Introduction: Pentachoron - Delta 3D Printer

I desided to make some improvements to my delta 3D printer (Kossel mini). So I re-designed everything and build a complete new frame using 4020 aluminium extrusion profiles and 10 mm rods, Igus bearings, GT2 belt for the motion. In addition I, designed a magnetic effector using neodym magnets, 10mm ball bearing balls and 6x4mm carbon rods.

The printer on the picture does not have the measurements recommended in this instructable - it's only 750mm high and the arms are a little bit to long - if you order / cut the parts according to the parts list you will get a taller printer.

The footprint is about 420 x 500 x 1000 mm
The print-volume is about 220x600 mm.


I build this printer fairly small (in regard to z-height). If you want to have a greater height, you should

Step 1: Parts List

Frame (Motedis):

  • 3x1000mm 4020 aluminium extrusion
  • 9x390mm 4020 aluminium extrusion
  • 1x200mm (approx.) 4020 aluminium extrusion (spool holder)
  • 1x piece of plywood (or other material you'll mount your heated bed and electronics to, at least 390x340mm)

Linear Motion and Effector Motedis:

  • 6x steel rod, d=10mm, l = 865 mm
  • 6x Igus lineare bearings (RJ4JP-01-10)
  • 6x carbon rod 6x4mm, l = 300 mm
  • 3x GT2 pulley 3x GT2 deflection pulley
  • 3x 5x38(mm) steel rod (for GT2 deflection pulley)
  • 3x GT2 belt (about 6m, I ordered 10m)
  • 12x 10mm x 3mm round magnets
  • 12x 10mm x 3mm round magnets with sink
  • 12x 10mm ball bearing ball
  • 1x bowden tube, about 500-700mm


  • 90x T-Slot Nuts (M5)
  • 90x M5x10 (for the frame corners)
  • 45x M3x12 (for rod holder, effector and carriage)
  • 12x M3x10 (for Nema 17)
  • 3x M3x20 (for carriage)
  • 6x M3x30 (for carriage)
  • 40x M3 hex nuts
  • 3-6x M3x10 (for heated bed - I only use 3)
  • 3-6x M3x6 countersunk (for heated bed - I only use 3)
  • 3-6x M3 spacer, 10 mm long (for heated bed - I only use 3)
  • 6x M2.5x10 (for endstops)


  • 1x set of favourite electronics (I'd recommend something like a Smoothieboard)
  • 4x Nema 17 steppers
  • 4x mechanical endstops (one for auto delta calibration with smoothieware)
  • 1x 30mm fan (to cool E3D V6)
  • 2x 40mm fans (part cooling fans)
  • 1x heated bed (FilaBase)
  • 1x E3D V6
  • 1x bowden extruder of your choice (i.e. E3D Titan)
  • 1x USB pass / adapter to type B
  • 1x LAN / Ethernet pass
  • 1x connector for mains power (Kaltgerätestecker)
  • 1x power supply unit (PSU)
  • cables, connectors, general electronics stuff you'll need

Printed parts:

  • 6x delta arm carriage belt clamp
  • 1x delta magnetic effector
  • 1x delta magnetic effector fanduct
  • 1x delta calibration tool (only if you want to use auto delta calibration in smoothieware)
  • 1x delta effector clamp1
  • 1x delta effector clamp2
  • 12x delta rod end
  • 12x delta rod holder (type a or b, see step 5)
  • 3x delta top corner
  • 3x delta bottom corner
  • 3x delta arm carriage
  • 1x delta fan holder electronics
  • 6x delta feet
  • 1x delta i o panel (or delta i o panel with lan - has usb and lan pass)
  • 2x delta spool hanger
  • 2x 000 delta axis alignment tool (optional)

If you also want a LCD-enclosure, I'd recommend one of these:

Step 2: Pre-Build Preperation

Prepare all the tools you'll need for assembly. I only used some screw-drivers and allen wrenches. Be careful when you assemble your electronics to not damage them or probably hurt / kill yourself. Be especially careful when wiring mains power.

Printed parts preparation

First you have to print all the parts listed before - obviously. I designed them to print without support. Maybe you have to use a raft, depending on the machine you print them on - I did all my parts with 25% triangular infill.

Check all holes before starting to assemble. Sometimes holes come out smaller then you want them to be - I checked the tolerances of the parts for the printers with publicly available files on different 3D-file-repositories to make sure, the tolerances fit - but your mileage may vary.

Step 3: Upper Frame Assembly

Upper frame

Take the three "upper corner" printed parts and insert the 10 M5x8 screws and T-Nuts. You can also mount the GT2 deflection pulleys using the 5x38mm steel rod (you may also use a M5x40 screw) and the endstops using the M2.5x10 screws. The holes in my endstops were tight enough (that's what she said) to hold them in place just using screws without nuts. If you have problems holding them in place just use M2.5x12 screws and M2.5 nuts instead. Be aware: after completly assembling the frame the screws to mount the endstop will not be reachable.

Build the first to sides of the triangle and install all "top corner" parts. Lay down the last side of the 4020 extrusion next to where they should go and measured (eyeballed) where the T-slot nuts have to go. Then put everything together. At last I put in the screws to attach the upper frame to the vertical 4020 extrusions.

Step 4: Lower Frame Assembly

Lower frame

First install the Nema 17 Motor using the M3x10 screws. Then insert the M5x10 screws and T-Nuts in 2 of the 3 printed "bottom corner" parts and fit them together with the 390mm long 4020 aluminium extrusion. For the last side of the T-slot nuts into the aluminium extrusion, measured where they should be and fittet the last 2 4020 aluminium extrusion profiles.

Befor continuing the assembly us the assembled lower frame to draw out the contours of the plate, on which the PSU, micro controller and heated bed will be mounted. For the basic shape put the assembled lower frame onto a piece of plywood, drew the outline and cut it out. Do not drill any holes to mount the plate to the frame yet! To drill out the mounting holes for the PSU just put the PSU on your scanner and copy the bottom of it. I already have a mounting solution for my Smoothiboard - but tracing out the mounting holes for your electronics should not be a problem.

To get the spacing for the PCB heated bed right draw the center verticals and place the PCB on top. To get the parts mounted as easy as possible install the heated bed spacers first (to your plywood plate). After this you can install your PSU and your electronics. As a spacer for the PSU I simply used some Nylon washers.
At last: put in the screws to mount the vertical 4020 extrusion profiles for the final frame assembly.

You can install the electronics and now or later - what ever floats your boat. I recommend to install them later, so you don't damage them by (man) handling the plate while assembling.

Step 5: Final Frame Assembly and Linear Motion

Before you assemble of your frame you have to install the linear motion system. To do so, you'll need following printed parts: arm carriage (x3), arm carriage belt clamp (x6), holder (x12). Also you'll need your 10 mm steel rod, the IGUS-bearings, 12 x M3x12mm screws, 6 x M3x30mm screws,18 M3 hex nuts, 12 M5 T-Nuts and 12 x M5x12mm screws.

First you have to pre-assemble the frame. Just put and screw in (tight) the 4020 aluminium extrusion for the vertical struts into the bottom corner parts. Then put the upper frame on top - don't screw this one tight right now! You have to wait until you installed the steel rods for your linear motion!

Now you have to assemble the carriage. Put the IGUS bearings into the printed part and secure them using 4 M3x14 screws and 4 M3 hex nuts (per carriage). Then install the belt holder using 2 M3 hex nuts and 2 M3x30 mm screws. finally you can insert the last M3 hex nut and the M3x20 screw for leveling - make sure to screw it only half way in so you can compensate in both directions. At last, glue in the magnets using super glue - each hole needs 2 magnets, one "normal" and one with the sunk hole.

To align the rods correctly use the simple axis alignment tool. Try aligning the axis with the plate for the electronics / PSU on the printer, it may be possible that you have to (a) trim off a part of the plate to make place for the rods or (b) mount the axis partially on the plate. For this reason there is a holder / mount for the rod for Version (a) and (b). Version (b) accounts for a 6mm thick plate. Be aware that you have to use version (a) for the upper frame - because there is no plate.

Before you finally assemble / screw in the rods make sure, the plate for electronics / PSU is centred on the frame and draw out some mounting holes (I used 3 per side). Now you can lay the plate on the lower frame - while assembling the frame, mark out spots for the mounting holes. Then slide the assembled carriage onto the rods and clamp the holders on the ends of the rod using M3x12 screws and M3 hex nuts. Now you can finally install the linear motion system. Put the carriage on the rods, then clamp both sides with the respective holder. Install the part which goes to the upper partition of the frame first. For a first alignment (if you dont want to use the alignment tool) a distance of around 51-52 mm between the rod an the first slot of the aluminium extrusion (see picture) is ok.

At last you can install the deflection pulley for the GT2 belts. First slide the 5x38mm stell rod into the hole in the bottom corner parts (but not completly through). Then put on the printed part named "spacer", then the deflection pulley and at last the 5mm collar ("Stellring"). After that push the 5mm rod through and screw down the collar. Make shure nothing binds or rubs.

While assembling the linear motion system you have to note multiple things. First you have to measure the distance between top and bottom frame on each steel rod - they should be about the same. Make sure, the steel rods are perfectly parallel. To do so, loosly tighten the M5 screws for the clamps on the frame, move the carriage up and down severeal times and use the alignment tool to check, if everything fits. If it does and the distance between lower and upper frame parts is nearly identical screw down the steel rods on lower and upper frame. Double checke the distance afterwards! Then you can lastly tighten the screws securing the upper frame to the vertical 4020 aluminium extrusion.

You can insert the spool holder / hanger now, but you don't need to.

The main frame is completly assembled now.

Step 6: Effector Assembly, Electronics and Wiring


Now you can start to installe the electronics. It is important, that you mount the spacers for the heated bed first! Then you can mount spacers for the PSU, install the PSU and add your electronics. You can install your heated bed now as well. I drilled an additional (bigger) hole near the center of the heated bed to route the cables thorugh.

The cables for the endstops where routed through the center of the vertical aluminium extrusion profiles - I also routet the cables for the extruder motor through this holes.

Wire your parts correctly and you'll hopefully not fry your electronics.


Then start to assemble the rods connecting the carrier to the effector. Glue in the 10mm ball bearing balls into the "rod end" - you need to build 12 of these. Then glue them onto the carbon rods (don't use quick drying glue) - make shure all pieces are exactly the same length. To do so you can clamp them between two pieces of wood and adjust the length as needed. Now you can start assembling the effector.

For the effector you have to insert 12 magnets into the holes as well. Then you can put your E3D V6 through the effectors center hole and clamp the clamp parts around the mounting notch. Put 3 M3 hex nuts into the magnetic effector fanduct part and join the clamp (with hotend), the effector and the fanduct using 3x M3x12mm screws. You can mount the fans (2x 40 mm, 1x 30mm) to the fanduct either using self tapping screws or some M3 screws. When mounting the 30 mm fan leave out the two lower holes if you want to use smoothiewares auto delta calibration - the "delta calibration tool" will mount there with an endstop to perform the calibration routine.

You can now put your effector and rods into the printer and wire everything up.

Step 7: Setting Up the Firmware - Marlin RC8

Setting up Marlin should be straight forward - I included my configuration.h for reference, the values to start the Delta calibration are:

#define DELTA_DIAGONAL_ROD 345 // mm

#define DELTA_SMOOTH_ROD_OFFSET 192 // mm

#define DELTA_EFFECTOR_OFFSET 25 // mm

#define DELTA_CARRIAGE_OFFSET 24.04 // mm

For calibration I recommend this video - but if you value your time just buy a smoothieboard and use smoothiewares awesome auto delta calibration:

Step 8: Setting Up Smoothieware

I uploaded my config file for you to download. If you use it, it should work fine. A z-probe is setup there - but you'll only need one for auto calibration. The temporarly attached endstop for calibration is shown in the picture.

Always remember: when you change a setting in the config or config_override-file you have to reset the smoothieboard. You can to so by using the hardwar-reset-button on the board or issue "reset" through pronterface.

If you have any problems you can consult the documentatiion for smoothieware.

Smoothieware Delta Calibration

Smoothieware Delta

Auto Delta Calibration

Auto Delta Calibration in smoothieware is pretty straight forward. First plug the probe into the z-min endstop pins on your board. Then install the temporarly probe on the effector.

Go to your firmware and set your "gamma_max" to about 20 mm less then your build height - so you avoid that your probe crashes into the buildplate.
Then connect to the board via usa (using pronterface) and issue the "reset" command - the smoothieware will reboot and activate the values from the config-file.

Then issue the G32 command. The Auto Calibration will start and calibrate your printer. For this, the probe will probe 4 points (each tower + center) several times.

After the probing is completed use M500 to store the values. Reset the smoothiboard once again to activate the values.

Then open the "config_override" file on your smoothieboard. I had the problem, that it stored my "gamma_max" value so I couldn't change it. Whenever you change a value in the config-file, make sure, this value doesn't get overwritten by the config_override. If something is in the config_override, you don't want there, simply delte these lines.

z-Height Calibration

Z-Height Calibration is straihgt forward as well - first remove the probe. Just use a number whichs is bigger than your expected build height for the "gamma_max"-value (Make sure, this values does not get overwritten by the config_override).
Then drive your hotend down to your heated bed slowly until it graps your paper. To get your z-height just subtract the distance you have done from the distance you have set in your firmwarwe.

Delta Bed Leveling

At last you have to level your bed. For this you have to turn the screws in the top of the carriage. If you tighten them, the distance between nozzle is raised, if you loosen them, the nozzle is lowered.

You have to calibrate the nozzle on each tower, calibration points are:

G1 X-78 Y-45 Z0

G1 X78 Y-45 Z0

G1 X0 Y90 Z0

Dimensional Accuracy

At last you have to tune your dimensional accuracy. This is mostly dependend on the arm length. You can find a good guide here:

Delta calibration for dimensional accuracy