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Part and Design Choices: Electronics

A project log for DIY Silent 3D Printer

My experience designing and making a building DIY 3D printer

Luke BrandonLuke Brandon 08/15/2020 at 07:180 Comments

Electronics

Strain Relief

Strain relief is something to keep in mind when building/designing 3D printers. 3D printers are always moving, this can easily strain and break wires. My printer design has strain relief mounts designed into it. These points allow for cables to be zip tied to the moving carriages.

A handy tip that I found (Maybe from Makers Muse on YouTube, cant remember exactly) is to use whipper snipper (brush cutters, weed whacker, grass trimmer, whatever you call them) wire in your wiring looms. The nylon wire is quite stiff and can be bundled together with your wires to give them support. The cord helps prevents wires from kinking and bending. It can easily be hidden inside the cable sheathing used around the wiring.

Stepper Drivers

I chose to go with silent stepper drivers. These are slightly more expensive than regular drivers, however, I prioritised the printers silence over its cost. The drivers I used were the TMC2130 drivers. These drivers have silent stepping with sensorless homing. Sensorless homing is nice as it eliminates end stops making the printer look cleaner (another design goal).

I did use A4988 (regular) drivers on my extruder and Z axis motors. These axes move less often and produce less noise. This decision was made to save some money, TMC2130s could be used on all axes if preferred.

Fans

Noctua. If you want to get super silent fans, Noctua fans are the best. They aren’t cheap or good looking, but they are silent. Silence was a top priority for me so Noctua fans were used on the hotend and PSU.

I bought a cheap 360 Watt PSU which had a loud fan and no thermostat. I could have added a thermostat to the PCB and the fan would likely remain off for almost all printing. I decided against this as I would rather stay away from mains wherever possible. I chose to replace the included fan with a Noctua fan. Unfortunately, the Noctua fan was thicker than the included fan and didn’t fit. I ended up just attaching it on the outside of the PSU. This wasn’t great but it did work, it also meant I didn’t waste an expensive fan. (INCLUDE PHOTOS OF FAN).

In places where not as much cooling was needed (the electronics box) I used a cheap 12v fan. To silence it, I simply ran it at 5v. This was a cheap way to get silent cooling fans.  

The part cooling fan used 2 50mm radial fans. These are loud fans, they sound like a jet engine, and are the loudest part of the printer. I tried using 2 fans at lower speed to reduce noise. This reduced the noise produced slightly. Truthfully, these two fans are still rather loud. I have a few ideas for an external ducted fan for a future upgrade.

Hotend and Extruder

I chose a E3D v6 clone for my hotend. The clone (also known as J-Head) works well for what I need. Despite using a clone, I would always recommend a genuine hotend if you can afford it. I wanted to save money so went with a clone. As mentioned previously, the hotend cooling fan was replaced with a 40mm Noctua fan.

The extruder used is of my own design. It’s a simple, ungeared direct drive extruder. A drive gear and idler combination. I considered a Bondtech extruder and Bondtech clones, in the end I decided to design my own extruder. The clone Bondtech’s seemed to have a bad reputation and the genuine ones were pricey and hard to source. My extruder works well for PLA, ABS, and PETG.

My previous printer used a Bowden extruder. After having used my new direct drive extruder I would never use a Bowden again. The print quality is far better when using the direct drive compared to the Bowden extruder. Direct drive extruders add weight to the moving carriage which is why they are sometimes avoided. For a moving bed design this weight saving isn’t so critical. The bed mass is already limiting your speed, so it doesn’t hurt too much having a little more mass on the extruder. (Actually, thinking about this further, I’m not sure if that last sentence is correct. More testing might be needed to verify. In any case, the printing speed is fast enough for me.)

Heated Bed

The heated bed used was a simple 12v aluminium heated bed. 24v systems heat up faster but make choosing other electronics difficult. Aluminium was chosen over PCB because I wanted to use an induction probe.

PSU

As mentioned earlier the PSU chosen was a standard 12v LED PSU. I went with 360 watts because it provides a good margin of error. This margin for error is especially handy when dealing with cheap Chinese equipment. As mentioned earlier the fan was replaced. If you wanted to add in a thermostat you can check out this video by Tech2C (https://www.youtube.com/watch?v=LNyZnfy3bRE).

Control Board

 My previous printer used a ramps 1.4 control board. It worked well enough for a few years. The ramps boards aren’t the best, but they do work. I really like being able to easily remove the stepper drivers. The ramps board needs to be attached to an Arduino mega 2560. The ramps 1.4 and Arduino combo is a really affordable solution and I have had good experiences with it.

One of the flaws with the ramps 1.4 is that the input power plug cannot handle the current required. I removed the plug entirely. I soldered the leads to the power supply directly to the board where the plug used to be. This eliminated burning of the plug over time.

I have heard of people having problems with the temperature fuses and voltage regulators on the ramps and Arduino. I haven’t had any issues on this new design, even printing ABS. I would still recommend an external electronics box with a cooling fan. Cool electronics are better, and fans aren’t too expensive.

If you wanted to use a different control board that is completely up to you and your budget.

Connectors

I wanted to go with an external electronics enclosure. This was to keep the electronics cool and out of the warm enclosure of the printer. To do this neatly, I wired all the printer electronics into a sort of junction box on the printer. This junction box wired all the printers electronics into neat, sturdy connectors that could be used to connect to the electronics box.

If I were to rebuild the printer, I would try to find a better way of wiring the printer. Maybe one big connector as compared to the 5 connectors I used. Maybe individual connecting cables as opposed to one big loom with 5 connectors attached. If you were to build the printer, I would recommend inventing a new method of connecting the printer and the external electronics.

Induction probe

Ease of use was a key goal of my new printer. Auto bed levelling is a major time saver. I went with an induction probe for my printer. It works well with an aluminium heat bed and saves so much time. Add one to your printer, it makes printing so much more enjoyable.

Raspberry Pi

A raspberry pi was used for convenience. It eliminates being tethered to the printer and fiddling with SD cards. The raspberry pi runs Octoprint and allows for wireless remote printing. This adds to the convenience of the printer significantly. 

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