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Geeetech A20M Review – A Dual Extruder, Color Mixing 3D Printer

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Geeetech A20M 3D Printer Review

Geeetech A20M 3D Printer SamplesClick on to Enlarge

Hey Karl right here with a 3D printer evaluation. I do know it has been some time for a printer assessment and grateful for Gearbest sending the assessment unit. They shipped me the Geeetech A20M a single nozzle, mixing, twin extruder 3D printer. Man that was a mouth full. It’s a comply with as much as the A10M which is analogous however a smaller construct quantity. The A20M clocks in with a 255x255x255mm construct quantity. My final foray with a multi materials printer was a Tevo Tarantula and it was mildly profitable. I didn’t understand that this was a mixing extruder and the implications. I’ve finished some very cool wanting prints resulting from the truth that it’s a mixing extruder.

I all the time come to anticipate some QC points with these low value printers. However I’ve to say that this printer has had probably the most. Let me listing with fixes

  • Z stepper motor bent…..substitute z stepper motor
  • Fan for half cooling died…..designed new elements cooler and changed with 40mm axial fan
  • Fan won’t shut off any extra…..nothing to do however set up change to show off manually
  • 2040 that the mattress rides on is wavy and wanted changing….changed with some 2040 that I’ve available.
  • Stepper drivers wanted vref adjusting.

I all the time be a part of the Fb group. I see 1 perhaps 2 points at a time on 1 printer. One good factor is Geeetech appears to all the time make it proper. After sale help is great. However please be suggested that when buying from Gearbest that they’ll ship any alternative elements, and never Geeetech direct. Please maintain that in thoughts. I’ve additionally seen the Geeetech representatives help with resolving points with different distributors despite the fact that they didn’t purchase from Geeetech instantly.

  • 255x255x255mm construct quantity
  • 24V System
  • Bowden Type
  • Not an all metallic hotend
  • 1.75mm filament
  • Principally extruded aluminum body
  • Particular nozzle to scale back purge
  • Filament runout detection
  • Energy Fail
  • Actually Loud Followers….hehehehe
  • Tremendous Plate….aka diamond glass aka ultrabase…aka greatest construct platform imo

Geeetech A20M BuildClick on to EnlargeGeeetech A20M User ManualClick on to EnlargeGeeetech A20M dual extruder board power supplyClick on to Enlarge

The construct course of was not horrible however for a primary printer it might be difficult. 1 double sided paper was included for directions. It took about an hour when all was stated and executed. I needed to tighten all of the eccentric nuts with the hotend carriage being the toughest. I assumed one thing obtained bent and I lastly realized that I needed to maintain the bolt as a result of it was spinning with the nut. There have been a pair additional bolt holes that helped maintain on the shroud and that i added these to maintain from wiggling.

Boy I used to be stunned to see Scott Lahteine aka thinkyhead publish modified firmware for the AXXM household of printers on fb. Scott is a serious contributor to the Marlin undertaking. He forked the firmware from Geeetech and began making enhancements right here. Since then Geeetech has taken in his modifications into his department. Fortunately Geeetech is sharing all their code and the enhancements that they’re making are serving to the primary marlin department as nicely. Kudos to Geeetech. I extremely advocate upgrading the firmware as quickly as you get it should you determine to buy. One in every of my favourite options in marlin is allow now, child stepping. Child stepping lets you modify the Z peak on the fly to get that good first layer. Simply after the print begins its first motion double press the management knob after which you possibly can modify the nozzle up and down very slowly. I’m unsure what comes from the manufacturing unit now however it gained’t harm to flash the newest from GitHub.

Geeektech Color MixerGeeektech Color Mixer ProgramGeeektech A20M Gradients 3D PrintsPersonal samples (left and middle), Macki FB Group member (proper)

The print on the left just isn’t cleaned up and straight off the printer, whereas the one within the middle is likely one of the first prints with Z wobble.

One of many cool issues that may be executed with this printer is slowly transition from one extruder to the opposite. You’ve gotten the power to set a transition by means of the menu and with the software that they developed. With the device you possibly can go one step additional and do a number of gradients like within the image above. I did two transitions from orange to yellow after which again to orange. Please take into account I used to be nonetheless tuning this printer at this level. I just lately put in a function request so you would do a number of gradients with a number of instruments. What I imply by that’s in case you are doing a two colour print I might gradients one software a method and the opposite device the opposite method one other approach.

3D printer gradients towerClick on to Enlarge

Not all filaments mix collectively completely as you’ll be able to see within the image above. Or perhaps I didn’t print scorching sufficient to combine properly. Within the image above I used to be mixing brown and blue and I’ve obtained a bizarre impact and the filaments didn’t combine nicely. It’s a cool impact the place the brown was totally on one aspect and blue on the opposite. I used to be additionally testing the construct peak to its max and you may see that by the highest I used to be not capable of print the whole 255 mm. I used to be solely capable of print 250 earlier than I began getting points.


I designed this stl file to assist check mixtures. It’s 100 mm tall and every rib is 10 mm. This manner you possibly can experiment mixing filaments to seek out your required shade/combination. So if making an attempt the combination your to realize ends on the 4th rib you already know you want a 60% 40% combination. I actually need to do extra experimenting with mixing totally different sorts of filaments. I did a couple of mixtures thus far. I hoped that mixing a transparent PLA with a strong would improve shininess like a silk filament and was mildly profitable.

Keep in mind roygbiv.


Lastly the half that I needed to share with you probably the most. OK….So the A20M comes with a 2 shade mixing hotend.. You may assume to your self that we will do solely 2 colours. WRONG. You possibly can setup digital extruders with predefined mixtures in your beginning gcode in your slicer. I ended up making a information within the Fb group with all of the settings and a small the best way to. It wasn’t precisely straight ahead so I shared my experiences within the information. You possibly can argue that you could have 100 totally different shades however it’s troublesome to actually see variations of a pair %. As a place to begin I selected 5 and they are often tweaked from there. 100/zero 75/25 50/50 25/75 and zero/100. Good even numbers. You’ll be able to see within the prime proper-hand nook I’ve received 5 totally different extruders obtainable.

Geeektech-a20m-multi-color-printingClick on to EnlargeGeeektech-a20m mult -color printing testClick on to Enlarge

Right here on this image was of my first check with digital extruders. I didn’t have a large enough purge block so the check cubes are a inconsistent. I loaded white and black into the printer after which assigned every dice a special digital extruder.


I did a reside stream on my YouTube channel and on the finish I used to be displaying the place I used to be testing out taking an image in inkscape and changing down to 5 colours to make printable. I by no means did print it however I feel it’s a proof-of-idea and there’s a snapshot above.

Prior to now when establishing Cura it has been fairly straightforward and I used to be capable of dial in a printer in a short time. I’ve a information that I’m engaged on exercise like I discussed beforehand however will share a few of the aha moments.

Jam jam jam jam jam jam….I fought this for a very long time considering that I used to be getting a jam. Take every thing aside clear begin once more. I wasn’t truly jamming in hindsight. The a20m has a three:1 extruder for a cause. It takes a whole lot of drive to push filament by means of the hotend. With that being stated you must tighten the gear that pushes the filament via the nozzle almost all the best way. I’ve mine set to max. I can barely load and unload the filament. As soon as I did this I had no extra jamming points. Took a very long time to determine this out.

Stringing took some time to determine for me. Prior to now all I did was modify temps retractions and air move and be carried out. Largest factor I did to resolve that is improve my journey velocity to 150mm/s in addition to earlier settings.

From the manufacturing unit the printer seems to have a problem with the e-steps in firmware. The extruder is about to 340 steps per mm in firmware. To push 100 mm the stepper is meant to take 34,000 steps. I ran via the calibration course of and calculated with one filament that I wanted about 420 steps per mm. That may be a 20% do delta. You’ll be able to both calibrate and proper the e-steps or modify the movement. I opted to regulate circulate. I set my stream to 115-120 for many filaments however I had one which I needed to regulate right down to 105 or it was pushing approach an excessive amount of out. With a single extruder setup you possibly can modify circulate on the fly. However proper now on this printer once you modify the stream it applies to each extruders

For my part I solely assume there’s one flaw within the design of this printer and that’s the distance from the Z stepper motor to the bracket that holds the Z nut. Sometimes they’re farther aside and permit for somewhat extra forgiving in Z mechanism. It took me some time to get this all lined up and eliminate the Z wobble. A simple repair is for Geetech to implement it to maneuver the on off change and place the Z motor within the physique to extend the space. They must set up an extended lead screw.

They supply a particular nozzle with this printer. Solely obtainable via Geeetech. I used to be curious as to why and Bruce on the Fb group nailed it. They designed a nozzle with mk10 threads however a lot smaller inside quantity so much less filament must be purged. Right here is his publish quoted the place he in contrast.

I printed some purge exams. at zero.20mm layer peak. ( simply lengthy rectangles 20mm vast)

I used to be switching between a darkish Blue, and White.

with the previous type geeetech nozzle, it took 30mm x 20mm to purge out the blue. With the MK10, it took 160mm x 20mm to purge !!!! 5.33 occasions MORE purge to modify colours.

So, we do some math. The quantity contained in the Geeetech nozzle is 28.27 mm³. The quantity contained in the MK10 nozzle…. 150.79mm³. Roughly 5.28 occasions the quantity.

So the maths works out. 5.28 occasions the quantity, 5.33 occasions the quantity of purge.

Okay, properly, that , to me, says that the MK10 nozzle on A10M or A20M for colour printing, is just about UNUSABLE.

I suppose in the event you’re solely printing one shade, or perhaps gradient prints, it’s “ok”. However, even the gradient prints will endure , as a result of it is going to take 5x longer to vary colours, so you would need to account for that distance when calculating the gradient/layer peak change

Thanks Bruce!

I actually like mixing nozzle now that I’ve had time with one. And from wanting on the mixing software program I might guess they’ve a three materials within the works.. The potential for experimenting with not solely colours however totally different supplies is superior for my part.

It took me a very long time to get dialed in. Including a second shade/ mixing hotend will increase the problem. General the printer has been truthful.

The excellent news is Geeetech sells the recent finish by itself. This coupled with a pair three to 1 extruders can flip any printer right into a multi-materials mixing beast.

I’ve spent almost three months tinkering and doubtless 2kg of filament. First month was fail fail fail till I noticed the extruders have to be tremendous tight. Take into account I solely get a pair hours an evening after the youngsters go to mattress and “jams” take some time earlier than they happen. Then it was on to fixing the mechanical stuff and testing.

I nonetheless need to play with mixing extra. A number of colours are cool, however waste a lot filament.

Now the query is… would I like to recommend this printer. My reply is perhaps. I see fairly a number of actually good prints on Fb proper out of the field however I didn’t expertise that. The check prints printed properly however have been underneath extruded and had a Z wobble. If I used to be not seeing the success and solely this one pattern I might not advocate. I can say that the hotend and the extruders are good so in case you are the tinkering sort I undoubtedly see them as a pleasant improve to an present printer….simply crank right down to seize the filament tightly.

That’s all I’ve. I actually respect GearBest and their endurance whereas I put the A20m by means of its paces. You should purchase “GEEETECH A20M Mix-color 3D Printer” from them for $349.99 presently.