Documentation

M667 – Plasma – Turn THC Function On

On MASSO plasma, M667 turns on THC (torch height control) automatic Z-axis control. F sets how fast Z moves the torch up and down under THC. It takes effect on the next axis move.

Syntax

M667 F__

Machine

Plasma

Takes effect

Next axis move

1. Parameters

Word	Meaning
F (optional)	THC feed rate: Z-axis speed while THC adjusts torch height. If omitted, the last M667 F value is used; if none has been set, the axis maximum feed rate is used.

2. Examples

N10 M667 F500
N20 G01 X1 F1000

Turns THC on with a THC feed rate of 500, from the next axis move.

N10 M667
N20 G1 X1 F1000

Turns THC on using the last M667 feed rate (or the axis maximum if none has been set), from the next axis move.

3. Choosing the THC feed rate

THC feed rate	Effect
Too high	Z overshoots and THC reverses to correct. In extreme cases the torch keeps overshooting and hunts up and down during the cut.
Too low	Z may not climb fast enough to clear the material, and the torch can hit the material.

Adjusting it while cutting

Use the THC feed rate slider on the Overrides page to adjust it in real time. The slider shows the current value, which you can use as a starting point for future cuts in the same material.

THC feed rate override slider — THC feed rate override

You can also see the current THC feed rate on the Plasma page and type a new value in the box. It stays active until replaced by a new entry or a G-code command.