Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: wilfoude on February 04, 2013, 07:05:40 AM
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I have to produce a new aircraft (glider) panel again and have finished the design. Normally I first put a pencil in the tool holder to draw the panel. This is the final check before cutting the real panel. But I did not believe my eyes when I saw that Mach 3 was simply skipping drawing some of the partholes. They were clearly visible on the screen in the Toolpath display, but were not reproduced by the machine.
The skipped part was the second one out of a series of 4 identical parts.
How is this possible, What did I do wrong ? How can such a mismatch between Mach-3's own screendrawing and actual drawing develop ?
My machine (Portal CNC, 3*4 feet) normally works without the slightest problem.
I need urgent help in order to deliver the product in time.
Wilfried Oude Vrielink
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Hi Wilfried,
As far as I am aware – if it shows in the toolpath window then Mach3 will output the correct step and direction signals to follow that display.
My guess is that you are either loosing communication between your PC and the machine or else that your PC is off doing another task whilst it is running the Mach3 GCode.
Tweakie.
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I'm afraid this is not the case. My technical PC runs only one program and that's Mach3. It knows no other tasks. After the "lost part", the rest of the work is completed correctly.
When I repeat the test-drwawing it makes the same mistake exactly the same spot again.
Wilfried
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Wow, never heard of this one, can you possibly take a video showing this, or possibly give a step by step detailed picture of what's happening on the machine and what shows in Mach 3 when it is happening?
Is it completely jumping the part to another part altogether? If not, maybe your depth on that particular part is not set properly in the CAM program?
I'm sure one of the pros here will help, but that is definitely first for me.
Dave
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I will try to get some pictures to show what is happening.
The "lost parts" are drawn (or should be) with the same subroutine, without any change in settings.
Here is part of the code that produces 4 holes for circuitbreakers in a vertical row.
"
G00 X-32 Y-210 M98 P90 (Fuse 1)
G00 X-32 Y-190 M98 P90 (Fuse 2)
G00 X-32 Y-170 M98 P90 (Fuse 3)
G00 X-32 Y-150 M98 P90 (Fuse 4)
"
O90 is the sub that draws the Circuitbreaker outline (no tool comp used. I know that that will not work correctly).
Nmbr. 2 circuitbreaker is shown on screen (as expected), but not executed on the machine.
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Have a look and shudder !!
I have attached 2 pictures. One from the Mach 3 screen and one of a part of the pencil-drawn part (tool replaced by pencil).
As you can see on the pencil drawing, the second hole of a vertical series of holes (circuit breakers) is missing, although the screen picture shows that MAch 3 nows its existence. The holes are called for in sequence with nothing happening in between.
Why is Mach 3 refusing to produce that second hole.
Wilfried
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Ok, thanks, and there will be others that are a lot smarter than me when it comes to Mach, but you may want to list what your using for your CAM program and the post processor you use as well.
Also, upload your Mach 3 XML file (rename it something like "wilfoude13.xml" when you upload it).
What get's me thinking it's a CAM thing is the fact that you say Mach 3 normally works.
Dave
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Hello Dave. thanks for your quick response.
But, I Don't use CAM software or a postprocessor and make all G-code part programs by hand. These panels are relatively simple. So I use I library of components and only have to put them on their right coordinates on a panel. It's very straight forward.
But whatever I try to do, to upload the XML and the part program, I always get the message that there is already a file with that name and I should rename and try again etc.
Wilfried
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Hello Dave,
I now try to get the part prgram uploaded.
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Hi Wilfied,
I've contacted Graham here on the forum for you as he's a GCode Guru, and will possibly be of some help to you.
Dave
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Hi Wilfried,
I appreciate that is not much help in resolving your problem but all 4 fuse cut-outs were executed when I test ran your code here.
Which version of Mach3 are you using ?
Tweakie.
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Hi Tweakie
I'm using version Version R3.043.022.
Did you really do a real-life test run ? I mean on a real machine ?
Wilfried
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Did you really do a real-life test run ? I mean on a real machine ?
Hi Wilfried,
I only ran the tool-path (engraved into a piece of scrap) mainly because I was most interested in the efficiency of your GCode and how so much was accomplished within the 500 line limit. ( and I spotted the deliberate mistake ;D ).
I was using version R3.043.066 so, in retrospect, your problem may be to do with a possible restriction placed on the demo version but Graham is much more of an expert than I am so hope he can shed some light on the issue.
Tweakie.
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Good catch on the demo thought, Tweakie-
Dave
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Hi Tweakie and Dave,
Thanks for helping and the effort you put in the problem.
I now installed the newer version R3.043.066, and that version runs the partprogram OK.
But I now see other strange things. While running the part program and observing the Mach3 toolpath screen, it stroked me that while the active point was drawing instance 2 of an instrument hole, Mach 3 was highlighting the first instance of that hole. See the attachment.
This means that Mach3 does not completely release subroutines and their waste data after they have been used. I encountered similar things some time ago when I was trying to use tool compensation within subs. That clearly did not work and as far as I know, has not been solved yet. That was the reason I hesitated to buy and still work with the demo version. I think there still is a major issue within Mach3 with subroutines.
Wilfried.
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Hi Guys,
sorry for the delay, its been a very busy week so far.
I can see no obvious problems with the g-code, the only thing that can be off putting is Mach3 and a combination of subs and G91 code can cause the tool path to be drawn wrong. If you are not using tool compensation then the G40's can be removed as Mach3 is not over keen on tool comp codes in subs ether. Blank(s) or comment(s) as the first line(s) of the sub can cause problems too in some circumstances. Lastly it is a good idea to have a % only as the first and last line of the code, none in the middle.
You will all be pleased to know that Mach4 has none of these problems :)
Regards
Graham
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Hello Graham. Thanks for replying,
I know I use a lot of G40's were the are not necessary. That's because I make use of a general purpose library, and you never know what happens around those subs in the different part programs. So I always leave every sub with a G40 and a G90 to be sure that nothing is left behind.
In an attempt to understand what was happening, I also made a version without G90/G91 changes in the subs. This did not solve the problem.
Personally I think that there are still a couple of bugs in the way Mach3 deals with subs. I know of at least one, and that is the toolcompensation within subs. This does not work.
Wilfried