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.

_Ogre

still working on setting this table up. working on a coolant pump setup so i can cut tube.

i'm using the rotary head on my plasma table to cope ss exhaust tubing for making h-pipes. i'm getting extreme slag deposits on the bottom of the tube where the plasma cutter sprays. this is not dross hanging off the cut, but built up inside the tube. this makes it hard to expand and slide together.

thru trial and error i figured out to run water from the water table thru the tube to cool the slag before it sprays on the tube. the blade runner has 2 aux outlets built in the control box. looking thru the mach3 manual i believe i can use the m7 and m8 to turn on these aux outputs on and m9 to turn them off. config -> ports and pins -> spindle setup -> flood mist control.

anyone know how i can add m-code into the g-code to make turning the aux outputs on and off automatically?

this is what i'm cutting with the rotary head

this is where they go in the exhaust system

and this is one of my first cuts. you can see the slag build up inside the tube, i get minimal slag if i run water thru the tube.

jeepsr4ever

Air mister through the tube or even air through the tube helps. You can try dropping your amperage for tube cutting dramatically.

_Ogre

i have the rotary head working fine now. use a small pump to run coolant thru the chuck into the tube to keep slag from sticking to the inside of the tube. inserted a few gcode mods: one M7 at the beginning of the cycle to turn the coolant on and an X15 at the end of cycle to move the torch out of the way for load/unload of the part.

you can see both gcode mods in the video. coolant on at the beginning and x axis move to clear the part.
i've been using the x axis moves for loading/unloading a lot as most of our cutting is production parts

youtube video of rotary head cut

[video=youtube;Ilc_ldF7eLE]https://www.youtube.com/watch?v=Ilc_ldF7eLE[/video]

_Ogre

first time cutting thin gauge steel. 22 ga steel, 315 ipm, 120v; dross free cut.
problem is the corners should be sharp angles, like the starts, not radiused corners.
what happened?

jeepsr4ever

You have exceeded the acelleration and cornering threshold at 315ipm. From here if you want to cut that fast youll need to start to play with the CV settings. CV DISTANCE TOLERANCE is the distance from the end of the line to where the arc starts rounding (.03-.05 can be tried). CV settings do a sharp stop at any angle greater than the angle you set in Mach3/Config/General config. You can try setting CV STOP ON ANGLES GREATER THAN "60" or "80" or even "90" degrees and also click the box to activate and restart MACH. Now here is where the challenge starts. When your cutting the machine will come to an abrupt stop then take off in the other direction. We know that the HAZ will melt away more material without ramping down the plasma cutter. This is the biggest difference besides the actual beam intensity between plasma and Hi Density/Hi definition plasma. Cutting shapes as we send the machine out from us is setup to calculate the algorythm for motion using the acelleration and decelleration numbers for X and Y. Defeating this to gain and exact stop can cause overburn. It is always best to run fine cut consumables and slow it down unless you can ramp down air pressure and amperage while your cutting (RAMP DOWN AIR AND AMPERAGE...THIS IS A SERIAL PORT CANDCNC FUNCTION THAT IS AVAILABLE HOWEVER IS REQUIRES THE SHEETCAM DEVELOPMENT VERSION AND ACTION POINT DEFINITIONS, CURRENTLY NOT SUPPORTED BY BULLTEAR BUT COULD BE RETROFITTED TO YOUR PLASMA CUTTER). The alternative is to increase accel numbers for X and Y to 50 however lost steps may occur.

_Ogre

thanks for that, but no upgrades in our future. i have no need to cut at those speeds. just following the cut speed in the hypertherm manual. what ipm would you recommend? i was amazed at the cut speed when i hit start. i called the mechanic over to see, but by the time he got there it was done cutting. long done :D luckily that was a test cut for fit

jeepsr4ever

I have personally cut at 800ipm on a Bulltear table but that was very simple geometry on 28ga. 60 to 80 percent cut speed above 180 imp is a safe barrier. The machine is quite capable of high speeds however the absolute stop will cause dross buildup.

_Ogre

i slowed the cut speed and voltage to 180 and 80 worked fine, warped the crap out of it but cut fine.

new problem today with the rotary head.
tried to cut text in a 3 inch tube, turned out like the first pic.
i re ran the text for flat cutting and the file cut fine.
will call you to fix this.

i figure it's an acceleration thing, we have the accel turned way down.
in rotary plasma the gantry is slow to accel and when i let of the joy stick it coasts 18''
in flat plasma the gantry accels great and stops in an inch or two.

text on tube, 'teel' from 'steel'

same text on 22 ga flat steel

jeepsr4ever

Need more info on the cut speed, cut height and were you on center? Also what was your acelleration rates for all axis for that job. It looks like you didnt cut through on some areas and possibly used the same cut speed for flat as you did round.

_Ogre

had to cut some flat plate today, so didn't get to work on the rotary head until late. i thought i had this rotary head sorted out. i pulled the cover off to check the set screws on the pulley. the whole motor was loose, got the belt tight and cut the same text today fine. one problem is i never load the part, i have a helper/trainee that loads the part. had i loaded the part i would have noticed play in the chuck.

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