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CR-10 3D Printer Dual Z Axis Upgrade. Low Cost, High Precision.





The CR10 has a single Z axis leadscrew and I have no issue with this it really produces superb prints. From an engineering point of view a better idea would be to have a leadscrew at both ends. There is an upgrade kit available which uses a second stepper motor but I understand these can get out of sync when power is switched off and on and the bed must be re leveled every time. 
My solution links the screws with a toothed belt and is driven by the existing single stepper. It cannot get out of sync.
All the parts cost less that £12.00 ( US $16.00)  including delivery!
There is a bit of metalwork involved but you only need a saw. file and drill. If you really cannot do metalwork I have designed a printed bracket with the same dimensions. Be warned though this has not been tried out but it should be OK.
Parts needed include
600mm leadscrew and nut https://goo.gl/fM8znL
GT2 Aluminum timing belt pulley 36 teeth : https://goo.gl/hv9dVU ( 2 required be sure to order the 36 toothed one)
GT2 852mm Timing Belt: https://goo.gl/iXa4sv ( be sure to get the correct length)
Flexible Shaft Coupling: https://goo.gl/qfUhEe
Bearings: https://goo.gl/HnzTqr 
You also need 
2 x M5 x 16 screws and Tee nuts.
2 x M3 x 16 screws and nuts.
A few washers.
2mm sheet metal for the bracket if not using the printed one.

Creality 3D printer: https://goo.gl/wXrkMi
Discount code 20%off for CR -10 3D printer: bg3dprinter
3D printer special page: https://goo.gl/xEdxVB (15%off coupon: bgprinter)

STL files https://www.thingiverse.com/thing:2569379
Video https://youtu.be/-ASBhJiU8NI

The existing leadscrew is replaced by a longer one so that a toothed pulley can be mounted above the printer frame. 
The existing leadscrew is reused on the other side and a bracket added to connect the leadscrew nut to the right of the gantry. 
The top bearing for the existing leadscrew is replaced by a new printed one. The ball bearing in this can be adjusted to line up with the screw and then locked in place.
A similar bearing block is printed to go on the right hand side.
The position of the leadscrew nut is also adjustable and is locked in place when everything has been aligned.

Print out the parts required.

The bracket is made to the dimensions shown below.
The 3 holes at the top are best marked from the printer itself as described later.
If you would like a full size copy of the plan send me an email.








Installation


It's worth checking if the Z stepper motor is correctly lined up with the leadscrew.
I found mine was not so I cut 2 strips from a plastic Clover spread container, punched 2 holes for the screws and fitted it between the yellow motor mount and the printer vertical frame. Now it lines up perfectly.

Undue the 2 screws securing the leadscrew to the flexible couple and remove it from the printer.

Shorten the new leadscrew to 535mm and screw it through the leadscrew nut and connect it to the flexible coupler on the stepper.

Assemble the new LH bearing block. The existing flanged ball bearing is reused and 2 nuts and screws hold the retaining plate in place. Move the Z axis fully to the top and fit the new block. The bearing  can be adjusted so it lines up with the leadscrew by sliding it left and right along the frame and the moving the bearing in the block front to back. It is then locked in place with the 2 screws. Fit a pulley to the protruding leadscrew.






Fit the RH bearing block loosely in place and put the bit of leadscrew that was cut off into the bearings with a toothed pulley attached to it. With the belt fitted on the pulleys tension the RH block and tighten the fixing screws.

Fit the new bracket to the gantry with a washer over the wheel stud so that only the centre part of the ball bearing is clamped to the bracket. Check it is square to the frame and tighten up. At this stage the 3 holes in the bracket have not been drilled.  Remove the belt and pulleys and using an 8mm drill through the bearing mark the hole position. See video.



Remove the bracket, drill the holes, paint and refit , this time with the nut and printed parts loosely fitted.
Fit the new leadscrew with a pulley on top and a flexible coupling, which is acting as a collar below the block. A washer is used on each side of the bearing. Also fit the belt.



With the gantry in the top position tighten the screws on the bracket printed parts to lock the nut in place.
Installation is complete.


Adjusting the axis

If you have a digital caliper this can be used to set each side to the same height. As the travel will always be up when making a print make sure the gantry is moved in the up direction before taking measurements. It's easy to move the Z axis now, just pull on the belt.
Measurements are taken from the extrusion the print head runs on (X ) to the printer frame front to back extrusions.
Start with a distance of about 125mm. Take an exact measurment from the stepper motor side and compare it with the other side. 
If the dimensions differ slacken the screws on the right hand pulley and hold the pulley still whilst rotating the leadscrew to move the axis up or down as required and then tighten it up again. Check again by lowering the gantry and then raising it again.
If you have no caliper, use a length of rod, plastic metal or wood as a gauge to check the sides are equal.
All that's left to do now is to re level the bed and the job is complete.



24 comments:

  1. You say to be sure and get the correct length belt (855mm) but neither Amazon or Banggood sell that length. Where did you get it?

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  2. Everybody seems to have 852mm but no 855mm.

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    Replies
    1. Sorry it was a misprint. The correct length is 852mm

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  3. Sorry it was a misprint. The correct length is 852mm.

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  4. Thanks, what about the bearings, just 1 or 2?

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    Replies
    1. There are 2 in the new bearing block, as show in the video.

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  5. Sorry to keep bugging you. What are the washer things that fit in the channel, where do I get them and how many do I need?
    Thanks,
    Steve

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    Replies
    1. https://www.banggood.com/Suleve-M4TN20-Carbon-Steel-M4-20-Thread-Sliding-T-Nuts-Screw-10x6x4_3mm-50pcs-p-1157019.html?rmmds=search
      You only need 2 so you will have planty of spares!

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    2. Great upgrade!I can't wait to implement it on my CR-10!
      since i'm not very experienced I have a couple of questions.
      The t-nuts are not supposed to be M5 since the screws are M5?
      What is the use of the flexible coupling acting as a collar? Is it for moving the leadscrew for adjusting the axis?
      Thank you for your patience!

      Delete
    3. Tee nuts are M5. This is shown in the instructions above. I did wrongly list them as M4 in the beginning.
      The flexible coupling acts as collar and stops the leadscrew moving up and down. The coupler and the gear wheel should be fitted closely to the top bearing so there is no vertical play in the leadscrew.

      Delete
  6. Hi. Can you post 1:1 sketches so it will be possible to print it and so easy to mark the holes. TNx

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  7. I can send you a pdf is you give me your email as mentioned in the description.

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  8. Interesting modification!
    I will do a similar one based on this idea.
    Thanks for sharing!

    I am also using octopi and like the idea to turn the printer on and off.
    Can you give a few hints what you used for this (simple relay module ?) and show some pictures how you have done it?

    Thanks a lot!

    ReplyDelete
    Replies
    1. You need to get the Printoid Pro App. This has command buttons to control a relay board.
      I used a 4 relay board connected to the Pi. There are videos on Youtube showing how this is done (not mine). I wired power sockets through the relays so when the relay is operated the socket it turned on.
      I had trouble with the script needed for the commands and a friend did this for me so I cannot help with that part.

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  9. Hi ! When I received my CR-10 I saw two upgrades really interesting to do. Yours, and this one : https://www.thingiverse.com/thing:2123233

    But, as you can see, it's currently not possible to put those two upgrades on one CR-10, so I want to try mixing those two clever upgrades. But, I don't want to make it without the permission of the two original creator. So : do you permit me to use your models and post the result on Thingiverse ?
    I will certainly make a lot of change in the design, but it stay your idea :-)
    Thanks for your time !

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  10. My designs are already on Thingiverse. You are welcome to use them but you should give me credit for the original idea, i.e "From an idea by Caster" and give the link to https://www.thingiverse.com/thing:2569379

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    Replies
    1. Thanks for your quick reply ! I'll do it !

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  11. That is a great upgrade, thank you for sharing.
    The enclosure you are using , is that one of the mini green houses you can buy from Bunnings?.
    If it is what size did you use?



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  12. I don't know of Bunnings. The item is this one https://www.amazon.co.uk/gp/product/B00DN68Z8C/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
    It needs shortening and some curved sections added to the back as it is not deep enough without. very successful. I could do a video if there is enough interest.

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    Replies
    1. Totaly confused, the link you give me above is to a greenhouse. I am talking about the bearings in your parts list above for the CR-10 upgrade. The link to the bearing you provide ( Bearings: https://goo.gl/HnzTqr) are out of stock. Is there anyplace else to get them? Thanks

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  13. Could you point to the bearing on AliExpress that are needed (and how many), your sourse is out of stock? I am ordering the other stuff on Ali?
    Thanks

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  14. Its a standard bearing available from bearing suppliers or Ebay.
    My enclosure was made by modifying the growbag greenhouse and was an answer to a previous question not yours.

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  15. How have you secured the lower end of the new lead screw...like there is nothing in the photos regarding the same...are they left free? ( I guess you said something about the use of coupling to prevent the play)
    Also can we use the lead screw bearings instead of printing the bearing cases...it would be more durable and accurate
    Finally, would you send the pdf for the brass nut mount to this address : Sudarshan.potter@gmail.com
    I would use it as a template. Thanks

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  16. Brilliant design! Do you share the original CAD files and the template file? Thanks.

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