Building the Anet A8 - my experience

After reading through SilentChill's build thread, I decided I needed a 3D printer as a preliminary step before beginning my own 6DOF build. It took about 5 hours at a moderate pace to put the Anet A8 kit together and start printing. It was an enjoyable experience (a bit like putting together a Meccano set) and it produces really good quality prints.

A few months ago, I purchased the Anet A8 (Prusa clone) from Gearbest for $217AUD + $15 postage. It seems to be on 'special' all the time. I paid with Paypal and it took 2 weeks to arrive in Melbourne. While, I waited for it to arrive I trawled through YouTube watching other people build it and noted anything that might be an issue.


The box was surprisingly small but heavy. The first step was to unpack and check that nothing was missing or broken. It was very well packed. The packing label was upside down which tripped me up as I opened the box upside down. All tools needed to assemble the kit are included - screwdriver, Allen keys, spanner. While it doesn't include a reel of filament, it does come with 10M of white PLA filament to get you going.

The frame is made of 6mm acrylic and held together using mostly M3 bolts/nuts using a technique known as t-bolt. Tip: when putting pieces together put the nut in the t-bolt slot first then join and insert the bolt. If you try and put the nut in once the pieces are joined you are most likely to loose the nut on the floor. This will happen anyway so make sure you are in an area where you can find them!

Part 2 coming up...

Once all the parts were un-boxed, I began the process of removing the protective acrylic paper which is on both sides each piece. OMG - it took nearly an hour to get it all off . My thumbnail was pretty beaten up by the time I had finished. Some people simply leave it on but if you are bit OCD then it MUST come off.

The first step is to check the electronics. The motherboard uses the Arduino Mega. The sketch that it comes loaded with can be replaced with an open source alternative based on what is called Marlin. The sketch is known as Skynet3D. I did eventually upload this version to my printer after it was running and working.



All the wiring has clearly marked labels so it is easy to find out where they all go. A colourful detailed layout of the motherboard wiring is on the box it came in. There is no printed manual but there are videos and assembly details on the included SD card which comes with a USB carrier. The SD card also contains some models to print/test. This step was straight forward. Tip: the power supply comes with a sliding switch to choose 110/240V - make triple sure it is correct before applying power . Many people have fried their power supply at this point. The second thing to note about the power supply is that the mains terminals are exposed and therefore not safe. Be extremely careful when wiring it up. Later on you can print you own cover and make it safer.

Part 3 following...

While I waited for the printer to arrive I got 3 Ikea Lack tables which were on special for $7AUD each. These are used by some builders to make enclosures for the Anet A8. The photo below shows the parts on this small table.







The finished kit


The printing bed comes with what looks like masking tape. This is needed for your first print so don't take it off!

Part 4 following...

The first print come out perfectly...a Chinese chess piece in the PLA filament supplied with the kit



Now the fun part (if the first part wasn't already fun) - the upgrades... The white fan duct is the original. I purchased a reel of orange Anet PLA filament from Gearbest for $39AUD including postage and printed a new higher efficiency duct.



The 12V 20A power supply that comes with the kit, I replaced with a 40A model. Some builders found that the 20A version was just too under powered. The one I got also had a built in fan to keep things cool. You can also see in the photo the glass I tried. I have now moved away from this to a Vertex mat (still in the post).



Without boring you with all the other minor upgrades one thing that just had to be done was replacing the power connector that feeds the hot bed. This connector is very cheap and under spec and together with lots of movement eventually begins to work loose and spark. One machine actually caught fire due to this engineering oversight (or cost cutting factor). So I got a few metres of heavy gauge silicon covered wire from eBay, removed the connector and soldered directly to the hot bed. You will need a pretty decent soldering iron to do this as the wire and the hot bed are really good heat-sinks.

Part 5 following...

The last upgrade to be completed was to replace the extruder (hotend) and move the stepper off the gantry and mount it to the frame in a configuration known as Bowden. In addition, I added the ability for the printer to auto level the bed itself. This is a challenging upgrade which needs lots of thought and preparation because once you start there is no going back and so you can't print something out if you have forgotten it. The main reason for the E3D upgrade was to improve speed and quality. I used a $9AUD E3D clone and a inductive sensor at $4AUD from eBay which are working fine - but they don't work with glass.

Firstly, the extruder stepper was removed and attached to a bracket



Next the linear bearings were removed from their housings and put onto a new X carriage



X carriage is now mounted ...I didn't want to cut off any belt just in case I might need to add a tensioner later



All of these designs are from Thingiverse
Next part following..

Finally...

The extruder mounted on the frame...


...and the new hotend with auto bed level sensor



A very good printer and well worth the money and effort.

You are welcome!

Here are a few links to help you out further (the ones I used):

Electronics check:


Assembly:


Solder the heatbed:


Silicon wire for the heatbed (very flexible - you only need 1M):
http://www.ebay.com.au/itm/1-Pair-1...460920?hash=item2cb0c80a78:g:CwAAAOSwaB5Xrd2x

You will also need to install a MOSFET for the heated bed so current will bypass the power supply. On YouTube search for: How to install a mosfet Anet A8 by Fiddle Electronics Reviews

For some reason I couldn't paste the link in here?

Soldering the heatbed connector and installing the MOSFET are considered almost mandatory to improve the safety of your printer. They are cheap mods which will bring you some peace of mind

I bought a sensor for self bed levelling but I have never got round to fitting it as it seemed like a pain to change all the settings. How did you do it did you have a decent tutorial for it ?

Setting up the sensor has a few points. I will briefly list the steps then post again with some more details. These are the general steps without elaboration.

(Assume no sensor - just change the Arduino firmware to Skynet3D which does almost the same as things as the orig)

1. Download Skynet3D
2. Choose your printer from a list of pre-configs without a sensor
3. Start the Arduino IDE that comes included with Skynet3D
4. Connect your printer via USB and chose the COM port
5. Upload the sketch.
Done

It is that easy. In the next post I will explain a bit more about the sensor (I have to leave the pc right now)

1. The sensor: I chose an 18mm sensor because it is more sensitive than a smaller one. This simply means that it can be positioned higher over the bed and is less finicky when trying to sense non-ferrous material like aluminium (that's how we spell it in Aus). The next issue with the sensor apart from size is whether it is PNP or NPN and whether it is normally open or normally closed. Hmmm - seems like too many choices right? Based on what I had read I purchased: LJ18A3-8-Z/BX 8mm Inductive sensor on eBay $4.90AUD posted. Couldn't really go wrong - so I gave it shot. All it needed was a 1n4148 signal diode (reverse biased) in line with the signal wire and a connection to the printer's 12V rail. I then looked on Thingiverse and found a bracket for my extruder. The Thingiverse models also give an approx. distance the sensor will be from the nozzle. This will be used in Skynet3D later on. Now that I have actually installed it, that side of auto leveling was really quite easy. Have a look at this YouTube video, I found it the best of the bunch:



2. The software: I downloaded (skynet v2.3.2 fix2.zip) from Google drive with this link:
https://www.facebook.com/skynet3ddevelopment/

This is zip file contains the skynet firmware, a copy of Cura, a standalone version of the Arduino IDE and most importantly a how to guide (which is a very good - step by step instructional). There are a couple of things to note. Firstly, even if you have the Arduino IDE on your pc, you can't use it - you must use the one that comes in the package as it has the 3D printer drivers baked in. Secondly, the main Arduino Skynet sketch needs to have a configuration.h file copied into it. So in my case I first chose the Anet A8, then within that subfolder I chose the model of my A8, then within that subfolder what type of auto-level sensor I had (or not). At first I simply chose the config file without a sensor added it into the main sketch and uploaded to the printer - just to check that everything was working. A few test prints went fine. Then I went back and, using the how-to guide, chose the new config file for my sensor, changed a few variables (info about dimensions from Thingiverse) and uploaded it. What changes you need to make are well written in the how-to guide.

I initially tried it with the glass I was using on the bed and while it seemed to auto-level OK and sense the bed distance, the actual printing was completely stuffed. I faffed around for ages trying to find out what the problem was and eventually found it was the glass. So I removed it an ordered a Vertex mat from the UK on eBay to replace it (still waiting for it to arrive). In the mean time I am using marking tape which is working pretty well and of course I don't have to level the bed.

Thanks dude doesn't sound too difficult

I have bought a different sensor LJ12A3-4-Z/BY, I will get what you have at some point and try and get it done. Does it work with an Aluminium bed ?

i bought an anet like yours but somethng went totally wrong with it, i have not touch it since 1 month, i will try to do your modifications.

thanks for all the info

fer

@SilentChill
The LJ12A3-4-Z/BY is a PNP normally open inductive sensor that can sense ferrous based material from 4mm away. When using the Aluminium bed of the printer that distance is reduced by 40%. In other words, your sensor should be fine and it would be worth testing it on 5V to see if it works above the bed. All you need for this test is a 5V supply and simply hold it above the bed to see if the detection LED on the sensor lights up. If it does and the distance is more than 1mm and the LED brightness looks normal then it will simply replace the Z microswitch without needing a diode or a resistor divider. Anything more than approx. 1mm above the bed is OK. It needs that clearance so it doesn't hit whatever is being printed. The reason I chose 18mm was the need for greater sensitivity to work with 3mm of glass on top of the bed.

The actual height difference between the sensor, bed and nozzle is not important. You don't need a vernier caliper to measure the difference between the nozzle tip and the bottom of the sensor for example (which no one seems to mention anywhere). The reason is, you initially set up your bed with a sheet of paper between the nozzle and the bed, manually. You only need to do this once. With auto bed leveling enabled, Skynet reads the differences between the sensor head and the bed at 9 different points and uses this matrix of readings as an offset for the nozzle height. Therefore, the repeatability of the readings is much more important than how high you can get the sensor to trigger above the bed. There is a test setting in Skynet which you can enable and send a command to start a repeatability test from Cura. It will take 10 readings one after the other in the centre of the bed then calculate the standard deviation between the readings. Mine was 0.002mm which apparently is quite good.

Hope that helps

@ferslash
Rather than introduce another variable such as auto bed leveling or the E3D hotend, I would concentrate on getting the original hardware working. The first test I did before putting the printer together was to hook up all the electronics and test the motors, bed and hotend. From that point you take the next step of setting up the printer mechanically such as the X axis carriage alignment. Thingiverse has an active forum where you can ask further detailed questions. All the best

Sounds good value for the price, but it seems many of its systems and components are soon upgraded .

yes, it may need upgrates... but, if you are in a country like mexico (like me) and consider a good branded printer, the prices rises like rockets, i should work more than a month to buy a makerbot

i will stick with the anet even if it will cost me some time

(on the other hand, i guess that if you buy a us$1,500 printer, you would'nt be traing to desmantle it to make repairs, i guess you have to take it to a certified shop ..)

fer

I had a Prusa i3 before that needed constantly repairs, you don't know how much time i spend on failed prints and upgrades. The cost for upgrades went up to $800, then I finally cracked... A few months ago got the UM3 extended and had nothing to repair so far! I only took apart the bowden feeder to clean dust from filament grinding. I printed some "no friction spool rollers" for larger spools and there is no grinding now either.

So happy that i just focus on the design side of parts now, knowing that the UM3 will print anything I'll throw to it!

The Anet A8 is a kit to learn about 3D printing. It is an introductory printer which doesn't need a lot of upgrades to print some fairly good quality prints especially if care is taken to set it up correctly. The mods I did were really for fun, apart from the MOSFET and soldering the heatbed which were done for safety reasons. I couldn't really justify spending lots of money on a printer such as the UM3 or Makerbot etc which will produce better quality prints out of the box. However, the Anet A8 has exceeded my expectations and I have certainly learnt a lot about 3D modelling and printing. So simply from that aspect alone it is totally worth it.

If the Anet is built with care (and a little luck) it is good little printer

@SixDegreesOfFlight - Would you mind stepping me through your settings to get the Autobedlevel working?

I set this up last night and I still consider this to be the black arts of 3D printing. So many issues with it and so much mis-info on the UberWeb. Mine is working, but I am not convinced it is setup correctly.

What I did.

1. I have a 4mm proximity sensor (soon to be changed to 8mm), it's wired to the Z Min as recommended and works fine. No issues there.
2. I've entered the Z probe offsets and when I run "Auto Home" the probe goes to the centre of the bed and does the probe thing.

All good so far.

However, regardless of how large or small I set the Z Offset (to account for the gap between probe and nozzle), my nozzle is a good 1-2mm away from the bed. It's driving me nuts as nothing I change in the Firmware (Skynet3d 2.3.2 Fix2) seems to compensate for this.

Would you mind sharing your experience/settings on this one? Many thanks

I followed this video as an example of where I am at: (Skip to 2:20 for the procedure start)