Essential Guide to Achieving Perfect Parallelism – MXY Machining

In this article, we will share with you the basic criterion of a 3D printer that prints perfectly, every time. This criterion is the parallelism of a 3D printer and this is played out as soon as you unbox the 3D printer.

Eagerness to Start Using a New 3D Printer

Common Beginner Mistakes

Upon receiving a 3D printer kit or one that is already assembled, any user will be eager to use it as soon as possible! Indeed, the excitement is palpable for any 3D printer user upon receiving a new machine, beginner or not.

But when you receive a large number of printers, whether for the creation of a 3D printing farm or an independent workshop, it is important not to make the first mistake of beginners: assembling your 3D printer(s) quickly, in a rush.

Building, calibrating, and testing any 3D printer requires patience and attention to detail. While some modern 3D printers can be built in 10-15 minutes, this is not the case for all printers.

Some examples of assembly times:

Some examples of assembly times:

• Creality CR-10: about 10 to 15 minutes
• Creality Ender-3: approximately 30 minutes
• Dagoma DiscoEasy200: about 5 to 7 hours
• Anet A8: about 5 to 7 hours
• Prusa i3 MK3: about 10 hours

And we’re not even talking about custom 3D printers, which alone require several days of assembly and adjustment (especially for large format 3D printers).

And there is a very important criterion that is the basis of any good functioning of a 3D printer: parallelism.

Importance of Parallelism in 3D Printing

The concept of parallelism

Before talking about parallelism, let’s talk about the concept of parallelism. And seriously, let’s go back to the basic concepts of geometry. So, first of all, what does parallel mean? In geometry, we talk about two parallel lines when they have no points in common. They go in the same direction and do not intersect.

These two parallel lines represent the two bars of our printer’s carriage. These two lines form a single plane. The printer’s print head will move along these axes and this plane. If this plane is inclined relative to the plate, the print will be more crushed on one side and tend to come off on the other!

Steps to Adjust 3D Printer Parallelism

Why is this the first adjustment to make? Parallelism is the first adjustment to make on a 3D printer, otherwise, the correction of the flatness of the plate by probing in 6 points or 9 points will be distorted. The same goes for the offset, whether it is an offset adjusted manually or automatically using a sensor on the Z axis. For good parallelism of a 3D printer, it is necessary to ensure that the printing carriage plane is parallel to the plane defined by the printing plate.

On older 3D printers with threaded rods, this adjustment had to be done by hand, by turning the threaded rods yourself in order to level the print carriage relative to the bed.

These rods have been gradually replaced by trapezoidal rods which allow for greater rigidity on the axis and better support of the print carriage on the Z axis.

The important thing on recent 3D printers will be to correctly mount the printer by tightening the axes, screws, etc.

The objective here will be to minimize as much as possible the mechanical play on the chassis and to leave a minimum play on the various guide elements.

If everything is correctly assembled, tightened, and adjusted, you can perform this test to check the parallelism of your 3D printer:

• Perform a reset of your print head (G28)
• Place the printhead in the center of the bed using the printer controls
• Raise the nozzle a few centimeters
• Measure the left carriage-to-plateau distance using a square or a caliper (more precise)
• Measure this same height on the right
• Compare the values ​​(they must be equal)

Case Study: Adjusting the Dagoma DiscoEasy 200

Ahh… How nostalgic! This good old Dagoma. It is also an excellent example accessible to all. The DiscoEasy 200 has the disadvantage of having a chassis that is not the most rigid. Strongly inspired by the Prusa i3, it takes its codes: PLA chassis, and cylindrical guidance on steel rods for each of the axes.

In addition, in its first version, the Z axis was guided by 2 unsynchronized threaded rods. In short, a horror to adjust! But a treat, as soon as you understand that the parallelism had to be readjusted from time to time.

Parallelism Adjustment Tutorial

First of all, the most important thing is to check that the printer is level. To do this, check that there are no wires or cables running under the printer that could destabilize it.

Use a spirit level to check the level of the printer. The plate must be parallel to the table and the table must be stable on the ground.

Once this criterion is verified, we can adjust our parallelism. Two schools of thought clash here:

• Those who check squarely directly at the guide rods of the “X-axis” of the printer.
• Those who place flat support on the threaded rods in order to have a flat and not cylindrical reference for the square check.

We of course recommend the second method. The first is not very precise, but more than enough for a quick check of the parallelism. To do this, we place my spirit level on the carriage. Once on the left side, and once on the right side. And we measure the distance to the plate with a ruler, on each side. This distance must be the same on the left and on the right!

You can also use a square or a caliper to increase precision. The better your parallelism, the less you will have to touch your printer when starting a print! For more prestige, we recommend this square including the spirit level.

Impact of Motor Placement on Parallelism

On many DIY 3D printers (Anet, Dagoma, Creality, Prusa…), the X-carriage mounts the motor on the left side of the printer. This results in a weight on the left side of the carriage. And this weight will have a very small influence on your parallelism over time.

The motor on the left side of the Z axis will need more torque than on the right side to lift the heavier weight on the left side. During accelerations up or down, the parallelism can slightly go out of adjustment over time. It’s all a question of precision, PID, and mechanical play.

This is why it is important to receck the parallelism occasionally. Poor parallelism of your printer is noticeable from the first layer of a part: plastic peeling off the plate, overly crushed layer, or clicking of the extruder.