In the last few months alone, the budget friendly Anet A8 has been responsible for more than half a dozen fires and counting. The “It won’t happen to me” mentality is all too common and nearly as dangerous as the 3D printer itself. Often hailed as the perfect beginner machine, many reviews fail to point out the electrical problems and safety mods necessary to fix them.
On the bright side, the community behind the Anet A8 is absolutely massive. There is no shortage of printable upgrades and aftermarket products, plus a wealth of learning resources are available online, making it an excellent foundation to build upon over time. There are however some critical safety mods that should be at the very top of every owners to-do list.
Starting with the most immediate concerns, we will look at the reason(s) each mod is needed and details to help you get started. There is often more than one way to fix these problems, but we will explain the most common solutions. If you have any questions, feel free to leave a message in the comments below.
The MOSFET Board is one of the most important safety mods for the Anet A8. When the heated bed warms up, it draws a large amount of current through a small connector on the board. Since this connector isn’t rated for the power it pulls, it will inevitably melt the terminal and when it does, there is a decent chance it can start a fire.
One option is to upgrade it using a beefy XT60 connector instead, but this also means we have to solder the board. As a better alternative, a MOSFET Board is cheap, easy to install and won’t require any special tools. Once we are finished, the power for the heated bed will come directly from the power supply and bypass the connector almost entirely.
Note: Do NOT install a second MOSFET for the hotend. While this has become a common practice, it is unnecessary and creates an additional point of failure. The hotend does not draw enough current to warrant the need for another external MOSFET board.
Thermal Runaway Protection
Thermal Runaway Protection is a standard safety feature that prevents a 3D Printer from overheating and starting a fire. It is disabled on the Anet A8.
If the thermistor were to fall out of the hotend, temperature readings would report lower than what is expected. The 3D Printer would then crank up the heat to compensate and in doing so, eventually melt the heater cartridge. Thermal Runaway Protection is designed to detect such events, shutting down the machine if it doesn’t correct within a certain amount of time.
It’s easy to fix, takes less than 10 minutes and doesn’t cost a cent. There is no excuse for the company to neglect this feature, yet they continue to ship the machines without it. Take a few minutes and watch this 3 minute video (instructions start at 0:47) which covers how to install the latest Marlin firmware with Thermal Runaway Protection enabled.
There are plenty of safety concerns when it comes to the cheap Chinese power supplies included with the Anet A8. Above all else, they are just not powerful enough for the 3D Printer, unable to handle the amount of current needed for the various electrical components. Worse yet, it doesn’t even have a cooling fan on the unit, meaning it can easily overheat and burnout during normal use.
Some owners have attempted to fix these problems and upgrade the stock unit, but do yourself a favor and just replace it. When it comes to power supplies, Mean Well is considered to be the top of the line, but even cheap $18 units from brands like eTopxizu will be a huge improvement by comparison.12V 360W Power Supply - $19.99 Mean Well 350W Power Supply - $69.49
While not critical, it is a good idea to print a cover that supports a power socket and rocker switch. The Anet A8 power cable is wired directly to the terminals, where you have to unplug it from the wall to shutdown the 3D Printer. The cover is not just for visual appeal, it also makes it possible to power down the machine with the flick of a switch. There are plenty of designs on Thingiverse, but here are a few of my favorites.
Heated Bed Connector
The white JST power connector on the heated bed is a glaring flaw with the Anet A8, known for burning out and identified by a charred black spot. This appears to occur as the result of several different factors, such as poor wire crimps, a lack of strain relief on the cables and the 10A connector being underrated for the electrical draw. Any combination of these problems can be a point of failure, but there are several methods available to fix it.
The easiest of which is to just purchase a new wiring harness. While this doesn’t solve the underlying issue, it is the most practical choice for the majority of owners. A better alternative is to make your own, using thicker 16 AWG wire and utilize both +/- pins on the bed in parallel to spread the current.Anet A8 Heated Bed Wiring Harness - $12.55
The most preferable option however is to solder the wires directly to the heated bed, which can be quite reliable if done well. Soldering thick wires to a PCB board can be a rather difficult task though, and cold joints are dangerous to say the least. Unless you are proficient with a soldering iron or know someone that is, it’s best to consider a different solution for this issue.
No matter what route you choose, there are several printed parts that can help improve the safety of the heated bed wiring. As mentioned before, proper strain relief will drastically reduce the wear on the wires and connector. A cable chain can also improve wire management and provide some strain relief as well. There are dozens of designs on Thingiverse to choose from, but these are a couple of my favorites.
Clamping Style Heater Block
Several months ago, This Smart House posted an article called Don’t burn your house down 3D Printing. A Cautionary Tale. Despite having numerous safety mods for peace of mind, they overlooked the hotend as a potential point of failure. The heating cartridge came loose during a print and ignited the plastic fan duct, which quickly engulfed the machine in flames.
The Anet A8 hotend uses a tiny set screw that holds the heating element in place. This design is obviously flawed as illustrated by the article, where this tube is often in excess of 200 degrees Celsius and can easily start a fire if it comes loose.
The solution is to use a clamping style heater block, often found in the E3D style hotends. As the name would suggest, the block clamps the heater cartridge in to position using a large screw. Unfortunately no one has designed such a replacement for the Anet A8 as of yet, where the best option is to install an E3D V6 hotend or clone equivalent.V6 Style Direct Drive Hotend - $0.00 E3D V6 Direct Drive Hotend - $58.60
AM8 All Metal Frame
The frame isn’t necessarily a safety risk, but the black acrylic is far from stable and leaves a lot to be desired. There are hundreds of designs that you can print to make it more robust, but for a 3D printer with so many fire hazards, we would prefer to reduce the total number of plastic parts.
Enter the AM8, an all metal design for the Anet A8 that replaces the acrylic frame with thick aluminum beams. With a total build cost of around $50, it’s a small price to pay for such a massive upgrade. It keeps all of the original components to minimize costs, and uses pre-cut 2040 extrusions from Misumi to reduce the work involved.
Thingiverse: AM8 All Metal Frame
Safety Mods and Resources
While these are the most critical safety mods for the Anet A8, they are by no means the complete list.