I always see these posts, and no one ever mentions the material.
People, the material you are cutting is a variable, not a constant. No sheet is going to be perfectly flat. Without THC the variance in your material and it’s effect on your cut quality is more so than those with THC.
Depending on how the cable slack is it can pull the torch slightly this way or that way during the cut causing random bevel.
I had some time last night to mess with it. Checked over the table. Table is level, gantry is square and level. I installed a new 1.0 tip and electrode, squared the torch as well as the human eye can… Same bevel result.
My previous cuts were closer to the 0 end of the table. Last night I changed to a new piece of material and made my cuts closer to max X location. It seems the bevel is always on the +X side of the part, no matter how far I move in the X direction.
I put my speed back up to 45ipm so the cuts are cleaner at least. The other weird part is that the long side cut with the bevel, is really clean, almost no dross. The other 3 sides have very heavy dross. It chips off easily with a tap from a chisel, but it seems odd to me that dross is so different between sides.
I am missing something, hopefully it becomes obvious to me at some point. I’ll have more time this weekend to play with it.
This is a common problem using a hand torch and some times can drive you nuts trying to get it right.
Give me a call and I will try and help you out with this.
Is it not reaching the program speed on the shorter cuts? Probably not the cause of the bevel but could answer why your results are different on different sides. When you are cutting watch the actual speed vs the program speed. I am not a sheetcam user does it have feed optimization or something similar that you may have checked that is causing different cut speeds on the different sides? Could you video the cut?
Swirl Ring Direction ?
This topic link discusses it at length.
Thank you @mechanic416 I’ll take you up on that this weekend if you have the time.
@72Pony I haven’t touched anything in Sheetcam for optimization that I am aware of. I will post my settings for anyone who is a Sheetcam user. I use SolidWorks in my daily life, so I didn’t want to cross streams and go between two 3D systems. I can take a video on my next test cut.
@TinWhisperer I was hoping it was the swirl ring, but I checked it last night. The orientation matches the picture from the thread you posted. Air swirls same direction as the electrode threads in. I will check again tonight, as it was getting late and frustrating last night.
I need to post some pictures of two parts I cut last night. One with typical bevel and cleaner cuts. The other I did not reverse cut direction, so I cut the outside shape in counter clockwise and the bevel changed sides.
keep in mind sheetcam is only a post processor…it takes your drawings from Solidowrks and converts it to g-code…
many find it easier than fusion for post processing
Right, I was a bit misleading. I use Solidworks, draftsight, and Inkscape for any drawings that I need. Then I use Sheetcam for the post processor. The use of Solidworks is what drove me away from learning Fusion modeling/drawing and post processing.
I am in a similar boat…I use Inkscape…AutoCAD and Sheetcam…works for me.
Here are my Sheetcam settings and my .tap file. I am at least learning something… I haven’t messed with the g code much but I stepped through it and verified that at least in the code, my speed is correct. The only speed reduction is on one corner and that is set from a cut rule.
I haven’t changed any settings outside of the red rectangle on the basic tab below.
spray brkt 2.tap (642 Bytes)
Did you say that it the bevel is on the x side? Have you rotated the part to see if bevel moves? How did you square torch and are you squaring the metal to the torch?
You are way off on sheet cam settings.
Pierce height should be 0.15, plunge rate 60, cut height .060
I don’t have THC, so those settings are irrelevant. Cut height is manually set to .060.
Settings for Ihs on the pro, sorry thought you have crossfire pro table.
@rat196426 no problem, all input is appreciated!
@Phillipw Correct, cut is always on the +X side of the part, cutting in Y direction.
I will try rotating a part next time and see how it looks.
I square the tip of the torch off of the material, or usually the shim. With the torch holder loose, I set the tip on the shim and make sure the flat of the tip is flat against the shim. Then I check all directions to make sure I can’t see any light between the tip and the shim. That seems like it should be squaring the torch to the material, but I am wide open to input.
Here is how I do my squaring. It may not suit or work for everyone. I used a level to square my z axis the torch holder. When I cut thicker metal I always remove my torch holder put metal on the slats. Then use a good quality square and shim material to the piece that holds the torch holder.
Maybe try to up your Pierce delay to 1.5 seconds.
My thinking is that the 5° side of the part is the first cut after the Pierce, so maybe the arc is trailing slightly and then when you hit the corner it catches up and the rest of the cut is a more bearable one degree bevel?
Just brainstorming.
That’s a good theory.
