A 3D printer’s “magic numbers” are the layer heights that are a multiple of the minimum height your Z axis can move.
By choosing one of the magic numbers when slicing your STL model you’ll get much better-looking prints. This is because the mechanical movement and slicer heights will be aligned.
What are the Ender 3 Magic Numbers?
The base step height for the Creality Ender 3 and all Creality printers is 0.04. As a result, your layer height should be in multiples of 0.04:
- 0.04 mm
- 0.08 mm
- 0.12 mm
- 0.16 mm
- 0.2 mm
- 0.24 mm
- 0.28 mm
- 0.32 mm
On the stock Ender 3 nozzle, I would not go higher than a layer height of 0.32mm.
More: Is 100 microns good for 3D printing?
Why magic numbers are important
Magic numbers are important because they help your 3D printer produce the best quality 3D print that it can. You’d be surprised at how much of an improvement you’ll see once you implement the magic numbers correctly.
My first printer was a Tevo Tarantula. I could get really good prints with a 0.2mm layer height on my Tarantula, but prints using a 0.1mm layer height would always turn out just OK.
Had I known about magic numbers back then, I would have been able to get much better high-resolution prints!
3D printers are not based on a closed-loop feedback system: this means that communication goes in only one direction. So if your 3D printer tells your stepper motor to move in so many steps, the printer assumes that the motor did indeed move. There’s no way for the printer to know whether it actually moved that far or not.
As a result, the next set of instructions is delivered regardless of whether the first set was correctly followed, which is why you end up with failed prints!
Stepper motors move in steps, hence the name.
This can be a full step or a micro step. A full step is a turn that finishes in alignment with an electromagnet. A full step is very accurate, and you can know for certain how far it moved.
A micro-step is a turn that finishes halfway between two electromagnets. Two magnets are activated to get the shaft to stop halfway, but there is no way to know for sure if the shaft is exactly halfway or off by a little.
The key term here is “by a little”.
Even if you don’t use magic numbers, your prints will not be disastrous, as the difference is quite minor. But if you do use them, the improvement in quality will be quite significant.
By aligning your layer heights with the steps on your motors, you can eliminate the need for any guesswork!
How to calculate magic numbers
You can find the magic numbers for most popular 3D printers on forums and social media, but in case you want to calculate the magic numbers yourself, you can do so using Prusa Research’s superb calculator.
Here’s the information you’ll need:
- Motor step angle
- Leadscrew pitch
- Gear ratio
- Pitch presets
- Finally, enter your desired layer height
If your layer height does not align with the motor steps, the calculator will show that to you in red and suggest a better layer height in green.
You can study the results in green and find out what they’re multiples of to get to the magic number so you don’t need to use the calculator every single time.
Now that you know what magic numbers are be sure to use them when slicing models for your Ender 3.
You may also want to be sure that you’ve properly calibrated your e steps and after, tuned your Ender 3 for maximum speed.