z axis floating head

orbita

Hi!

There is a way for z axis floating head, for plasma cutting?

Thanks, Tomas

Repetier

Makes no difference where z axis is mounted as long as you have end stops for positioning.

orbita

Repetier wrote
Makes no difference where z axis is mounted as long as you have end stops for positioning.

But how machine knows when wait for confirmation of height and start to work? Which command for G code? Did lot of search, found nothing.

orbita

My issue is by using SD THC. Because working area (X, Y) very large, when stops cutting, the torch stays on the very low Z axis, where THC has stopped, and can get stuck when traveling from one cutting point to another, so to avoid this, machine (Arduino) lift Z axis for traveling after cutting stopped, but it should make sure that are in correct altitude when arrives to another cutting point, because could be too high to start cutting and no arc formed because of this, or point of cutting start will moves and you won't get fully cut. No issues for small part, but for large area there is a big fluctuations of heigth.

Repetier

Sounds more of an issue with the gcode generator then with firmware. If you send G1 with Z... it will move to that height. That is why you need the end stop so after homing height is known and moves are where expected.

But I have no experience with plasma cutter g-code generation, here you better ask the producer on how to modify z when changing pieces.

orbita

Repetier wrote
If you send G1 with Z... it will move to that height...

Yes, this is what i mentioned, after THC stops (G0), microcontroller takes control - it will move to that height... (travelling height), and moves to new cutting point, but there is unknown height, in that new point, need to be checked, because if too high, no arc could be formed, or point where cutting start will moves and you won't get fully cut. So microcontroller need to recheck the heigth before Gcode goes to G1.

When arc activated (G1), THC takes control over microcontroller, THC measuring voltage, and get diving to settled voltage/height, diving/calculation can take a time, and part of cutting will be missed (machine already moving because G1, but the torch still at the wrong height - too height. Torch also takes a time for full power able to cut), that why z axis floating head needed for plasma cutting.
G0 - microcontroller
G1 - THC
So need Gcode diving command of repetier firmware (before G1), that waiting until get confirmation from the end stop - zero point of z axis reached (Z0.0000), lift to (say Z2.0000) and good to go after that.
I can modify Gcode myself, just need to know which command of repetier firmware good to use in this case.
A Sample
G02 X86.3900 Y11.7731 I-108.3064 J-1.0374
G01 Y11.0013
G00 Z2.0000

G00 X200.0000 Y11.0000 Z2.0000 F3000
diving command that waiting until get confirmation from the end stop - zero point of z axis reached (Z0.0000), lift to (say Z2.0000) and good to go after that
G01 X204.8892 Y10.9991 F300
G01 X204.8885 Y9.0500 F1000
G01 X172.9900 Y9.0508
G01 Y13.4471
G01 X185.5972 Y13.4500
G01 X204.8900 Y13.4492
G01 X204.8892 Y10.9991
G00 Z2.0000

orbita

Could be used command M109? Like this;
M109 Z0.0000
G00 Z2.0000

M119 or M116?

Repetier

G0 and G1 are identical.

You only need homing once, but how do you home in your case? cnc also often has different homing and as said I have no plan about plasma cutting.

I see G1 Z2 to go up, but why not just G0 Z0 to go down again to old height?

You can use
M400
to wait for all moves to finish if you need to ignite plasma with a command.
M109 is heating extruder and wait for temperature. Has no Z parameter at all. M119 just outputs position and does nothing.
You can also use G4 Pmillis to wait for end of moves AND then milis milliseconds.

orbita

<a rel="nofollow" target="blank" title="Link: null">Repetier</a> said:

I see G1 Z2 to go up...
G0 and G1 are identical.

Where do you see G1 Z2 (G1) in my code? Have in use only G0 Z2 (G0).

G0 it's a traveling/Rapid move command (plasma cutter switched off). G1 is working/Linear move command (plasma cutter is On). The same as with the laser, just plasma cutter must start of cutting from correct/fixed height - not too low, not too high. The worst scenario when torch end and cutting surface too close. So they aren't identical in this case.

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<a rel="nofollow" target="_blank">Repetier</a> said:

...why not just G0 Z0 to go down again to old height?

You can go down once arrived to new cutting point, but i have mentioned - because surface imperfections, working height could be changed (+/-) when you working with very large areas like 1 metre by length, you have to recheck and correct if changes detected. If torch too high from the surface of cutting - you getting one kind of problem, if too low - you getting another kind of problem, which was explained above. It would be time waste explaining all of them, and absolutely not related to topic. Point of z axis floating head is avoid this issues. So i need to make working z axis floating head (diving command that waiting until get confirmation from the end stop - zero point of z axis reached...).

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<a rel="nofollow" target="_blank">Repetier</a> said:

You can also use G4 Pmillis to wait for end of moves AND then milis milliseconds.

I'm now using G4 (pause), correcting the height manually if needed, but why do manually if could be done by machine?? That why im here. That why we all are here - make life easier.

I found G30: Single Z-Probe - this could be a solution. Just have no knowledge/experience about this command.
G29 Auto Bed Leveling also looks promising.

As in understanding, G30: Single Z-Probe no need for Z-Probing configs in the sketch? Enough parameters?

G30 H2.0000 - it goes to height 2 once triggered?

Repetier

Ok uneven heights of product is a problem. Not really meant for that case. As 3d printer firmware a more or less planar build plate is a must.

Anyhow, G30 might be a solution here to update. How do you home Z otherwise? I mean what is reference for normal homing. You could otherwise simply home G28 Z0 and assume that as 0 height if it would measure material height as well. G30 does the same and assumes the trigger height is Hxxx - goes back to start position which is than not the same as before value wise. In your case H0 it would be 2mm plus/minus height change. Send G0 Z2 again to move to new Z height.

orbita

Repetier wrote
How do you home Z otherwise? I mean what is reference for normal homing.
I don't do homing at all, no need for me.
I did the code as following, but it wont work for me ...G30 H2.0000 command ignored;

G02 X86.3900 Y11.7731 I-108.3064 J-1.0374
G01 Y11.0013
G00 Z2.0000

G00 X200.0000 Y11.0000 Z2.0000 F3000
G30 H2.0000
G01 X204.8892 Y10.9991 F300
G01 X204.8885 Y9.0500 F1000
G01 X172.9900 Y9.0508
G01 Y13.4471
G01 X185.5972 Y13.4500
G01 X204.8900 Y13.4492
G01 X204.8892 Y10.9991
G00 Z2.0000
How to make working G30?

Repetier

G30 requires a z probe to measure the hight. If you do not home you probably have none. And if you have one you must ensure there is material below probing point so it measures the material and not the bed.

I guess with cutting an additional problem is to not check height where you recently have cut.

orbita

<a rel="nofollow" target="blank">Repetier</a> said:

I guess with cutting an additional problem is to not check height where you recently have cut.

Maybe i'm wrongly understanding you, but this is what i'm doing here - looking a way to check height where recently have cut ...z axis floating head.

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<a rel="nofollow" target="_blank">Repetier</a> said:

... it measures the material and not the bed.

believe me, i know that. But wiki probably won't agree with you, take a look below - G30; Probe the bed at the current XY position ...Probe the bed ...bed. Probe and measuring a bit different things.)))
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<a rel="nofollow" target="blank">Repetier</a> said:

G30 requires a z probe to measure the hight.

It must go lowering following to this command (G30), because microcontroller has no eyes, he does not know that z probe attached or not, just waiting for trigger. But in my case he does not go lowering, following logic, must be in configs something must be change to get this option active.

-----------------------------------

https://reprap.org/wiki/G-code#G30:_Single_Z-Probe</div><div><pre>G30; Probe the bed at the current XY position. When the probe is triggered, set the Z coordinate to the probe trigger height.</pre>

Repetier

> It must go lowering following to this command (G30), because microcontroller has no eyes, he does not know that z probe attached or not, just waiting for trigger.
But if no z probe is defined it is not implemented.

reprap wiki is not exactly what repetier does. See repetier.ino in sources for list of commands and parameter in repetier. The H2 parameter is an extension meant for cnc to define z with a probe interactively instead of just testing the z probe. What it does is change Z depending on where it triggers and assuming trigger height was at H2 so Z is defined afterwards just like during G28 Z0.

orbita

Repetier wrote
> It must go lowering following to this command (G30), because microcontroller has no eyes, he does not know that z probe attached or not, just waiting for trigger.
But if no z probe is defined it is not implemented.

reprap wiki is not exactly what repetier does. See repetier.ino in sources for list of commands and parameter in repetier. The H2 parameter is an extension meant for cnc to define z with a probe interactively instead of just testing the z probe. What it does is change Z depending on where it triggers and assuming trigger height was at H2 so Z is defined afterwards just like during G28 Z0.

I have no idea why you decided that im about parameters? I clearly pointed - How to make working G30? Command G30 not lowering as should. Nothing about parameters. Could be i can't understand your terminology, but you are wrong if you believe entire world knows your terminologies.
Have activated in configs FEATURE_Z_PROBE, and all working now, z axis lowering as expected. Now time for parameters. I cannot "play" with parameter until G30 not working.

orbita

So now, which parameters for G30 to go down until triggered and lift up to Z2.000 after triggered?

Repetier

If I remember correctly G30 always goes back to start height. What the H variant does is modify the official Z height assuming the sensor was triggered at height Hx. So if you say H2 it means when you triggered that was height 2. If you want surface ob object to be 0 and move to 2mm above you need
G30 H0
G0 Z2 F600

for example. You chould see now that M114 reports Z2 and be 2mm above the object.

orbita

Repetier wrote
G30 H0
G0 Z2 F600

for example. You chould see now that M114 reports Z2 and be 2mm above the object.

This is what showing
15:59:28.693 : N12 M117 ETE 00s48
15:59:28.698 : N13 G30 H0112
15:59:28.700 : Printjob finished at 19/05/2024 15:59
15:59:28.700 : Printing Time: 0s
15:59:28.700 : Lines Send: 2
15:59:28.708 : N14 G0 Z2 F6004
15:59:28.708 : N15 M104 T0 S021
15:59:28.708 : N16 M140 S082
15:59:28.708 : N17 M8441
15:59:34.786 : Z-probe:151.83 X:0.00 Y:0.00
After triggered, slowly going back up to point where lowering started an after get back to this point of start, jumps up to G0 Z2 F600.
By theory, shouldn't back to point of start, but must go to position G0 Z2 F600 after triggered.
Why are you giving me that useless information in my case? Can you just let me know what code to stop G30 after triggered? You know that im not using 3D printer, i don't need for "Bed Leveling", just to lower z axis until triggered and then stop.
If no code/parameter, just point me in configs (IDE), which folder and which line to make changes for G30 to can stop after triggered? Or analogue way for floating head?

Repetier

> Why are you giving me that useless information in my case? Can you just let me know what code to stop G30 after triggered? You know that im not using 3D printer, i don't need for "Bed Leveling", just to lower z axis until triggered and then stop.

that does not exist for G30 it always goes back in our firmware, only homing with G28 Z0 stops at trigger point. So as long as trigger point is your Z=0 you can use homing also then you get the retesting of the point with lower speed. Plus is you can also say it should move up 2mm after homing in configuration.

orbita

Repetier wrote
> Why are you giving me that useless information in my case? Can you just let me know what code to stop G30 after triggered? You know that im not using 3D printer, i don't need for "Bed Leveling", just to lower z axis until triggered and then stop.

that does not exist for G30 it always goes back in our firmware, only homing with G28 Z0 stops at trigger point. So as long as trigger point is your Z=0 you can use homing also then you get the retesting of the point with lower speed. Plus is you can also say it should move up 2mm after homing in configuration.

When G28 Z0 in use, Repetier-Host app get frozen.