[slowbob]

Hi all,

I’m trying to get my first 4th axis cut running. I’m pretty certain I have the steps and velocity set correctly. Steps/per = 400 with a 1.8 deg stepper and 10 uStep and a 72:1 rotary table. 200*10*(360/72)=400.
I have my A-axis velocity set to 3000 and the accel to 1000.
The X,Y and Z velocities are set to 50ipm and accel 15 ipm.


Rapids are fine but when I get to the G1 codes the rotational (angular federate) is limited by the linear feed rate.
Am I missing a G-code for the A axis or is there a setting that I’m missing?

The problem code is commented (C style) below.
T1M6
M3
// next line runs fine
G0 X0.0 Y0.0 Z0.02 A0.0
// next line runs fine, fast to 90 degrees
X0.0 Y0.0 Z0.0825 A90.0
// this line the angular feed rate is limited to the linear feed rate (rotaion is soooo slow)
G1 F22.5 X0.0 Y0.0 Z0.0625 A90.0
// ditto (rotation is soooo slow)
G1 F22.5 X0.0015 Y0.0 Z-0.2054 A99.0001
X0.003 Y0.0 Z-0.1959 A108.0


See you at NAMES
Thanks in advance,

Bob Stack

[dertsap]

its feeding in degrees/minute

[slowbob]

Dertsap, thanks for the reply.

I understand it is feeding in deg/min.

I guess what I want to know is how do I get the A axis to run at a acceptable rate. It appears to me since the feed rate for X, Y and Z are set for 45ipm, the A axis is forced to run at 45 deg/min, or 1 rev in 8 minutes.

Is there a way to increase the feedrate of the A axis seperately?

I have considered setting my feedrate to 3000 and letting the max rate of the motors on the other axis limit them. Simulating this seems to work. But I think I must be missing a setting in mach3 or need to edit my g-code to get this work the way I would expect.

If this is any help, I genereted the xyza code in gmax using the cnc-toolkit script.

Thanks again,

Bob

[ger21]

Set the A axis diameter on the settings page, and check the box in Config>Toolpath to use diameter.

[slowbob]

Gerry,

Thanks! I'll check it when I get to the shop.

Off topic: BTW, I noticed you are in shelby. You, and others in the area, may be interested in a group we have that gets togehter the 2nd tuesday of every month. GoTech. This is a drop in group. We're in Ann Arbor and although it is a drive for you we have folks find it is worth comming from Lansing. Check out the yahoo group NotBaGo, that was the pervious name of the group. Tuesday we had about 40 folks. We are a group of folks who like to make anything. Lots of engineers, cnc enthusiests, a couple of PHD's, machininsts. We have guys comming in from Warren, you could car pool with. Lots of cnc enthusiests. We hold it in a shop I share with some other folks "a2 mech shop" the coolist shop on earth. If you are going to names stop by the booth where the control software uses the penguin (it will remain unnamed in this thread) and talk to Dale about it. He is a partner at our shop and heads the gotech group.
Here is a link to a makezine article about it:
http://blog.makezine.com/archive/200...ght_11309.html

Here is a link to an ann arbor chronicle article about our shop:
http://annarborchronicle.com/2009/04...duced-in-scio/

Let me know what you think.
Thanks again,
Bob

[slowbob]

Hi,

I just changed the a axis to use diameter, but it didn't make any difference. The max speed is still limited by the 45ipm of the feedrate set in the g1 command.

Thanks,
Bob Stack

[ger21]

I guess I misread the question. When using the A axis, feedrate is in inches per minute. You have it set to 22.5ipm.

[slowbob]

I'm running an emco f1 with a max ipm on xy of 50ipm. So I set the feedrate in the code to 45ipm the 2nd g1 line. Mach is running the code on the A axis at 45 deg/min or 1 rev every 8 min.

Is there any why to set the A axis feedrate in the gcode faster than the x, and z feedrate?

Thanks again,

Bob Stack

[ger21]

Did you enter the diameter on the settings page?

[slowbob]

> Did you enter the diameter on the settings page?
no

Thanks Gerry that did the trick.

Did you checkout GoTech? Without a doubt in my dull life it is the most fun I have during the month!

Thanks again,
Bob

[dertsap]

thanks Ger thats a huge help for me as well
Bob how have you been making out with the toolkit , i found it to be a bit of a learning curve but it puts out some decent code , i cut out a full 3d skull last weekend with the code generated from it , its a great plugin

[slowbob]

OT:
Dertsap,
I like the the toolkit alot. Danny's ebook and cnc4free.org has been invaluable. I would have not endevored into the 4th axis stuff without it. The cut I'm testing the 4th axis with is a fat bird. I used a comercial package to generate a indexed 4th axis with 16 sides and the gcode file was 15meg. The same non-indexed file done with the toolkit was 500K.

Thanks to everyone for their help!

Bob Stack