Prusa Mendel thereprapkitstore

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This page is about the Prusa Mendel version sold by

Detailed Assembly Instructions can be found in this reprap-wiki: ABSPrusa.

High resolution photos are published on the seller's page.

construction is discussed in the RepRap Forum

batch sales

Batch 1:

Batch 2: This batch was shiped with a one week delay and it did only contain the mechanics. Three weeks later electronics and belts were shipped. Instead of a Melzi board, a Sanguinololu board with an additional SD-plugin was shipped. A forum thread about this delay can be found here[1]

Batch 3: These later batches all shipped with the melzi electronics. [2]

Batch 4 (PRE ORDER for DISPATCH on May 31st):

difference to the standard Mendel

M8 lock washer instead of plain washers are used.

A smaller M8 Mudguard washer is used, allowing easier jigging.

The inside jiging length is 273mm instead of 234mm. (The 290mm outside frame jiging length is the same.)

tips on how to build the ABSPrusa

wrong: The four bar clamps now need to be spaced correctly, measuring from the inside of the nearest frame vertex, the nearest side of the the bar camp needs to be 70mm. correct: the photo shows the correct 60mm.

The purpose of the optional bearing is to keep the x-axis belt level. Better take a bigger 5mm bearing, simply drill a 4.5 mm hole into the plastic and screw the bearing into it :-)

This ABSPrusa has a clever way to mount the x-end holders :-) If you find it too hard to push the two smooth rods into them, just take an 8mm steel drilling bit in your hand and chamfer the inner clamp a little bit.

If you have been so stupid as to cut down the wrong belt for the y-axis, this is not the end of the world. Just lay the leftover from belt1 onto the end of belt2 and tightly fix it with a sticky tape :-)

Absprusa - lengthening a belt.jpg

This should be a better way for the final step to mount the y-axis and the z-axis rods:

With the ABSPrusa, the length of the x-axis smooth rods determine the final distance between the z-axis rods. Therefore, you should check, that the two z-steppers have the perfect distance to each other. To do this, simply put the assambled x-axis on top of the two z-steppers.

Absprusa - zy 1 checking width.jpg Absprusa - zy 1 checking width zoom.jpg

the two z-axis smooth rods should perfectly slide into upper brackets.

When inserting the threaded rods, lag some cheap sticky tape around the M13 nuts, because the holders still can take M14 nuts :-/

Absprusa - zy 3 m13 to m14.jpg Absprusa - zy 4 spring offset.jpg Absprusa - trick lighter.jpg

To get the propper tension on the optinal springs, just position the upper nut accordingly.

Little trick, if the M3 nuts do not fit into the couplings, heat it up with a lighter for 6 seconds, than pull them into position :-)

Now put the x-axis onto the aluminium plate and screw the threaded rods upwards until they meet the shafts of the z-axis steppers.

Absprusa - zy 5 ready to connect.jpg

After having mounted the couplings (larger holes downwards!), bring the x-axis parallel to the upper assambly.

Absprusa - zy 6 leveling y-axis.jpg

And last, the final measurements to fasten the smooth rods perfectly in the middle :-)

Absprusa - zy 7 final fit.jpg Absprusa finaly.jpg

wireing the electronics


And add four little cooling elements on the four black little square chips of the stepper motor drivers ! Also find a dissipator for the mosfet powering the heatbed.

the software

As the firmware "sprinter" ist already installed, you do not really need to install the Arduino IDE. This will only lead you into trouble, because you have to tweak the firmware settings yourself..

For a quick start, simply download and install

You will also need an usb-serial driver like this one: FTDI drivers

Now you can already operate your new machine manualy :-)

You can download 3d objects on thingiverse

Or download blender and make your own things :-) (Set the center of your blender objects to x,y = 100,100 and the bottem to z=0 and export to .stl or .obj)

Here you can download cad-files for lots of sprockets, etc:

To convert the .stp files into .stl, download and install HeeksCAD (import the .stl file into blender to move the bottom-center to 100,100,0 and rotate the object into a printable orientation.)

Have fun :-)

installing a new firmware

Download and install the Adurino Software: [3]

Download the Sanguino hardware files [4] and place them in the arduino-1.0.2/hardware folder.

Change the following two lines in the boards.txt file W/ ATmega644P


Download James original sprinter firmware (batch sale 2, spring 2012)

Load the Sprinter.pde / Sprinter.ino into the Adurino IDE.

Modify the firmware to compile with Adurino 1.x.x:


#include <WProgram.h> --> #include <Arduino.h> 


void write(uint8_t b); --> size_t write(uint8_t b); 


#include <WProgram.h> --> #include <Arduino.h> 

void SdFile::write(uint8_t b) { --> size_t SdFile::write(uint8_t b) 


#include <WProgram.h> --> #include <Arduino.h> 

Modify the Configuration.h It is possible to extend the footprint, for example:

//Max Length for Prusa Mendel, check the ways of your axis and set this Values
const int X_MAX_LENGTH = 240;
const int Y_MAX_LENGTH = 230;

Select: Tools->Board->Sanguino W/ATmega644P

Choose your serial port: Tools->serial port->yourComPort

Hit the "->" button :-)

trouble shooting

  • If the x- or y-stepper is losing steps, switch the connectors of the stepper/endstops to test if the mechanics is the problem or the Sanguinololu board. In the later case, mount a cooling element to the stepper driver chips. And/or get better stepper drivers. The Pololu-drivers are said to be better..

people having such a Mendel

Robo reprap.jpg Cdtray side.jpg Stepper dissipator.JPG