3D Printer calibrations...

Okay, so; I've had a 3D printer for about a week now and I've spent probably most of it running various calibrations. They were numerous.

Here's a short list of what I think you should do when you first start out with a 3D printer, and that's with knowing what I know now.

First, get a decent hotend. As I indicated in the last post, the prior hotend was pure garbage.

There other is to start printing cubes. Just a simple 20mm cube will do. You can find a bunch available online at various places. The objective with printing cubes is to determine your optimal retraction setting for the filament feed going to the hotend.

The general idea is that as you're printing, the hot liquid filament will have a tendancy to drip. The operative mechanism on feeding the filament to the hotend is called an extruder.

The extruder is a stepper motor in one of two major configurations. The first is direct feed, this involves placing the stepper motor right at the hotend and feeding filament into the hotend directly.

The other is what is called a bowden extruder. This setup involves a tube which is mounted elsewhere that the filament is fed into which leads into the hotend from elsewhere on the printer.

I have a bowden setup on my 3D printer.

Here are a couple of photos illustrating the slight difference between the two.

Direct feed Notice the extruder motor being placed right at the hot end. That setup generally involves a brass gear, with several teeth with a bearing that is pressed up against it to compress and grip the filament and move it into the hotend.

Bowden feedHere is what I have, a bowden extruder. It essentially places the extruder off the hotend.

In any event, back to calibrations. The stepper motor will advance filament according to whatever the firmware on the controller board indicates.

There are a lot of variables affecting the quality of your prints, but the biggest one will be calibrating your extruder to advance exactly the amount of filament the firmware says it needs to be. This will involve taking the filament from the output of the extruder and measuring it.

The second big variable is retraction. Usually the hotend will melt any filament in the hotend leading to a problem causing stringy, annoying waste on the print from that tripping. Setting the retraction for printing will cause the extruder to pull back the filament leaving the hotend with no filament to melt. Usually, it's set to a number between 2-5mm. This means when it isn't supposed to be printing, the extruder pulls back the filament by that amount. This actually leads to a related issue, movement speed.

Setting the non-print related speed fairly high leaves the hot melty stringy bits little time to drop onto areas it doesn't need to be. There is still a little melty stringy bits, but ussualy you can substantially improve the quality of your 3D printing by doing this.

This leads me to something else I figured that I aughta do. I decided I needed to add a Raspberry Pi to my 3D printer. Specifically, I installed Octopi, a distribution aimed at a 3D printers. One of the neat things that it supports is a webcam streaming function.

Anyway, here's a picture of that.


(I'll be setting up a live feed that you can watch on my website next week so you can watch what I'm printing life.)

How cool is that?