RepRapPro Tricolour Mendel

by RepRapPro, published

RepRapPro Tricolour Mendel by RepRapPro Feb 15, 2013

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Here are all the 3D printed parts for the RepRapPro Ltd version of Mendel. This is a three-head machine, so it will do colour and multi-material printing. But if you only want one colour, just leave off two extruders and drives, and the slave controller electronics...


The master version of all the files for this is on Github here:


See that link for the latest version of all the files.

The .ZIP file contains the trays of printed parts you need to make a complete RepRapPro Tricolour Mendel except the extruder. For the extruder, see Github here:


The two production trays are included for ease of printing if you have a 3D printer with a build area of 200x200mm or greater. Or the individual STL files are also included; it should be possible to print all these on virtually any 3D printer.

RepRapPro Tricolour has been specifically designed to work with three colours or three different plastics at the same time. Also we've made a lot of changes in order to make it ease to use :

-The volume and number of printed parts have been reduced so it's easier to assemble and more reliable.
-We have enhanced the widely-used Marlin firmware to allow the addition of a slave controller board to drive the extra extruders. And we are using the Arduino-compatible Melzi electronics for both the master and slave controllers.
-We've released our own RepRapPro Slicing software(Beta) in order to print multimaterial parts. Whilst Slic3r also supports multiple colours, we are currently working on modifications in order maximise multicolour print quality.
-The extruders are now specifically designed to come apart when the plastic filament being driven is in the drive the filament itself holds the drive together securely. But with no filament in it, the drive dismantles without tools for easy cleaning and servicing.
-The build volume has been increased when using multiple extruders to 210x190x140mm.
-The x-carriage is capable of supporting up to four extruders with future electronics, but three with the current generation. However this fourth extruder mount also allows for other tools and accessories, such as an extruder fan mount for higher quality PLA prints at fine layer heights.
-The Y bed is now mounted on stiffer springs and cap screws to ensure a more rigid bed and higher quality prints.
-The Y motor mount has now been redesigned to be made from laser cut MDF or to be printed and results in a much quieter machine.

  • Belt tensioners are now easy to access for improved maintenance

All the assembly and commissioning instructions are here:


That is the master version; the instructions are also on the
RepRap Wiki here:


RepRapPro sells both complete kits (and also kits containing everything except the printed parts if you want to print your own) here:


Of course, anyone else is free to do the same.

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RepRapPro Tricolour Mendel by RepRapPro is licensed under the GNU - GPL license.

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How can i use Extruder with M8 Bolt? In my country, i can't find hobbed insert use with M3 inside. Thanks

Jun 9, 2015 - Modified Jun 9, 2015

Hello I am researching on a few printers to build. This printer looks like it can be modded fairly easy. I was wanting to build a printer that is exactly like the Gmax XT 1.5 with a 16’’ x 16’’ x 18’’build volume. my question is; how do I modify this RepRapPro Tricolour Mendel to have a 16’’ x 16’’ x 10’’ build volume, and what all would need to be modified? Also, what is the current price in total for building this RepRapPro Tricolour Mendel? Thank you for your time.

When people ask about large format printers, we usually send the following:

There are quite a few problems increasing the size of an FDM (Fused Deposition Modelling) printer to larger volumes:

  1. Plastic shrinkage. PLA shrinks for hot temperature to cold about 0.5 to 1%, ABS a little more. If you print solid objects, this becomes a problem as they get larger - 1% of 10mm is 0.1mm, but 1% of 400mm is 4mm! So you have to use printing strategies to overcome this, or make sure the part is not printed solidly.
  2. As you scale up the printer, you end up scaling up everything else. To make it solid, and to move the larger parts around, so you need larger structure and bigger motors. If the bed is going to move in the Y direction, it's a lot more weight to move, and to change the direction of, quickly.
  3. If you plan to have a heated bed, you'll need a lot more power. Our current 200mm x 200mm bed uses about 120 watts of power (the bed draws 10A at 12V), and can reach 100C. 300mm x 400mm is about 3 times this size; we don't supply anything that will heat this. You could put two beds side by side, run from a separate power supply (or two), and use the Duet to control a relay to switch them on and off.
  4. Having a flat build surface, and levelling the build platform becomes even more of a problem as it gets larger.

That's not to say it's impossible, just that these things need to be considered to come up with a workable design. There are a number of printers that are larger scale, eg http://bigrep.com and http://www.dirkvanderkooij.nl/en/content/endless-process.

Another consideration is that it's often easier to increase Z height, rather than X and Y. Our Ormerod printer has a volume of 200x200x200mm, but it's easy to use longer extrusion for the Z axis, to make it taller. We have built an Ormerod that doubles Z height, to 400mm. This comes with very little extra cost; all the axes are the same weight, just more extrusion, smooth rod, threaded rod (Z axis leadscrew) and longer wiring.

Also consider what axes should move. If you have a particularly large bed, it will be heavy, so you don't want to move it more than you have to. So move the bed in Z, and the X and Y axes move the hot end, like an Ultimaker, or the bigrep I linked earlier.

There are plenty of threads on the http://forums.reprap.org regarding building large printers, and the problems people have building them.

We have recently updated our Tricolour Mendel and it is currently on sale here: https://reprappro.com/product-category/reprap-kits/

Ok that's great, is there a possibility you can send me a coupon? I tried using LOVE50. I will commit to a sale once I get that coupon

No need for a coupon - 15% off until Sunday in our Sale - https://reprappro.com/shop/reprap-kits/tricolour-mendel-3/

Guess I can't get that extended 15% coupon huh?

I don't get paid till next Friday can I please have a coupon code for 15% off for when I come and purchase the hardware kit-? can you make it a one time code/ expire it next Sunday, that would be so awesome, and I would be forever grateful. I am looking forward to doing some business!

Hi, Get in touch via email - https://reprappro.com/support-page/ and we can see what we can do for you.

This comment has been deleted.

The Hardware kits also have 15% off until Sunday - https://reprappro.com/shop/reprap-kits/tricolour-mendel-3-hardware-kit/. Make sure you are printing the correct files to go with this version. Details are in the build instructions https://reprappro.com/documentation/mendel-3/#Printing_parts_for_Mendel_3

I don't know what coupon you are talking about - We don't have a LOVE50 coupon for our webshop.

We do offer a 5% educational discount on the full retail price of our kits, but as the 15% sale is on, the 5% discount is disabled at the moment.

Ok thanks, is it possible that I Can get an Extension or coupon code for 15% off cause I won't get paid from work till next Friday?

The Y motor mount is missing -- probably because they're a laser-cut part. Still, including the DXF's would be nice.

They are included on our Github repository here: https://github.com/reprappro/Mendel/tree/master/dxf

hello, i'm interested about this machines and i would like to build my own, but i'm in colombia, could you share me any guide to build one?

Sep 30, 2014 - Modified Jun 12, 2015
RepRapPro - in reply to felifelipe

Hi, The most up-to-date instructions are here: https://reprappro.com/documentation/mendel-tricolour/

Best wishes

Edit - even more up-to-date instructions are here: https://reprappro.com/documentation/mendel-3/

Trying to print out a new extruder for my Tricolour, but the files aren't included here?
Even better yet, is there an improved extruder available?

The master version of all the files for this are on Github here:
See that link for the latest version of all the files.
The .ZIP file contains the trays of printed parts you need to make a complete RepRapPro Tricolour Mendel except the extruder. For the extruder, see Github here:

Is there an improved Tricolour Mendel Extruder? I am not satisfied with the way this one works.

We use this one on the majority of our production Mendels (there are a few with the older extruder drive design still running). The production machines all run 24/7. What about the way this extruder drive works are you not satisfied with?

would it be possible to have two hotends share a heater block

with heater block in the middle and the nozzles on either side....

Yes, this would be possible in principle, however you would then be forced to use the same material in the two nozzles and also they would both have to be on at the same time, which would mean that the one that was not being used would tend to ooze.

what electronics are used?

Is there a heatbed?

The Tricolour uses two Melzi boards and there is a heated bed.

Is this the same as the master/slave melzi thing?

Where can I get schematics, instructions, firmware, etc.?

Is it possible to have 2 slaves?

And can you use the slave board for another 3 endstops?

what would need to be done to the first RRP Mendel to upgrade the X axis to this new version?

Print out the new parts, obtain a MXL belt and obtain a MXL pulley with a 5mm shaft hole.

Why would you need an MXL belt and pulley? I already have a belt and pulley for my X-axis. It looks like I have everything I need except the larger head, extra extruders and stepper/drivers.

ajayre - in reply to

I just used what RRP used. Ask them...

You've misunderstood. I have a working machine, so I already have an x-axis belt and pulley - why would you need another one? Or have I missed something?

The carriage has been designed to be a tight fit for MXL belt. MXL belt is slightly smaller than T2.5, and so T2.5 will not fit. twisterss has modified the design, and that should work with T2.5. That can be found here: http://www.thingiverse.com/thing:129202.

Alternatively we can supply you with MXL belt and pulleys - https://reprappro.com/shop/components/mxl-belt/ and https://reprappro.com/shop/components/pulley-aluminium-18-tooth-mxl/

Simpler X carriage | RepRapPro Tricolour Mendel

So if I use this design, I need an MXL belt and pulley to replace my T2.5 - or I can use twisterss design and keep my existing belts?

Great answer, thanks.

ajayre - in reply to

No, I haven't misunderstood.

So you are being deliberately uninformative. I see. Thanks.

Aug 13, 2014 - Modified Aug 13, 2014
ajayre - in reply to

You asked me why I used the MXL pully and belt. I told you I used it because that is what RRP uses and I told you to ask RRP why. I simply copied what they did and trusted in their design. As you can see they have now given you an answer. What is hard to understand about that?

Why can't I download a item at a time??
It will for sure go wrong to print a hole "tray"!!!

You can get the individuals from github, link above I think.

Just wondering does it come with 3 hot-ends (would be amazing)

it does!

What will be needed to also upgrade the Y Frog? When I increase print speed the spring mount is what shakes on my current Mendel.

My RepRapPro Mendel is only a few weeks old, and I would like to be able to bring it up to spec with this new Mendel. Are there plans on selling a full upgrade package vs. paying for the color upgrade pack that only adds the extruders and Hot Ends to the now old carriage design?

Again the Y axis is running on MXL belt, but we've upgraded the mounts and springs to M5 from M3 to improve rigidity and to easy the issues you mention. The exact BOM is now on the wiki, but the frog itself is a slightly different design to make it symmetric and to allow for the M5 mounts.

There aren't any plans at this exact second to do an upgrade kit, but we welcome the feedback and it may happen if enough people express an interest :)

Is this new x-axis and carriage design a direct swap for the axis and carriage on the older frames?

No - it is not a direct swap. We have changed the design to offer more Z head and a greater number of extruder mounting points.

What about hardware for putting the x-carriage together is that swapped off from the old design, screws washers nuts etc?

Or alternatively list an actual BOM for this particular upgrade, the M3 and bearing hardware is easy obviously but a bit more specification on the belts pulleys and spring washers would be good. Thanks

Belt is MXL - you need 2M ideally 1/4" width. Pulleys in the kit are 17 tooth but 16/18 should do. Spring washers are M3 double coil spring washers (unfortunately these are fairly rare, but 2 M3 normal spring washers with a washer between the two should do. We'll have a small BOM at the start of each section within the instructions. This will be on the RepRap Wiki and is work in progress at this exact second.

Hello, I emailed you last week trying to source some of the parts to upgrade my Mendel to current spec, I am struggling to find mxl belt, and some of the springs required, as well as the new spec laser cut parts. Can you check up on your email and get back to me.



Yes it is definitely a neater design and looks like it would be easier to monitor and maintain the print job as well.

Any chance you could offer the hardware parts as a small upgrade set on the emaker shop and I will print the other parts myself?

It would be a good idea if they also sell an upgrade kit for the RRP Huxley.
I would be very happy :)

Unfortunately very little carries over between the Huxley and the Mendel besides the hot end and the Melzi. As such an upgrade kit would be more costly for us to produce than a regular kit. However we do produce a hardware kit where you print your own parts with your existing Huxley.

idolcrasher All of the design files for the Mendel, including the DXFs, may be found on our Dev-v1.1 branch. https://github.com/reprappro/Mendel/tree/dev-v1.1https://github.com/reprappro/M....

All of the design files for the extruder, again with part drawings and DXFs, may be found on our Dev branch,https://github.com/reprappro/Mendel/tree/devhttps://github.com/reprappro/M....

Bare with us, we're having a few issues merging all the relevant branches into the master. We're not due to ship any of the new machines for 30 days, during which time we will work on the instructions and finalising the bill of materials.

I believe the extruder can be found here:https://github.com/reprappro/Mendel/tree/master/Mult-material/Print-mendel-mult-material/Individual-STLshttps://github.com/reprappro/M...

In fact, the extruder seems to be the only STLs listed under the Multi-Color Printer on GitHub. The STLs here on thingiverse don't appear on Githhub?

I am also not sure I see dxf files for the multi color mendel.

We've just updated all the files on thingiverse, hopefully thats a little more coherent.

Nice but why not post this as four head printer, as the head mount is for four heads.

At present our electronics only support three heads although the mechanics could potentially support four.

Good Day,

It is great to see a new RepRap Pro machine!

I downloaded the STL trays you posted and noticed that they did not include the extruder. Where my I download the STLs for the extruder?

Thanks much!