3D Printer Calibration

3D Printer Calibration

Luke Howard

Mar 2nd, 2019

HOW DO I KNOW THE PRINTER IS CALIBRATED CORRECTLY AND DOES THAT MATTER?

Propper printer calibrated is essential to getting precise prints that match the dimensions and scale that you designed. Calibration is not a daunting task. When printing detailed prototypes, parts that are meant to fit together, or reproduce prints to an exact scale you need to calibrate the machine carefully. For hobbyist printers that want to print fun, exciting, and unique objects, the minimum calibrations work well. Whether you are an expert or an enthusiast, testing your calibration is the only way to get the most out of your printer.

I focus on the following tests:

Bed calibration and “Z” height test

Calibration test for the steppers (XYZ calibration cube)

Bed leveling square

Torture test (Benchy)

Overhang test

SETTING THE Z HEIGHT (FOCUS ON THE FIRST LAYER)

The first print layer is crucial for print adhesion to the print surface. If the nozzle is too close to the print bed, it can scrape the bed, or print to thin of a layer to be effective. If the nozzle is too far away from the print bed, the filament won't adhere properly to the bed, and the print will peel off during the print. The goal is to set the nozzle approximately 90% of the height of your layer height.  This distance creates a small "squish" in the first layer of printing. That "squish" helps the first layer adhere better as the filament is force downwards instead of printing as a full bead. "Squish" is also important for fusion between every other layer of the print.

The Taz 5 printer that we have has a manual z height adjustment — using a piece of paper you can test the Z height. Other printers have auto Z height features and allow you to adjust the Z offset on the printer software. Whichever method your printer uses for adjusting the Z height, make sure to use it, and know its importance.

STEPPER CALIBRATION TEST

Calibrating the X, Y, and Z steppers is a more involved process. For the sake of this article, I am keeping my explanation simple. There are plenty of resources and articles that can help you understand calibrating steppers for your specific machine. Check out my resources links at the end of this article.

Stepper motors are critical for CNC machines to remain accurate as they print over and over again. These motors break down rotations into multiple steps to complete a full rotation. These incremental steps allow for precise movements that can be repeated many times over. Stepper motors can get out of sync and need recalibration.  

I linked an XYZ calibration cube to the list of tests below. This test is beneficial to see if or where a 3D printer is out of sync. If you print a standard sized 20 mm cube, you can look for any abnormalities, warps, or size issues. Using a ruler or calipers, you can measure if the printer accurately produced a perfect cube.

BED LEVELING SQUARE

The print bed is another area that can fall out of alignment. If the bed isn’t level prints can be warped, or the nozzle can be too far or too close in certain areas. Bed leveling tests consist of a couple of layers at most and show you if the bed is level from one corner to another.

TORTURE TEST (Benchy)

Benchy is a small boat that has become a trendy print for testing how well the extruder head is calibrated. It shows you if the extruder head is under extruding, over extruding, or stringy.

OVERHANG TEST

Prints with extended and angled parts need support structures printed below. 3D printers need a base to print from. A tree branch that extends out from the base at an almost 90-degree angle would need support material while printing. This test allows you to see how severe of an angle your printer can print without needing support material. Support material, while useful, adds time to prints and requires product clean up.

RESOURCES

Extrusion Problems

How to Accurately Calibrate Your 3D Printer

Tune and Fine Tune your printer and filament

Stepper Motor Calibration Calculator