|Part/Model:||Anet A8 Filament Guide Arm|
|Layer Height:||0.2 (Adaptive)|
|Notes:||Still needed blue tape to assist with bed adheasion|
|Final Thoughts:||For a first time printing in ABS was happy with the results, design is simple and effective and will serve the purpose well.|
I needed a new filament guide for the Geeetech as I broke the guide that came with the machine when I bought it and since then have been using a very agricultural stop-gap solution in the form of a small bar clamp just to assist with the filament being guided into the top of the extruder. The clamp was never meant to be a permanent solution for the broken part and so I went on the lookout for a suitable replacement for the wrecked filament guide.
While I couldn’t find an exact replacement of the busted part to download and print, I found a suitably functional solution for what I needed and one that would be a step up from the clamp. Found on the Thingiverse and designed by DevDorian, it is a simple ‘arm’ which slips over the top of the frame and is then held in place with a single nut and bolt to stop it from potentially sliding around. As the frame on the Geeetech is slightly different to that of an A8 (which is what this is actually intended for) a new hole needed to be drilled into the acrylic to allow for the fixing nut and bolt to be put into place for securing the arm. This stops any movement caused by the back and forth motion of the X-carriage itself.
From the mounting block, which is fixed to the frame itself, is the arm which extends out and offsets the filament from the surface of the frame and places it on a common plane with the input for the extruder. At the end of the arm is the guide loop (I don’t actually know the correct term for this bit but I’m calling it a loop), itself is an elongated circle as opposed to a regular symmetrical circle which was originally on the i3, in my opinion this tends to suit the movement of the extruder on the carriage more-so than just a regular circle would.
Material used was an unbranded ABS in neon yellow. I make a habit of choosing bright, highlighted colours for parts which are intended to be interacted with by the user, in this case there will be filament fed through the opening. The bright colours are used to literally highlight an area which must be given attention, hence the colour choice of neon yellow. ABS was the preferred material as the guide is going to have lateral loads put on it during printing, I wanted something more durable than PLA to ensure it wouldn’t just snap after a handful of uses.
The ABS is able to flex enough without breaking, this bend in the guide arm is just enough for it not to snap and still guide the material properly. Feeding the material in from above would suit this particular design (of filament guide) better as there wouldn’t be as much lateral load from the material coming in from the side and then being pulled downwards by the extruder. Having the spools of material directly above the printer and feeding downwards is something maybe to consider in the future.
Now I have a confession to make, for the amount of printing that I actually do I have never actually used ABS for anything printed prior. I’ve done loads of other materials, PLA (obviously), PETG and flexible materials but I have always been less enthused about ABS due to the difficulties that are associated with working with the material itself. As a result, I’ve need rushed into printing with it nor really had a need to print with it either.
So what has changed? Why all of a sudden urge to take a plunge into the world of ABS? There’s a few reasons actually – 1) as I mentioned earlier, I needed a durable material for the part itself; 2) the CR-10 is dialled in nicely and printing really well at the moment so it makes logical sense to try this notoriously difficult material on a machine which is operating well and 3) As I got a roll of Neon Yellow ABS thrown in for free when I bought my latest printer, the Tevo Tarantula, I had nothing really to lose.
One of the most important things to note is that this being the first time I having printed in ABS I was going to be ‘pushing’ the CR-10 with temperatures it had never been subjected to before but in theory should cope with fine if the manufacturers specs are anything to go by. The hot end was always going to be fine, as expected, when reaching the required temperature of 220°C with no issues. As for heating the bed to the setpoint of 100°C this is where the printer started showing its limitations.
Starting the gcode from cold, the heated bed took so long to warm up that it would constantly time out causing temperature time out errors from the marlin firmware. The only way around this was to preheat the bed manually and then gradually increase the temperature set point incrementally. I had to first start at a point where I knew the bed could reach the temperature, 70°C, then I was simply going up by 5°C at a time, waiting 5 minutes until the temperature was reached and then increasing a further 5°C all the way until 100°C was reached. This was a tedious process and took the best part of half an hour to complete. It leaves me asking the question, do I change the firmware to allow more time before the temperature time out or do I change the heated bed to something which doesn’t take forever to heat up for printing in ABS? At the time of publishing this I still have yet to make a decision but I’m leaning towards the less shit heated bed option.
In the end I ended up with about five failed attempts at printing this part with the most common issues being bed adhesion, either the corners of the part were curling up and warping or the part was just not sticking to the bed at all ending up in a pile of ABS spaghetti. Eventually with enough tweaking of the settings, bed tramming and blue tape a print eventually stuck.
The overall print quality off the CR-10 for a first print ABS was encouraging. I followed the good advice that is littered all over the web for printing in ABS such as printing without a part cooling fan and printing in an enclosed area, luckily enough the CR-10 already lives in an enclosure. The outside air temperature was around the 9°C mark and inside the enclosure was a constant 33°C or there abouts for the duration of the print, having the machine in its enclosure proved to be a big advantage and I’m sure eliminated many ABS printing headaches.
There were only a couple of quality issues with the finished product, a small segment of a single layer separated and some of the corners warped a tiny bit, I didn’t actually notice the warping until the part was removed from the bed and had the part laying on a flat surface.
An unexpected casualty of printing was the EZABL probe mount. This bracket which holds the sensor to the X carriage is printed from PLA and obviously got too warm, at such relatively high temperatures, and with the weight of the probe caused it to bend out of shape. To be honest, this probe mount was only ever a provisional fix many moons ago and really should be made from ABS also. In a positive twist, it’s a good reason to reprint this part in the correct material. Surprisingly though, despite also being made from PLA, the fang cooling duct were not affected at all by the heat and did not succumb to the same melty fate at the ABL sensor. If I am going to be printing more frequently in ABS, which I intend to do, then this part must reprinted in ABS before it goes blob too.
The Anet A8 filament guide arm is simple in its design and functionally effective. While it may not have been intended for use on the Geeetech specifically it was made to work with no compromises and complements the Prusa style frame fittingly. Additionally printing in ABS, while challenging, is something worth the effort for and will becoming more frequent out of the workshop.