I didn't want the Z axis to miss out on the Taurus love, so I gave it a makeover. It's like viagra for your Prusa. Part of Z is already included in the Taurus X since that is the nexus of the two. I made this one more modular so you can upgrade parts or in stages. It comes with the obligatory overt excess, some fixes / innovations, and a dash of biomimicry. Here is what is changed:
- optional cross members to stiffen top of Z frame
- reinforced Z top with improved smooth rod coupling
- optional frame lash and Z rod height set screw to manage cantilever
- accessory mount on Z top
- reinforced Z motor mount with increased smooth rod connection
- optional stabilizer feet to support center frame and reduce vibrations (coming soon)
- new FDM-friendly slot-lock extrusion mounting system
This compliments Taurus X axis and Taurus Y axis upgrades but is independent and can be mixed/matched. Also see Taurus frame brace to remove PSU from frame. Lastly, Taurus LCD available to finish out.
Update 1/19/19: I discovered the Z frame is not symmetric. I mirror the parts as you can tell from the version stamps. Turns out the bottom anchor hole I added to the motor cups is offset on the left side of the frame. I fixed and replaced both motor cups as r1b. If you already printed, don't sweat it and just leave the left anchor screw out as it is optional.
I also completed the assembly instructions.
Update 1/7/19: fixed Zrod parts to sit flat for print. added optional Zfaring to cover nut (see photo). r1b: improved homing screw position on Ztops
recommend PETG at 0.15 layer height, 12% Gyroid, 2 (or 3) perimeters, as oriented in STL, e.g. do not rotate the clip.
Print one of each part except:
As always, make sure parts are clean of burrs, etc on mating faces, clearance screw holes are open, and fit together cleanly before attempting to install.
For optional cross-member, you will need:
- 2 threaded rods: 5/16" x 15" or 8mm x 380mm
- 8 hex nuts to fit your threaded rod
The threaded rod is kind of garish and reminds me of MK2. I found some cheap 5/16 heat shrink at HF for $2 and fits great. See photo. You need <12”, leave room for nut to move. Expose as much as is below top of horn. I added a finisher piece to cover that (fits 8mm, shrink ~3% for 5/16). I still need to trim the end of the threaded rod in the photo. Don't heat shrink until you know you have it the way you want. I left mine unshrunk for now.
Remove Z tops and Z motors. If you are clever you can keep X axis in place.
Insert a hex nut in the bottom pocket in the motor cup. Attach cup to frame using the 3 main M3x10 screws into holes that are tapped into the frame. Add optional M3x12 anchor screw from behind frame to set into the hex nut you added. Slide Z stepper motor into cup with lead screw passing through opening and press up into place. Make sure wires slide into channel in the cup and exit out near the anchor screw to pass under frame. Motor should snap in a hold itself up. But place a support underneath while screwing down (XYZ cal cube works well). Slide Z door into opening between motor and cup top, completing the assembly. Screw down to motor using 4 M3x10, tightening in a diagonal pattern.
Press smooth Z rod down into hole. It should snap in and you can hear it click up against the top metal face of motor. If you are unsure, you can see the end of the rod through the viewing port using a flashlight. Repeat on other side.
Press the Z top onto the top of the smooth rod. Screw to frame with 2 M3x10 (or M3x16 if adding lash as described below). There is a window to allow you to see the inner screw (homing screw) while tightening. This window is also to check the X axis is homing cleanly against that homing screw.
Optionally, use a small M3 screw, say 8mm, and thread into hole over end of smooth rod. Make sure Z top is perfectly level, then tighten until the screw just touches the smooth rod.
The Z tops have optional lashes to secure extra tight to frame and help counteract the cantilever. T goes over the top, S goes around the side. Insert in direction of arrow. Use longer M3x16mm screws instead of M3x10 and tighten until about 2mm sticks out of frame rear. Hook lash over screw end, tighten screw the rest of the way, then secure lash with hex nut.
Optional cross-member install:
Note: this is compatible with stock setup or skelestruder with pancake. If you have larger stepper there may be clearance issues on right, in which case you can just install the left side.
To use the slot-lock system, insert hex nut into wedge and fit into clip. insert M3x18mm through clip and screw into nut. push wedge out back out of clip so there is a gap. insert into extrusion slot and press clip until it snaps into place, also pressing screw to keep the wedge out of the clip. Now remove screw. clip should slide easily in slot but not come out. slide up against frame and slide horn over the clip. Should be snug. Now insert screw back through horn and screw down. should lock in place with no play in any direction, including twisting.
Insert one large hex nut into horn and one into Z rod coupler.
Thread two nuts onto threaded rod about 50mm (2 in) from each end
Screw Z rod coupler onto one end
insert other end into horn and turn until it passes through nut
turn Z bracket to bring it down in line with Z top
screw to Z top using M3x18mm and hex nut
the goal is to lock your frame in position, not preload it with any tension