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Author Topic: Random positioning motion on each operation start.  (Read 1601 times)

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Re: Random positioning motion on each operation start.
« Reply #10 on: April 23, 2019, 01:14:19 PM »
Brand new to this site, so please be kind. I too am having this same problem. It has occured for years now. In looking at the M6end macro I am questioning the second to last line:

Code"G00 X" & x & "Y" & y

Are the parenthesis in the correct position? Thanks

john f

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Re: Random positioning motion on each operation start.
« Reply #11 on: April 23, 2019, 10:35:25 PM »
Brand new to this site, so please be kind. I too am having this same problem. It has occured for years now. In looking at the M6end macro I am questioning the second to last line:

Code"G00 X" & x & "Y" & y

Are the parenthesis in the correct position? Thanks

john f
Nothing wrong
"the gift of God is eternal life through Jesus Christ our Lord"

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Re: Random positioning motion on each operation start.
« Reply #12 on: April 23, 2019, 10:57:29 PM »
Hey guys

Sorry if this has been covered- I have searched here and elsewhere and have not found anything.

On Mach3 Mill, I experience a random positional motion at the start of each operation in a file. Example- at start of program, on hitting Start, the table may be commanded to move to X7 Y2, but it may initially travel to something like X8.4 Y1, and then (if it has not hit soft limits) will move to the commanded position correctly.

I am doing nothing strange in my gcode, no Macros have been called etc, and this effect is seen on both .62 and .66 versions of Mach3.

Because the motion can be random for the same code (i.e. if I export only a single operation, and run that- I can see different directions of motion prior to the motion towards the correct start location), I don’t expect this is a gcode problem. In fact, the ‘random’ direction seems to be influenced by where the spindle is in relation to the operation’s starting point. It seems almost to generate some exponential vector, where if it is 1” from the target, it may travel 2”, but if 2” from the target, it may travel 4”…

It also seems to switch signs/direction if the starting position is on the opposite side of the starting position (i.e. if -X relative to the target, it tends to move in the +X direction, and vice versa). I don’t know if this is a hard rule- but it seems to be a pattern.

There is never a problem once the system begins the cut- I only see weirdness in Mach on the op start.

Below is some sample code which is doing this. It does it for all code I export, from all posts I have used. So, Im wondering if there is some bizarre config option in play, or if some registry corruption could cause the system to pull in random offset data as with motion in one coordinate system and then switching to G54 for the actual operation…

It is frustrating as hell, because this can and does cause tool crashes, and requires frequent re-zeros mid-program since a softlimit trip can yield a few thousandths bias…

Any thoughts are appreciated-

Rob

Code: [Select]
%
O0000 (Trunnion Test Part)
 (PROGRAM   - Trunnion Test Part.NC)
(DATE      - FEB-11-2018)
(TIME      - 1:36 AM)
(T120 -  3/8 FLAT ENDMILL    - H120 - D120 - D0.3750")
N110 (COMPENSATION TYPE - COMPUTER)
N120 T120 M06 ( 3/8 FLAT ENDMILL)
N130 G00 G17 G90 G54 A95. X7.5302 Y.6396 S3600 M03
N140 G43 H120 Z2.3295
N150 Z1.4295
N160 G94 G01 Z1.3295 F2.
N170 X7.4802 F3.17
N180 X3.5302
N190 G00 Z1.4295
N200 Z2.3295
N210 M05
N220 G28 A0.
N230 G90
N240 M30
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1. The Gcode file says in comment
N110 (COMPENSATION TYPE - COMPUTER)

Does that mean the radius of tool#120 which has a diameter of 0.3750" (3/8") has not been compensated?
G41 that turns on radius compensation and G42 that turns off radius compensation are NOT found in the program so cut dimensions may be incorrect because of tool radius.

2. Operation.
Normally, you need to jog the machine to your work piece origin x and Y and Z (tool tip on top of the material surface), the in work coordinates (no red square around Machine Coordinates button) click [zero X] [zero Y] and [Zero Z].
Then click on [reg. toolpath]
BEFORE
you click on
[CYCLE START]


« Last Edit: April 23, 2019, 10:59:46 PM by reuelt »
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Re: Random positioning motion on each operation start.
« Reply #13 on: April 23, 2019, 11:09:17 PM »
@extrapilot @kabover

I recommend you read concise STUDENT CNC GUIDE first
https://www.kth.se/polopoly_fs/1.686422.1550155780!/Student%20CNC%20Guide%20v0.4.pdf

Then
as RICH suggested
Mach3Mill_1.84.pdf that is available in this forum under USER DOCs.



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Re: Random positioning motion on each operation start.
« Reply #14 on: April 23, 2019, 11:33:24 PM »
The reason that I asked the question is for some time when I do a tool change, after pushing start, the machine will take off in a random direction for a given distance and then go to the position it is suppose to. In reading M6end is suppose to send the tool to the next starting position after tool change. I moved the " mark from in front of the G00 to In front of the X and now the machine works as it should. The random motions have stopped. At least 6 dry runs and not one problem. It looks like it is fixed, but I am not sure and you say nothing is the matter with the statement. Is it fixed or not???

john f

PS  I am quite familiar with G-code but the macros are foreign territory.
« Last Edit: April 23, 2019, 11:36:42 PM by kabover »

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Re: Random positioning motion on each operation start.
« Reply #15 on: April 24, 2019, 02:02:55 AM »
I moved the " mark from in front of the G00 to In front of the X and now the machine works as it should.

imho by doing this, you should see a scripter Compiler error in the Status line, and the M6End macro
will not be executed at all. -> so no move
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.