Hey guys, I’ve been utilising the Christmas break to work on a design that I just completed and installed but still welcome input from some more experienced guys. This is also not trying to take away anything from the design that is mentioned by @edf above. It is worth to note that I’ve been looking to install the linear rail mod for some time but never got round to it, so this is was my first attempt after reading about it on the forum for months.
Purpose:
Design a system that would work with both the quick swap kit for Snapmaker 2.0 as well as the SBR16 linear rails.
Reason:
The inclusion or adaptation of the linear rails is covered in multiple locations on the forum, however the man reasons include:
- The prevention of bed wobble on 3D printing,
- Additional support for while doing CNC work, and
- Prevention of bed damage in the event of accidental toolhead-bed impact as a result of a failed 3d print sensor or incorrect interpretation of G-Code (read user error).
My Requirements:
- Compatible with SBR16 rails, while easily adaptable to other rails should the community wish
- Should retain the main functionality of the quick swap kit, i.e. it should not be difficult to transfer between CNC, heated bed or laser sheets,
- Needs to be adjustable (height) to allow for correction of the bed warping, and
- Be printable without supports as far as reasonably possible.
Credits:
What follows is an adaption of a lot of designs from other people’s design that has been uploaded to Thingiverse - Digital Designs for Physical Objects.
First and foremost, positioning of the rails so I have a fixed location to work of, Snapmaker 2.0 350 SBR16 Rail Holder by 3Dingo - Thingiverse, these brackets are used as is with no changes.
I originally got the idea when I saw this design snapmaker quick swap riser blocks for linear mod by wrencher9 - Thingiverse from wrencher9, however I suspected that the bearing blocks would be moving around a lot when trying to change systems/beds, this is purely suspicion and not something I tested or confirmed. The system was also rigid in terms of height and was not adjustable. This is the same system @edf mentions in his post above.
Before I got the quick swap kit I looked at implementing the linear rail mod utilising the adjustable system as designed by @brvdboss - Snapmaker 2.0 SBR16 linear guides support by brvdboss - Thingiverse, but just never got round to it. His design was the main inspiration for my concept design.
The last part was being able to secure the units to ensure that any levelling that is done by the adjustments (whether pushing up or pulling down) would be kept in tack with something, and Silvercat’s quick swap design seen in the link below was the main inspiration - snapmaker toolhead quick hitch printed in 1 part by SliverCat - Thingiverse.
Lastly none of this would have been possible without the 3D models done by the late Stefix, Sebastien Deux and Ryan Tuscher, all files which can easily be found in the very convenient GitHub - shurushetr/awesome-snapmaker: Curated list of things that help you make something awesome with Snapmaker machines created by jthegedus.
Concept Design:
I believe I was able to achieve all the goals I set out originally. Please note, for those with a keen eye, I originally designed the system with the “hebel” (from - snapmaker toolhead quick hitch printed in 1 part by SliverCat - Thingiverse) to create a clamping situation, but having printed a test and trying it out, I decided that it added unnecessary complexity that the system did not need and the version I currently have implemented does not include this.
Figure 1: Assembly
Connecting the bearing blocks
Figure 2: Bearing block connections
I am of opinion that fixing the bearing blocks to each other and at specific distances from the Y-axis prime movers was/is key to ensuring that when the bed with quick swap kit was installed the bearing blocks should not “scatter” everywhere. I started out with a 2020 profile connecting these, but it quickly became apparent that height would be an issue, I then drew up a 2010 profile but again was of opinion that there would be insufficient height.
It is important to note that if the desire for an adjustable system was not needed, height most likely would not be an issue and a 2020 profile should be able to be adapted fairly easily.
I ended up just drawing an angle with some slotted holes that I printed. Alternatively some can be bought from your local hardware store. The one angle does have a riser to be able to connect to each of the Y-axis’ movers.
A note for those looking to print these, as I did, look to orientate them at a diagonal on your print bed, they would fit on the bed normally but the shortened distance due to the quick swap kit (you loose a couple of mm) it cut’s it off without notifying you, unless you’ve adjusted your slicer’s bed dimensions.
Files:
Far side runner.stl (31.9 KB)
Linear rail runner V2.stl (56.3 KB)
Adjustable rail connector:
As previously mentioned, this part of the design is heavily based on the adjustable system designed by brvdboss, however I needed to make some adjustments to be able to make it be able to “slide” in and out with the quick swap kit.
Figure 3: Assembly of adjustable connector
To be able to print this part relatively easy, I decided to not follow the same approach as some of the other designs where the frame fits into a part. This was made available by the “spare” M5 threads that are no longer being used because of the quick swap kit on the 3D heated bed, so I just went with a flat surface that screws to the bottom of the frame - note that I have not made any adjustments yet for the CNC bed, this will follow in future.
Figure 4: Top with thread
Using Fusion360’s built in thread functionality I designed this as M20 with 2.5mm thread pitch to make it “easily” printable. The length of the thread is something that might need to be adjusted but worked fine for my install and believe it will be good for all, at least in the first instance.
The intent for this part is to be fixed to the bed, and remained fixed, thus each bed should have its own set printed and installed.
Files:
Top with Thread V4.stl (474.5 KB)
Clamp:
This part is to be fixed to the bearing blocks with the angles (mentioned earlier) already installed. It has space for countersunk screws to ensure the part that needs to “slide” in will not be hindered by the screws installed.
Figure 5: Bearing block clamp
Files:
Clamp without hebel V3.stl (144.2 KB)
The Nut:
Again, heavily based on the adjustable system designed by brvdboss, I created a nut to match the M20 with 2.5mm pitch thread, however the nut has a 45mm base that slides into the clamp. I’ve also recreated the holes in the nut to allow for a M3 screw (grub screw if you wish) to be installed,
The intent here would be to fix this to the “top with thread” part and once bed level calibration has been done, the nut can be locked in place and thus, when removed and later reinstalled, this should still be accurate for the level it was previously set to.
The only challenge I foresee might be being able to rotate the nut due to the clamp being in the way, however to retain the maximum amount of “adjustment” I did not want to increase the height of the nut.
Figure 6: Nut in the clamp
Files:
Nut V3.stl (795.7 KB)
Outcome / Conclusion:
I do not have access to my printer right now, but as with everybody else’s results pre-quick swap, my bed level delta dramatically reduced, and I have increase stability.
It took me some time, with multiple iterations of doing the bed levelling sequence, removing the bed, adjusting the nut, replacing the bed and redoing the bed levelling sequence, etc. but the reduction in bed level delta was worth it already.