Oldboy Slinger MK1 (Original Bed Slinger 3D Printer)

Important note: 3D Preview of parts files on printables can be incorrect because I made this design in PrusaSlicer (I know, I know, it is too late) and negative spaces do not show in this .3mf PrusaSlicer format.

Oldboy Slinger MK1 is a minimalistic featherweight bed slinger designed from scratch by myself.

Print size: 14x14xZ (Z depends on your Z axis smooth rod lenght, X and Y axis lengths depends on your endstop placement but max it can be 14)

Short story of this printer: I had a SmartRap 3D Printer lying in the corner, a cantilever model, single motor for Z axis.  I wanted to use the parts to make a new original bed slinger with double Z axis motors . My idea was to not use any aluminium profiles etc. just add one extra motor (and another m5 lead screw) for the second Z, and totally new printed parts. Original Smartrap design uses 4 motors as a solid base, I got inspired (but not revised, my design is original) by this simple design.

Design: 

Oldboy Slinger MK1 uses a cross shaped 3d printable base screwed on 4 motors: Y axis motor, double Z axis motors and extruder motor(Bowden tube). The base fits to Prusa MK3s+ bed if you turn it between 42.66-42.9 degrees. 8mm smooth rods for Z axis can be attached on top vertically, on each side near Z motors. Y axis 8 mm smooth rods can be attached horizontally between extuder and Y axis motors. A belt/fishing line tensioner (printable) and a pulley (printable, I used some other design for template, I will give link to the original but it is quite different) for Y axis can be attached to extruder motor side. Again there is a square hole for mechanical endstop attachment at the extruder side. At extuder side there are  holes for extruder motor to be attached. I sandwiched this end between extuder motor and metal extuder parts. For more stability some counter part (printable) is needed at he other side of th extuder, again needed to be sandwiched.

Bed carriage (printable) is for a 4mm glass non-heated bed (mine is 18x22 cm, I use blue painters tape on top of it for prints), but some other bed types can be adapted with minor revision. I use clips (printable) to attach the glass bed. Belt/fishing line for Y axis can be attached to the hook on the bottom side. Again, Two Lm8uu or 1 Lm8luu can be attached with zip ties, for Y axis movement of the bed carriage.

X axis has two parts (printable) similar to many other bed slingers like prusa. There are 2 screw holes in both parts, for 5mm lead screws (just simple long m5 screws) for Z axis movement. Again each part has holes for double Lm8uu linear bearings, used for Z axis 8mm smooth rods. Left side X axis part has screw holes for X axis motor. The other part at right side has a hole for X axis belt/fishing line tensioner (printable) and pulley (printable). These x axis parts can be revised for other sizes of lead screws or ball screws etc.

Hotend carriage and hotend holders are designed for a typical E3D V6 hotend but it can be adapted to other hot ends with some revision. The carriage is 4,5 cm wide for Lm8luu linear bearing, you may use 2 lm8uu's too but will lose some max. printable space in X axis. Linear bearings can be attached with zip ties. There is a hook on the back of the carriage for belt/fishing line attachment. Hotend is sandwiched between two holders(printable) and then fixed with m3 screws to the hotend carriage.

I used two mechanical switch holders (printable) for Z axis and X axis, these are not my design I will give links to the original design. I know Z axis mechanical switch position is a pain in the *ss, but for this first version I will not touch this parts.

Electronics box is not my design, I just revised it to attach to right side Z axis motor. I will give a link to the original.

In my own build, base plate is on top of some taller axis step motors (because of a damper attached) but extruder motor is attached on top of a shorter motor (without a damper) I also designed a simple spacer/riser (printable). If you don't need it just dont print it. The key point here is to create a stable, same height 4 motor base.

Notes: I build the braided fishing line (0.6 mm) version, but it is easily convertable to belt drive. For fishing line attachment, just google how to tie a slipknot (or some other knot) and use it to attach to bed carriage hook. At motor side I wrap around motor shaft 5-6 times. At the other (tensioner side) I just wrapped only 1 time around the pulley. After a bit loose fit tensioner screws can be to used. Attaching the bed carriage to smooth rods and also to fishing line is a bit tricky, but managable. I am sure there can be many methods here, I leave it to your imagination and creativity for now. Geared belt installation should be easier compared to fishing line.

What's next (maybe one day):

1. level: Better adjustable Z endstop holder or integration of Z endstop to left X axis part, again integration of X endstop to X axis part (dropping the endstop holder), parts cooling fan holder, LCD screen box and attachment (right now I simply attached it with zip ties to right side Z motor).

2. level:  Z axis probe revision for hotend carriage

Endstop holder by gringer (I just used this without change):

Link to electronics (Ramps 1.4) case by ModularMapping3D (I added a motor attachment to this): 

Spool by vdivision (I totally revised this to create a pulley):