Messages

11

LazyCam (Beta) / Understanding LC settings

« on: May 28, 2006, 12:54:23 AM »

I am attaching a DXF file of a control horn I am using as a test file for calibrating my new 3 axis mill I built. I am doing this so I can see if someone that knows what they are doing could maybe set it up in LC so I can compare it to what I am doing to see if I am setting it up properly.

I am not getting the compensation set correctly. The parts are coming out .050 smaller than I want.

Here is my set up: I am using a .0420 (#58) end mill. I set up this diameter in the tool set up on the main screen of Mach 3.

I am not sure what all of the settings are in the Layer Controls setting. I can figure out some of them, but I am not sure how the units are measured: is the settings in what ever the table is set in? So if I am set in inches, is the feed rate of +100.00 equal to 100 inches per minute? DOes this over ride the calbrated settings in the feed rate in Mach 3?

Final depth, Rapid height, start depth all in units per as set in the homing/limits in mach 3? (so in my case, inches?) Example, if start depth is set for +1.000 in the LC layer control, will it be +1.000 inch in Mach 3?


Also, a big curiousity for me is how I can draw a drill hole in a CAD program. This control horn has 3   .0420 holes for the wire controls to go through. I drew these as circles in the CAD program very small. I edited the G Code by removing the G2 codes and just made Z -0.1000 type replacements, but I am wondering if this is the right way to do this, or if there is a symbol I should put in my CAD files to be interpreted as a drilled hole the diameter of the end mill.

Whew! Thanks for the teaching!

Mark

12

General Mach Discussion / Re: Motor tuning question

« on: May 27, 2006, 06:18:16 PM »

BTW, I DID find that using 500 RPM was way too fast. I dropped the velocity to 40 ipm and saw a decent torque to speed, so I left it there.

I actually cut my first part and now am trying to learn how to compensate for the tool diameter.

THAT is a subject for a new thread in the Lazy CAM area

13

General Mach Discussion / Re: Motor tuning question

« on: May 27, 2006, 06:15:12 PM »

Hey Guys!

Thanks for the encouragement! I will look at modifying the machine with the pully system. Great idea.

After posting, I hit my x carrage and it moves on it's own, making me look underneath and seeing the motor connector was loose and not even connected to the motor. This was causing the 'slipping' to the extent it was. I re-attached the lead screw, and now at least I have movement. What I was initially thinking was a stalled motor, was an un-attached motor (Good grief!).

BUT, I am having some erratic motor speeds (the lead screw does not turn very smoothly, but in rapid jumps of turns). It is rapid enough to get a decent linear motion, but not the silky smooth operation I had thought I would see.

Most of my requirements will not require .001 accuracy, so your suggestion to make a ration reduction unit is well taken. I too and just cutting wood and foam, so it is not like I am doing the kind of machining the big boys here are doing.

Thanks again for the encouragement!

Mark

14

General Mach Discussion / Re: Motor tuning question

« on: May 27, 2006, 02:14:53 PM »

***EDIT***
Just discovered my X axis lead screw motor coupler was loose... BIG problem if you want to get a motor to turn the lead screw....Friction fitting will only move the screww so much   Maybe this is the source of my problems !!   


Hi Again:

I don't have enough hair left to be pulling it out. So, I again turn to the gurus of Mach to see if I am missing something.

I am getting almost zero torque today when testing at any setting. Do I need to shut the program down and re-start it when I make changes in the motor tuning section? I hit the sliders (per video instructions) and then reselect the axis and push the arrow keys.

What I am getting is jumpy motors. I believe I have set the speeds up properly (500 rpm to start = 100 inches @ 5 tpi) and the acceleration is around mid way on the sliders.

I am running at 12 volts, so I am not really sure the speed I should see at max velocity. So, I am going to spend forever trying to get this set up to work, but atleast I see movement!

I ran my first cut last night and the dropped steps left my X axis about 1/2" short of the place it should have stopped. Y seemed fine.

Sorry if this just seems like repetitive questions on the same problem, but I am stumped, and I used to think I was pretty good with thinking this stuff through.

Perhaps it is my laptop? I tried to get it set per the optimized recommendations, and STILL had the same graph profile as before I did anything! BIG spikes and lots of them. Using a Dell Laptop with 1.5 GHz processor and 1 gig of RAM. My desktop has a great graph profile when testing and I am thinking of trying this one to see if that matters....

Thanks for helping me think this one out!

Mark

15

LazyCam (Beta) / Re: Can't find Lazy Cam

« on: May 27, 2006, 12:11:22 AM »

Man, am I glad for this thread! Thanks for asking the original question, as I did EXACTLY the same thing, and was too afraid to ask... (not that anyone has been even a little less than helpful here...).  I am just the newbie to the whole CNC thing, and I did just as you: built my own 3 axis mill, and now an trying to learn the software thing so I can actually use it

Thanks for the question, and thanks Brian for all of the patient answers! I have been reading the EMC2 users manual to learn the basics of nc coding, and was feeling as though I was going to have to live with the import DXF feature of the Mach 3 program, and just tweek the files until I got a license for Mach 3...

So, thanks for the info. I'm off to the downloads page

Mark

16

General Mach Discussion / Re: Motor tuning question

« on: May 24, 2006, 09:17:09 PM »

I am just checking motor movement and have yet to get a cut made with the table. I will see what I am missing at 12 volts by trying it together. I don't think basic movement will over stress the motors to pull more than the 3 amps each that they are rated for.... Will it?

17

General Mach Discussion / Re: Motor tuning question

« on: May 24, 2006, 06:45:57 PM »

For the record, the HobbyCNC board will take a max of 48 VDC 

I am curious, I have 2 12 VDC supplies, one with a 10 amp rating, and one with a 60 amp rating. If I were to put these in series to get 24 VDC, would that work (at least to run tests until I get the whopper transformer I am ordering)?

Thanks for the feedback!

Mark

18

General Mach Discussion / Re: Motor tuning question

« on: May 24, 2006, 11:06:38 AM »

I spent quite a bit of time in the motor tuning section today, and what I see happening is this:

If I set my 'Steps per' to the 4000 setting (1/4 step setting on the driver board = 4 microsteps per step*200steps = 800 per turn*5 lead screw turns per inch = 4000 "Steps per'), then tough the sliders as instructed, I get jumpiness. I then move the sliders to lower settings and I get better movement, but much slower travel.

I am guessing I need more voltage (only 12 volt supply @ 60 amps for a 3 motor @ 3 volts each set up).

More tinkering to come, but I think you guys have given me the right direction. What I wish I knew was what speed I should be satisfied with using this set up...

19

General Mach Discussion / Re: Motor tuning question

« on: May 23, 2006, 12:08:03 PM »

Uh Oh! The last post was based on testing the settings in Mach 3 without connecting it to the driver board. When I do connect it, and run the axis with the arrow keys, I get a VERY erratic jumping of the motors and NO torque. So, I know I am over stepping them with this setting. I have tried the slowest settings on both vel and acc and had the same thing happen.

When I set the motors at '20' steps pe, I get slow travel and rock hard torque.

Setting at 2000 per gets similar jumpiness and loss of torque. My driver board micro stepping is set for 1/4 step.

Any ideas as to what is happening?

Thanks again!

mark

20

General Mach Discussion / Re: Motor tuning question

« on: May 23, 2006, 12:44:55 AM »

WOW! What a difference that makes in the cut speed! I KNEW something was wrong, as the speed was SO slow. Thanks again!