What Is 3D Printer Backlash? How Can You Fix It?
Factors that affect backlash are very important to take care of and I’ll explore the reasons why in this article.
The best way to fix 3D printer backlash is to tighten up any loose belts and make sure they are in good condition. If your printer has the relevant software, adjust backlash speed to 1500mm/s then trial and error from there. X & Y backlash settings should be between 0.2-0.6mm & 0.4-1.3mm respectively.
There is more to the backlash setting, from understanding what it actually is, to learning how to properly fix it. This article will aim to explain both of these to you so you can solve any backlash issues.
What Is 3D Printer Backlash?
Backlash is not a very well-known term in the 3D printing world or very well understood, so I’ll give you a simplified definition of it.
Backlash is the necessary correction for the looseness or slack in the moving system of your X and Y axis. It can also be referred to as the amount of play between the lead screw and the nut that runs through it to the Z-axis.
As you know, when your 3D printer is extruding material, the print head is vigorously moving on the X and Y axis in different directions, as per the software’s command, following the digital file you have put in.
Your G-Code is in control of these movements which are extremely precise, which is why 3D printers can display such high quality.
Now that drive is well controlled by different rods and belts, which provides flexibility to the head of the print.
The problem of backlash comes about when the movement in the system has slack from moving parts such as rods, belts and bearings. The parts that are flexible are the worst because they very slowly change in their flexibility over time.
After some time, that extra flexibility will have an effect on the precision of your 3D printer.
A good clue into identifying backlash is when infill diagonal lines don’t meet up with the perimeter lines.
The video below goes into more detail about backlash, as well as explains how to use the backlash tower to calibrate backlash.
Backlash Explained in Real Life
Let me give you a practical example of how backlash applies.
Imagine you are standing still and I tell you that you have to step backward and then come back to your original spot.
The chances of you stepping back and coming forward to the exact spot that you were on are very thin. Similarly, your 3D printer can have a hard time going back to the same spot.
The print head moves backward and then tries to come back to the original spot, however, it may miss just by a very small difference depending on the flexibility level of the belts on the 3D printer.
This is where the backlash comes in, adjusting the flexibility of the belts to correct the flexibility and make sure the head of the print comes back exactly where it was before, to ensure high quality prints.
Bad cases of backlash can easily result in print imperfections like gaps between walls, especially in circular objects.
Fixing the Backlash of Your 3D Printer
It’s important to know, many 3D printers don’t usually experience backlash. The M3D printer is one that is known for having backlash and its software even allows you to adjust for backlash compensation.
There isn’t always a backlash setting that your 3D printer can adjust, so how do I stop backlash from happening?
Your belts are usually the main culprit for backlash effects, so a good tightening of your belts should help a lot. If your belts are worn out, a replacement might be in order to get your high quality prints back.
Speed is one of the main factors where backlash will show itself. Your jerk & acceleration settings also contribute, so keeping these at a low level should help reduce backlash.
Ideal jerk & acceleration settings are. I wrote a whole article just on getting jerk & acceleration settings perfect which you can feel free to check out.
If the stuff you are about to print is a circle in nature, it becomes a must for you to set your 3D printer for the backlash setting so that there are no visible gaps in your circle and the shape of your circle stays perfect.
Muele designed a Quick Test Cylinder on Thingiverse to quick check your 3D printer backlash. There is an added version which has a flat spot, making it easier to identify the orientation after you remove it from the print bed.
Update: Added a version with a flat spot to make it easy to identify the orientation after removing it from the build-plate.
Changing Steps Per mm
You may have to adjust the motor speeds for your 3D printer to compensate for backlash issues. This is done by changing the steps per mm for X & Y in the firmware.
Follow these steps:
- Send an M92 command in your GCode header or – M92 X78.74 Y78.74 or,
Set it permanently in firmware by issuing:
- M500 stores current settings
- M501 retrieves the data from EEPROM
- M502 reverts to the ‘factory defaults’
From RepG/Printrun etc, send M501 to view what they are currently
- Print something which is 100mm x 100mm
If your Y setting is currently 75, while your print comes out as 85mm in Y direction, you need to calculate a new Y.
It would be 75 * 100 / 85 = 88.235
Now you would send:
Doing the same for X should leave you in a good position for your backlash.
How to Install an Anti-Backlash Nut on a 3D Printer
You can install an anti-backlash nut on your 3D printer by using something like the Z-Axis T8 Anti Backlash Spring Loaded Nut from Amazon. Users have mixed reviews on the product though, with some saying it worked perfectly and others mentioning that it is difficult to thread properly.
One user said that it really helped with the backlash on the Z-axis, also improving layer adhesion.
Check out the video below on this product by BV3D on YouTube.
Backlash Settings in 3D Printer
Frankly, you can control the backlash setting of your 3D printer manually through changing its speed or simply controlling the backlash along the y and x-axis.
However, the Y axis can prove to be difficult to adjust as it is controlled by belts instead of rods which are rigid and allows for only as much fluctuation as given instructions on.
Once you have adjusted the speed, you can ensure that there are no skipping occurs that causes gaps. Remember, the higher the speed of the backlash, the more chances are that gaps would form.
You may also have to play around for a while with the settings to get the exact outcome you desire, as every printer differs from others.
The speed of the backlash that is recommended to avoid any gaps and deformation of the circle shape is 1500mm only.
Now that we know what’s going on, let us see how can we make the settings right on our 3D printer;
So, are you wondering what exactly you have to do to make sure your 3D printer is well-equipped in the field of backlash? Well then, remember that you need to have the following backlash settings done.
Your X-axis backlash should be 0.7mm.
Your Y axis backlash should be 1.03mm. And the speed of your backlash, as mentioned earlier, should no more than be 1500 mm.
Please note that these settings are only for one printer. Your printer’s setting may not be the same, and you may not get the same results. Therefore, you need to check with your printer by following my simple steps.
Step by Step for Backlash Setting
To attain the settings mentioned above, follow my step-by-step guide so that we are on the same page, and you don’t get lost in the middle of the process.
Now, in the advanced calibration setting, you would have the option to set your x and y-axis measurements.
Depending on what 3D printer you have, these backlash settings can vary. Some printers may need more of a correction to solve a backlash issue to trial and error would be needed. The level of flexibility of your machine will vary from printer to printer.
Remember that the aim of setting your backlash setting is to have a perfect circle, with no gaps whatsoever. So, therefore, with a very composed mind, you have to keep changing the adjustments until you have a perfect circle shape.
I would suggest you to remember those measurements for later use also as if you plan to use the same 3D printer even in the future, it is very likely that you will have to make the backlash measurements again.
However, with time, your 3D printer’s belt and rod may lose its flexibility and become loose, so make sure you keep your printer well maintained to get the best result out of it.