Flexion Retrofit Kit Review

Wanhao Duplicator I3 Extruder Upgrade

My Monoprice Duplicator I3 V2 3D printer has been under extruding and I needed a way to print flexible filaments. I researched many solutions like the Flexion Single Extruder, Bondtech QR Universal Extruder and the E3D Extruder Upgrades.  I read articles and watched YouTube videos reviewing each. In this article I will be reviewing the Flexion Single Extruder and providing my thoughts and experience with the flexion.

My Choice

I decided to go with the Flexion based on price and ease of installation.  Next I looked into where to make my purchase and decided to purchase it directly from the manufacturer DIABASE for $149 plus free shipping.  While others such as the Titan E3D where cheaper they required more modification of my printer.  The only other Extruder Upgrade Kit that came close was the Bondtech, because it like the Flexion came ready to install on the Monoprice Duplicator I3 V2 3D printer.  What impressed  me most about the Flexion was its ability to print flexible filaments with ease and the excellent reviews given by other reviewers.

Flexion Function

So, what did DIABASE do with Flexion that makes it so special? While it does have a radicle look, there are really two main things achieved by this extruder assembly.  First it maintains control of the filament throughout its journey through the extruder by use of dual PTFE tubes. Second and most importantly is its use of a cam dial and cam follower screw which replaces the old spring loaded tensioner arm.  The cam dial is adjusted from 1 – 4 based on the type of material being extruded. Also, included was a roller brush for continually keeping the driver roller clean.

Installation and Use

The Flexion came in a small black box held securely in place by a shape fitting foam container. The Flexion website contained very easy to follow directions for installation.  I didn’t know about the direction on the website at first though.  The box contained no instructions only a sticker explaining what number to set the cam dial on based on the type of filament. After trying to follow a YouTube video to explain installation and I turned to the manufacturer support website.  I was then able to quickly install the extruder upgrade.  Installation took about thirty minutes with the proper instructions.  Be warned though the heater and thermal sensor cables are extremely fragile and should be moved only with extreme care.


  1. When properly leveled, prints perfect first layers
  2. Easy to install
  3. Flexibles’ print with ease
  4. Filaments don’t get jammed
  5. The Duplicator I3 is faster and prints at higher resolutions
  6. Comes with 3 nozzles – 0.3, 0.4, 0.5 mm
  7. A roller brush for continually keeping the driver roller clean


  1. No instructions come with the upgrade
  2. The hot end is not all metal (Can be added with the “Flexion HT
    High-temp Flexion Extruder kit“)
  3. You have use the software to load and unload the extruder
  4. The Flexion is not cheap

Final Thoughts

So, would I recommend this upgrade? I love this hot end! This printer hasn’t worked right for months and now  it’s working great!  Flexion made my printer great again.  Ok, maybe I went a little too far on the last, but all jokes aside the Flexion extruder for the Wanhao Duplicator I3 is an excellent upgrade for those that can afford it.  It will give you the ability to print flexible filaments and improve the resolution and speed of your PLA and ABS prints.  I have not tried nylon or PETG as of yet but I am told that it does well with both.

3d printer extruder3d printer upgradesflexible filamentflexion
Comments (10)
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  • Michael Perkins

    Looks like a cool upgrade

  • Richard Bynum

    I’m wanting to print with flexible filaments to make some tires for my R/C truck and cars. Also wanting to print with nylon for spare R/C parts. Good to know about these extruders and the hands-on review of this one. Thanks!

    • Henry Jolly

      I could print tires so easily!

  • Ronan

    It looks like a fine bit of kit. Thanks for review

  • Brian Martin

    Swapped and running a Benchy now on the Flexion (in PLA). At the moment I can’t test it with flexibles as I don’t have any currently how ever I do plan to get some in the future (hopefully very soon).

  • Tom Baxter

    I’m glad that you are happy with the results of your upgrade. I could not justify spending that much to upgrade a printer in that price bracket though. It’s like 1/2 the cost of the printer itself. I have an MPSM v1 that I wanted to use to print flexible filament with. By turning off retraction and using the following print from Thingiverse, I had great results.

  • Tomasop


  • Tammy Young


  • Alan

    I added a dual Flexion Extruder to my Flashforge Dreamer. On one side I had the HT option. I have multiple 3D printer, so this was a bit of a test. I am currently in the process of removing and restoring the printer to stock. For me, it was a mistake.

    For Ninjaflex, it worked well, but so did the stock extruders. I ordered a “very flexible” filament available from Diabase, called X60, and never could get that to print, even with the Flexion. It would spin around the wheel.

    But the real reason I’m dumping it was because it really did not work well with filaments I use more, like ABS and PLA. I could get it working, but it was very fussy, and pretty much had to be finetuned for every new filament. And if a filament wasn’t very consistent in diameter, it would just stop feeding mid-print. If it was tightened too much, the extruder would not turn, too weak and filament would stop moving. When it did work, it worked well, but much too fussy for me, and on the HT side, it was even worse. I seldom could get PLA to work, ABS was better but not great. I lost maybe 50% of my prints because of Flexion problems during a print. For me, the benefits were not worth the hassles.

  • Darren

    Truly an impressive upgrade with this printer many people will like to see.