Thoughts and Tips on Assembling the ATOM 2.5EX

First off, this is not meant to be a step-by-step tutorial on how to assemble the ATOM 2.5EX kit as the instruction set provided already does that very well. Instead, we intend to touch on some of the thoughts and tips we have during the process of assembly so that hopefully some of you who are also embarking upon this may benefit, or even to share some of your own tricks and tips with us!

At some points we will like make comparisons against the assembly of the ATOM 2.0 kit so for more on that, check out our earlier posts here:

In any case, onwards!

Manuals and Getting Started

Opening the box, there should be a pack of the manual sheets and the warranty card sealed in the anti-static bag. As compared to the past ATOM manuals where it was literally a booklet it felt much easier in the end to use these loose sheets as there was no more fumbling with trying to keep the pages of the booklet open. However, it does take a fair bit more table space, though we reckon wall space if you have handy would do the trick too. For the warranty card, its a nice thing to keep and have as a easy reference of the serial number of your machine and how to reach out to ATOM (though that is as easy as it can get already).

Another new change to the packing of the small parts is that they now come in 2 handy boxes (A and B) for the ATOM 2.5. And actually there is also another box for ATOM 2.5EX parts. A nice improvement in helping to keep the small parts safe and neat though during shipping and moving of the kits, the parts do inevitably move while inside these boxes. Still a nice touch overall and helps to keep the extra pieces they ship with every kit neatly packed and within reach!

Frame Construction

Coming to the assembly of the main frame of the ATOM, this is a very very crucial step to take note of – the threaded hole of the 2040 extrusion needs to be facing outwards on the machine. This point is both highlighted in the assembly manuals and on the wrapper of the extrusion itself. If you missed on this step to realize it only much much later, it can easily be an entire day of dis-assembly and re-assembly!

But really, once you’ve removed the protective plastic, it’s easy to mix things up. Especially if you needed to put it down for a bit to focus on assembling another part. So a quick tip here would be to lightly thread an M5 30mm bolt as a temporary visual indication so you remember the orientation of things for this step.

Hot End Platform

One of the improvements over the ATOM 2.0 is the inclusion of these 2 side fan ducts which much more precisely direct the air flow they generate towards the tip of the hot end. Pretty nifty design which meant that the lower heatshield is no longer required here.

Putting the hot end platform together does tend to be a little tricky as most of the parts are rather small and so is the space to maneuver them around in. So, it’s generally helpful to have a bit of tape to temporarily hold parts in place, such as the side fan as show above as you go on placing and tightening the tiny nuts and bolts. Additionally, a pair of small needlenose pliers¬† or tweezer to help hole the nut as you screw in the bolt is going to be a life saver.

And there, all done with he lower bits!

Dual Extrusion Junction

The dual extrusion junction which sits directly above the hot end platform is another part which takes a little bit of finessing to get right. It is key to know that you don’t want to overly tighten the junction as that would squeeze the 2 feed tubes so much that they will not allow the filament to pass through easily. Instead, it is more likely you will have a bit of a gap in the junction, but use the lower bolts to secure the entire junction to the hot end platform. A handy trick here is to use a length of filament and run it through up and down the junction to see if it is too tight.

Extruder Motors and Electronics

More of a little tip here, the ends of the E0 and E1 extruder motors are actually packed with the motors themselves and not in the small parts boxes. In case you had to hunt high and low for them!

For both E0 and E1, though the manual states to install the extruder drive gear 6.5mm away from the tip, it’s actually a good idea to double check again that the curvature of the teethed gears line up nicely with the PTFE tubing of the extruder base and readjust as necessary.

For the electronics assembly, it’s actually very well documented with the steps ordered such that there is as little re-work for the addition of the heated build plate as possible. It would be good to note here that you will want to double and even triple check every single connection here, otherwise a wrongly connected part can and will fry your machine!

Additionally for the heated bed’s power source, do double check your country’s voltage settings and make sure that it is switched to the correct voltage. (We have fried things up before, no fun, trust us!)

Another thing we appreciated is that there already is a version of the ATOM 2.5EX firmware pre-loaded onto the board so if that’s updated, it would save you a lot of time in getting the necessary files and Arduino software to get it flashed in your machine. Still gonna be something which need to be done down the road with new firmware releases but as the ATOM 2.5EX is very new, its likely the pre-loaded one is the latest already.

Auto Bed Levelling

Once your machine is fully setup, one of the first operations which you need to run the automatic bed levelling. During this process, it is recommended to watch over the machine as there may be extreme spots on the bed where the nozzle may push too hard and dis-locate one or more of its magnetic rods. If that does indeed happen, you can remedy it by either stretching the effector tension spring and/or slowing down the speed for auto bed levelling.

And there you have it, you should be all set up and good to go with your new ATOM 2.5 EX!

But wait, there are a few more addition upgrades you can do too!

Extruder Motor Gears Upgrade

While the new extruder arm and base design with the additional PTFE guide tubes help better control and guide the filament’s path, they do make it somewhat harder to load/unload the filament. To solve this, the ever resourceful member of the ATOM community, Phil Xing, came up with and modeled these extruder motor thumbscrews ( These allow you to load and unload the filament without pressing down on the extruder spring and thus changing the angle of the guide tubes which make it hard for the filament to go in straight. Do remember to check that your stepper motors are disabled though, and do not force or turn anything too quickly to avoid inadvertently damaging anything.

Happy Printing y’all!

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