Messages

1

G-Code, CAD, and CAM discussions / no

« on: May 31, 2007, 06:44:31 PM »

What I want is a combined linear axis PLUS rotational axis move. Think of drawing spirals. That's a change in radius at the same time as a change in angle.

My original question is how to figure feed rate when you're dealing with mixed units (inches and degrees). I understand inches per minute. I understand degrees per minute (the example you just gave). What I don't see is how to mix inches and degrees to calculate a feed rate.

Or should I look at it all as generic "units", where the x might move 1.000 unit, and the a moves 90.000 units? If I wanted a 1.000 inch and 90 degree move done in one minute, the feed rate would be sqrt(1^2 + 90^2) = 90.006 units / minute?

2

G-Code, CAD, and CAM discussions / Re: Question about G1 speed

« on: May 31, 2007, 04:21:17 PM »

Chaoticone,

I don't understand. I spent this past long weekend outfitting the rotary table with the servo. I went to set up Mach2 to use this as a fourth, rotary axis. It comes up as axis "4" along with "X", "Y", and "Z". I set it up to read degrees. If I jog it 90 units, it turns the table 1/4 of a revolution. This is a 90:1 table with a motor that has an encoder that gives 2000 steps per its revolution. So one degree is 90*2000/360 or 1500 steps/unit.

My question is more a g-code one. If my (x,y,z is) at (0.000, 0.000, 0.000) and my table is at 0.000 degrees, and I run this line:

G1 x1.000 y1.000 z1.000 a90 f???      (this is just as an example)

What do I put for the speed (after the f, in the line above)? Or should 90 degrees be represented by 0.25? That would make one unit be one full revolution.

I'm just confused. I've never programmed g-code for rotary tables before.

Hey Tiger,
    As far as your step per units, they need to be set to what ever number will give you one reveloution I think. I think it gives trouble if you set your steps per to= one degreee I think, not certain though so maybe someone will verify this.

3

G-Code, CAD, and CAM discussions / Question about G1 speed

« on: May 28, 2007, 08:47:34 AM »

I am familiar with the G1 command, where the 'f' value sets a speed in units/minute. I am about to bring on a fourth axis, a 6" rotary table, and am wondering how the speed gets calculated if I have a G1 command that has both a rectangular coordinate move (x,y, or z) as well as a rotational move (a, b, or c)? My x,y,z is in inches and I assume the a,b,c is in degrees.

So at some point the CNC software has to calculate a vector length, based on the current position and the desired final position. Then, with a given speed rate, it gets the movement done in (length divided by speed) minutes. But if there's a combination of linear and rotational movements, I am not ure how it will calculate the vector length. For this purpose, does it treat one degree of riotation the same as one inch of linear movement? Would a one degree rotation and a one inch movement of the z-axis equal a vector length of 1.4142 "units"? To get that I took the square root of 1 squared plus 1 squared, or the square root of 2.

I ask this because I usually use a speed of 3 to 5 units per minute when doing linear stuff. But if a complete revolution is going to be considered 360 units, then the speed will need to be significantly faster. I'd still want the z-axis to descend at about 5 units per minute and for it to finish a one inch boring depth therefore in 12 seconds (0.2 minutes). So the table would need to revolve completely in that same one 12 seconds, or 30 units per second or 1800 units per minute. This is where my confusion comes from. Is the speed rate then the square root of (1800^2 + 5^2)

Any help is appreciated!!!

4

General Mach Discussion / mach2

« on: May 22, 2007, 04:23:15 PM »

The software I am running has a greyed-out menu option for importing an image file. I assumed that it was because I have a demo version that the option is greyed-out. I can't find any documentation on this though.

5

General Mach Discussion / tell me about importing a jpeg image and converting it to G-code

« on: May 22, 2007, 03:10:12 PM »

I am using Mach2 from 2004-05. It is the trial version. I am interested now in using it commercially and getting the licensed version to make pantographs in aluminum plate from a customer provided image, if this is possible. Can some kind soul show me some examples of what is possible? I have seen examples on the web of intricate patterns having been turned into carved wood, acrylic aluminum, etc. Also I am curious how the software deals with different colors. Does it convert color to tool depth? Thanks in advance for any help!

6

General Mach Discussion / tell me about importing a jpeg image and converting it to G-code

« on: May 22, 2007, 03:09:07 PM »

I am using Mach2 from 2004-05. It is the trial version. I am interested now in using it commercially and getting the licensed version to make pantographs in aluminum plate from a customer provided image, if this is possible. Can some kind soul show me some examples of what is possible? I have seen examples on the web of intricate patterns having been turned into carved wood, acrylic aluminum, etc. Also I am curious how the software deals with different colors. Does it convert color to tool depth? Thanks in advance for any help!