Prusa Research MINI+ User manual

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Table of Contents
Manual changelog MINI+ semi-assembly 3 ................................................................
Step 1 - Version history 4 .................................................................................................
Building your MINI+ 5 ...........................................................................................................
Step 1 - Preassembled vs kit version 6 ...........................................................................
Step 2 - Different hardware revisions 6 .........................................................................
Step 3 - All the required tools are included 6 ...............................................................
Step 4 - Use labels for reference 7 .................................................................................
Step 5 - We are here for you! 7 ........................................................................................
Step 6 - XYZ-axes parts preparation 8 ..........................................................................
Step 7 - XYZ-axes parts preparation 8 ...........................................................................
Step 8 - Foam pads - preparation 9 ...............................................................................
Step 9 - Foam pads installation 9 ...................................................................................
Step 10 - Opening the box with the electronics 10 ......................................................
Step 11 - Connecting the LCD cable 10 ..........................................................................
Step 12 - Connecting the Y and XZ-axis assembly 11 .................................................
Step 13 - Joining the parts together - preparation 12 ..................................................
Step 14 - Protecting the LCD cable 13 ...........................................................................
Step 15 - Joining the parts together - phase 1 13 ..........................................................
Step 16 - Joining the parts together - phase 2 14 .........................................................
Step 17 - Joining the parts together - phase 3 14 .........................................................
Step 18 - Aligning the XZ-axis assembly 15 ..................................................................
Step 19 - Final tightening 15 ............................................................................................
Step 20 - Haribo time! 16 .................................................................................................
Step 21 - LCD parts preparation 16 ................................................................................
Step 22 - Mounting the LCD 17 .......................................................................................
Step 23 - Connecting the LCD 17 ...................................................................................
Step 24 - Guiding the LCD cable 18 ...............................................................................
Step 25 - Connecting the Y-axis motor 18 ....................................................................
Step 26 - Connecting the heatbed cable 18 ..................................................................
Step 27 - Filament sensor (optional) 19 .........................................................................
Step 28 - Filament sensor installation (optional) 19 ....................................................
Step 29 - Connecting the filament sensor (optional) 20 ............................................
Step 30 - Covering the electronics 20 ...........................................................................
Step 31 - Haribo time! 21 ..................................................................................................
Step 32 - Spool holder parts preparation 21 .................................................................
Step 33 - Spool holder parts preparation 22 ................................................................
Step 34 - Assembling the spool holder base(s) 22 ......................................................
Step 35 - Adding the spool holder rails 23 ....................................................................
Step 36 - Adjusting the spool holder width 23 ............................................................
Step 37 - Attaching anti-slip pads 24 ............................................................................
Step 38 - Haribo time! 24 .................................................................................................
Step 39 - Finalising the assembly 25 .............................................................................
Step 40 - Connecting the PSU 25 ..................................................................................
Step 41 - What is next? 26 ...............................................................................................

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Original Prusa MINI+ semi-assembled 3
Manual changelog MINI+ semi-assembly

Manual changelog MINI+ semi-assembly
4Original Prusa MINI+ semi-assembled
STEP 1 Version history
Versions of the MINI+ semi-
assembly manual:
11/2020 - Initial version 1.05

Original Prusa MINI+ semi-assembled 5
Building your MINI+

Building your MINI+
6Original Prusa MINI+ semi-assembled
STEP 1 Preassembled vs kit version
Important! There are two versions of the Original Prusa MINI+. Before you
continue, select yours:
Semi-assembled version: the printer is almost assembled and requires you to
connect the major parts together. You can continue using these assembly
instructions.
Kit version: you have to assemble the printer using individual parts from the
ground up. Please continue using the online version available at
help.prusa3d.com/MINI-kit or you can use the PDF version included on the
silver USB drive.
STEP 2 Different hardware revisions
There are more hardware revisions of the XZ-axis, please check the following
photos to select the appropriate assembly procedure:
The XZ-axis has the opening on the right, continue using this assembly guide.
The XZ-axis has the opening on the left, jump to the following guide Building
your MINI and early MINI+

Building your MINI+
Original Prusa MINI+ semi-assembled 7
STEP 3 All the required tools are included
For this manual, please prepare:
2.5mm Allen key (1x)
Mini bag of Haribo bears (1x)
Only the Allen key is required for the assembly. Other tools will be used for
maintenance of the printer, see the enclosed handbook part for more information.
No soldering or wire crimping is required.
Keep the bag with the Haribo bears closed for now and hide it! Unattended bags
tend to mysteriously disappear.
STEP 4 Use labels for reference
Most of the labels are scaled 1:1 and can be used to identify the part :-)
For identification of the most common screws, nuts and PTFE tubes, you can also
use the enclosed letter, which contains the Prusa Cheatsheet on the other side.
You can download the Prusa Cheatsheet from our site prusa3d.com/cheatsheet.
Print it at 100 %, don't rescale it, otherwise, it won't work.

Building your MINI+
8Original Prusa MINI+ semi-assembled
STEP 5 We are here for you!
Lost in the instructions, missing a screw or dealing with a damaged printed part?
Let us know!
You can contact us using the following channels:
In the online version, use comments under each step.
Use our 24/7 live chat at shop.prusa3d.com
Write an email to [email protected]
STEP 6 XYZ-axes parts preparation
For the following steps, please prepare:
XZ-axis assembly
M3x40 screw (1x)
M3x20 screw (1x)
M3x12 screw (1x)
Note the second M3x20 screw in the package, will be used later on.
The list continues in the next step...

Building your MINI+
Original Prusa MINI+ semi-assembled 9
STEP 7 XYZ-axes parts preparation
For the following steps, please prepare:
Y-axis assembly
Foam block or foam pads set (1x)
STEP 8 Foam pads - preparation
Gently push all the pads out of the block.
You will need five foam pads for the following steps.
Keep the remaining sixth pad as a spare.

Building your MINI+
10 Original Prusa MINI+ semi-assembled
STEP 9 Foam pads installation
Peel the protective film from all pads. Be careful, there is glue (adhesive) applied on
the pad.
Lay the XZ-axis carefully on its side and the glue the first foam pad into the groove
on the bottom side of the electronics box.
Rotate the Y-axis so that the heatbed is facing down. Put a soft pad or cloth
underneath it to prevent scratches.
Glue four foam pads onto the ends of the frame's aluminium extrusions, like in the
picture. Mind the correct orientation.
STEP 10 Opening the box with the electronics
Make sure that the Z-axis is in the upper position. If not, using your fingers turn the
leadscrew and move the Z-axis up.
Release and remove the M3 screw on the box with the electronics.
Remove the printed cable cover.
Lift the electronics cover slightly. Before you remove it completely, pull it first
towards the vertical aluminium extrusion to release both pins from the slots (holes
on older design).
Keep the box opened, we need to connect multiple cables throughout this manual.

Building your MINI+
Original Prusa MINI+ semi-assembled 11
STEP 11 Connecting the LCD cable
For this step please prepare the LCD cable (flat grey).
Take the LCD cable and push it through the hole in the box with the electronics.
Make sure the "tooth" on the connector is facing up.
Make sure the cable fold in the connector is facing up.
Connect the LCD connector to the board. Mind the orientation of the connector,
there is a notch on one side (see the arrow).

Building your MINI+
12 Original Prusa MINI+ semi-assembled
STEP 12 Connecting the Y and XZ-axis assembly
IMPORTANT: Read the following lines carefully. You need to align all three silver
M3nE nuts in the Y-axis assembly with the correct counterpart holes in the XZ-axis
assembly!
There are a total of three M3nE nuts in the extrusion:
The first (the longest) on the right will be used to connect both parts together
using the M3x40 screw.
The second (the second longest) will be also used to join parts, but using the
M3x20 screw.
The third is located in the top part of the extrusion (not visible in the picture).
The instructions on this one will be provided later on.
Do not insert any of these screws at this time. Wait for the instructions in the
following steps.
The second photo shows the inner side of the XZ assembly, which will be in the
direct contact with aluminium extrusion and the silver M3nE nuts. Make sure the
first nut fits inside the "clamp".
Take a look at the small hole on the bottom edge. We will use this hole in the
following steps to guide the cable from the Y-axis motor.

Building your MINI+
Original Prusa MINI+ semi-assembled 13
STEP 13 Joining the parts together - preparation
Locate the Y-axis motor cable placed in the extrusion and pull it out carefully.
Take the rubber band off from the cable, guide the cable below the extrusion and
out (see the picture).
Move the heatbed all the way to the right.
Place the right M3nE nut approximately in the middle of the extrusion's length, but
make sure it is not under the heatbed structure.
STEP 14 Protecting the LCD cable
WARNING: From now on proceed carefully while moving the XZ-axis. The LCD
cable is facing down and might get damaged.
In order to protect the cable, please follow the instructions below. Also, don't try any
other orientation, because it will complicate the assembly.
Carefully lay the XZ-axis on its side (see the picture) and start wrapping the LCD
cable around the box. Don't stretch the cable.
Now, tilt the axis back to get better access inside the electronics box and gently
insert the cable in. Make a loop under the power button cables. Note, that this is
only a temporary solution.

Building your MINI+
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STEP 15 Joining the parts together - phase 1
Move the XZ-axis closer to the Y-axis so that the Y-axis motor cable reaches the
electronics.
Guide the Y-axis motor cable through the hole in the electronics box. Do not
connect the cable to the electronics yet, we'll connect it later.
Push both parts together and try fitting the "clamp" (XZ assembly) directly on the
M3nE nut, which you have moved to the centre of the extrusion.
WARNING: Be careful not to pinch the Y-axis motor cable between both parts!
Use the M3x40 screw to connect both parts. In case you can't reach the thread of
the nut, wiggle with the screw a bit inside the plastic base of the printer. DON'T
tighten the screw fully yet!
STEP 16 Joining the parts together - phase 2
Take the second M3nE nut from the left and move it all the way to the right, use the
Allen key and gently push it in. There is a notch inside, which will align it properly
for the second screw.
Use the M3x20 screw and again tighten it just slightly, but ensure you have
reached the nut. DON'T tighten the screw fully yet!

Building your MINI+
Original Prusa MINI+ semi-assembled 15
STEP 17 Joining the parts together - phase 3
Now, take the M3nE nut in the upper part of the extrusion and slide it under the
steel plate.
Make sure the hole in the nut matches the hole in the plate. Use the Allen key to
align it.
Fix both parts together using the M3x12 screw, tighten it slightly. DON'T tighten
the screw fully yet!
STEP 18 Aligning the XZ-axis assembly
In this step, you will move the entire XZ-axis, avoid pushing (grinding) it against the
aluminium extrusion, or you might scratch it. Leave a small gap while moving the
parts.
Rotate the back of the printer towards you.
Push the heatbed all the way to the "front".
Hold the Y-axis assembly.
Move the XZ-axis assembly to the back.
There is a notch, which indicates the correct mutual position of both parts.

Building your MINI+
16 Original Prusa MINI+ semi-assembled
STEP 19 Final tightening
Once the parts are aligned, tighten all screws in this particular order:
First, the M3x12 screw at the top.
Second, the M3x40 screw on the side.
Third, the M3x20 screw on the side.
STEP 20 Haribo time!
Arrange the bears in a similar
pattern as in the picture.
Your package might contain fewer
bears. In such a case, run
immediately to the nearest candy
store! The exact dosage is
absolutely critical!!!
Eat the upper row, leave the others
for the next stages.
I said, leave the others!

Building your MINI+
Original Prusa MINI+ semi-assembled 17
STEP 21 LCD parts preparation
For the following steps, please prepare:
LCD assembly
M3x20 screw
Note there is a protective film on the screen, keep it on until the end of the
assembly to prevent scratches.
STEP 22 Mounting the LCD
First, carefully tilt the printer on its side. See the picture.
Place the LCD into the LCD holder. There is a notch, which fits inside the printed
part on the printer.
The design allows you to tilt the LCD into multiple positions. You can do it now or
later.
Use the M3x20 screw to connect both parts together.

Building your MINI+
18 Original Prusa MINI+ semi-assembled
STEP 23 Connecting the LCD
Carefully remove the free end of the LCD cable from the box with the electronics
and guide the cable between the Y-axis motor cable and the extrusion.
Connect the cable to the board on the LCD. Mind the correct orientation of the
connector. Use the notch as a guide
Insert the connector in the socket on the board. Make sure it is all the way in.
STEP 24 Guiding the LCD cable
Gently insert the cable inside the
extrusion. Leave some slack outside
near the LCD, so you can tilt it later
on.
Pro tip: to insert the cable in the
extrusion carefully bend it into two
halves along its length.
STEP 25 Connecting the Y-axis motor
Gently pull the Y-axis motor cable into the electronics. Do not stretch the cable. Do
not use excessive pulling force. You can damage the cable.
Connect the Y-axis motor cable into the empty slot in the top row on the Buddy
board. Create a loop with the rest of the cable like in the picture.

Building your MINI+
Original Prusa MINI+ semi-assembled 19
STEP 26 Connecting the heatbed cable
Take the cable bundle from the heatbed and guide it into the box from the top,
there is no dedicated hole. Connect the individual cables to the board:
Thermistor (H)
Heatbed heater
Gently push the cables inside the box and position the wrap near the top left corner,
where most of the cables enter the box.
STEP 27 Filament sensor (optional)
Some of the following steps are
marked as optional. If you have a
printer without the filament sensor,
please skip to the step Covering the
electronics
For the following steps, please
prepare:
Filament sensor (1x)

Building your MINI+
20 Original Prusa MINI+ semi-assembled
STEP 28 Filament sensor installation (optional)
Slide the filament sensor onto the PTFE tube. See the picture for the correct
orientation of the sensor.
Check the position of the PTFE tube through the groove:
Wrong installation. The filament sensor is not fully pushed onto the PTFE tube.
The filament sensor will not work properly.
Correct installation. The filament sensor is fully pushed onto the PTFE tube.
Now, tighten the screw gently to ensure the sensor won't slide from the PTFE tube.
Use a piece of filament and slide it through the filament sensor to ensure there is no
deformation of the tube. In case of any resistance, release the screw slightly.
STEP 29 Connecting the filament sensor (optional)
Guide the filament sensor cable behind the extruder cable bundle and the heatbed
cable bundle. Connect the cable into the last empty slot in the right row on the
Buddy board.
Arrange the cable according to the last picture. Keep in mind that the electronics
cover must fit into place.