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  1. #1
    Join Date
    Jun 2017
    Posts
    54

    Waves/Chatter

    Hi Everyone,

    I just recently bought a used Laguna 5x10 Smart shop II. Its two years old and has been used pretty lightly with the previous owner. I cut 3/4" HDPE to make outdoor furniture. I am having and issue with wave like patterns on the edges of my cuts. Its happening on every axis. I use Vortex Bits and reached out to them and they looked at the pics I have attached and said that this was not a tooling issue. I also sent my VCarve Pro Toolpaths to Vectric for review and they said everything was good. So next I called Laguna Tech department and they say that this type of pattern is associated with loose belts or bad pinions. Today I am going to remove the pinions and check for damage. The belts look good. It seems like the issue is very present coming out of corners after the bit starts to speed back up. I thought that maybe there is a parameter in the control software that needs to be changed but were not there yet. I have attached pics. If you have any idea any advise would be appreciated

    Thanks
    Nick
    Attached Thumbnails Attached Thumbnails thumbnail_20170705_170317.jpg   thumbnail_20170705_170324.jpg   thumbnail_20170705_165435.jpg   thumbnail_thumbnail_20170629_154153.jpg  


  2. #2
    Join Date
    Apr 2008
    Posts
    203

    Re: Waves/Chatter

    yup loose belts or pinion gears that aren't seated properly. Y is probably the worst since it moves the most weight and longest use. If you push and pull the axis there shouldn't be any slop. Could be belts, pinion gear not seated, loose set screw on pinion gear, loose set screw on belt driven gears etc etc.

  3. #3
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    I took everything apart and looked at it. It all seemed like it was tight and in good condition. The only thing that I did notice is that one of the pinions was kind of wobbly, but not to much. Is there something else that could be causing this? Is it possible that this is happening because this machine has steppers and not Servos? Could it just be the design of this machine?

    Thanks

  4. #4
    Join Date
    Apr 2008
    Posts
    203

    Re: Waves/Chatter

    when your steppers are on grab the y and push and pull does it move without resistance on either side? do the same for the x

  5. #5
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    If the machine is powered up and I try to move the gantry on the X and Y it is quite difficult. I can do it but there is resistance for sure. The Steppers are completely off the machine right now and the gantry (x and Y) both glide very easily with no effort at all

  6. #6
    Join Date
    Apr 2008
    Posts
    203
    I'll try to shoot a video tonight for you. So you can see it. Since mine is direct drive there are less places I have to adjust. I know for a fact I need to readjust my pinion gear.

  7. #7
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    Thank you very much. I am kind of on my own right now because Laguna is playing amateur hour right now and not really leading me in a positive direction to resolve this issue. Thanks again for your help

  8. #8
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    I actually just made another round on the machine and found that one set screw on the Y axis stepper was completely loose. Could that "one" screw be the problem?

  9. #9
    Join Date
    Apr 2008
    Posts
    203

    Re: Waves/Chatter

    I wasn't able to get in the shop last night. I was drawing all night. But it may be all of the problem or just a part of the problem. What you will notice is the three waves on the beginning of the cut were probably worse on that side of the table and probably no existent on the other side.

  10. #10
    Join Date
    Apr 2008
    Posts
    203

    Re: Waves/Chatter

    chatter on arcs can be reduced but are mostly two axis that need to be tightened as it is a compounded effect of slop on an arc. So I would almost guarantee the something is needing tightening on the x. Wether a belt needing tightening, pinion gear being seated in the rack better, or set screws.

  11. #11
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    I tightened everything down on all Axis and again today I am having these issues. One thing that I do notice is that this machines movements are very jerky. It will run full feed rate right up to the corner and then stop go around the corner and then stop and then continue on. I would think that is should just slow down and glide into the corners. Is there any other thing I can do. Are there software parameters that I can change to make it move more smoothly?

  12. #12
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    So what I am definitely seeing is the machine is stopping at every node point on my drawings. When this happens it is leaving a mark in my material. Is there anyway to make it so that it just does one consistent pass without stopping at all?

  13. #13
    Join Date
    Aug 2009
    Posts
    655

    Re: Waves/Chatter

    I've worked on a similar issue extensively. What controller do you have?

    I've never been able to remove it entirely but there are some things that help.

    I'll try and review the whole thread a bit later.

    Sent from my LG-D852 using Tapatalk
    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...

  14. #14
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    B and R Controller

  15. #15
    Join Date
    Aug 2009
    Posts
    655

    Re: Waves/Chatter

    Hmm never heard of it.

    So first, yes loosen all your pinion, push them into the rack and tighten, same with belts etc. As others have said.

    Then find your rapid jog speed and reduce it a bit, it might be set crazy high. This will increase cycle times a little if its crazy high but likely worth it. Actually you could do that second if you want.

    The main thing is the acceleration time of cutting and rapid moves. If you slow that down (which will increase cycle times) it should jerk less and therefore introduce less of the machine play into the cut. Again test compromise of speed vs results. I recently put mine at min acceleration possible but it was too slow and so I've moved in back a bit.

    I'm cutting a lot of HDPE these days and it helps. I still see them, but the aren't as bad. They are now a non commercial problem (ie I notice it but no one else seems to). Circles and big arcs seem the worse and it's still worse where the axis are both changing direction (backlash).

    I've played with a number of other speed and acceleration parameters like jerk but only the basic time one seems to help.

    Oh I also took off the shield from the ride along tool changer to reduce the weight cantilevered off the gantry.

    I currently think it's less then great bearings that have too much play. So regardless of the pinion and belts there is some play left and that's what we see.

    I've even tried going into the servo packs and adjusting parameters there (which did help a little at the time).

    Its a tough problem.



    Sent from my LG-D852 using Tapatalk
    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...

  16. #16
    Join Date
    Aug 2009
    Posts
    655

    Re: Waves/Chatter

    Also the full stop should be something you can change as a parameter or maybe in the post py. That's a bit of a weird behavior in real life and should be easy to change.





    Sent from my LG-D852 using Tapatalk
    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...

  17. #17
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    Can you explain how rapid rate effects my feed rate? I thought Rapid rate was the movement of the gantry from point A to B above the material. When my machine is actually cutting the material it should be going off my feed rate (300IPM that I have set) My display panel shows this. My rate is set at 100% but it doesnt show me what the actual number is. Also I noticed that whenever my machine doesnt stop for a node and make a corner I get these ripples. If the machine comes to a complete stop then makes the radius cut it looks good. Is there a way to make the machine stop at all nodes?

  18. #18
    Join Date
    Aug 2009
    Posts
    655

    Re: Waves/Chatter

    The rapid effects cycle time just in the movements from cut to cut. You are correct that it does not effect cutting speed. It looks like rapid is set as a percentage of cutting speed?

    That B&R controller looks a bit opaque as far as I could dig up. Do you have a list of available parameters? If not - try and get that. It looks like you can export the parameters via .xml file that you could (after backing up) presumably change and test out that way. Hopefully the XML file would also have descriptions in english of what the parameters are because you need to know what is what.

    You might need to get the exact control details from B&R if Laguna can't or won't.

    Interesting on the nodes. So when does it do a full stop if not at curves (just at 90 deg corners?. It really shouldn't seem to "stop" anywhere I would think. Even when I set my acceleration down to 5 seconds, it would slow right down at points but not 'stop'.

    You really probably don't want it to fully stop but just glide into the curves better. I mean I guess the full stop is an option but its one most people avoid in the name of speed.
    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...

  19. #19
    Join Date
    Jun 2017
    Posts
    54

    Re: Waves/Chatter

    Correct it only does complete stops at 90+ degree. So what I am experiencing is when the machine comes to lets say a 40 degree angle and doesn't stop it leaves ripples as it is exiting the corner. But on anything greater than 90 the bit stops and I dont get that ripple effect coming out of it. I have cut the same piece at different locations and angles on my table and the ripples mirror each other. I have tightened all the axis rack and pinion. I am using a brand new collet, bit, and nut. To me what it looks like it is doing is that when the machine makes a -90 degree and does not stop it makes a very rapid movement around that corner. Please see pic. Bit is moving from right to left in this picClick image for larger version. 

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  20. #20
    Join Date
    Aug 2009
    Posts
    655

    Re: Waves/Chatter

    Yeah looks familiar. I've attached some shots of mine. One is 3/4" acrylic where it shows up quite a bit (aluminum too). The other is some 1/2 cutting board but on a flat. You can maybe just see the ripples on that one and it's not that near a corner.

    The acrylic at its worst is maybe pt 005in. But that is enough to see and feel.

    To be fair, my old machine was worse.

    If you've tackled the mechical, I would dig into the settings.

    BTW, these are after spending significant time trying to figure it out. It was worse before.

    Sent from my LG-D852 using Tapatalk
    In case anyone is wondering, I'm the twin of the other gfacer on cnczone...

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