CNC changes xy zero coordinates shortly after run starts

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jbouldin
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Joined: Mon Mar 23, 2015 12:42 am
Model of CNC Machine: CNC Shark HD 3.0

CNC changes xy zero coordinates shortly after run starts

Post by jbouldin »

I have a Laguna IQ, running VCarve Pro8.

I home the router on startup. Then I set the XY coordinates in the center of the wood. The machine starts and shortly it will change and move the X position coordinate 1/2 the width of the job size, moving it to the left. If the job is 10" wide and the XY is centered in the piece, the machine will change that coordinate 5" to the left, and then ruin the wood with passes that extend past the material. I tried resetting the program, turning the machine off and on, etc., but no luck. If I change the direction of the wood, and the program itself, the machine will then move the Y coordinate 1/2 the height of the job, so if it is 14" high, after a few moments it changes the Y coordinate 7" higher, and then ruin the wood with passes that extend past the material.

I have contacted Laguna, and they tested the controller and say that it is ok, and it is likely a software problem. Any help will be sincerely appreciated.

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Rcnewcomb
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Re: CNC changes xy zero coordinates shortly after run starts

Post by Rcnewcomb »

I'd start with some very basic debugging.

1. Unless you already have free material I'd suggest getting a few blue or pink foam sheets from one of the big box stores. This material can be used for practice cuts. If the machine goes wild you are less likely to trash the bit and collet.

2. Create a new 12x12 project with XY zero in the center

3. Create a 10x10 square centered in your project

4. Select profile ON the vector and cut it 0.1" deep so the bit can do it in a single pass.

5. Preview it in Vcarve. When everything looks correct save the toolpath file as you normally would do.

6. Open the toolpath file using Notepad and look at the G code. You should be able to figure out what the instructions are telling the machine to do.

7. Run the file and see if the machine still exhibits the odd behavior.

8. If it does, put the CRV file and the toopath into a ZIP file and upload it here for others to look at. Tell us what postprocessor you used to save the toolpath.
- Randall Newcomb
10 fingers in, 10 fingers out, another good day in the shop

jbouldin
Posts: 5
Joined: Mon Mar 23, 2015 12:42 am
Model of CNC Machine: CNC Shark HD 3.0

Re: CNC changes xy zero coordinates shortly after run starts

Post by jbouldin »

Thank you Randall for your reply. Here is what I discovered:

I reduced the program from 22" wide x 17 high down to 11" wide x 8.5" high. It ran just fine, BUT I only ran the Profile toolpath and the 3D Finishing toolpath. The job took about 3 hours, which is about what the computer said it would take for the smaller size.

It appears the 3D Roughing toolpath is where I encountered the problem. It occurred twice on wood, and once on air. The 3D Roughing Toolpath would run about 1 minute and then readjust itself for where it thought home was, and then just ruin the piece.

So I don't know yet if just reducing the overall size solved the problem, or if it is just a bust on the 3D Roughing toolpath. What is confusing is that I ran this job on practice runs 3 times before, and had no problems with the 3D Roughing toolpath. When I had the problem now, it (the 3D roughing toolpath) was running Raster left to right when it had the bust, and then I turned a new piece 90 degrees and went Raster top to bottom and it did it again, ruining the wood on both efforts. (sorry if terminology is confusing).

One thing I did notice on the 3D Roughing (on all 3 times I encountered the problem), is that the rhythm of the machine spindle/router seemed to pause literally just for a second, and then the next pass is when the error occurred, and it kept occuring, since it readjusting the XY home coordinates.

I looked at the Gcode in notepad several times now, and am new to this view, so I will need to study it more to understand cause & effect. I did not see any obvious errors at first glance, but it is going to take some more study.

Am running a Laguna IQ HCC.

I am going to try to run a larger piece today, using the 3D Roughing in air, and see if it occurs again before I put wood down. I will let you know the results.

jbouldin
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Joined: Mon Mar 23, 2015 12:42 am
Model of CNC Machine: CNC Shark HD 3.0

Re: CNC changes xy zero coordinates shortly after run starts

Post by jbouldin »

Hi Randal,
I ran a slower speed and less aggressive settings on the 3D roughing, and all seemed to run ok for a week. Then today it did it again today (shifting the XY home about 2 inches left for no reason), but this time it was the 3D Finishing, after about 8 hrs on a job, totally ruining it. Altho my CNC is running on a separate 220 wiring, the glitch occurred precisely when the safety valve on my 110 aircompressor kicked off. So I don't know if it was purely coincidental or not. But it had been running for 8 hours with no problem. I am going to try and save the program directly to the controller next time rather than running off the USB stick. Perhaps that will help.

But if you have a moment, give me your advice on running a 1/32" Solid Carbide Tapered Ball Nose toolbit, hardwood, 3D image. I have been running it at about 18000 rpm, 300 feed rate, 85 plunge rate, and 20% stepover. Do these setting sound reasonable to you, or too ambitious?? Processing time on a 3D image of 22"x15" hardwood is about 9-10 hours. I have experimented in the vectric program changing some of the settings, but it pushed the processing time out forever.

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martin54
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Re: CNC changes xy zero coordinates shortly after run starts

Post by martin54 »

I don't know the shark set up or controller but I would never run directly from a usb memory stick, transfer rates on them can be pretty slow depending on what version of USB both the stick & the port are for one thing.

I can't see the relief on your compressor lifting causing a problem, the compressor kicking in causing a surge on ring main or electrical interference would be more likely but you never know, can you try to recreate the problem running a file that you know cuts ok & lifting the compressor relief manually??

After it has made this move does it carry on with the job in the new position or haven't you let the program continue to run??

jbouldin
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Joined: Mon Mar 23, 2015 12:42 am
Model of CNC Machine: CNC Shark HD 3.0

Re: CNC changes xy zero coordinates shortly after run starts

Post by jbouldin »

Thanks Martin.

I am running a Laguna IQ.

I am now uploading files to the controller. I also have re-keyed the settings for the 3D Roughing and Finishing toolpaths to be less aggressive. The piece I am working on takes 8-10 hours run time. So when an error occurs toward the end of the process, it is a terrible loss in material and labor.

All my cuts are on hardwood. My 3D finishing toolbit is always 1/32" tapered ball nose, trying to get as much detail as possible, but also trying to keep the process time in an acceptable range (i.e. less than 10 hrs max). Considering reasonable speed, and a need for detail engraving, Is there an optimum setting for for the 1/32" toolbit on the following:

Stepover -
Spindle Speed -
Feed Rate -
Plunge Rate -

Thanks for any recommendations on these items!

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martin54
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Re: CNC changes xy zero coordinates shortly after run starts

Post by martin54 »

Yer sorry about the mix up with machine, I looked at the details on the right of the page where it says you have a shark, post did say Laguna though :lol: :lol: :lol:
Makes no difference to my answer though, don't know anything about laguna & its control system either :lol: :lol: :lol:

You might get better or quicker answers to this type of question on the laguna forum, same thing with speed, feed settings as these can be very different from one machine to another due to things like how rigid the machine is. People on their forum all running the same brand machine can probably give you a more accurate answer.

What sort of 3d models are you machining & where do you get them from ? Reason I ask is because Vectorart3d, Design & Make & the Models within the Vectric software are all designed to be finished with a 1/8" ball nose at the default import size, you are actually scaling them up if the sizes in your post are typical. Using a 1/32" bit will not give you any more detail it will only take more time, in fact with a 20% stepover you may even find a 1/8" at 8% will give a better finish.
I use the preview to check different bits & always try to use the biggest bit I can to give the level of detail I want, there is a point however where using a smaller bit won't increase the level of detail that can be achieved so your just wasting time :lol:

jbouldin
Posts: 5
Joined: Mon Mar 23, 2015 12:42 am
Model of CNC Machine: CNC Shark HD 3.0

Re: CNC changes xy zero coordinates shortly after run starts

Post by jbouldin »

Thanks Martin for your feedback. I am working on a 3D of the Alamo in hardwood. I had someone design it, and then I imported it into Vectric as an OBJ file (25meg+), and tried both the 1/32 and the 1/16 tapered ball nose toolbits on pieces ranging from 22"x15"x1.75" to 28"x19"x1.75". But lost a lot of detail on the 1/16, so went back to the 1/32. But after reading your reply, I am now wondering if I just had the settings wrong on the 1/16" (too aggressive?), and perhaps that is why the detail faded away. I would certainly like to use a larger toolbit if at all possible and cut down on the time (now @ 8-10 hrs & more), but when I do the side-by-side comparison, the detail just fades away when using the 1/16".

Since I started uploading the file to the controller, the problem of the machine losing the XY home position seems to have stopped (knock on wood). But I have also reduced the size of the piece and softened the toolbit settings, trying to avoid having to scrap a piece.

The Laguna online forum is not very informative, unfortunately.

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