hi evryone
i plan building a plasma table for cutting 6 to 12 mm thik and 1.75/2.2 m steel plates.
the mobile water bed table should help me loading and unloading the heavy plates whitout the risc of ruining my cnc table by :
1. slide the water table from underneath the plasma table
2. load the plate on the water bed (no risc of knocking the expensive machine)
3. push the water bed back underneath the plasma.
4. do the job
beside this ,having that spare room i can fit an removable rotary axis to mill some foam or wood.
i have purcesed the 20 amp 3 axis kit "logitrol" from www.lowcostcncretrofits.com ,
and made the frame of 100/100 "V" profile 2.5 / 3.0 ml
i have ordered drive belts/pinions for X axis , slideway with belt incorporated from isel for y axis and ballscrew 400 mm module from isel as well

no plans for this project just building it and planing as it goes

ANY CORECTIONS ARE WELCOME
I HAVE NO EXPERIENCE ON CNC BUT THE STUFF I HAVE LEARNED FROM THIS WEBSITE ALONG 3 YEARS OF READING

Post a few pics as you go along, good Luck!

Nice idea if you have the space. good luck

some pics in today
what plasma system should i go for?
did any one used "telwin" ?

pics with my work up to this time

Hypertherm.

John

Hypertherm.

hi again
i made some more work as you can see in the pics

got the gantry on and sliding wiht ease but if i hold one side fermly i can push the other side about 5 mm max . is this ok or is an major problem ?
(i want to use only one side belt drive )

i'm expecting the z axis on monday and the guide way for y on wensday or so

I got a price for powermax 1650 hypertherm at 9800 $. that is the best price i found
DOES ANY ONE KNOW WHERE CAN I FIND THIS SYSTEM FOR LESS MONEY ?

it sems to my that for 10 mm steel plate i need 100 A plasma to cut at
60A/100% duty cycle

hi again
i made some more work as you can see in the pics

got the gantry on and sliding wiht ease but in i hold one side fermly i can push the other side about 5 mm max . is this ok or is an major problem ?
(i want to use only one side belt drive )


I guessing you will see some flex during direction changes. It just depends on your product if that is ok or not. It would be simple enough to add a shaft to drive the opposite side...

John

hi again
I got a price for powermax 1650 hypertherm at 9800 $. that is the best price i found
DOES ANY ONE KNOW WHERE CAN I FIND THIS SYSTEM FOR LESS MONEY ?


60A/100% duty cycle

List price on that machine is only $4795. Shipping could get tricky though, but not $9800. Check Ebay.

hypertherm

I agree with John T. I'd add a jack shaft possibly through the center of your gantry tube. That way 1 stepper will drive both sides equally.

hi got some progress as you can see in the photos but i have ran in to a problem (see videos ) my axis move in steps (vibrating) the longer i go the harder it vibrates
can anyone help ?
i got hypertherm 1650 machine torch

Where is the video?

What type of move are you doing G0, G1, G2/3 jogging?

Are you thinking it is a mechanical problem or other?

Does move smoothly without the belts attached?

What software are you using?

Which axis is it or is it on all three axis?

John

hi got my machine mouving
i'm hapy about this but is still jerkyng
it seems that i can not load videos here
any help is greatly apreciated
the fault is in the soft somewhere and i soupose
and the z servo screems all most of the time (i have no PID setings)(is a difrent type of servo then the other 2 ametec

I'm just a lurker and haven't built a table yet, however I've devoured every bit of information on this sire and others.

Is the direct drive setup an issue? How far does the X and Y axis move for one motor rotation? Most of the information on drive ratios suggest at least a 3 to 1 reduction prior to the rack and pinion or timing belt drive. Even greater gear reduction is recommended for servo drives because they don't lose power at higher speeds.

Looking at the Y drive it appears that you have say a 40 tooth pulley driving directly onto the fixed timing belt. If the timing belt has 5 millimetre tooth spacings then one motor revolution would transport the torch holder 200 millimetres.

This is way too high and may explain the jerky motion.

I intend to build a table with timing belt linear motion but will gear the servos down 3 to 1 and have a 20 tooth pulley driving the fixed linear belt. This means that one motor revolution will result in actual axis movement of 33.3 millimetres.

I like your setup and the general layout. Do you think there will be a problem pushing a tank full of water back and forth when you load and unload the water table?

I'm just a lurker and haven't built a table yet, however I've devoured every bit of information on this sire and others.

Is the direct drive setup an issue? How far does the X and Y axis move for one motor rotation? Most of the information on drive ratios suggest at least a 3 to 1 reduction prior to the rack and pinion or timing belt drive. Even greater gear reduction is recommended for servo drives because they don't lose power at higher speeds.

Looking at the Y drive it appears that you have say a 40 tooth pulley driving directly onto the fixed timing belt. If the timing belt has 5 millimetre tooth spacings then one motor revolution would transport the torch holder 200 millimetres.

This is way too high and may explain the jerky motion.

I intend to build a table with timing belt linear motion but will gear the servos down 3 to 1 and have a 20 tooth pulley driving the fixed linear belt. This means that one motor revolution will result in actual axis movement of 33.3 millimetres.

I like your setup and the general layout. Do you think there will be a problem pushing a tank full of water back and forth when you load and unload the water table?

I used steppers on my plasma table and geared the motor 6-1 then used a 10 tooth .375 pitch belt so I get 500IPM at 800 RPM and stay well in the torque range of the stepper. I assume you would want even more reduction on a servo as the rpm of most servos is at least double if not triple a stepper.

John

hi
sorry for not answering ,busy trying to keep up whit the plasma table and the regular day by day work
"Is the direct drive setup an issue?"
yes it is my axis are jerking and the belt has an elasticity that you can see whit the naked eye it may not by an issue if u wont have any jerking
so i wont use them again for driving so long axes
i have jerk even if i added a 3/1 reduction

Do you think there will be a problem pushing a tank full of water back and forth when you load and unload the water table?

it can be ,but this is the last thing I'm worried about
now i have another 2 problems
1 i have to buy another air compressor for hyphertherm
2 my z axis is getting me crazy
every time i run this code thrum Mach the z Axis remains about 2 mm higher
so for 10 runs i will have the z approx 20 mm higher then at the beginning do Mach displays the same height. i attached the file maybe some one can look at it and tell me Watt the problem can be.
thank you

Well the jerk can be an acceleration setting... I don't know about mach but EMC you can configure this in the ini file.

John

I had some Z movement like that, the z made the movement for piercing in the DRO but the torch did not rise, then get down to cut getting close to the plate, at the next movement the torch got crash to the plate,. I told this to Scott (MACH) he told me to change the steps and dir wave. In the settings it says 1-5, he told me to start at 12 and rise it no more than 20. at 16 I got the best movement for all the axes.
Give it a try
Luis

i found this in a doc that i paid 10 $ on ebay some time back

^^G92 - Programming of Absolute Zero(Do Not Use)
This Code is an old way of programming. You are redefining the
machine coordinate system, when using this code. Normally you
move to Part Zero, and set Zero by running code G92X0Y0. This
sets a new Absolute Zero for machine, overrides the Work
Coordinate System. In order to reset Absolute Zero in the machine,
Zero Return the machine manually to Machine Zero and run the
G92X0Y0. Some machines don’t like this code, I would strongly
advise against it.^^
what do you guys think

The only thing I know about Mach is I don't use it. However if mach uses g code similar to EMC then you have a couple of G92's that are changing your Z zero...

John

I use G92 on every part in EMC. I don't know how mack handles it. In EMC I use a G92.2 after the part to cancel and clear the G92...

John

how do i edit g code ?

i soupose sheet cam should not put this code in there is only a cercle on a plasma cutter

thank you john for replaying
it feels that i'm not on my on here trying to dyscover the complicatet world of cnc
by the way what "EMC" stands for ? (the short version)

EMC = Enhanced Machine Controller. Software for Linux for running all types of CNC machines. Did I mention it is free!

http://www.linuxcnc.org/

I just open the file with a text editor and make my changes.

If sheetcam puts things in there you don't want you can edit the post that you use tailor it to your needs.

John

HERE ARE SOME OF MY FIRST CUTS

MY FIRST CUTS

Nice cuts you have completed. The table looks great!

Thanks for sharing you progress.

I use to have jerking also.I solved my problem with CV settings.Uncheck plasma mode and exact stop.And put some low assceleration...