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Thread: Z Adjustment Question

  1. #1
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    Dec 2007
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    Appalachian Signs & Design, Boone North Carolina
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    Default Z Adjustment Question

    Does anybody out there know how to adjust these? Everything I've found in manual and online is very vague. Many Thanks for reading!
    Attached Images Attached Images

  2. #2
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    Mar 2011
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    Marietta, Ga.
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    https://www.smslinear.com/pdfs/GuideWheelsWeb.pdf This may be of some help.. One side has non-adjustable bushings and the other has the adjustable. You would probably need to unload the Z carriage and disengage the motor and try to come to a smooth even motion when moved by hand and no slop.......hope is of some help...joe

  3. #3
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    Jan 2004
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    iBILD Solutions - Southern NJ
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    It isn't a fast ordeal - esp if it is your first time doing it.

    Observe that there are eccentric/cam bushings on the one side & stationary ones on the other side. You're going to leave the entire (left side in pic) alone and focus on the right side. You'll need a 1/4 & 1/2" box wrench (if my memory serves me)

    Start by loosening the Z motor plate on the back of the YZ car using a 3/16" allen key (Horrible Freight hex sockets are great for this) - disengage the pinion from the rack.

    Make yourself a looped piece of wire to hook one of the springs, release it from its perch and let it hang there. Leave the other one on. Then run the entire stroke of the Z up and down by hand.

    Adjust the v-rollers via the adjusting cams by first loosening the axle bolt (going through the bearing) - a LITTLE...then adjust the cam to create tension against the rail. MAKE NO LARGE ADJUSTMENTS - this is fine tuning...so even small adjustments to clock position will make a big difference. You want to make absolutely sure to stroke the Z up and down while or right after adjustment to make sure it runs smoothly & that it isn't adjusted against the rails too hard.

    It's going to be 'about right' when you tension the roller against the rail and you can no longer rotate the v-roller by hand without the Z moving up or down.

    After adjusting, tighten up the through bolt and check it again - work the Z all the way up and all the way down. How does it feel? Wiggle it all over - feel how much resistance there is as you roll it. Do you feel that is 'right' ? Will the motor struggle to get the Z moving? You should be thinking all these things and adjusting for them - and also making sure it isn't too loose (duh).

    Then pull the spring back up to its perch, engage the Z motor/pinion in the rack and make sure it isn't loose (backalsh) afterwards by turning on the control box and wiggling the Z up and down. Adjust as needed.

    Take your time - you'll be fine.

    -B
    High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com

  4. #4
    Join Date
    Dec 2007
    Location
    Appalachian Signs & Design, Boone North Carolina
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    Smile

    Quote Originally Posted by Brady Watson View Post
    It isn't a fast ordeal - esp if it is your first time doing it.

    Observe that there are eccentric/cam bushings on the one side & stationary ones on the other side. You're going to leave the entire (left side in pic) alone and focus on the right side. You'll need a 1/4 & 1/2" box wrench (if my memory serves me)

    Start by loosening the Z motor plate on the back of the YZ car using a 3/16" allen key (Horrible Freight hex sockets are great for this) - disengage the pinion from the rack.

    Make yourself a looped piece of wire to hook one of the springs, release it from its perch and let it hang there. Leave the other one on. Then run the entire stroke of the Z up and down by hand.

    Adjust the v-rollers via the adjusting cams by first loosening the axle bolt (going through the bearing) - a LITTLE...then adjust the cam to create tension against the rail. MAKE NO LARGE ADJUSTMENTS - this is fine tuning...so even small adjustments to clock position will make a big difference. You want to make absolutely sure to stroke the Z up and down while or right after adjustment to make sure it runs smoothly & that it isn't adjusted against the rails too hard.

    It's going to be 'about right' when you tension the roller against the rail and you can no longer rotate the v-roller by hand without the Z moving up or down.

    After adjusting, tighten up the through bolt and check it again - work the Z all the way up and all the way down. How does it feel? Wiggle it all over - feel how much resistance there is as you roll it. Do you feel that is 'right' ? Will the motor struggle to get the Z moving? You should be thinking all these things and adjusting for them - and also making sure it isn't too loose (duh).

    Then pull the spring back up to its perch, engage the Z motor/pinion in the rack and make sure it isn't loose (backalsh) afterwards by turning on the control box and wiggling the Z up and down. Adjust as needed.

    Take your time - you'll be fine.

    -B
    i just can't even thank you enough for this information. I have been working at it for quite some time now and am getting so frustrated. It pains me that no matter what the left rollers will never align with the wheels. Is there any modification you might recommend to remedy this? Should I have the spindle mounted when making these adjustments. Again. I'm so excited to have these replies. Feel much better now.

  5. #5
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    Jan 2004
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    Yes - leave the spindle on there - but there's no problem taking it off. No problem taking off both springs either. It's totally up to you.

    In terms of "no matter what the left rollers will never align with the wheels" I need some clarity. Please post a pic or two showing the issue you speak up and explain the problem.

    Keep in mind they only used this exact setup for a year or two until SB realized just how much of a cluster it really was...this is not to say it won't be OK, just that there isn't much in terms of documentation - as you've already discovered.

    Now just going off of memory here....there is a possibility that the aluminum block(s) that hold the rollers on, somehow walked over . What I mean by that is the AL blocks are bolted to the big plate on the back side. It is possible that the bolts have loosened or walked outboard so that no matter how much you adjust the cams/eccentrics, there isn't enough adjustment.

    If you determine that's the case, you'll have to remove the 2 bottom v-rollers from the big plate & lift the entire assembly off the gantry. You may find first removing the spindle & z motor - and just let them lay on the table (and Z motor on top of gantry beam) - and the Zzero plate and Y proximity switch wiring - drape them off to the side (and the Y motor - just watch straining the wires - don't let it dangle). You'll only need some zip ties to get them back on so no big deal.

    After the whole deal is off - it will be a lot easier to track down and fix the problem. Don't over-think things - this is strictly a mechanical issue. The fact that it's attached to a robotic tool means nothing...it's easier than working on a riding mower shift linkage or something like that - so dive in. Take pics and video as you disassemble if you're not sure, but....I don't think you need to.

    Post back to let me know how you make out.

    -B
    High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com

  6. #6
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    Dec 2007
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    Appalachian Signs & Design, Boone North Carolina
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    I definitely will send a pic when i get back to my shop. Shopbot told me that they would never line up just right. The blocks are securely in place. It appears that something would have to get shimmed if those wheels were going to line up... Thanks so much for your support. It means a ton!!!!@

  7. #7
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    Quote Originally Posted by Brady Watson View Post

    In terms of "no matter what the left rollers will never align with the wheels" I need some clarity. Please post a pic or two showing the issue you speak up and explain the problem.
    HAHAHAHA...did I say that? I apologize...For some reason I keep calling the Z the X and so forth and so on. Not great for getting support. What I meant is that the V Rollers will never align with the Rails of the Extrusion. It does not appear to be physically possible. ....

  8. #8
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    You know what...I don't know what the problem is. I have lost sight of it at this point. I started down the "Mechanical Issue" road 2 weeks ago and still nothing. I have removed and replaced the entire ZY carriage twice now. Nothing changes. I have created problems searching for answers. Still now I am faced with getting it all back together. Sorry keep posting...but just needed to let that out. -SE

  9. #9
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    Take a deep breath...from experience, it usually something stupid going on. Nothing is unfixable...

    Have you called SB to find out how much it is to have a tech come out and get you going again?

    -B
    High Definition 3D Laser Scanning Services - Advanced ShopBot CNC Training and Consultation - Vectric Custom Video Training IBILD.com

  10. #10
    Join Date
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    Marquette, MI
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    I ran into the same issue back in 2007. Made this post: http://www.talkshopbot.com/forum/showthread.php?2605
    Gary Campbell
    GCnC Control
    GCnC411(at)gmail(dot)com
    Servo Controller Upgrades
    http://www.youtube.com/user/Islaww1


    "We can not solve our problems with the same level of thinking that created them"
    Albert Einstein


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