Messages

51

General Mach Discussion / Re: Feedrate for 4th-axis rotary table

« on: August 20, 2011, 12:08:20 AM »

Hi TP yeah my bad, all my comments pertained to a single set up.  And I agree my method is not widespread, perhaps the entire user community consists of one user (me).
But I don't understand why? Would you rather have (as in my example) a 6 inch flywheel that was made using my method with a single setup on a rotary and that's known to run true or one that was cut half way, then removed, rotated 180 deg, re-clamped and completed? To me it's a no-brainer. I am ready to defend my position too  
Al

52

General Mach Discussion / Re: Feedrate for 4th-axis rotary table

« on: August 19, 2011, 07:09:40 PM »

<snip>
You can program the machine to cut the part without the aid of the Rotary table setup. Yes even LARGE parts.
<snip>
(;-) TP

TP, I have a problem seeing how a circular part that is larger than the throat clearance can be cut in a single set up without using the rotary. For example take a 6 inch flywheel. When the work hits the column I’m only half way across the part and can’t go any farther (even with clever programming<grin>). With the rotary I only need 3 inches of throat travel for the whole job. Tell me what I’m missing? This is a 5400 Sherline with 3 ½ inch throat. This is the situation that prompted the use of the RT in the Z-axis.
Thanks,
Al 

53

General Mach Discussion / Re: Feedrate for 4th-axis rotary table

« on: August 19, 2011, 02:59:49 AM »

Hi Rick, I looked into this a while back and no, the C-axis (rotary table axis parallel with the spindle axis) is not supported. I had written a little Gcode conversion app for a one time project (a 10 inch clock dial) back 9 or 10 years ago for CNCPro, (a DOS program that predates Mach). The feed rate solution was to calc a new F-word for each block. I wanted to convert the app to Mach but was stumped on the feed calc. Someone, I think from this group, suggested using G93, Inverse Time Mode and that did the trick. 
In response to TP's comment, the referenced clock dial was my reason to convert from rectilinear to polar.  My Sherline 5400 mill only has a 3 ½ inch throat clearance.  So that is the max diameter of a round part that I can cut using X-Y. Convert to polar and it doubles; I can cut anything that will fit inside a 7 inch circle. Or by offsetting the RT in the Y axis I can cut the outer 3 ½ inches of any diameter part (within the limit of the Y travel).  And then admittedly it turned into a challenging fun project that I may never use. 
Al

54

General Mach Discussion / Re: Axis stay short of where they should go

« on: August 07, 2011, 12:50:35 AM »

Oh man, if I had a buck for every time I did that! But again, I used a digital caliper for the lack of dial indicator.

I think you may have misunderstood TP’s comment (recalculate the steps per unit).  Calculating the steps per unit and using Mach’s axis calibration feature are two totally different procedures. The former will result in an exact correct value while the latter will be subject to measurement inaccuracies (and I would guess errors approaching the magnitude that you describe).

You will need to know the details of your system as TP mentioned in a later post, i.e., stepper deg/step, lead screw pitch, etc.

There is a spreadsheet at:
 http://www.machsupport.com/forum/index.php/topic,16315.0.html
That will do the calcs for you.

If you don’t know some of your system parameters, then give us as much info as possible and I’m sure we can work it out with you.

Al

55

General Mach Discussion / Re: Missed Features

« on: August 04, 2011, 03:07:05 AM »

But to the subject line, THAT is the price you pay when you use a custom screen set and the Author does NOT do the maintance to keep it up to data for the newer versions.

Hi TP

I was going to ask how one is expected to be made aware of such screen set changes, but a review of the version log turned up this:

Feb 10/2008
Release 3.034
-- Fixed Display for Machine softlimits
-- Added new HTML Gcode help dialog
-- Added VB Debug messages to help fix reported VB problems

So the “Author” (me) wishes to apologize to the user (also me) for this negligence in maintaining the screen set. I can’t imagine how I (the author) let this slip by me. <Grin>

Seriously, I only wanted to point out that new releases may have changes/enhancements in the screen set that the average user may or may not be aware of and in any case will require manualy adding to their screen set.

Al

56

General Mach Discussion / Missed Features

« on: August 01, 2011, 11:15:32 PM »

I just noticed that if one has been using a customized screen set for a number of years, then some enhancements found in the updates may not be in effect.

Namely, the case at hand is the Gcode button. Even tho I have .042.020 loaded, my Gcode button still returned the older rather basic spreadsheet type format.

Screen4 showed that my Gcode button had the “OEM Code Function 8” checked and that the current 1024 screen set has “VB Script Function Edited in Mach3” selected.

Changed the function option selection and copied and pasted the VB code “HtmlDialog(GetMainFolder()+"Mach3MillGcode.htm" )“ into the Gcode button.  Now I have the enhanced format. The file “Mach3MillGode.htm” was already downloaded from the newer updates.

Makes me wonder if I’m missing any other new features?

If this has been previously discussed I apologize, I missed it, and so it’s new to me. (And possibly others?).

Al Lenz

57

General Mach Discussion / Re: mach3 not downloading

« on: August 01, 2011, 12:36:13 AM »

To quote George Gobel on the Johnny Carson show:
“Did you ever get the feeling the world was a tuxedo and you were a pair of brown shoes?”
Happens to all of us.
 

58

General Mach Discussion / Re: dro and gcode don't match

« on: July 22, 2011, 04:04:22 PM »

 

59

General Mach Discussion / Re: dro and gcode don't match

« on: July 22, 2011, 03:48:55 AM »

Ed,
It may be due to the resolution of your system. For instance my controller is ½ step and with 4tpi lead screws each step is 0.000625 inch. So if the G-code is in 4 or 5 decimal places it is unlikely that Mach can drive to that exact position. Mach will drive to and display the step that is the nearest to the commanded G-code. For example if I step in 0.001 increments the DRO will show steps such as .0000, .0006, .0019, .0025, .0037, .0050…. etc.  As you suspect it’s quite likely normal and not a poblem.
Al

60

General Mach Discussion / Re: g16 / g83 interaction ??bug??

« on: April 27, 2011, 11:44:23 PM »

Roger and TP,

This thread is the most interesting (to me) and informative of any that I’ve followed recently on any of a dozen forums that I routinely follow. Thanks guys for all the info and examples that I hadn’t picked up on from the manuals.

 Excuse me for butting in, but I just wanted to express my appreciation.

Thanks ,
Al Lenz