Based on the brilliant design of Matsekberg, here are some improvments:
- a full Y-axis motor support including the left part, diagonal stiffeners and an enlarged right part that can be attached inside the cylindric hole of the ANET back plate. (All this to improve rigidity)
- the Y axis motor support allows to add an external back plate carbon stiffener that will make a very robust frame (please see also my exokeleton https://www.thingiverse.com/thing:2430113). Even if it remains optional (it will do great job without),I think this is a must. if you do not install this carbon rod, there might remain some flexion of the back plate when applying pressure on the belt. The right rod is pushing the support and the back plate still moves. And during fast prints you can feel vibrations induced by the motor and the Y carriage at the center of the back plate... Install the carbon rod and it becomes RIGID !!!!
- the front plate adaptor does not see any effort, I've simplified it removing the L bracket. The front support for the rods has an open hole so that everything can be assembled without dismantling the ANET's frame.
- the belt tensionner is more or less the same, but as for the other parts it is designed with openscad to be fully parametric !
Please note that the motor mount piece (the big one) is designed for an anet A8 of new generation bought in july 2017 I cannot promize it will fit the other models...
The square and cylindric supports fit exactly their associated holes in the ANET's back part. I did not need any sanding or filing, Only remove the little plots left by the supports.
Thank you again Matsekberg for this very clever idea for sure the best mod for Y belt!
EDIT (170904) : There was a mistake in an equation of the Y-frame piece which lead to non parallel rods by 8mm. I've fixed this in this new release. Thanks to Sinobi for having pointed that out.
EDIT (180113) : Under High speed the 6mm threaded rods might vibrate in the front support. I redesigned the whole front support adding 2 threaded M6 nuts that fit perfectly inside the front support holes.
The Y_frame shall be printed with some supports.
The other parts do not need support.
The pulley_holder sees all the efforts transmitted by the belt. i printed it with 80% infill
Quite easy, do it in the following order :
- remove the Y motor an Y pulley original supports. Do not unscrew the belt from the bed just remove everything from the front plate
- re-align the 8mm rods
- install the Y frame
- prepare the 6mm rods
- install the carriage
- install the exoskeloton
- tighten the belt
aligning the 8 mm rods
If you want to add the exoskeleton carbon rod (which Il strongly recommend ☺️), you must first realign the 8mm threaded rods.
On my ANET, the original 8mm are a bit too long by about 4 to 5 mm which we will recover to install the nuts in which will be inserted the 6mm carbon rod...
- Just untighten the nuts allowing to push the rods backward. The front nut shall be right at the extremiity of the rod, then screw all the other nuts to recover 3 mm of rod...
- Tighten all the nuts but the last one you can screw it only manually as we will unscrew it later in the process.
installing the Y frame
- check that the support fits in the ANET's back plate, if not fix it !
- check that the 6mm threaded rods fit in the support's hole, if not your printer is not accurate, check also that the Y_nuts screw easily on the M6 rods ;-)
- then install the motor on its new support. The original screws will do the job. The motor shall be oriented so that its connector is facing you (see first picture)
If there is some room between the support and the motor, add an adjusting shim (a piece of plastic or paper in order to fill the gap). this will forbid the motor to tilt when the belt will be tensionned.
- install 3 nuts in the holes of the new support
- insert the support in position and screw it (the original screws should do the job, they are just long enough ! (but if you go for the carbon rod exoskeleton, you'll have to find 2 screws 5mm longer...)
preparing the rods
- first screw a nut so that you get around 9 mm of rod. For this I use those nylon loaded nut that cannot self unscrew (I do not know the english word !). If you don't get this kind of nut, apply some glue to brake the nuts or just use a double nut.
- insert one rod from the front of the printer through the midlle frame up to its final position. the nut shall be in contact with the front face of its cylindric support.
- measure the needed length of rod to stop one millimeter behind the ANET's front plate. mark the rod and remove it.
- cut the rod to length
- do the same for the second rod
installing the carriage
- screw two nuts on each rod, place them far from the extremity to get around 10 cm of free space
- insert the two rods under the bed through the middle plate up to their final position
- insert the pulley_holder (belt tensionning part) on each rod
- screw the 2 printed Y_nuts as shown in the picture
- insert the Y pulley front frame on each rod
- push them around 3 cm from the extremity
- pull the Y pulley front frame
- screw the 2 Y_nuts. Do not tighten them too much you do not want to bend your front plate ;-)
- screw the Y pulley front frame in position
installing the exoskeleton (optionnal)
- cut a 19.5 cm long carbon rod of 6 mm in diameter
- trim the 6 mm holes of all printed parts with a drill so that everything will slide tight
- slide the intermediate pieces on the carbon rod (take care that the "support center" is not symetric)
- insert the tip rod nuts
- remove the two M8 nuts and washers at the extremity of the back plate
- remove the two screws of the motor and get the 5 mm longer screws
- screw everything in place
tighten the belt
- cut a 3 mm nail to the length (26 mm) (you might as well use a M3 screw)
- insert the two original ball bearings
- add some washers to keep the bearing well in the center
- insert the pulley inside the belt loop
- insert the axis inside the pulley holder slider
- if needed trim the pulley length from under the bed (the original length should work)
- tighten the belt using the first nuts
- once in position screw the second nuts to block the other nuts in position
Et voilà !
my other ANET A8 mods