Ogre 4x8 turn key plasma table

[jeepsr4ever]

There may have been a change to the drive pulley so try 19.35 as your ratio. Also go into Mach 3 settings and click THC corrections to -.02 and leave the positive number at +0.100. You can also boost your antidive to 80-90 and that should work great.

[_Ogre]

thanks. i'll try those tweaks

[jeepsr4ever]

PM sent

[_Ogre]

the rotary table is working well now after talking on the phone with matt. still not sure what fixed the problem. we still had some discrepancy when reversing directions, some were cutting some left 1/16'' uncut. i pulled the cover off the rotary head and found some play in the motor pulley, tightening a set screw fixed that. thanks for getting us going.

[jeepsr4ever]

Fantastic! Be sure to drop some pics when you can

[_Ogre]

still working on the rotary table. right now my max speed is 48 fps which is half of what i have entered into sheetcam and mach3 profiles for finecut consumables. we have the acceleration down so low that it takes forever for the rotary table to speed up. we turned the accel down on x and b axis's so the tube would cut all the way around. both axis's almost stop as x axis changes direction on a tube cope. the accel is so low that when i rapid travel x axis, it takes over foot to stop when the control is let loose. in flat work the axis's stop with in an inch or two.

cutting 16ga ss tube 2.5'' and 3'', getting a lot of dross because the rotary is cutting so slow. suggestions?

[_Ogre]

my 48 fpm speed is rough calculated by timing the cut.

[jeepsr4ever]

48FPM = 576 IPM that would be too fast so I am thinking you meant 48ipm. Also did you loose a number in the reduction? The system like any other CNC system that uses acceleration chooses a point to start a decal and that point is further away from the target the smaller the number. If your numbers for division are correct you should have no problems getting a full rotation. The other thing that can cause that is no pierce delay with the plasma cutter on low amperage. Meaning is doesn't pierce the tube for 1/4 of travel.

[_Ogre]

yes. i meant ipm. i also used fps which would be ridiculous.

honestly, i am impressed with how this table cuts flat plate. i need to post some of my success pictures on flat plate. (need to take them too) i'm so focused on getting this rotary table working that i overlook the flat plate cutting i've done. i drew up a fixture, cut it out and welded it together yesterday and today. easy peasy. i'm getting clean cuts and sharp angles on most flat cuts.

i figured out why the tube wasn't cutting all the way around. or at least figured a way around it. my tube measures 2.55'' diameter, the drawing is 2.55'' around; but i had to enter 2.5'' in mach3 rotary screen to completely cut the tube. no problem there. i figured it out when i cut a 2.55'' tube at the 3'' setting and it cut way to far. the fix/math was easy after that.

back to my problem areas... i'm not sure the dthc is working correctly. when cutting tube the torch touches off, starts cutting and finishes one cut. the next cut the tube may wobble a little from the torch touching off. from what i read of the dthc is it should go up and down as the tube wobbles. instead it goes from long arc to scribing a line on the tube as the torch cuts out midway in the cut. i've repeated the cut and watched the z axis motor; it does not move after initial pierce adjustment. i'm also getting extreme dross on the rotary head cuts. i figure this is from slow speeds and accelerations.

in my extreme dthc test (pic below); where i'm trying to cut an oval in a fixed pipe the z axis does not move at all after the initial pierce adjustment. with my thc voltage set to 100 volts, i see the voltage climb to 128 volts with no movement of z axis. i understand i will not get an optimum cut doing this method of cut but we have a specific need to do this. the thc lite blinks and the thc on line lite is lit. all the tests for z axis reference back to home switches of which there are none.

i will call you tomorrow.

[jeepsr4ever]

You might want to try giving it a 3 second THC delay.