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The incomplete REPRAP beginner's guide is an attempt to gather in one document all the basic information about the Mendel Prusa RepRap, that is available in the internet.

The reason for doing it, is that it is sometimes more practical to have some basic information gathered in one place, than trying to get fast and accurate answers, for issues that a newbie cannot even understand and express.

Mostly this work is a ‘copy&paste’ of documents and websites scattered around the Internet and Internet Relay Chat (IRC) dialogues that took place in the IRC channel #reprap, which I had the chance to log.

Although it is focused on the Mendel Prusa model, I hope it may be useful for builders of other models.

Under no circumstances should this document be considered complete.

Original document by COS_ (Konstantinos Tziampazis). You can download the pdf here.

Note: Due to user edits, this version of the document (on the RepRap Wiki) may vary considerably from the link above.


What is 3D printing?

…“3D printing is a form of additive manufacturing technology where a three dimensional object is created by laying down successive layers of material. 3D printers are generally faster, more affordable and easier to use than other additive manufacturing technologies. 3D printers offer product developers the ability to print parts and assemblies made of several materials with different mechanical and physical properties in a single build process. Advanced 3D printing technologies yield models that can serve as product prototypes.” (

…“A large number of competing technologies are available to do 3D printing. Their main differences are found in the way layers are built to create parts. Some methods use melting or softening material to produce the layers, e.g. selective laser sintering (SLS) and fused deposition modeling (FDM), while others lay liquid materials that are cured with different technologies. In the case of lamination systems, thin layers are cut to shape and joined together.” (

Reprap Mendel prusa is an FDM 3d printer. Here are some videos on how FDM works. You can find many more on youtube.

…“Industrial 3D printers are made by companies such as Objet Geometries, Stratasys, 3DSystems and Z-corp. The average price of such a printer is €10,000 or more.” (

I found these videos of commercial 3d printers:

Object260 connex

Zcorp 3D Printer 650


What is reprap? … “RepRap is a free desktop 3D printer capable of printing plastic objects. Since many parts of RepRap are made from plastic and RepRap can print those parts, RepRap is a self-replicating machine - one that anyone can build given time and materials. It also means that - if you've got a RepRap - you can print lots of useful stuff, and you can print another RepRap for a friend... …RepRap is about making self-replicating machines, and making them freely available for the benefit of everyone……RepRap was the first of the low-cost 3D printers, and the RepRap Project started the open-source 3D printer revolution. It is described in the video on the right.” (

… “RepRap is short for Replicating Rapid-prototyper. It is the practical self-copying 3D printer introduced in the video on the left - a self-replicating machine. This 3D printer builds the parts up in layers of plastic. This technology already exists, but the cheapest commercial machine would cost you about €30,000. And it isn't even designed so that it can make itself. So what the RepRap team are doing is to develop and to give away the designs for a much cheaper machine with the novel capability of being able to self-copy (material costs are about €350). That way it's accessible to small communities in the developing world as well as individuals in the developed world. Following the principles of the Free Software Movement we are distributing the RepRap machine at no cost to everyone under an open source license (the GNU General Public Licence). So, if you have a RepRap machine, you can use it to make another and give that one to a friend... …The RepRap project became widely known after a large press coverage in March 2005, though the idea goes back to a paper on the web written by Adrian Bowyer on 2 February 2004.” (

Adrian Bowyer explains his 3D printer RepRap:

There are various reprap models such as:

NOTE: you must have in mind that choosing a mendel-like model, may be hard to find specific parts when these will/may brake.

Ok, I want one

Well done! Before you make up your mind you need to make some research on the subject. After all you are a newbie …..( since you are reading this).

Before reading further, you must understand that reprap is an open source project that is under development, and requires some technical skills (from soldering to crafting). If you are excited with 3D printing only and NOT with building, I suggest you buy a pre-assembled, commercially sold machine and don’t bother reading the rest of the document concerning building and fine-tuning.

Remember …“it's generally suggested not to buy a full kit because you will have a hard time finding someone to repair the machine once it does break. All 3d printers eventually break. If you INSIST on buying an assembled machine, try: Mosaic [1] Makerbot [2]” (

Also: UP!




For assembled-ready machines please read #Acquiring

It is a good idea to read this document BEFORE you even start searching in the internet. This can save you time from unnecessary or misleading information. After reading, you may be more focused on what you want and how you are going to find it.

1st stop is the website of Here, you will find almost anything, although some info may be obsolete, other may be up-to-date.

I suggest you read A LOT. You can use the glossary to familiarise yourself with new terms (, select one of the ‘how to build’ pages ( just to get the taste of what awaits you…. Also there is a search engine within the website that you will find very useful, since the tons of info cannot be easily found through page browsing. For example type in the search field: object, extruder etc. I found it quite useful as a dictionary for unknown technical words (i.e. heated bed)

The machine I am going to focus is this :

All the necessary information about building can be found here:

2nd stop is irc:// (for chatzilla) or a simple browser-based chat interface.

Those with IRC clients, simply select the freenode server, then the #reprap channel.

In irc you will get help right away, by very experienced users. Just introduce yourself and ask your question. In irc, information is up-to-date, although sometimes you may find difficult to explain exactly what is the issue that you are experiencing. This can happen because of language barrier and lack of technical experience. But don’t worry, almost everybody is willing to help.

3rd stop is the reprap forum at Here, your question may have been already answered. Check this thoroughly.


Warning-general-2.gif.png Caution
Hazards during Construction, Assembly, Operation and Maintenance of a RepRap

Construction, Assembly, Operation and Maintenance of a RepRap should be performed by competent persons only.

NOTE: This section briefly mentions common hazards encountered with RepRaps, it does not cover all possible hazards. It is not a comprehensive guide. It is up to the reader to verify the information below, identify and research any additional relevant hazards and how to handle them. Use your favourite search engine to research any hazards applicable and how to deal with them, ask in IRC or on the forums. The reader may edit this page and add or modify as appropriate.

IMPORTANT - DO RESEARCH FIRST – example: If you have never soldered anything before and think you might want to learn how to solder, research first, find out what you need and how to do it safely. During this research you can decide whether you really want the expense of a soldering iron, solder, eye protection, Ventilation, a Respirator or other Personal Protective Equipment (PPE), storage for that equipment and a space to use it for what may be a one-off project or buy a fully assembled Printed Circuit Board (PCB) with firmware loaded and ready to go. Apply the same "research example" to all other processes or things that are 'new' to you to prevent buying something you might regret.


Some heat hazards include:

  • Hot Plastic - During 3D printing, hot, sticky, plastic (think lava >200°F) is extruded onto the build bed
  • Build beds - The area that hot plastic is extruded onto, some may be heated or hot from contact with extruded plastic.
  • Wires to the heated bed may get hot during use
  • Extruder (hot ends) - Hot metal parts with a hole for molten plastic to 'extrude' from
  • Wires to the extruder may get hot during use
  • Electronic components (stepper motor drivers, MOSFET heater bed transistors)
  • Soldering irons (during construction or maintenance) - wear eye protection, ensure adequate ventilation and other PPE requirements as detailed in the Material Safety Data Sheets (MSDS).


Ask an electrician to verify that your house or workshop is fitted with a form of electrical protection suitable for your country or region (example: Residual Current Device (RCD) or an Earth Leakage Circuit Breaker (ELCB)).
Do not modify or play with the "mains power supply". The power supply for your RepRap should be contained in a properly earthed case as supplied by the manufacturer with only low voltage DC power output.
Do not attempt to make your own power supply or modify a power supply.
Do not apply electrical power to anything without knowing: "What is supposed to happen", "what could go wrong" and "What do I do if it does go wrong".


Always consult the MSDS for the products in use. The MSDS contains information regarding Storage, Transport, Usage and Disposal of the subject chemical. The use of hazardous chemicals may apply in the following procedures:

  • Do It Yourself (DIY) Printed Circuit Board (PCB) etching - not recommended for newbies.
  • Solder - Wear safety goggles, some solder may contain lead, other chemicals (fluxes) and metals. Use Personal Protective Equipment (PPE) and all other directions as detailed in the MSDS.
  • 3D Printing - When printing using some types of plastic there may be 'fumes', 'vapours' or other emissions, use Personal Protective Equipment (PPE) and all other directions and requirements as detailed in the MSDS.


A RepRap has moving parts, you must ensure your clothing, hair, body parts and that of others (also pets and other animals) does not become entangled, crushed, struck or burned.

Before powering up and before each use, check the area around your RepRap. Ensure that there are no open containers of liquids, remove all flammable liquids and aerosols from the area. Remove any 'thing' or part of a 'thing' that is not a part of your RepRap, including but not limited to: soldering irons, cloth, plastic, string, chip (crisps) packets, cheese wheels, pizza boxes, soda bottles or anything that may become entangled or interfere with the safe operation of the RepRap.

During operation of your RepRap, stay away from and keep other people, pets or other animals away from moving parts, heated parts, motorised parts and electrical components.


In the event your RepRap or something nearby catches fire: NEVER Spray it with water. Turn the power off (at the wall)) and use a suitable fire extinguisher. Never leave your RepRap running unattended.


Consult the Prusa_Buyers_Guide. You have 3 options, arranged in ascending order of difficulty:

  1. buy a fully assembled Mendel
  2. buy one complete Mendel (or Mendel-like) kit
  3. build one (buy all the parts from different dealers)

Option 1 Fully Assembled

This option usually applies to models of Option 2 but the models are sold already assembled. However, I wouldn’t recommend it since they are delicate and heavy for shipping:

  • Mendel-like Axis and Glider from botmill
  • Mendel
  • Skb-Kiparis ltd - Fully assembled 3D printer Gen X with new verticax X axis and new generation of electronics!
  • ac123dc -stampanti reprap 3d in kit ,-- RepRap Prusa assembled and tested Italy based
  • Greg Frost Mendel - Heated Bed, Machined Pulleys, Lm8uu Linear Bearings, removable glass bed, hinged accessible wades, all metal hotend.
  • 3dStuffmaker cheap Kits and fully assembled/tested units and plastics. Shipping world-wide. Launch Sep/Oct 2011
  • Mendbot Shop fully built calibrated reprap 3d printer, Metric Prusa, SAE Prusa, Mendel, Wade Extruder, almost complete kits, fully built plastruders.”

Option 2 Complete Kit

Is the playfield for the average amateur who does not know much about electronics, crafting, soldering, engineering, programming, or does not have easy access to all the parts needed to build a machine. It is for those who have fun building plastic kit models, or for those who have some experience with tools such as screwdrivers, multimeters, dremel, solders, etc. It is for the majority (like me) who want to build a printer fast and easy.

The recipe is easy: the kit comes in a big and heavy box, you spend some time building it (lot of fun for model kit builders), you spend some time calibrating it, you spend the rest of your time printing and sharing our knowledge in #reprap.

“………Full Kits

  • BotMill - Full 3D printer kits with many free extras. Variety of colors, blue, rep, yellow, green, white, black +more!
  • Skb-Kiparis ltd - Full kit of 3D printer Gen X with new verticax X axis and new generation of electronics!
  • Kent's Strapper - risorsa italiana di stampanti reprap 3d in kit ,in versioni gia assemblate e pronte alla stampa,e kit separati di elettronica, plastica,meccanica ed estrusori
  • eMAKER Huxley - Full kits available to pre-order on indiegogo campaign. Only a few days left and limited stocks.
  • MakerGear - has been providing providing kits and accessories to the Reprap community since 2009. We offer high quality Prusa Mendel kits with all stainless steel fasteners, stainless threaded rod, precision ground stainless smooth rod, precision self-aligning bearings, heated bed PCB, high-quality printed ABS parts, RAMPS electronics, the field-tested and botter-approved MakerGear hot-end and more. 1000s of botters use gear from MakerGear!
  • - True reprapped printed full kits incl GEN6 electronics.
  • ac123dc - RepRap Prusa assembled and tested Italy based
  • 3dStuffmaker cheap Kits and fully assembled/tested units and plastics. Shipping world-wide. Launch Sep/Oct 2011 …..”


Option 3 Build from Various Dealers

Is for the more experienced builders (ex-builders of Option 2). Machines build that way cost considerably lower, about 50% less than option 2, but there is always the risk of finding parts with lower quality (like smooth rods that must be straight and very smooth). Nevertheless you have the overall quality control over each part, so you make your choices.

A reprap consists of several different types of parts:

  1. RP parts (repraped parts, that are used to mound the rods that make the frame, mound motors and x-y carriages). These are printed from another reprap
  2. Mechanical parts. Are the smooth rods (to slide the carriages) and threaded rods (to make the frame), nuts, washers, belts, bearings, springs etc.
  3. Electronics parts. The controllers of the motors. All these are connected to a main “controller” that reads the gcode from the computer and translates to motor moves. Today, the most popular electronics are Arduino with pololu shield (or RAMPS, ), Arduino with Sanguilolou shield ( )
  4. Electrical parts. Like cables, power supply, stepper motors, endstops, etc
  5. hot-end parts. This is the most tricky part to find/make. More info at
  6. The printer firmware. Sprinter by Kliment is the suggested FW for Ramps machines. It uploads to Adruino via the arduino control software
  7. The software. This includes A) the HOST software that connects the PC with the printer (repsnapper, or preferably Kliment’s pronterface), and B) the application to convert the solid model into a series of gcode instructions that your printer understands (replicatorG, or preferably skeinforge/SFACT-by Action68)

There is a list of suppliers at the Prusa_Buyers_Guide.


Assuming that you have all the needed parts, it is time to start building….


Wade's extruder

If you are making the WADE’s extruder, you will need this manual: Wade's geared extruder visual instructions

Sells Mendel

If you are making the Sells Mendel, see the Mendel_Build_Manual


Spacexula on a step-by-step building of a Prusa.

Makergear Prusa (under the series “still extruding”).

Sells Mendel video.


Here is a step-by-step guide of RAMPS v1.2 Build continued here:

some info from reprapwiki on: Gen6



Makergear Prusas

Here are a series of instructions for Makergear Prusas. They are prusas with some parts modified for better. Makergear is also known for its good quality of hotends

Soldering Skills

Improve your soldering skills


How to crimp without crimp gun How to crimp with crimp gun


How to jumpstart atx psu


Arduino drivers, control application, and install instructions (you need those to connect arduino with your computer and upload the firmware)

Installation: Step-by-step instructions for setting up the Arduino software and connecting it to an Arduino Uno, Mega2560, Duemilanove, Mega, or Diecimila.

Host Software

Pronterface host software (needs python to run), please read the installation instructions carefully.

Video tutorial on sfact & printrun from spacexula

pronterface compiled version for windows (my favourite)

Pronterface info.

repsnapper application, the all-in-one host initially written for Sells Mendel.

Skeinforge, ReplicatorG and SFACT

Skeinforge application and manual
replicatorG application and manual

SFACT is already merged into Pronterface. You can also download SFACT from here.


Sprinter firmware download it, unzip it, load it to arduino connection software, and then upload it. Remember to specify what arduino you have, from the ‘tools’ menu.

Video tutorial on sprinter by spacexula

Prusa Calculator

Josef prusa’s calculator. You need this in order to insert correctly your microsteps in firmware.


Thingiverse. This is the repository for 3d objects ready to print. You need it to download test pieces for your machine calibration. Also your main source for objects to print.

15th stop

Create a folder in your hard disk named REPRAP or whatever you like, in order to keep there everything related to reprap; from software to tutorial videos and docs for future reference. Subfolders named software, objects, videotutorials, manuals, irclogs, etc keep everything organised.

16th stop

Log in to irc #reprap and start logging…… (simple browser interface) irc:// (firefox chatzilla plugin) IRC Server: You may not know, but your query may already have been answered in there just minutes before you ask. Always check the log thoroughly.

Reprap’s bot, kthx:

17th stop


18th stop You need this to paste your problematic gcode instead inserting to irc reprap channel

Not Yet Completed

  • Building Tips
  • Advanced lessons

Troubleshooting Guide

Ask for help on the | forums or in IRC

Image Sharing

Flickr account or similar. You may want one in order to show your prints and printing problems.