THC torch volts?

[turboboy]

On the THC box the torch volts. What effect does this have on cuts ect..I just got this plasma table so trying to figure it out. They dont come with much of instructions

Also what would be a good starting point to cut 3/16 and 1/4" steel plate. I have the hypertherm 1000 with hand torch mounted on my machine. What should the torch volts be set at, feed rate ect... Any help would be welcomed. thanks

[Torchhead]

Torch volts = cut gap. Cut gap = good cut/bad cut
Open your Hypertherm manual to the cutting charts. Note that each thickness of material as a recommended cut voltage and feedrate. Also note that each tip has it's own chart. Make sure you are not trying to use the THC with a contact (drag) type tip. Preset your cut voltage to the number on the chart and define your feedrate in the CAM toolpath program. You will find the charts pretty close.

Each plasma machine will have different numbers so it's not possible to give exact numbers or general instructions. The numbers vary by the type of tip you are using.

My manual calls for 138V with a 60A tip and 1/4" steel. Recommended feedrate is about 85 IPM. Once you have the unit cutting adjust the voltage as you cut so you are maintaining about a 1/16 gap between the tip and material. It should not be mor than 3 volts away from the recommended target.

[turboboy]

Torchhead higher the number is the cut gap more or less than a lower THC number?

If i set the THC at 140 for example and you say it should stay within 3#'s. What would cause the THC numbers to jump down to 130 then to 142 when cutting ect.. Just as a example.

Thanks

[Torchhead]

gap Volts is porportional to height (but not 1:1 or even linear)

Voltage will vary as you cut in different directions, slow down for turns or run over areas with grate below. The important thing is that the gap stays consistant. If the head is "bouncing" (oscillating up and down slowly as it moves along there may be an issue with the debounce setting in MACH.

If your voltage is bouncing a lot as you are cutting long straight lines or long arcs then then there might be an issue.

Noise is always a concern in plasma cutting. That and ground loops can cause voltage variation in the tip volt read circuit.

[turboboy]

I was just cutting with it some more and on the straight cuts it seems to stay within 2 numbers of what it set it at. Must be the corners as you say cause it to jump more. Thanks for your help

[jcc3inc]

Gentlemen,

You set the torch height and speed for the best cut quality; whatever voltage results is the correct voltage for your conditions. As to corner slowdown, some cutting systems disable the THC on slowdown.

Jack C.

[bossfrog]

I started with 138 THC with a hypertherm 1000 on 3/16 material, but occassionally was catching the torch on the sheet (too low). I have gradually increased the THC up to 146 or so to avoid crashes, but not sure what this is doing to cut quality...

[turboboy]

I seem to be getting best cuts with 135 on the 3/16" steel.

Is there any tips on plasma cutting holes so there nice and clean. My 1" holes i been cutting dont seem to round or clean. I tried to cut out the center with a .75" holes and then do the 1" cut. It helped but not how i would like to have them. I guess maybe I should ask does a well set up plasma cut a nice round hole?
thanks

[Torchhead]

Slow way down on holes less than 2" 50% feedrate for holes around 1" and even less for smaller ones

Use a perpendicular lead in

Turn on anti dive

Make sure your X&Y are calibrated (dead on)

Check how accurate your table is using a marker and paper.

I get good holes down to about 1/2". If they need to be really round, just center pierce the holes and drill conventionally.

[turboboy]

were do i look for antidive?

thanks