From RepRap
Jump to: navigation, search
BoomBOx Documentation
Crystal Clear action run.png

Release status: Obsolete

Prusa meets Mendel
CAD Models
External Link

Logo3boombox.png <videoflash>iqUPxjismV0</videoflash>


The BoomBOx design is now obsolete. The initial prototype was fully assembled but fully calibration was never completed. The prototype was later converted into a miniature mill by future engineering and design students. This page is used for historical reference in the Reprap community. BoomBOt was one of the first RepRap designs to pursue the theory of printing in an enclosure to trap heat.

BoomBOx (aka. BoomBOt) is a Cartesian XY-head machine that was created as an undergraduate research project at the University of Michigan Flint. During initial testing, the name "BoomBOx" was coined in the reprap IRC after the LCD screen repeatedly shorted during meetings in google hangout. (Causing the electronics to release much pent up anger into the mini-speaker and eventually burning the BUS cable). BoomBOx no longer requires an LCD display.

BoomBOx stands 2 feet tall, with a standard 8x8 inch printbed. Designed within the 6 months of research completed on reprap 3D printers, the goal of BoomBOx is to adapt to great ideas and make improvements along the way. The original BoomBOx extruder was inspired by the removable tip of the J Head Nozzle extruder. The BB extruder head, longer than the JHead's, was designed for stability. Like the JHead, the BB extruder had a block for the resistor. The extruder was solid copper with a relatively large peek block. The anticipation of this design was that extrusions would be smooth after preheat and require fewer heating cycles during print. However,the original BB extruder was not able to reach the preheat of 230C for ABS plastic due to its relatively large mass. Though copper is difficult to machine, a relatively large copper extruder like the BB should still be suitable, in theory, for PLA. Maximum temperatures met before replacement with a (machined) brass extruder were between 197-200C.

The BoomBOx printer uses MendelMax printed parts, with slight changes to the design of the MendelMax printbed assembly. The primary changes which set the BoomBOx apart from the MendelMax, as well as other printers, are the inverted X and Z axes. The printer base is fully steel-encased and this encasement allows smooth rod to escape, through precisely drilled holes, into pressure holds inside of the frame. The smooth rod for the Y axis is held in place exclusively by the pressure hold and, due to inverted axes, the frame sits nicely inside of itself. A polycarbonate chamber will encase the print area (as seen in photos) after initial testing is complete.

The bowden for the BoomBOx was inspired by the hobbed bolt of Greg's Hinged Extruder. Designed by John O'Brien, engineering technician at the University of Michigan Flint(UMF), the BB bowden features a roller bearing with a grove. The bowden has adjustable spring pressure support and uses a hobbed gear to feed filament into PTFE tubing.

Using the GRABCAD MendelMax model, BoomBOx was designed in CAD assembly mode and creators are in the process of constructing the full CAD model. To save on time, many changes to the machine were done on the spot. The inverted x axis and y axis systems have yet to be sketched into Creo.

Boom1.png Boom3.png



Amanda Hansen, past engineering student and club president at the University of Michigan Flint, initiated the build of BoomBOx as part of a research grant she received in Fall of 2012. BoomBOx was a team effort, with participation from engineering club members, even during finals week. The grant project started with materials research and major design changes. As student interest in aluminum extrusions peaked, the MendelMax and Prusa models were adapted for a final design which would accompany larger prints.

With schedule changes of winter semester, many club members became unavailable. The engineering technician John O’Brien became especially helpful and gave much of his time to BoomBOx construction.

BoomBOx is different, with backwards motors and upside down axis; this printer was created custom. With a display of spontaneous modifications, BoomBOx is a tribute to creative engineering. With the BoomBOx design, sheet metal and polycarbonate (Lexan) are introduced to the extrusion frame in an environment which could be heated or fumigated if desired. Reminiscent of Prusa and as rigid as Mendel, this stellar combination is over 3 times the height of its inspirations.

Historical documentation concerning how BoomBOx got its name can be found here:

BoM Bill of Materials


Qt.10 - LM8UU (Asia) or LME8UU (US, Europe) linear bearings OR 8mmx25mm brass bushings

Qt.5 - 608 "roller skate" ball bearings "6082RS" for sealed, "608ZZ" for shielded.

M8 threaded Rods

(can all be cut from 6 1m lengths of M8 threaded rod)

Qt.6 - 370mm M8 threaded rod Three per side

Qt.4 - 294mm M8 threaded rod Front/rear. Can use 300mm too

Qt.3 - 440mm M8 threaded rod Top/Bottom. Can use 450m too

Qt.2 - 210mm M8 threaded rod z-axis lead screws. Can use 300mm too

Qt.6 - 405mm M8 smooth rod


Qt.2 slabs of metal

Qt.4 springs

Qt.4 extra pieces of threaded rod

Qt.4 brass bushings

Belts, eBay

Qt.1 - 840mm GT2 toothed belt, matching pulleys Gates Corp.

Qt.1 - 900mm+ GT3 toothed belt, matching pulleys Gates Corp.

Qt.2 - 16-tooth matching GT2 pulleys bore dia. 5mm Gates Corp.

Qt.2 - - 16-tooth matching GT3 pulleys bore dia. 5mm Gates Corp.

(GT2 belt advised if long enough, 16 or 12 tooth pulley- 16 advised)


1 3mm ABS/PLA roll


Qt.1 12AWG THHN stranded wire 8ft


5 NEMA 17 Stepper motor 40N/m


Qt.1 Heatbed MK1 PCB

Qt.1 8x8 in glass plate


  • BoomBOx extruder custom made in a machine shop

Qt.1 Hot end

Qt.1 High Heat Braided wire McMaster Part No. 8209K11 (or equivalent)

Qt.1 Teflon (PTFE) sleeve (2 feet) for thermistor lead insulation and filament tube McMaster Part No. 5335k11 (or equivalent)

Qt.1 Kapton tape roll for thermistor mounting

Plastic Parts

Mendel Max Parts kit


Qt.4 8-foot, 1.5 inch aluminum extrusions

Qt.50 M8 screws (½-20), 20mm length

Qt.1 4ftx4ft sheet of plexi/lexan for the encasing

Qt.2 Sheet metal for the backing and the bottom of the machine (we use sheet on back, steel on bottom)


Qt.1 ATMEGA2560 with RAMPS 1.4 (original) or ATMEGA328P Board + USB

Qt.1 H-bridge for Z Stepper Motors


Qt.1 Machine Shop with a mill, lathe, band saw, and 1 large cart

Total Estimated Cost: $850

DIY Extruder

Note: Nice work, but I think this should go into a separate page. --Traumflug (talk) 01:46, 18 January 2015 (PST)
Note: Thanks, will work on it. This design didn't quite turn out but it was still a learning experience. --PseudoVoid (talk) 20:44, 17 January 2018 (EST)


Do it yourself BoomBOx extruder build




Qt.1 Chunk of copper (small) UPDATE: The extruder shown in the follow pictures is ~2.5 by 2 cm and only goes up to about 159 C. Copper is still a great material choice but an improved BB hotend design would be significantly smaller as well as one solid piece.

Qt.1 Section of copper rod


  • Keep in mind to build the extruder before you build the x-carriage


1) Take about a 3.5 inch length of copper rod, drill a 1mm hole in it.


2) Take a drill bit a little bigger than your PTFE tubing and drill over the hole. Drill down until there is about 1.5-2cm left for the head on the bottom.


3) Use a lathe to shave the nozzle down towards the hole, but not touching the hole- therefore, creating a 'nozzle'. This nozzle will not be like a cone. More...think of a little piece of the straw sticking out of your soft drink. Try to lathe about 1mm away from the hole and move down about 2mm, to create a 1mm long tip. Move VERY SLOWLY with copper. VERY VERY SLOWLY

4) Flip the rod piece in the lathe with only 1.5-2cm inside of the lathe, nozzle facing inward. Now shave the length of the rod down.

Threading.jpg Threaded.jpg Done.jpg

5) Take the extruder piece out and place it in a copper clamp.

6) If you have decided on threads for your peak block, thread the extruder accordingly. I think we used 2/3 threads- in any case, they should be large.


7) Cut/prepare your block accordingly with a drilled hole and threads for the extruder.

8) The fun part- if you can't thread straight, you may have to stick the head back into the lathe and turn the lathe to get the block on. Warning: this may take three people to do

9) Drill a hole smaller than your resistor into the block.

                     Withpeak.jpg  BoomHaircut.JPG

10) Drill a hole the size of your resistor a little more than halfway into your block. This lets the resistor rest there without having a way to coming out from the other side. You're done!

UPDATE: The BB hotend has since been replaced by a significantly smaller (brass) custom made hotend. A smaller copper design has not been attempted.

---Pop off the top and put Prusa in the box; Mendusa was born.--- -- PseudoVoid 04:46, 16 August 2013 (UTC)