torchmate auto height controller seems slow

[danmurphy68]

i cut mostly 10 gauge, hypertherm 65 fine tip, 45 amps and 100 ipm, but when i cut fine detail seems too slow and burns thru and ahc seems to drop below and torch drag, i need help!!!

[ben de lappe]

A plasma performs in the same manner as a race car. It will slow down upon entering the curve, and will accelerate upon exiting out of the curve. It's possible that your ramp rates need adjustment. Arc voltage settings may play a role in this issue as well. Torch dragging can most often be attributed to arc voltage being low, whereas the torch rising too high is a symptom of voltage set too high.
Ben

[islander261]

Hi

While not being an expert on HT settings I can tell you this. I have a TM AVHC on my TM2 table. The thing is pretty easy to use but at the same time pretty crude compared to others. I am sure that about 75% of my previous consumable problems and 100% of my miss fires are because of it's problems. I can go on for ever about the test programs I have run to pin point the problems I have had but I will not bore you. You must physical verify your height settings if you are using the TM torch mount. Mine has a good .050 backlash and that is after replacing the lead screw and nut. It senses zero by smashing the torch into your plate (at least the old ones did that) until the drive stalls. This means if your plate or it's support flexes down under the point load when the torch raises to pierce height it will still be too low. These also dive when going into corners, I know that TM claims that their sw won't let this happen, just watch closely when cutting. If this is the case why do they have a corner lockout function that the docs don't talk about? Look on the terminals on the back of the unit. The voltage setting is also sensitive to the speed you are cutting at. Be sure to cut speed test lines at a fixed height you want to cut at and use the voltage reported for the speed you want to cut at. Sorry if this isn't clear, they talk about in the TD docs but don't offer much explanation as to why it is important. Start by verifying that your actually running at the correct initial cut height, this took me a long time to figure out. I use feeler gauges and/or number drill bits to do this. Use the backlash you get, set height on unit - the measured height, to correct the pierce height as well. I am just trying out my franken torch HT/TD hybrid on 14 ga HR. Running at 40A and 150IPM, good on long (>1") straights but still plenty of dross on corners.

John

[jimcolt]

The Torchmate AVHC height control is not interfaced to freeze height in corners and intricate details like most cnc machines with height control. When the machine has to decelerate, the slower speed causes a wider kerf, and higher plasma arc voltage...so the AVHC moves the torch closer to the material in an attempt to correct it. A well designed cnc/height control system will sense the speed slowdown and freeze the torch height until the speed gets back to at least 80% of the programmed speed.

Here are some things you may be able to do to minimize the diving:

- Increase your machines acceleration rates as much as possible.
- Reduce the Z axis speed setting
- Increase the arc voltage feedback delay to about 2 to 3 seconds.

Jim Colt Hypertherm