Another plasma component...

mkardasi wrote:

Kerf crossing might be an exception for a small subset of users because your kerf crossing algorithm is better at detecting a torch dive than corner lock.

One could argue that a small subset of plasma users are hobbyists with low amperage machines and do not cut the range of material thicknesses cut in industry so they do not see some of the conditions that become evident in a production environment.

Kerf crossing (void sensing) and corner lock are two totally different conditions.

kerf crossing deals with the sudden spike in voltage when the torch traverses a void. The voltage rise rate is orders of magnitude higher than in normal cutting. Whilst the term implies it happens when crossing a kerf (to save production time), it also happens at the end of a hole when the slug drops away. It is more evident on thicker material. The THC responds to the voltage increase by a massive downward movement to correct the increased voltage. So we need to lock out the THC until normal cut conditions return.

Corner Lock (or velocity anti-dive) senses a reduction in cut velocity. Torch voltage is stable if the height and velocity remain constant. Slowing down the velocity will increase voltage so the THC will try and compensate by lowering the torch which can also cause a crash or poor cut quality due to wrong heights. This does not impact on just corners are there are many situations where the Trajectory planner cannot honour the commanded cut velocity. eg. short segments and irregular shapes.

phillc54 wrote:

The enable checkbox will still be in the Run panel. Do you need to change the override value often?

At the present, I adjust it when I change material thickness and correspondingly cutting speed. ie. A job cutting at 760mm/min to a job now running 1,900mm/min

rodw wrote:

One could argue that a small subset of plasma users are hobbyists with low amperage machines and do not cut the range of material thicknesses cut in industry so they do not see some of the conditions that become evident in a production environment.

Kerf crossing (void sensing) and corner lock are two totally different conditions.

I don't understand how this is relevant to Phil's question about Kerf Crossing Override not changing too much.

mkardasi wrote:

I don't understand how this is relevant to Phil's question about Kerf Crossing Override not changing too much.

Sorry, I missed who the poster was. Really the point is that people with small amperage machines don't see some issues that arise on thicker material and that Kerf crossing and Corner lock are two totally different features

We are GMT +10 so its 7:30am now. Nothing like a 4:00am start though!

phillc54 wrote:

mkardasi wrote:

phillc54 wrote:

The enable checkbox will still be in the Run panel. Do you need to change the override value often?

At the present, I adjust it when I change material thickness and correspondingly cutting speed. ie. A job cutting at 760mm/min to a job now running 1,900mm/min

That is probably because I haven't sorted kerf crossing out yet.

Kerf crossing might be an exception for a small subset of users because your kerf crossing algorithm is better at detecting a torch dive than corner lock.

This is based on my particular machine which is only 600mm and capable of very high acceleration rates. Unfortunately, I have not been able to revisit this other than what is in the kerf crossing thread I started.

That is interesting, most others seem to think the opposite. Maybe you acceleration is too high?

Non-sense! Can never have too much acceleration, just ask any car guy! Kidding aside yes, I'm able to out accelerate the arc, my fly weight gantry allows me 1.3G in X/Y which is why I see things that others, who have more iron to throw around, do not.

Image 2 of this post shows kerf cross locking torch height when cutting into the corners of a 25mm square hole. 5 corners & 5 lockouts of THC...

Just an unintended feature that I'm taking advantage of... Don't let that stop you from making changes that you see fit.

phillc54 wrote:

Non-sense! Can never have too much acceleration, just ask any car guy! Kidding aside yes, I'm able to out accelerate the arc, my fly weight gantry allows me 1.3G in X/Y which is why I see things that others, who have more iron to throw around, do not.

Wow, that's quite a bit more than HT's target of 40-50 mG.

Ooof. I didn't know that plasma was that low. Thought it might be similar to a quality machining center. Do you have a document that you can point me to, Phil?