Bondtech BMG Extruder on Creality Ender 3 Pro

Bondtech, E3D, Titan and Micro-swiss etc There are so many different ways to handle the extrusion on your 3D Printer.  Without even touching the debate about whether direct drive or Bowden is better. And then if you want to print softer filament such as TPU or TPE, you can be into another minefield

First Contact

I contacted Bondtech about testing their BMG Extruder on my Ender 3 Pro. They were very accommodating and soon I had a BMG extruder sat on my desk waiting for my time.

Unboxing the extruder was simple. The components were well packaged in high-density foam. It even comes with a handy little card. Featuring a Q Code, you can scan to get the instructions for FAQ, Settings and Support. This is great as it can save ages searching for the right information on the net.

Who Reads instructions?

I’m not generally one for instructions, but in this case, they are easy to follow and concise. So I grab my tools and jump in! Choosing to fit this unit to my Ender 3 Pro. I am hoping to review the direct-drive systems for the CR10S Pro at a later date after its release.

Installation takes mere moments. It took longer to make my coffee. Assuming you have removed your filament, it is a simple case of unplugging the PSU. A word of caution here NEVER work live. Although Ender 3 is only 24V, it doesn’t take a severe shock to hurt you.

Installation Ala Extruder

PSU Disconnected and safe, I proceed to unplug the stepper motor and remove its Bowden tube. Removing the Creality extruder I put it aside for fitting to one of my other machines at a later date as it was the uprated Aluminium unit.

With that done, remove the drive gear and replace it with the brass one supplied in the kit. Ensuring to take its orientation into account along with how deep on the drive shaft needs to sit, Bondtech specifies this is important. Incorrect height will lead to poor drive or an inability to close the extruder case.

Pop the new bracket over the stepper motor and fit the extruder ensure to align the screw holes. Tighten down,  but not excessively using the new screws supplied, fit the tensioning screw with its spring and tighten following the Bondtech guide dependant on your material.

I am using PLA so screwed it down around three turns which I find works well for me. This complete, fit the extruder to the bracket on the Ender 3.

This will be perpendicular to the original mounting. Once fitted screw in the Bowden tube fitting and connect the tube, and now you are ready for the wiring connected. On my Ender 3, the stepper is wired using two pairs of wires each feeding a pair of coils in the stepper. Each pair of wires drives a step of the motor, for ease of identification we will label them A-D + and –  running left to right along the side of the plug you can see the pins to indicate their charges and change of position.

I am looking briefly into the construction of the actual extruder. The casings are made of SLS printed high-quality nylon, for low weight and exceptional longevity. Bondtech’s signature duel drive system means even pressure is maintained on the filament helping prevent snagging.

A Change of direction

Wired from the factory, the Ender 3 Pro is A+ C- one step and D- B+ for the other. Because we are using a geared extruder, we need to change the direction of rotation. The easiest way to do this is to swap the pairs over removing the plug from the stepper. Carefully remove the two outer pins swapping them over, then remove the two inner pins and do the same, your stepper motor will now drive in the opposite direction. So your plug would now be B+D-  C- A+. You can also accomplish the same by trimming the locating guides off the plug and simply flipping it over if you wish.

Hardware now Firmware

You can also change this in the Marlin firmware, but I won’t go into this here as you should ensure you know what you are doing when making changes to your firmware. Extruder fitted and wiring reversed we now need to adjust the E steps to 415 for the gear ratio of 3:1. This is easily accomplished by connecting to your printer. via its USB interface and using a program such as Pronterface.

Once connected, send the command M92 E415. This will reset the esteps on the Eeprom, then send M500 to save the new setting. Once this is done, you can check your E steps have been changed by sending the command M503, and this will report the saved settings. Look for M92 in the report, and it will display E415 if you have done everything correctly.

Now you can feed your extruder and print away! I have tried it with PLA, PETG and TPU and have had no issues at all with any breakages of the filament. The extrusion has been reliable and without flaw, allowing my Ender 3 to print at 80mms as opposed to 55mms reliably I was previously running.

Cheap Copies – Bang for Buck?

Now its also worth mentioning that the Bondtech extruder has a lot of cheap copies floating around on the internet. Curious, I ordered one and tried a direct comparison. I promise you the cheap copies are a waste of time! I had nothing but slipping filament, torn TPU where it was either too tight or too loose, and the gear ratio was not as advertised. This lead to extensive over extrusion. It went straight in the bin!

The BMG is also designed to be able to work as a direct drive unit when coupled with E3D’s V6 Hot end. I have not tried this as I do not have an E3D V6 Hotend to try it with. However, I’m sure given the quality of both components, it would be a winning combination.

So when you’re looking for a go-to extruder upgrade that will work from the box without hassle. That will arrive quickly and has excellent backup support if you need it and an amiable sales and marketing team. Go Bondtech.

The version I was supplied will fit. Mirrored versions are available.

• Creality CR-10 – CR10S and Ender 3
• Tevo Tornado;
• Other similar models

Proof of the Pudding – Bondtech

Deciding that a decent test print was in order, I got hold of Poison Ivy by Daniel Thredson Art whom you can find on Facebook.

They are not a painter. Nor even a finger painter, I decided to print the model in different colours of PLA. Also figuring that putting three or more different manufacturers through the Bondtech extruder would be a good test, especially with the wood infused PLA. Ivy herself being Green Thumwan PLA. The vines and plants are Thumwan Red PLA. The base and gravestone are Technology Outlet Black PLA, and the tree is a combination of Tianse, and CCTree wood infused PLA.

Printability

The Bondtech made hard work of printing with wood infused PLA a breeze. I didn’t have a single broken filament the whole print! As for the model itself. A little reorientation of the parts in Simplify 3D and the supports arranged to suit, and it printed well. I used a layer height of 0.2mm and an infill of 12%.One for the Shelf.

Verdict

So having lived with the Bondtech BMG for a couple of months now, and having printed a variety of brands and types of filament, I am still as impressed as I was.

I genuinely believe that a portion of the reasoning why the Ender 3 fitted with the Bondtech isn’t suffering from nozzle blockages is down to the driving force and grip of the BMG extruder. There is no build up a PLA dust on the drive gears to find its way to the hot end and block it. You can’t go far wrong with this as an upgrade especially if you plan to print exotic or pliable filaments.

Enjoyed this review of the Bondtech BMG Extruder, why not check out Will’s experience when he fitted one to his Tevo tornado or Slice Engineering’s latest Kickstarter campaign for the next generation of hot ends!