MendelMax 3 Linear Rail Upgrade With Independent Dual Extrusion (LRU-IDEX)

  • Sale
  • Regular price $795.00

The LRU_IDEX kit for the MM3 combines the X & Z upgrades from our earlier MM3 Linear Rail Upgrade with our all new Independent Dual Extruder X Axis

Independent Dual Extruders greatly simplify the process of printing  with multiple colors or materials in the same print. No more hassles with leveling your hot ends or ooze from the second extruder causing your print to fail.


  • Recirculating ball bearing linear rails on all axes
  • Brushed Stainless Steel Construction
  • New, improved Firmware
  • Reuse your existing extruders and hot ends, or upgrade to our all new BMG Dual Drive extruders and MTW Mercury Hot Ends. 
  • X, Y and Z travel should be similar, but the exact travel may vary slightly compared to the stock printers.
  • A Raspberry Pi is required for operation. 

Frequently Asked Questions

Q: I have a Create that came with a Raspberry Pi. Do I need another?

A: No. You need a single Raspberry Pi that is used to run OctoPrint and the new Klipper firmware that is required for the IDEX Upgrade. It runs on a Pi 2 or above, however things like compiling, and page load times are considerably faster on a Pi 4. These are not enough benefit to buy a new controller if you already have a Pi, but we recommend a Pi 4 if you are buying a new one. 

Q: Should I upgrade my extruders?

A: There is no real need to upgrade your extruders, however these new dual-driver extruders do offer more reliable extrusion and are pretty jam-resistant. We mainly offer them for people who are upgrading from a single-extruder printer, and need to purchase the second extruder, but if you wish to upgrade you are welcome to!

Q: Should I upgrade my Hot Ends?

A: Our new MTW Mercury Hot Ends have two big benefits: 1) They make nozzle changes much easier. It takes just a minute or two to change your nozzle. 2) Because they require much less aggressive cooling than the E3D V6 does, you can turn the fan speed down on the hot end cooling fan, which greatly reduces the printer noise. 

 Q: I only have a single extruder, will this work for me?

A: Absolutely. You will just need to purchase the second extruder and hot end. You can mix and match the new extruders with the old, so if you have a MM3 that ships with the Left extruder standard, you will need to purchase a right extruder plus a new hot end. If you have a Create that shipped with a Right extruder standard, purchase a left extruder and hot end.

Q: Does this replace the Rambo?

A: No, the upgrade includes a secondary controller that adds on to the existing electronics. The Klipper firmware synchronizes both boards.

Which Hot End?

You can select a different hot end for each extruder, so choose the best mix that fits your needs. Both choices ship with a 0.4mm nozzle as standard.

MTW Mercury: The new MTW Mercury hot end offers a number of benefits including simplified assembly, much easier nozzle changes, improved thermal performance, and improved high heat printing capabilities. It is compatible with all E3D V6 nozzles. This is the hot end that we recommend for most users. 
MTW Mercury Plus: The MTW Mercury Plus hot end offers all the benefits of the MTW Mercury, but in a high-flow configuration. It is the best choice for high speed printing, especially with 0.6mm or larger nozzles (we stock up to 1.0mm, but up to 1.8mm are available from other suppliers). It also works fine with smaller nozzles, however you will get more stringing and ringing/echoing than you will with the standard flow hot end. The MTW Mercury Plus is compatible with nearly all filaments, however we do not recommend it for Flexible filaments. We recommend the standard MTW Mercury instead.  The MTW Mercury Plus is compatible with all standard E3D V6 nozzles. No special nozzles are required.  The MTW Mercury Plus is perfect for anyone interested in high volume production printing. 


Raspberry Pi Options

A Raspberry Pi is required to use the LRU-IDEX. Because of the Raspberry Pi's pricing policies, you should consider buying your own Pi directly from any official Raspberry Pi reseller. We can also provide one for you if you wish. We recommend the Raspberry Pi 4 for best performance, however it is compatible with the Raspberry Pi 2 and above. We do not recommend using the Raspberry Pi Zero.

All required software is available to download for free. It takes about one hour to install and configure the Software and firmware. You can read the instructions to do so here. It's not difficult, and we recommend you do it yourself, however we can install it all for you if you wish.

We will download and install the latest version of OctoPrint, several recommended plugins, and configure the firmware for you. There are a couple steps that can only be completed once the Pi is installed in your actual printer, but we will take care of everything else, and we are happy to walk you through the final steps when your printer is ready. 

The MM3 Linear Rail Upgrade converts your MendelMax 3 from the V-style Wheels to the MTW Create Style Linear Tails. This eliminates most adjustment and maintenance required, and greatly reduces print artifacts, particularly Z wobble and similar effects. 

Required upgrades

Please note that the following upgrades are required for the MM3 LRU. Most MM3's will already have some or all of these, but you may need to purchase them depending on when you purchased your MM3. All MM3 kits sold in the last couple years shipped with all required upgrades:

  • MM3 Machined Bed Upgrade. If you have previously upgraded, or if your MM3 included the machined bed, you are set. Otherwise be sure to add that upgrade to your order. You can confirm you have it by looking at your Y carriage (the plate that mounts the glass print bed). If your Y carriage is 3mm (1/8") aluminum, you have the Machined Bed. If it is bent steel, you will need to upgrade.
  • Extended Vertical ExtrusionsThese extrusions add an extra 30mm of Z travel to your MM3. Most MM3's were sold with these 370mm (~14 5/8") vertical 20x40mm extrusions, but the earliest kits shipped with 340mm (13 3/8"). We offer these at our cost if you need to add them.  
  • Our new Bronze-Nut Lead Screws offer significantly smoother performance than our older Delrin nuts. They produce a significant improvement in print quality. (2 required). 
  • Updated helical couplers are required if you need to purchase the above leadscrews.

Please allow approximately one week from the time of order for shipment.