Torch height way too high

[whiskeymike]

Brand new to all of this. Just got my table this week and still learning the basics. Running a HT 65 with 45a mechanized fine cut consumables. CandCNC electronics with DCTH IV and Ohmic. I run the test file included (2" square) and it's good clean angles, straight lines and quite a bit of dross. Not great, but ok for just starting. Torch height seems ok.

Then I created a simple 4 inch name plate in bobcad, put it into sheet cam selecting the 45amp 16gauge tool and processed it. Load it in Mach 3, run the cut and the torch height is about 3/8s off the steel during the cut. The settings in sheet cam is directly out of the book, including torch height of .06. What would cause the height to be so high? The result is that it's not cutting all the way through and not clean at all with a very wide kerf.

Another thing that is odd is that before I run the code, dthc is on, but when it hits the code, the dthc light goes off. However I still see the torch, go down, touch off, then comes up to 3/8‘s. I assume the code is turning it off, but it still seems to be executing a dhtc test and adjustment. Dthc is set to 1 in sheet cam.

Any words of advice???

[whiskeymike]

One thing I just thought of is I should measure the torch height when cutting the first test file. Maybe it's higher than it appears.

[whiskeymike]

This morning, I cut the test file again and see that it's at the high level for that cut as well. Looks like a light saber piercing the sheet. So I don't think it's a sheet cam config issue. I'm running through the CandCNC manual now to calibrate the dthc.

[sphurley]

Did you wrongly enter a floating head height? I don't think with Ohmic you use it. The floating head switch becomes a safety only.
Go thru the DTHC setup and try it again. It should go down, touch, Z up to pierce height, start, lower to cut height and move xand y.

[whiskeymike]

Making progress. Went through DTHC manual again and realized I had the voltage splitter still at factory of 7:1 instead of 50:1 on the Pwm sensor. Not sure if it's just me, but I'm finding the manuals hard to follow with multiple revisions included in one. Seems like it would be much more user friendly if there was a dthc II manual separate from the IV manual.

So now it seems to maintaining height at .15 for pierce and .06 for height. Out of 5 cuts, I did have one where torch dragged on material a couple cuts where I had to estop and start over. Not sure if it was a problem or anomaly.

I have much less dross. It's not perfect, but it's better.

In the dthc manual and on the forums, it references calibrating the DTHC, but in the manual, I did't see anything to calibrate except testing volts on the Pwm. Lots of settings explained, but no guidance on how to calibrate except in case of dthc II. My torch volts in test mode of the PWM came out at 125. Below the range of 126-128. Not sure if that's an issue. But it says to not worry about it for dthc II unless it's more than a couple of volts off, but doesn't say anything for a IV. Should I be changing other things?

[WyoGreen]

The CandCNC manuals are a bit confusing at first. I think they are trying to have 1 manual that covers all systems. After you've read thru them a few times (ok, a bunch of times) you start to figure out what's relevant to your set up and what's not. As far as the 125 volts on your test mode, it's nothing to worry about. Mine reads 125 also, and has for a long time.
As long as your cut and pierce heights are ok, you're good to go. I've found that those strange things that happen, (such as the torch hitting the material) can be eliminated by paying attention to grounding and routing of cables. After I went thru that, I quit having strange problems. Not to say that I don't have the occasional blip, but that's usually due to me changing something on the table and not adjusting software settings to match. After a while it will all make perfect sense and you'll wonder why it was so hard at first.

Good luck, Steve

[acourtjester]

Here are some things to check are you using the correct post processor 11J is the last on out. next after you had selected that post processor click OK then go back to it and you will see the box "set custom post options" click on that If you are using the feather touch put .001" into the bottom box and click OK if you put 0 I found it will put .157" in the G-code for the switch offset. See attached screen shot and check your G-code after you generate it to see what you have there you want 0.001".

Another thing you want a 1.5 second delay in the "DTHC delay -sec" in you tool menu so the DTHC does not start checking the voltage until it has moved off the pierce and has stabilized.

[steel 35]

Any words of advice???

Save the fine cuts for later and start with something other then 14 or 16 Gauge!

[whiskeymike]

Thanks guys. I think I got the problem licked that I originally had. I'm pretty sure it was the jumper on the PWM module being set for 7:1 instead of 50:1 at the HT65 is set. My assumed logic is that it was reading the voltage wrong and therefore making the height much higher? Since changing that, I've cut a dozen pieces and as I overrode the speed, the cuts became very clean except for holes and I've read some threads on improving that.

The next thing I'm researching is the difference in setting the tool in screen cam, versus the cut profile in Mach 3. Also how they don't seem to have the same tools created, so how do you deal with discrepanices. I assume I should be making new tools in Mach 3, but I'm going to put a call into CandCNC and verify. I looked for the Mach 3 manual on CandCNC's site, but don't see one. I thought they might have some docs that are particular to their implementation beyond the install docs in other manuals.

[acourtjester]

An easy way to look at it is the SheetCam tools setups are for generating G-codes and should be very close to the setting in the Hypertherm book. If not take the time to generate new ones after that save them as default or give them a name you will remember like HY65 (and date). That way you can load them back into SheetCam anytime. The ones in Mach (CandCNC type) may not be current and I would not use them. In mach you can make changes of the fly to try slight corrections for better cuts only.
After a short time you will find using SheetCam and having the tools all setup you just load the drawing and select the tool for the material you are cutting and generate the Gcode and you done.

[tcaudle]

There is a very specific manual just for the DTHCIV and a revision REV3.1 has been posted on the website in the Manuals section. It does not cover the DTHCII which is a separate manual. The revision starting on page 18 is detailed on tuning the DTHC Settings using the Hub Admin On page 100 is the preliminary test cut step by step first with the DTHC off then with it on. One of the steps is to check the actual Torch Volts against what the chart calls for with the DTHC in Manual and OFF. The section of setup and testing of the PWM module and the jumper settings is in the front part of the DTHC IV manual

[exapprentice]

Hi whiskeymike

have you thought about looking on the CandCNC forum
As the kit you have was supplied by CandCNC they would be my first point of contact, TC and his crew always seem to have the answers for thier equipment and how to set it up to get the best from it.
I know its a real PITA to keep reading the books but it does help, trust me like many others myself included it is a very very steep learning curve

regards
exapprentice

[whiskeymike]

Yep, I've been reading over there, but haven't posted. I've also talked to Luke a couple times and they have been very helpful. I'm starting to make good progress. Last night I was getting really good cuts and then worked with nesting. Now I'm on to designing more parts. It's definitely a fun adventure.