Messages

271

G-Code, CAD, and CAM discussions / Re: g-code verifying

« on: September 06, 2006, 01:19:23 AM »

Could this feature be added to a g-100 setup? Or does position communications (to the g-rex) take too much horse power to allow that?

Just curious.

Chad

272

General Mach Discussion / Re: Connecting to a computer that doesn't have a db25 port??

« on: August 26, 2006, 05:34:16 PM »

Quick answer, you don't.

I think I read somewhere back that someone had some luck with a pcmcia parallel port. This is going to be your only hope and at best it might be a 50/50 chance of it working. the usb ports won't work at all, serial is another thing entirely.

Now if you want to use mach 3 + the g-rex plug-in you could use Ethernet. And control it that way..

Chad

273

General Mach Discussion / Total NOOB Quick start guide. ?

« on: August 26, 2006, 04:39:21 AM »

HI all,

I read almost every email on both this and the yahoo forum every day. I see lots of the same noob questions pop up frequently. 99% of these are explained in the manual , wiki's  and other posts.
This got me thinking why the basics aren't coming across to the 'total new user'. Then it dawned on me, laziness and intimidation.

First laziness:
I have a feeling that people have a shiny new toy and just want to jump in with both feat and start making things happen and can't be bothered with the minucia of reading the manuals, searching the wiki's, searching posts. People just want it to work, and right now. And just to set the record straight, I was, and still am 100% the exact same way, I much prefer to just load and go, figure it out along the way. I think most techie / tinkerer ( <--i don't think that is a word ) types are the same way .

Intimidation:
When I first installed mach and the screen popped up with the blinking e-stop button I was like " Holy crap what the hell is all of this !?! And it just got worse flipping to the mdi, and other screens. At this point I know what most of the stuff is for, and as my machine design advances so does my understanding of the mystery buttons and functions.
I can easily understand (and relate) to the shock and awe of the total new user. 

Given this maybe we should alter our approach to the 'subsonic' new user. Compounding the problem is the fact there are new people with widely varying levels of experience. Some just get it, and well some, um, just don't.  This isn't a bad thing, it just is what it is. Some times people just get out of their tech comfort zone, and get frustrated, and need some help to get past the first hurdle (e-stop).

OK, so here is my idea. What if all of us 'experts' ( In my case I use the term VERY loosely) Get together and compile a 3 or 4 page Quick Start Guide to mach3? It could cover things like:

*Ports and pins, step and dir output for newbies
*Motor tuning 101
*Blinking,Blink, *^@& ,e-stop-stop, blink!
*Backlash makes my machine do goofy things with steppers (that one would have saved me a week)
*I am using chain-link fence wire for the conductors to my home and limit switches and my machine stops sometimes during a cut,no,like really! I was just sitting there and it stopped!
*The de-bounce blues.
*I am trying to run mach on my IMSI 8080 and it ain't working too good.
*I got a usb to mach-port parallel thingies = no bueno.
*I keep changing the motor tuning stuff and it is always the same when i go back, wazzup with that !?!
*up,down,over,under,left,right,north,south,east,west,+,- what way is plus again?
*IJ wasn't he that guy who was driving around in big cicrles in the white bronco? (obscure ref)
*My screen is too big, My screen is too small, My screen is chopping off stuff.
*I got a licence file and art told me so shove it somewhere, but i don't know where.
*eXtensible Markup Language?
*I am using the freebie version and my 55k g-code file won't run, program must be broke.

I am sure there are others. The idea is just a quick and dirty simple guide to get past a lot of the initial noob gotchas.
For in depth details on any of the above we can point them to the excellent manual, awesome videos, great wikis and knowledgeable folk on the helpful forums.

At this point in my mach experience, ~1 year I have learned tons and still have lots to learn and have zero problem helping others if I have an answer. If you print out the mach manual it is over 1/2 inch that's 12.7 mm for those who understand such things, that is a lot to absorb for a noob just trying to get the motors to spin. 

Well enough of my ramblings, what do 'yall think?

Chad
 

274

LazyCam (Beta) / Re: Video Tutorials on the Support Page

« on: August 25, 2006, 01:07:41 AM »

Hi Jim,   Brian can clarify this but i believe that video was for a early alpha version. Lazy cam is evolving daily and and they probably haven't made a more recent version of the video.

Chad

275

General Mach Discussion / Re: Digitizing

« on: August 22, 2006, 03:44:20 AM »

Ok cool, Have you given any more thought on a offsets edge finding probe plug in? I am trying to improve the accuracy of the 0,0 process. It sure would be nice to be able to just enter a probe diameter, and then jog into the edges and set the g54 or others.

As usual thanks for the awesome software!

Chad

276

General Mach Discussion / Re: Digitizing

« on: August 21, 2006, 09:46:59 PM »

Will this work with a g-rex also or is this a lpt thing only?


Chad

277

General Mach Discussion / Re: motors stalling

« on: August 21, 2006, 02:30:50 PM »

Oh yea, A voltage meter isn't going to tell you much looking at a stepper motor output. The stepper driver is going to be putting out pluses that are too fast for a dmm to react to. The only way to properly look at that signal is to use a o-scope. And even then unless you really know what you are doing and have a duel trace sampling scope it won't tell you much. If the other program runs them fine then don't worry about the motors and just work on the mach settings.

You are getting close. We have all been here

Chad

278

General Mach Discussion / Re: motors stalling

« on: August 21, 2006, 02:23:24 PM »

This sounds like a classic motor tuning problem (assuming you have your steppers hooked up correctly).
Your velocity and acceleration are too high for your steppers. The reason it works if you are at 15% is it is slowing the output down to the point the stepper can keep up.

Ok to find your max settings.
First you have to have your steps per unit correct ( or at least close to your machine parameters ). Second set the pulse width for step and dir to 5 (we can change this later).
Second set the velocity and acceleration to 5. I know this is slow but you have to learn to walk before you can run.
Click in the graph window and use the up and down arrow keys to try these settings. if the motors turn and behave as expected then you can go on, if not then you need to go back through the manual and make sure your ports and pins are set correct, etc.. You also have to make sure that your steppers are wired correctly. It is easy to screw up a stepper connection and get"some" some movement but not correct movement.

Assuming all that is OK now you can start to turn up the velocity. go from 5 to 10 , do not mess with the acceleration leave that at 5. Keep going up in the velocity until you start getting motor skipping again , this is your max speed stepper-skip point. Back off that about 20% and call velocity set. At this point you can start the same process with the acceleration value. Get it to the point where the steppers will skip and back this down by 20%

At this point don't forget to be hitting the axis save button alot.

If you change your step per unit number you will have to start this process over. This number has a lot to do with the tuning and if it is changed all the velocity and acceleration settings will be meaningless.

Just to pre answer a question you Will probably have, Backlash correction WILL cause your steppers to skip, don't use it, try to fix back lash in the machine.


Steppers getting hot: Yes they do. Even when they ain't doing anything. A stepper at rest will still have at least one coil energized to hold the position of the shaft. Just the nature of the beast. Even properly tuned steppers will be to hot to touch. If they are Really smoking hot then you will need to go to a different drive like gecko or rutex or some other pwm current adjustable driver. The resistors will also get cooking hot, also just the nature of the beast. The more advanced drives can limit current so you don't need any resistors. 


Good luck,

Chad

279

General Mach Discussion / Re: g-rex spindle analog

« on: August 19, 2006, 01:12:03 PM »

LOL What I lack in actual knowledge I make up for in tenacity, and some times I get lucky, and some times I let the smoke out

That applies to my life too

Chad

280

General Mach Discussion / Re: Tracing eye and mach

« on: August 19, 2006, 01:02:19 PM »

HI, I am trying very hard to imagine a a scenario why you would ever want to use the eye. The entire point behind CNC is to gain speed and accuracy in making parts.
If you were just given the entire setup then you probably don't have years of legacy hand trace drawings that might be cost prohibitive to redo in cad so that doesn't factor in. - advantage mach

If you just want to if you want to just take a marker and draw out a part and cut it you can do that on steel and get out the plasma torch and let her rip. If you want to change anything you would have to re layout and cut again. I find it WAY easier to change something in cad then re hand draw something complicated. - advantage mach

The fact someone just "gave" you this complete setup says something about this someones opinion of the setup ( boy that came out weird ). Just guessing, they decided to : a-stop cutting metal,b- company went belly up,c- switched to a cad,cam,cnc setup and realized the eye thing was a useless relic.

I looked it up and the entire thing is a neat hack , and i am sure back in the day it was state of the art. However that day was a LONG time ago. Presumeably thing thing works as is, if you want do just draw a part and cut it out you have everything you need. Adding mach into the loop just adds cost and complexity to a already functioning system. Hand draw-scan-mach-cut nets you zero benefit. Because you are still limited by the "scan" resolution.

Aside from the "just because i can" department , witch i do all the time too, there is no 'justifiable' reason for doing this, at least i can't think of one.


Any how just my .05c - good luck

Chad