[siegfried_74]

Hello,

I come to you because I meet a serious problem on a Messer machine, I cannot say exact model right now, but if necessary I will find it.
I met problem cutting chamfer on long plate, Generator is Hyperterm, HPRXD_MS (260A for thickness 20mm).

The problem met is I had to make a 12 meters long K chamfer all long of a plate.
The result is at the beginning, chamfer looks like a K, but after few meters, the chamfer got worse and look more like a Y chamfer(bottom chamfers at the end disappears).

Anybody would have some idea about it? in general, is it possible to warranty a good quality on such long chamfers and get the same quality as on small parts?

Thanks in advance for your answers

Siegfried

[skillalot]

Yes, that is definitely possible. I work at a cnc plasma machine builder, and we do it there on our machines as well. Don't have 12 meter tables at work though, but just did some testing for a client where we cut a 5 meter long K and Y bevel, that was consistent over the full length. 12 meters shouldn't be any different.
First thing that comes up in my mind is the height control. I don't know how this is done at the Messer machine, but if the torch to work distance changes when bevelcutting, the bevels move sideways aswell,
Easiest way to determine if the height is correct is to cut some length, and after you see the K-bevel is bad you then press the e-stop. Then it should stop still at the cutting height, and you can check if it is still good. But I can't think of anything else then wrong cut height.

[siegfried_74]

Yes, that is definitely possible. I work at a cnc plasma machine builder, and we do it there on our machines as well. Don't have 12 meter tables at work though, but just did some testing for a client where we cut a 5 meter long K and Y bevel, that was consistent over the full length. 12 meters shouldn't be any different.
First thing that comes up in my mind is the height control. I don't know how this is done at the Messer machine, but if the torch to work distance changes when bevelcutting, the bevels move sideways aswell,
Easiest way to determine if the height is correct is to cut some length, and after you see the K-bevel is bad you then press the e-stop. Then it should stop still at the cutting height, and you can check if it is still good. But I can't think of anything else then wrong cut height.

Thanks for your answer, but problem is another. On 12 meters it doesn't cut with good result s we need to send 3 cutting lines, and between 2 cuts, the plate moves and that's why K is not so good(we want a K bevel with an accuracy 1mm).
To solve this problem only one solution was found on the end : make connexion each 3-4 meters, so it will avoid your plate to move between the 3 cutting lines.
Now I reached ideal results

Regards.

[skillalot]

Tell me how your cutting strategy is, cause I don't see where this should give any problems of parts moving.
If it are long plates, where you only make a bevel on the sides, the plate shouldn't move, only the scrap metal on the side could move.
Normally every Y or K bevel you start from outside to inside. So you cut the Negative bevel first, then the land, then the positive bevel.
With these long lengths, I would advise to take the scrap away between each cut.
Cut the bevel side first, then the rest of the plate.
And with narrower plates, clamp / tag weld it to the table to prevent distortion or movement.

Regards.

[Lasersolution]