New to CNCing and Mach3

[PapaRubbery]

Hi all,

My name's Alex and I'm a Neuroscience/Surgery student from Australia. I bought a CNC machine through Ebay to let me custom make some computer components, but also to design different tools for my studies and for work. Also I have architecture friends that could use the CNC for some forms of miniature modelling. I should stress that I am fairly up to date with computers, but CNCing I think is beyond me. It's also out of my reach in terms of learning and time commitments to get things up and running smoothly unassisted.

So I come to ask for some assistance in getting my machine running, as I've run into some real trouble. I'll describe as best I can the situation and if anyone can assist, I would be greatly in your debt. Here goes;

I’ve managed to install Mach3 and have positioned the Zero of my machine at one end of travel, such that when I hit “GOTO Z” it finds itself at one polar end of travel. What I need it to recognise is it’s software limits. How do I do this? If I click To Go then Soft Limits nothing happens.

Ive also REF ALL HOME as my GOTO Z. Gathering that home should be safe as zero.

The physical limits of travel for the machine is about 600x400x100.

Steps per pulse is set at 200, Velocity is 600, Accel is 300 – Step pulse is 5 us, as is Dir Pulse. Each spindle motor generates 0.03059 G’s. Even though all are set at the same, it believes the dimensions of X is less than Y, which doesn’t make sense as they are the same values on Mach3 – but physically it travels 1.5x more than Y?

So help me please – how do I get Mach3 to recognise its software limits without using hardware switches? And if I have to, is there some form of prebuilt kit I can buy and install?

When I try to use Wizards, it sends itself outside of the Motor Home/Soft Limits, of which screen looks like:

AXIS   Reversed   SoftMax   SoftMin   SlowZone   Home Off   Home Neg   Auto Zero   Speed %
X   YES   0   -340.00   1   0   NO   YES   20
Y   YES   0   -650   1   0   NO   YES   20
Z   YES   0   -135   1   0   NO   YES   20

With G28 Home Location Coordinates set at 0 for XYZ

Yeah, so it’s not working because it’s not recognising it’s own dimensions – and I can jog it past those Software limits if I want, and no warnings or anything come up.

If Mach3 is too difficult – is there any other more simple software?  Otherwise what am I doing wrong? I followed the install guide from the ArtSoft website (which was amazingly helpful!) but now I’m lost.
I have AutoCAD freeware software that I’ve tried to convert into GCode from LazyCAM and import, but again, it just runs itself outside of it’s outer limits.

Any and all help is greatly appreciated – I’m going spare at the moment trying to work this out. The Australian heat and my shed being a hotbox isn’t exactly helping!

Regards,

Alex

[RICH]

Alex,
If you look in the Member's Doc's you will see "HOMING A MACHINE WITOUT LIMIT SWITCHES".
Frankly I found it to be a PITA and don't use it. I wrote it! 
You can make up your owne mind on it,
RICH

[ger21]

"To Go" just changes the DRO's to display remaining distance of the current moves. To set up soft limits, you mins should be 0 or slightly less, and the max should be the amount of travel. You have your max at zero and the mins negative.

What i do, is slowly run my machine against the hard stops, and then Ref All. My Home Offsets are set to -1, so 0,0 is 1" away from the hard stops. I set my soft limits to -0.5, so it stops 1/2" from the hard stops. But you'll need to turn off the soft limits to Ref All, and you need to Ref All from the same place every time. I've found that it's easier to just turn softlimits off.

[PapaRubbery]

Hi Rich and Gerry,

Thank you both for your help. Rich I can't seem to find the document you mentioned? Is it part of Using Mach3 Mill Rev 1.84 that is in the Downloads section? At the moment it's a MASSIVE PITA

I've changed my limits around as per your advice, Gerry, and now when I load Wizards for say Cutting Circles or Text Engraving, it comes up with the warning about travelling outside Software limits. Excellent. I had never had it say that to me before - most encouraging!

However, again, I can't seem to input any values into the Wizards that generates a GCode within Software limits! So I'm sure I'm doing something very basic that is wrong, however, I can't for the life of me figure it out.

Many thanks again to you both - sorry for all the questions, but I'm in struggletown at the moment!

Cheers,

Alex

[ger21]

What do you have the softlimits set to now? And can you post a screenshot of a simple wizard, with your values, that gives you the error?

[RICH]

Alex, Here is the link,
http://www.machsupport.com/forum/index.php/topic,11409.msg72346.html#msg72346
RICH

[PapaRubbery]

Hi Rich and Gerry,

Thanks again for your posts. After posting I found the link, thanks Rich - I've followed it, or at least I think I have, and here are some screen grabs of what's actually happening:







Cheers again guys, much appreciated. I'd like to show my appreciation properly. Does the forum take PayPal donations?

Regards,

Alex

[Hood]

Is your problem on the Z softlimit?
Normally you would have Z Max as 0 and Z Min as -135.
Hood

[RICH]

Does the forum take PayPal donations?

Not that I'm aware of, but you can repay the community of users by helping someone else when you can. 

RICH

[ger21]

Is your problem on the Z softlimit?
Normally you would have Z Max as 0 and Z Min as -135.
Hood

Shouldn't the Z MAX be higher? otherwise, you'll trigger the softlimits on a rapid move.

But the Z min does need to be less than zero, as that's where the cutting takes place.