Front belt tensioners and complete OneBox V-Core 3 mod files
Mod and all files fully compatible with both V-Core 3 and 3.1 upgrade.
Both STL and STEP files also included.
Update, It should be noted that Rat Rig have now followed this design with their 2.0 enclosure.
The front belt tensioners, etc from this design are compatible with the Rat Rigb V-Core 3 (and 3.1) 2.0 enclosure.
I have included the front belt tensioners and also some optional lead screw guides that integrate with the belt tensioners. These leadscrew guides are much more professional looking than the Rat Rig ones. You can either use the normal bearings in them or the TPU wiggle woggles that will last forever and are totally silent in operation.
I have also included magnet holders for a front panel in this mod. To fit these require drilling of the front panel (Easier than making square or rectangular holes).
There are many advantages to the OneBox design:
Allows the use of the included easier to access front mounted belt tensioners.
Being able to move the belt tensioners off the print head allows you to use a lighter and more compact modern print head for faster printing such as the fantastic Microlight print head. https://www.printables.com/model/595269-microlight-print-head-for-rat-rig-v-core-31
Cleaner better looking design.
Much cheaper to enclose (less panels to cut).
Easier access to printer and tool head for servicing (no front extrusion going across the printer at the gantry height and getting in the way).
Much easier to seal enclosure, as there are air gaps between lid panels and lower panels.
More rigid frame when enclosed. The bolted on full height side panels and roof panel add rigidity. By comparison, the standard Rat Rig hinged lid adds nothing to rigidity of the printer frame.
Coffee fund
If decide to make a donation to my coffee fund (which keeps me up late at night doing more of this stuff) I would appreciate it. There is absolutely no obligation for you to do this. My PayPal account is
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Please remember to post feed back as it is always valuable to me for future iterations.
Many thanks.
Liam Venter
MFBS Design
Bill of materials for upgrading and existing V-Core 3 OpenFrame
The following are the lengths of the extrusions required to convert a 300 x 300 V-Core 3.
For a 400 x400 or 500 x 500 the length of the extrusions will be different.
4 x new corner posts. 750 long for a 300 x 300 (240mm longer than current ones which are 510 mm long.) On a 300 x 300 printer this will give you enough clearance for a flying umbilical cable to the tool head. I find this height perfect for a 300, for a 400 or 500 you may want to go more than 240 mm taller especially if you you are still using a flying umbilical cord. Remember you can still lift the roof panel off to get in and service the print head quickly and conveniently.
Re use your existing 440mm top front extrusion for the top front extrusion.
Cut one old corner vertical extrusion to 440 for the rear rtop extrusion
Cut two of the old corner vertical extrusions to 505mm for new top side extrusions.
This leaves you one old corner extrusion spare. (I cut this to 440 mm long and use it as a cross brace to support the front of a modified rear Z motor mount - see my modified Z motor mounts).
Remove the eight right angle plates from the top perimeter of your existing frame.
Replace these with 6 x new T plates for fastening Y extrusions and rear extrusion to the frame.
https://www.aliexpress.com/item/4000217872846.html
Re use the 8 x Right angle plates that you removed for mounting the top perimeter extrusions on your new frame.
40x 6mm x 12 mm cap screws (black oxide).
40 x 6mm T nuts.
Recommend that you order 50 of these as I have probably missed a couple and always useful to have a few extra for mounting things to the extrusions. These are used for the new top perimeter assembly and mounting the two new front idler plates and two new XY motor mounting plates.
2 x extra front idler plates (Available from Rat Rig or Aliexpress).
2 x extra XY motor mounting plates (Available from Rat Rig or Aliexpress).
https://www.aliexpress.com/item/1005003503473525.html
8 x 3mm x 42 mm cap screws (black oxide) for XY motor mounting. May have to order longer and cut them shorter.
4 x 5 mm x 42 mm cap screws (black oxide) for rear idlers.
Front idler parts
1 x 5 mm x 36 mm pins (right front idler).
1 x 5 mm x 33 mm pin. (left front idler) I ground down a 36 mm one to save me needing to order different sizes). These pins are available from your local bearing supplier or Aliexpress. Some of the Aliexpress pins may need sanding in an electric drill for a couple of minutes to make them a nice sliding fit in the idler bearings.
https://www.aliexpress.com/item/4000233682608.html
2 x 6mm x 35 mm cap screws (black oxide) for belt tensioners
2 x standard 6 mm zinc nut for belt tensioners.
8 x 6 mm nylock nuts (4 for retaining front idler stationary block and 4 for clamping XY rear motor plates.
2 x 6 mm 50 mm cap screws (black oxide) for clamping left front idler stationary block
2 x 6 mm 54 mm cap screws (black oxide) for clamping right front idler stationary block
Side and roof panels.
I used 4 mm Dibond (Aluminium Composite material) for all my panels other than the front panel as it is very cheap and easy to cut by score and snap method and you can also cut any cut outs required easily with a hack saw blade.I bolted these in place with M6 T nuts and cap screws and placed a washer under the head of each cap screw to spread the load better.
Magnetically attached front panel
For the magnetically attached front panel I used 4.5 mm polycarbonate as that what was readily available locally.
On my full height front panel on my OpenFront '300' I recommend 4 magnet holders at the top and the bottom and six down each side. These each hold 3 magnets (1 or 2 proved not strong enough). For a larger panel I would use more magnet holders.
The receptacle holes in the polycarbonate are 7.75 mm in diameter and the magnetic holders are a tight friction fit in these.
Here is what you need for each magnetic catch:
1 x T-Nut. I use the 30-M6 sized ones from here https://www.aliexpress.com/item/32851320734.html
1 x Grub screw, socket cup, black oxide steel M6 x 8mm to hold T-Nut in place and improve magnetic performance.
https://www.aliexpress.com/item/33029779249.html
3 x Magnets 6 mm dia x 3 mm per magnet holder. https://www.aliexpress.com/item/1005001991968667.html
Optional Tensioner-less EVA back plate and fan mounts.
Because the tensioners are no longer needed on the EVA carriage (as they are moved to the front idlers) the EVA carriage can be made lighter and more compact.
The tensioner-less back plates are available for a range of upgraded fan options, Including 5015, 4028 and Pabst fans.
The belt retention system is also much simpler.
The full range of tensioner-less back plates are here: https://www.thingiverse.com/thing:5322790
For more of the mods on this printer please search "MFBS Gold Series" in thingiverse.
Updates
27/03/2022 Changed spacing of bottom mounting holes to provide more clearance for heads of cap head screws.
23/07/22 Added new leadscrew guide files.
28/08/22 Lead screw guides and caps updated to version 3. These offer more clearance on left hand side one for different Z probes.
Acknowledgements
This printer design is a derivative of the Rat Rig V-core 3, which I believe owes much of it's design to Pawel Kucmus
MFBS
