Messages

2361

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

« on: August 13, 2014, 10:35:26 AM »

I am using my plasma torch to make marks for drilling on a job, it has 6 marks on it. It works very well at low power setting and a 0.1s pierce delay. After the piercings I have added a pause in the code so I can up the power and make the following cuts as normal.

However, at the start of each run, the first pierce is always longer, maybe three or four times longer than the rest.

Is there any reason for this in Mach3, I have checked the code and each pierce is identical in duration?

Maybe a setting needs tweaking?

Thanks

2362

General Mach Discussion / Re: THC Setting Issue?

« on: August 13, 2014, 03:56:10 AM »

Thanks, I would never infer that Mach is the bottleneck, and also If i were to produce a unit like a THC i make damn sure I knew how Mach would react when connected.

Anyway, if i were to say change to a Hypertherm PM45 Would that help? I believe that is a "proper" cnc plasma cutter?

Having seen how useful this machine is, I am now looking at upgrades.

2363

General Mach Discussion / Re: Steel Selection

« on: August 12, 2014, 04:06:15 PM »

I'm a manual machinist, the only CNC I have is my plasma table so I won't be able to offer too much advice.

Yes, get a. Speed and feed chart but be careful as they tend to be biased for industry - maximum metal removal rates on big machines.

Googling speed and feed or milling speeds etc should bring up a wealth of info, it can all be calculated using metal type, cutter type and size plus chip loading per tooth etc, formulas are not too difficult once you get used to it.

SFM = 0.262 x D x RPM
RPM = (3.82 x SFM) / D
IPR = IPM / RPM or CHIP LOAD x F
IPM = RPM. x IPR
CHIP LOAD = IPM / (RPM x F) or IPR / F

For mild steel and 1/2" tool, I would guess around 80 feet per minute surface speed which gives around 600rpm.

You have make the tool cut, don't let it rub, taking tiny cuts is the best way to blunt a tool, it needs to work within a window of speed/feed/depth of cut combinations.

Check out eBay for small cuts of mild steel, something like 230m07 one EN1A in old style is a pretty safe bet to play with.

If you can find a slide-rule type speed and feed tool on eBay, they are great.

2364

General Mach Discussion / Re: Steel Selection

« on: August 12, 2014, 02:39:33 PM »

It's much better to test on known material.

Are you new to milling? Have you a speed and feed chart?

Have you tried the same tool and metal by hand?

Burnt chips is a sign of too much speed/not enough feed.

On an HSS cutter you want straw coloured chips, maybe a bit darker but not purple.

What size cutter are you testing on?

2365

General Mach Discussion / Re: THC Setting Issue?

« on: August 12, 2014, 02:29:35 PM »

1ms is amazing!

They do another unit with a response of around 80ms I think which controls the z motor directly and not through Mach, the issue with using that is that you lose the antidive feature in mach3.

What was the reason I couldn't use your system??  (Can't remember)

2366

General Mach Discussion / Re: A Get It Out Of The Way button???

« on: August 12, 2014, 03:07:35 AM »

Code added, works exactly as i wanted - press once gets the gantry out the way, press again returns to work zero.

A very useful button indeed


Thanks for the help.

2367

General Mach Discussion / Re: A Get It Out Of The Way button???

« on: August 11, 2014, 03:04:02 PM »

As simple as that

Excellent and many thanks again for the speedy help.

Dave

2368

General Mach Discussion / Re: A Get It Out Of The Way button???

« on: August 11, 2014, 10:45:40 AM »

I tried a G28 X0 Y0 but that moved first to my chosen point and then moved swiftly on to machine zero point?

Is there a way to stop it at the work zero or origin point???

2369

General Mach Discussion / Re: A Get It Out Of The Way button???

« on: August 11, 2014, 10:24:29 AM »

Ok

I have added another if-then-else loop which checks GetOemDRO(84) for a position >599

that makes sense to me as even if i tell it to go to 600 it seems to stop around 599.99995

BUT

what is the code to actually move the gantry X & Y to the Origin or work zero co-odinates??

I cant see a move command in the books, probably looking for the wrong thing, or is it coded as something else???

Basically the same as GotoZ but only on X & Y.

2370

General Mach Discussion / Re: A Get It Out Of The Way button???

« on: August 11, 2014, 09:31:42 AM »

Ok, then it seems not.

Machscreen seems to have no multiline control either.


Its working anyway so that's what counts.


One last point on this button, is it possible to code it as a "toggle" feature :-

Press once to park the gantry
Press again to return to X & Y zero positions.

Just wondering

I'm guessing it would need to toggle an LED on/off and check the state of that LED first?


Dave