Unclean backside and steep bevel, Heavy Dross

[Munnin88]

Hi everyone,
I'm having some problems with my bevels on my inner geometry, along with a high amount of dross.

I'm working with a powermax65 with Enroute6 and cutting 1/4in mild steel
attached is a photo of my settings as well as a cleaned piece backside.
the top of the piece is pretty clean all things considered, but for some reason the cut on the back is significantly smaller than the top and I am building up a significant amount of dross, as well as a little splatter on the top during piercing. Hopefully you guys have some advice, which i would greatly appreciate. If you need more information I would be glad to lay it out. Thank you all again.
Cheers!

[Thor]

Whats your lead in/out, overburn? Any feedrate override for the small holes/features? I typically run any feature smaller than 2" length of cut to 70% speed in thicker steels, maybe 75-80% on say 16ga etc. Then min length for torch ht control is set at like 5" so the slower little stuff it doesn't turn torch ht control on

[robertspark]

cut direction??

https://www.google.com/url?sa=t&source= ... NyPrgXm0HC

[Munnin88]

The cut direction could be it, thanks for that link, I'm still new to this and wasn't fully aware of the effect direction had on the quality. I will try that out today!

Thor, I will play with my thc and speed and see if that helps as well.
Thank you again guys!

[robertspark]

It catches a lot of people out that do not realise that there is a good and a bad side because of the way that the plasma gas (and swirl ring) turns / spins the plasma and it creates a bevel (I believe its called a "natural" plasma bevel, from the hypertherm online chat a few weeks ago).

you never stop learning something new as there is always something else.

[acourtjester]

I think you have an issue with the movement of your table, your cuts look like they have a wobble action. I would attach a pen to the torch and do cut movements on paper, there is something loose with your table. You may also have a slight tilt to the torch angle. If you cut a square with the sides aligned with the X and Y axis, all side should be straight up and down no slant. A slant will show a tilt in that axis movement. And a slant on all sides shows the torch height is wrong. IMHO These are 3/8" steel cuts

[Munnin88]

Courtjester,
with square cuts and the chart settings I don't get any bevel or much dross, it seems to be only these smaller inner cuts. To what you said about the wobble cuts however, what exactly do you mean by that, do you think my table is shifting as the torch jogs or is it the actual torch mounting?
Thanks again !

[weldguy]

My reply to your other topic applies here "If your inner geometry is smaller than say 1" be sure your machine is slowing down for these cuts approx. 50-60% and this may help to eliminate your bevel. Also pause the machine mid cut and get some feeler gauges and be sure your cut height is at .060". Proper cut height and proper slow downs for inner geometry is important. Also proper cut direction is important, CCW for interior cuts. Keep tweaking and documenting what works"

You may not get away from the dross on these smaller interior cuts but you can certainly make some big improvment's in other areas.

[acourtjester]

By wobble I mean unstable conditions while the torch is moving. Loose bolts on table, cut grate(slates) shifting with table movements, loose drive components (belts, gears, bearings, or binding areas). To small holes are oval in different directions.

wobble.JPG (71.06 KiB) Viewed 1397 times

wobble.JPG (71.06 KiB) Viewed 1397 times

[adbuch]

By wobble I mean unstable conditions while the torch is moving. Loose bolts on table, cut grate(slates) shifting with table movements, loose drive components (belts, gears, bearings, or binding areas). To small holes are oval in different directions.
wobble.JPG

I agree with Tom. It looks like you might have some slop in either your table or your torch mount. Most likely your table. As Tom suggested, check your belts, gears, bearings, pulleys, etc. I also might be a good idea to install a sharpie pen holder and draw this part so you can actually watch the tip of the sharpie to see when and where it deviates from your ideal cut path.
David

[adbuch]

Hi everyone,
I'm having some problems with my bevels on my inner geometry, along with a high amount of dross.

I'm working with a powermax65 with Enroute6 and cutting 1/4in mild steel
attached is a photo of my settings as well as a cleaned piece backside.
the top of the piece is pretty clean all things considered, but for some reason the cut on the back is significantly smaller than the top and I am building up a significant amount of dross, as well as a little splatter on the top during piercing. Hopefully you guys have some advice, which i would greatly appreciate. If you need more information I would be glad to lay it out. Thank you all again.
Cheers!

20220406_140228.jpg20220406_140204.jpg

Some taper will be normal for plasma. You might try setting your program so that the torch stops slightly before the end of the cut to prevent any possibility of double cutting at the pierce lead-in locations.
David

[Munnin88]

Hi everyone, thanks again for the advice, I tried the marker run with the file and saw some movement like you had suggested. first thing I checked was the slats and they do move quite a bit. I'm going to see if I can stabilize them and go from there. Thanks again!

[acourtjester]

With the slates I have a bend or curve in them to make the more stable. For a 4X4 table I use a single bend and the 4X8 I use an "S" type curve. I use a single 1/4" pin welded to the base frame in 3 locations so the slates are held under tension, the "S" needs 4 pins. The original 4X4 had 2 pins at each location but that become a pain to remove the slates, so changed to only a single pin design.

[Munnin88]

update,
after securing my slats and checking the rest of the machine(laser mount, jog arm, gear tract etc..) I decided to make a matrix of each in shape and play around with various entry and exit styles until I found one that worked and I think I got it! Thank you all to who posted and helped me out with this one. I learned a lot more than I thought i would. Gotta love troubleshooting!!
Take care and I hop everyone one has a great weekend!
Cheers

[acourtjester]

Good show, and the reply sometimes the reply will fit another situation to get them going too.