Around Christmas time 2016 a friend let me borrow his Micro M3D printer. I enjoyed playing with it and decided to get my own. I came across the Anet A8 DIY printer kit and purchased on from a seller on AliExpress.com (shipped from the US warehouse). During the time I spent many hours researching information on this printer. I found out that while it is a decent printer there are some major issues with it if you do not spend about $50-60 on some aftermarket addons to make the printer work better and safer. I am going to cover what the must do-s are for this printer are and what other modifications I did to mine. They will be broken down into 3 categories: required, recommended, and optional. The required ones are the most important since they are safety related. Each category will get it’s own post since I do not have time to write them all at once. After that there will be a general write up post on the printer and tips to get it to do what you want.
The factory heat bed mosfet is severely under powered and you will burn up the connector where it connects to the board OR completely fry your Anet board. This is a manufacturer issue but for the price I am not surprised that this was an oversight. The MOSFET can be had for between $10-15 on Amazon or EBay and looks like the image below. Some people also go with a SSR or Solid State Relay but it is really personal preference as both will handle the current required to run the heating bed.
To connect the MOSFET is simple. You will have a small 2 wire plug that will come with the MOSFET, these 2 wires go to where your heat bed + and – go now. Not connect the heat bed wires to the heat bed terminals on the MOSFET. Now run 2 more wires from the MOSFET + and – to your power supply directly. This takes the load off of the Anet board and puts it on the MOSFET.
In addition to this I would recommend going from the PSU to the MOSFET with 12 Gauge silicone wire and running dual (4 wires total) 16 gauge silicone wires to the heat bed itself. There are 2 positive and 2 negative terminals on the heat bed and they are the same connection that accept 12V. If you measure the bed resistance you will get between 1.0 and 1.1 ohms on a working bed. If you have anything different then your bed is broken.
The factory power supply is also very under-powered. It is rated at 20 Amps and actually puts out around 15 Amps. This leaves very little head room for expansion. This also causes the heat bed to take forever to warm up. Replace the PSU with a 30 Amp one like the one pictured to the right. You can purchase one on Amazon with THIS LINK. After just changing this my heating times for both the heated bed and the extruder were greatly increased. I highly recommend this upgrade as it is under $20 shipped.
That is where I will leave this post. I have also put some pictures of actual Anet board failures because the users were not listening to advice about using a MOSFET and checking their connections. This is a great printer but you will need to give it a little TLC before you start printing with it.