Messages

401

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 01:29:18 PM »

The correct sequence is to switch on, wait for arcok, introduce any required delay then do whatever... which may be drop from pierce to cut height as in a "regular" cutting process or in your "drill" marking - switch off.

However - there's a Mach bug which makes this more tedious to implement than needs be. For a discussion of this, see the thread you linked to earlier in reply 13.
 

402

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 12:04:42 PM »

If it went
M03
M05

I guess that is the absolute shortest bite it can give?

Whatever a "bite" is.

Is there a delay in going from pilot to main arc?
I mean, if the metal is clean, the torch is at pierce height and then fired, surely the delay is microscopic and of little relevance. Does it not move to main arc as soon as the pilot arc touches the sheet and current starts to flow?

Your...

M3
M5

keeps the torch on signal active for 0.1 seconds (here). So let's look at what you "hope" will happen in that 1/10th of a second.

Your THC see's the (torch on) signal go active, it turns on the relay (so mechanical), the plasma cutter fires the pilot arc and opens the solenoid valve (mechanical again and even slower than a relay) that allows the air to flow. The air blows the pilot arc out of the nozzle, the arc touches the metal, the plasma cutter detects the circuit and switches from pilot to cutting arc, only NOW does it even START to "bite" PLUS "some" time to "bite" to whatever extent you'd like it to. What do you reckon? - all in a tenth of a second?

So how the hell long does all this nonesense REALLY take?

The answer is, you don't give a toss. You WAIT for arcok - that's when it's just started to "bite". That's why the nice people who make THCs (or THC interfaces) give you an arcok signal - because it's really useful. Once you determine your timings from this you're home and dry.

(and DON'T call me Shirley)

403

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 11:20:28 AM »

Is it the F1000 at the end of the line between the m3 & m05 ??

It is.

I guessed that was just setting a feed rate but as there was no feed, it did nothing?

It takes time for the interpreter to process the line. There's more to interpret so it takes longer - doesn't matter that no movement results (in this case because of the axis already being at z=3).

So what's the result of making them all the same? Do you get consistent timings now?

Now back to arcok. It's important REGARDLESS of whether you're using THC or not.

Consider your...

G00 Z3.0000
M03
G01 Z3.0000 F1000.0
M05

(With or without the in-line feedrate). The TIME your torch is actually cutting (piercing, "drill marking", whatever) is totally in the lap of the gods. You have NO idea when it transfers from pilot to cut arc. You're just hoping/assuming that it does what you want. You may want to give your SCAM POST a lookat.

404

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 08:46:49 AM »

OK - take a look at your 6 "drills" in the code you just posted. It's not only the first that takes longer it's also the 5th...

405

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 07:41:13 AM »

What?
I can't see ANY posts from arcok in this thread, how did I dismiss anyone as being irrelevant?
...
...
I can't see how I've been offensive or dismissive to anyone in this or other threads, I'm just a frustrated user that's all, my apologies if it seems I have been short with anyone.

 

Have you had your coffee yet this morning Dave? "arcok" is not a person - it's a signal from your plasma cutter. I was commenting on your statement...

Arc-ok does not come into it as there is no torch movement

406

General Mach Discussion / Re: 1st pierce is longer...

« on: September 07, 2014, 03:56:06 AM »

The code you posted in #5 is NOT the same as you describe in post #19 and you're wrong (IMHO) to dismiss arcok as being of no relevance. You didn't post M5 and you've changed them to who knows what now. You haven't said which Mach version you're using. I'll leave you to it

407

General Mach Discussion / Re: 1st pierce is longer...

« on: September 06, 2014, 11:58:25 AM »

Time to post your xml, gcode (shortest sample that shows the problem), M3 & M5 macros and Mach version I think Dave.

408

G-Code, CAD, and CAM discussions / Re: What is a Macro? and what can it do for me?

« on: September 06, 2014, 11:47:05 AM »

is there a macro or a g-code in mach3 for THC on and THC off? How can I turn off/on the THC? I need that to solve the diving problem at the end of the cut.

This is not really the way to go about solving your issue. A dive at the end of a cut is either because your accel is too low OR because you're crossing a kerf. The second is easy to solve - don't do it. The first can be solved either by upping your accel if possible OR by using Mach's THC anti-dive.

Even if you did do what you want with a macro - you're going to get a pause in movement - no way around it.

409

Show"N"Tell ( Your Machines) / Re: Hypertherm Plasma Interface cable

« on: September 06, 2014, 11:38:16 AM »

Hi Brian

If I were you I'd ask on the Hypertherm forum at cnczone. When I was designing my THC Jim Colt (of Hypertherm) was very helpful.

Ian

410

General Mach Discussion / Re: No Motor Movements -- Newbie

« on: September 05, 2014, 05:55:29 AM »

according to the 3 axis manual on google the three axis enable pins are x=14, y=2 and z=6 all active high.