasma CNC book. I was doing some speed and acceleration tests and while running at almost .6 Gs, I decided to un tether the machine from the wall and raise the levelers so it was riding on the casters.

She is running at about 3000IPM at .6G

https://youtu.be/3k_s_AIoajU

The current prototype now has the X and Z axis attached so it has even more mass. Will have to let her out for a little dance to see what happens.

[SeanP]

Wow that thing fly's!

[msimpson99]

I am probably going to change it over to R&P as the belts tend to wiggle on the Y axis when doing high G's, due to the mass of the gantry. I will do more research as the belts are a very easy to hookup. When doing R&P, you have to add a spring tensioner to the pinion. Cost works out about the same though.

[msimpson99]

I found out much of the wiggle was in the bearing blocks. They have small grub screws to loosen or tighten the bearings against the shafts. What I did was to tighten each bearing until I could hear the balls clicking, then backed off until they stopped. This gave me a very smooth run.

In this video I have the homing switches installed and am doing a 5 hour break-in.
https://youtu.be/vqk2CgkyiWU

Its running at 500IPM at 0.4Gs. I still need to design the floating head. I want to make it so the main plate that holds the torch can be slipped off and another one inserted that holds a router.

I have all the parts for the slats, but want to be able to install a temporary table for routing that will set on the top of the slats.

[jimcolt]

Realistically if you can achieve 400 ipm at .3 to .5 G's acceleration rates then that is where you need to be for ideal plasma cutting conditions on thin materials. The acceleration is important so that the plasma does not dwell on small holes, cornering and fine detail. When you have that kind of speed you also need very tight mechanics.....zero backlash and flex on each axis....then you need to tune each axis through the drive software to ensure that at the max acceleration that the machine stays on path (know as "following error". With any machine that is tuned too hot....expect oscillation during acceleration and high following error numbers (the path the torch follows as compared to the programmed path).

On high production plasma machines used for industrial applications high traverse speeds are used to increase productivity....essentially shortening the time between nested parts on a large cutting table.

Nice videos! You could probably add a musical soundtrack for a great effect!

Jim Colt Hypertherm

[msimpson99]

This particular build is meant to be a very low cost DIY build, yet will produce good consistent cuts.

I set the following goals for this design:

• Low Cost
  Repeatability
  Ease of Maintenace
  At least .3Gs (As per another post you did)
  Relatively small size of 32" x 32" to 36" x 36"
  Up to 500IPM Cutting with 1000IPM Rapids.
  Able to handle smaller plasma cutters

I try to get the machine going as fast as I can in the early stages. I know as I start adding mass to the gantry and Z-axis, the speeds and acceleration will need to come down.

Notice the Corian used on the Z axis. I tend to use this when prototyping as its cheaper and easy to work with, while still rigid enough. Once finalized, It will be made out of aluminum. This, and the floating head will add much more weight.

I'm still debating if I want to go with the R&P on this build or stick with the belts. The belts are PowerGrop GT 3 Belts, and seem to be working very well since I tweaked the bearing block tension. Im running direct drive, but my electronics seem to be dealing with it very well. Lots of torque at the motors. I still have to do some more calibration and testing so, things may change.

Wait till I start my crash tests. This is when I really put things to the test. I'm not sure how well the belts will hold up.

[msimpson99]

Here I added some music to the crazy video.
https://youtu.be/3k_s_AIoajU

[little blue choo]

LOVE THE VIDEO! That thing is moving.

Rick

[david47julie]

That is very interesting it made me think that if I put shorter legs on my plasma cam and put it on a table and limited the travel and acceleration and deceleration with spring, small air cylinder,shock absorbed or something of that nature it would lesson the shock load on the P&P components when cutting arts stuff I know you would have to secure the material to the table so it doesn't move in relation to the table ( I seldom cut above 150 ipm on arts stuff because I don't like how violently it moves ) I know all this may not be practical and would only be applicabel to small and light machines but it is interesting to think about. thanks for video