Messages

171

General Mach Discussion / Projecting to plane?

« on: January 07, 2006, 10:33:12 AM »

Hi,any hints/short cuts on milling a 2 D carving onto a spherical surface without too much distortion and without too much depth variance(the sphere is hollow)?I have an image I'm rasterizing and would like to just make that impression(negative) on a small area of a plastic sphere.The sphere is about 4" diameter and the area with the image is negotiable but around 2", centered. I actually once had this done many years ago before I did any milling and I believe the guy that did it for me actually calculated the different heights and offset Z with these numbers but there's got to be a better way(curve interpolation?).Thanks,Keith

172

General Mach Discussion / Re: More Rotary confusion

« on: January 07, 2006, 10:16:37 AM »

Okey.Dokey.Got it ! While it seems that the acceleration was the most offending parameter,I also believe that because I had the feedrate 'crawling' that might have been equally the culprit because it reminds me of pulse width modulating any motor project I've done,controlled by a microprocessor ; if I ask too much at one 'end' of the drivers ,the motor will not quite respond because of the time constant portion the motor introduces in it's reactance.
Thanks Brian.Me happy now

173

General Mach Discussion / Re: More Rotary confusion

« on: January 06, 2006, 09:32:23 AM »

Thanks Brian,yes what happens with the code you posted is,I start my rotary table at 0 degrees,running the program it quite quickly is off by what looks like precisely 5 degrees (when I hit 180 on the DRO ,my rotary is at 175,when I go negative ,the DRO reads 0 and my rotary reads 355,back past the '0' on the rotary).Am I missing pulses? Keep in mind, when I say for instance, GO1 A15(starting my rotary at 0) it does indeed go to15 degrees.So if pulses are missed it's only in 'incrememtal positioning'.-Thanks,Keith

174

General Mach Discussion / Re: More Rotary confusion

« on: January 05, 2006, 07:01:36 PM »

The code looks something like this
: G00 G90
X0.0000 Y0.0000
Z.1000
F25.0
G01 Z0.0000 X0.0000
M98 P0100 L360
G90 G00 Z.1000
M30

O0100
G90
F25 G01 X1.0000 Z-.75000
G91
A0.500
G90
F25
G01 X0.0000 Z0.0000
G91
A0.500
G90
M99
It runs through fine but instead of going half a degree it goes more like a quarter and the DRO reads correctly(Start with '0' and ends,after the first pass through "A0.500" it reads .5 on the money.

175

General Mach Discussion / More Rotary confusion

« on: January 05, 2006, 06:15:08 PM »

Okay,so,I'm ready to cut my cone.I first tested my rotary table for motor tuning and with everyone's help,with a G01 A15 my rotary goes to 15 degrees as promised.Now with the addition of the suggestions of Brian and some particular details for what I desire I modify this code and yes indeed,as I 'cut air',I see that cone a formin' BUT.......screech! It seems with the G91 incremental code stuck in there with each line progressing .5 ,my rotary does not go to half a degree but more like a quarter degree! Checked and rechecked motor tuning,did the G01 move again and that worked to position to the degree I entered.What up?-Keith

176

General Mach Discussion / S command?

« on: January 05, 2006, 02:13:39 PM »

Hi the 'S' G-code  comes up in an imported .dxf that I'm about to edit for my purpose.Does this denote:'spindle'(it's followed by '1000')?Can't find it's reference in Mach2.Thanks ,Keith

177

General Mach Discussion / Re: Milling a cone

« on: December 23, 2005, 11:15:05 AM »

Thanks Brian.Think I've got it.I commented every line and my only questions are : line 6- (G98 P0100 L360 'Call The sub and run sub 360 times)..."P0100"? Is this a circumstantial use of a 'P' command?
And: I assume you are coding this so increment of A-axis is every half degree?
Thanks for your help,nothing like 'bouncing' questions off someone besides ones self.Looks like learning VBscripting is in my future as well.-Keith 

178

General Mach Discussion / Re: Milling a cone

« on: December 22, 2005, 06:12:46 PM »

I'd love to see some code as I haven't really gotten into 'macros' which I assume can give you a 'for x=n to n...next n' type of arrangement.If this was all micro code,I'd be a hit but I just haven't found the resources for 'logical' decision making in g-code yet.Thanks in advance,Keith

179

General Mach Discussion / Milling a cone

« on: December 22, 2005, 12:51:01 PM »

Hi,well now that I have my rotary axis 'pointing' where I want it,when I want it,I wonder if someone could 'shortcut' me to the 'accepted' way of milling a cone.My thoughts are to go crazy incrementally listing z cuts per 'x step' and a 360 turn per cut which seems to scream :"wrong" or do an interpolation of the 'z' and 'x' and have some ratio of 'z,x feed' to a-axis feed;which seems closer but being new to g-code,I'm not sure how to enforce the different feedrates to accomplish this within the code's lines.Just mssing the protocol of not changing one axis feedrate when enlisting a feedrate for another axis.Reminds me of first time head scratching for doing 'nested "if...then" statements in microcontroller coding.-Thanks,Keith

180

General Mach Discussion / Re: Quantifying A-axis rotary

« on: December 20, 2005, 11:41:31 AM »

I'd just like to add to all this,if anyone is using a stock Sherline package for this rotary business that although the motors are 400 steppers,the microstepping feature requires you to double this 400 steps to 800 within Brian's equation to achieve the desired resolving.I set mine up this way and 'bingo' ,works like a charm.Thanks for everyone's input.-Keith