Quote Originally Posted by MystiqueEngineer View Post
When it comes to the step/dir compatible servos, could you give me a link to an example? I've tried to find some, but without luck
The O-Drive and Mechaduino (type either of those into google) I mentioned in my previous post are the open source/hobbyist level ones I'm familiar with. Some of the name brands usually seen in CNC routers and higher budget projects like clearpath have products that can do this as well. These days I'm not convinced spending money on a clearpath or similar servo is worth it, projects like mechaduino and O-Drive tend to be more feature rich and customizable as a result of being open source.

Quote Originally Posted by MystiqueEngineer View Post
When it comes to the sound I want to get away from; I'll admit my prejudice is based on other 3D printers (My China kit in particular). But even the Stratasys we have at work (apparently a very expensive printer according to my superior) is noisy as hell. It's a pretty noticeable motor sound from it - a sound I have never heard from servos. Therefore my presumption that servos in most cases should be quieter. But of course, AC/DC or Brushed vs. brushless is also a factor. I was thinking going for a AC brushless servo. Also, the videos I've seen of guys converting to servo-drive on their 3D printers seem to gain quite amazingly low noise levels.
Again, this has to do with the drivers commonly used for steppers. I believe it's something to do with the frequency or chopping of the waveform, it's closer to the audible spectrum which gives that typical high pitched stepper whine people hear. Have a look at a printer using some TMC drivers and you'll notice the lack of motor noise. The prusa i3 mk3 is a common example if you want to watch some youtube videos on it, people tend to say the fan is the loudest part.

The main reason to switch to servos I think is speed, reliability (especially at speed) and maybe precision. I don't think most of these are relevant other than reliability. The extrusion speed will limit your printing far sooner than the stepper's max speed. And I think the bottleneck for accurate parts is also the fact we're squeezing molten plastic out of a 0.4mm or bigger bore. Servos will probably let you use higher accelerations though, which would help avoid blobbing with sharp corners and intricate details. On super detailed parts with lots of direction changes it might make the print noticeably faster.

As for type of servo, I'd ignore DC, they are noisy both regarding EMF (which can mess with endstops and other electronics) and audibly which is the opposite of what you're going for. AC and brushless DC are the same thing as far as I'm aware, at least as far as the motor is concerned.

I don't recommend making your own servo with an arduino. It is not easy an will require a good knowledge of control loops, and even then it will take a while. There's a reason so many printers use stepper and that open source servos have only really arrived in the last few years. Go with one of the existing projects, it'll be cheaper and if you want to improve or modify it from there, you can because they are open source.
https://odriverobotics.com/
https://tropical-labs.com/mechaduino/