IHS , correction
I’m manually establishing cut height only.
Let’s say you run two line tests. Both with THC off. On the first test you let IHS set the cut height. On the second test you manually set the cut height. If you get poor cut quality on the first test, it’s due to IHS setting the cut height too high or too low. You’ll need to compensate for this by either reducing or increasing the cut height in your g code.
IHS will set an incorrect cut height for two reasons. One is to compensate for spring back in the material. The torch and slide has weight which will cause the material to deflect (obviously worse for thin material). This has the tendency for the actual cut height to be lower than the programmed cut height. Second, there is some backlash in the z axis lead nut which must be compensated for. If it was not compensated for, it would have the tendency for the actual cut height to be lower than the programmed cut height. The backlash is the same whether you are working with sheet metal or thick plate and is built into the post processor of Sheetcam. I believe it’s .020”.
Let’s say that you program your cut height to .060”, but find that in reality your actual cut height is .080”. You need to set your cut height in Sheet CAM to .040” in order to guarantee a .060 cut height.
I only get poor cut quality when I do a line test with IHS on !
When I set the height manually it’s perfect.
Line tests in fire control create the G code I’m not imputing values, I’m manually setting the torch height to the correct height with a gauge and testing.
You can’t be serious!
I’m doing line test with fire control , I’m not creating a line test program on fusion and then imputing setting in cam.
I’m aware of the programed in setting of .020 in fire control for ISB.
I’m cutting 1/2 plate that has ZERO spring back.
My cut height is being manually set with a fire control line test.
I recommend that you post a program with a .150 pierce height and .060 cut height. Toggle off THC and turn off your plasma cutter. Run the program and then pause after the torch starts moving in XY. Use some feeler gauges to measure the actual torch to plate distance. If it’s .070”, go back into your CAM and adjust the pierce height to be .140 and the cut height to Be .050. Run the code and take a measurement with feeler gauges. Cut height should be right on the money at .060.
The straight cut canned cycles contain generic compensation values for spring back and backlash. Remember the purpose of straight cut mode is to rip sheets in half, it’s not meant to do precision cutting. You can use it to perform line tests to determine voltage targets for THC, but this HAS to be done with IHS toggled off and the cut height manually set.
In order to perfectly dial in the heights that IHS sets you HAVE to run the tests I’ve mentioned above where you compare the programmed cut height to the actual cut height and adjust accordingly in CAM settings.
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I’m well aware that fire control has an additional.020 of Backlash programed in, hence to get a true .063 cut height with regular un shielded consumables you must Zero out back lash in cam and set cut height to .043
For shielded you must take an additional.035-.030 off torch height in cam to achieve the same.
So if I want to rip a 900 $ sheet of plate in half and have that cut line a sorry excuse for a cnc cut part I have to dial in these settings with a program because the fire control isn’t precise enough to do this.
That’s udder BS !
How
If you’re ripping plate and want to dial your cut height to the thou and don’t want to create a program to do it, then toggle off IHS in straight cut mode and manually set you cut height to whatever is required by your plasma cutters cut chart and then edge start.
There are countless numbers of plasma cutters that require different cut heights based on material thickness, nozzle type, amperage, shielded/in shielded. There are a lot of factors at play. The IHS values in straight cut mode are generic for that reason. If you want to have tight control over IHS, you have to program it yourself in CAM.
Are you not reading my posts completely or are your dodging the questions?
These test I’ve done are with IHS OFF and with me manual setting torch height.
Yes you have said that when you manually set the cut height (IHS and THC toggled off) you get good cut quality with minimal to no dross.
When you run a straight cut mode with IHS toggled on. You get poor cut quality. I then explained that it was due to excessive cut height as a result of the generic IHS settings in straight cut mode and that to fix it you would need to adjust your IHS settings in CAM in order to ensure that the desired cut height is achieved.
Initially our conversation was about bobbing THC. Based on the input you gave me I provided you with three settings to adjust to correct that issue.
If I missed something please let me know.
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if I manually set a cut height in a line test in fire control that is manually measured with IHS off I use that actual cut height with the correct subtracted amount for initial spring back and back lash in my written cad, the program still bobs up and down regardless of what I do.
It’s only with shielded consumables and yes my actual measured cut height has been verified.
So your saying that with unshielded consumables and THC on it does not bob, but shielded consumables and THC on it bobs?
Yes the initial first post on this thread was excessive dross , with many different tests the problem seems to be THC with shielded consumables
Are you using smart voltage or setting your voltage?
Were do you have your plasma cutter wired for the THC. Are you using the cnc port or wired inside to RAV?
From some of his historic posts I see that they’re running divided voltage I would assume through the cpc port.
I think there was a few attempts to encourage the OP to wire it to raw voltage from inside the machine. It does look like through that last topic that the OP did wire it for raw voltage to test( whether this was from right inside the machine or just at the CPC port?)and experience no difference in cut quality.
@AultFab I used to run a Everlast 60s quite a bit. And my particular machine if it wasn’t wired for raw voltage from inside the machine the torch height control would not work correctly.
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The machine is running Raw voltage
From the CPC port or directly from the lugs inside the Everlast unit?
Directly from inside the front of the machine.
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