5 Ways How to Fix 3D Printer Nozzle Hitting Prints or Bed
Many users had situations where their 3D printer’s nozzle keeps hitting their prints. This can be very frustrating as they end up starting the print all over, ultimately wasting filament. Even after restarting the print, they still run into the same issues because they don’t know how to fix the problem. This article will give you the details on how to stop your 3D printer nozzle from hitting your prints.
To stop your 3D printer nozzle from hitting your prints, first ensure that your printbed is level. Once you’ve ruled that out, inspect the bed for warping or unevenness since it causes the height of the print to vary. Another fix is to tighten the eccentric nuts on the gantry. Also, you can adjust first layer settings.
While this is just the basic answer, keep reading for more information on how to fix your 3D printer nozzle hitting prints.
How to Fix 3D Printer Nozzle Hitting Prints
- Level your Bed
- Replace your Bed
- Adjust the Eccentric Nuts on the Gantry
- Improve First Layer Adhesion & Settings
- Ensure your Extruder is Extruding the Right Amount
1. Level Your Bed
One way to stop your 3D printer nozzle from hitting your prints is to level your bed. If your printbed is not level, it can cause the nozzle to hit your print when it travels from a low point to a high point on your printbed.
To fix this, simply preheat the bed and home the axes of your 3D printer. Then move the nozzle to one of the corners of your printbed and place a piece of paper on the printbed, just under the nozzle.
Lower the position of the nozzle until it touches the paper, till you can feel a slight resistance when you pull the paper. Repeat this step on other corners of your printbed. Once you have completed this process, move the printhead to the center of your bed and repeat this step.
At this point, your bed should be leveled and the nozzle is at the same height when it moves across the printbed.
Check out this video from CHEP on how to level your 3D printer’s printbed.
I also wrote an article called How to Level Your 3D Printer Bed – Nozzle Height Calibration. It goes through this and similar techniques in more detail.
2. Replace Your Bed
Another way to fix your 3D printer’s nozzle when it keeps hitting your print is to replace your printbed.
This is because, your printbed may begin to develop some unevenness (warping) across its surface area, and this could cause your nozzle to hit your models during printing due to the height differences across the bed.
This warping is caused by the periodic heating and cooling of the printbed (especially metallic ones) which causes it to expand and contract.
Once you begin to observe warping on your printbed, your best bet is to replace it. Depending on your 3D printer, you can buy a replacement from Amazon or the printer’s manufacturer.
You can check out my article Best 3D Printer Bed Replacements – Better Adhesion. It takes you through some great bed replacement options for your 3D printer.
One user stated that his nozzle would hit his bed whenever he tried printing at higher infill percentages or printing large components.
He calibrated the flow rate, printed and mounted bed supports, and attached more clips to his glass bed to eliminate the problem.
This was because, his metal bed was slightly warped, raising towards the corners, but the glass bed and clips helped eliminate the warp.
3. Adjust the Eccentric Nuts on the Gantry
Another way to stop your 3D printer’s nozzle from hitting your print is to adjust the eccentric nuts on the gantry.
Your 3D printer has various movable parts (e.g. POM wheels) that are held in place by eccentric nuts. These nuts get loose with time due to the back-and-forth movement in these areas.
As a result, there may be a tilt in the printbed or across the gantry which causes a difference in height across the bed during printing. Hence, the nozzle may ultimately hit the print as it travels during printing.
One user stated that his nozzle kept hitting the print on his Ender 3 Pro. He discovered that the eccentric nuts for his Z-axis were loose and were causing the gantry to wobble on the right side anytime it moved up or down.
The nozzle would smack into the infill on any model about an inch tall. He tightened the nuts and was able to print fine afterward.
Another user stated the nozzle on his Ender 5 was hitting his prints during printing. The X-gantry was not set up properly as the eccentric nut on the right side of the X-gantry was too tight.
He said that the first layer would print properly while the next few layers would print horribly like it was over-extruding. He adjusted the nuts and he was able to print well.
4. Improve First Layer Adhesion & Settings
A poor first-layer adhesion can also contribute to your nozzle hitting your prints. This is because, after a few poor layers, you can start to have material going in the wrong places, to a point where it gets in the extruder’s pathway of travel.
At this point, the slightest obstruction of the extruder’s pathway can lead to your print being knocked over, regardless of how long the print has been on.
While there are a host of ways to improve your bed adhesion, the easiest and most effective way is to apply adhesive on the bed. You can either make use of hairspray, glue stick, or painter’s tape.
Before you apply any of these adhesives, you need to first ensure that the bed is free from any form of debris. This is because most adhesives would not adhere to a dirty surface.
You can get the Elmer’s Disappearing Glue Stick or the ScotchBlue Original Painter’s Tape from Amazon.
Another way to improve bed adhesion is to increase your printing temperature. This is because your filament needs to be properly melted to ensure optimal adhesion.
To get the optimal temperature for your print, your best bet is to print a temperature tower since each filament has its specific printing temperature.
You can change them in 5⁰C increments until you find the sweet spot that produces print layers that stick together.
For your first layer, I’d recommend printing the first layer at a temperature 10-15⁰C higher than the temperature you’re printing the rest of the print.
Check out this video from Rickey Impey on how to print a Temperature tower on Cura.
Also, if you observe that your print does not still stick to your printbed, you increase your bed temperature.
A higher bed temperature will cause your print to cool down much slower. As a result, the print can bond much better with your printbed.
You should be mindful of how you increase the temperature of the printbed because if it’s set too high it can cause your print to develop elephant foot.
On the Cura slicer, you’re better off using the default value for your initial build plate temperature required for your filament of use. However, if you still have adhesion issues, you can increase the “Printing Temperature Initial Layer” by 5⁰C on Cura.
If you want to learn more about getting better first layer adhesion, you can check out my article How to Get the Perfect First Layer Squish – Best Cura Settings.
5. Ensure Your Extruder is Extruding the Right Amount
Another way to stop your nozzle from hitting your prints during printing is to ensure that your extruder is extruding the right amount of filament.
You would want to ensure that the extruder does not deposit more than the required filament (over-extrusion).
Two factors control the amount of filament deposited by the extruder at a given point. They are; Flow rate and E-steps.
The E-steps is a 3D printer firmware setting that controls the number of steps the extruder’s stepper motor takes to extrude 1mm of filament.
The E-step setting makes sure the right amount of filament goes into the hotend by counting off the number of steps the stepper motor takes for 1mm of filament.
The Flow Rate, also known as extrusion multiplier, is a slicer setting that determines the amount of plastic a 3D printer will extrude.
Have a read of my article How to Calibrate Your Extruder E-Steps & Flow Rate Perfectly for more details.
Using these settings, the 3D printer figures out how fast to run the extruder motors to send enough filament for printing through the hotend.
The default value for the flow rate is usually 100%. However, due to variations between filaments and hotends, this value is generally not optimal for printing.
If either of the values for E-steps or Flow rate is not properly calibrated, it can lead to over-extrusion.
When this occurs, there would be a build-up of extra filament being deposited at each layer which automatically adds up to become significant.
Since the nozzle cannot account for this increase at that particular layer height, it would end up hitting print.
This is because the nozzle would assume that the layer is at the required height when it’s apparently higher.
You can check out this video from 3D Printscape for a more detailed step-by-step process on how to calibrate your 3D printer’s E-steps.
Also, you can calibrate your extruder’s flow rate by performing a flow test on it. Here’s a video from Pushing Plastic that gives a detailed breakdown of how to conduct a flow test on your extruder.
One user said he had a situation where his nozzle was hitting his print. After investigating, he discovered that his nozzle was overextruding filament and it made the print a little bit taller than it should.
He recommended doing a flow test to correct this problem.
How to Fix 3D Printer Nozzle Hitting Bed
Your 3D printer’s nozzle hitting your bed and hitting your prints are very similar issues with similar causes. But the main cause of your 3D printer hitting your bed is when the Z-offset is not properly calibrated.
When it’s set too high, your prints will have adhesion problems and when it’s set too low, it will dig into the bed during printing.
The Z-offset setting is a slicer setting that causes the extruder to move a certain distance away or toward your printbed.
Before you get into your Z-offset settings, you want to check that your endstop limit switch is in a good place.
This endstop tells your 3D printer where to stop your print head from moving past so it doesn’t overextend or dig into your print.
At times, simply lifting this endstop up will solve issues with your nozzle hitting or digging into your bed. Also, you need to verify a few things:
- Is your endstop switched wired up properly?
- Have you firmly mounted the switch to the frame and adjusted it correctly?
- Does the endstop switch work?
Here’s a video from MakeWithTech on how to calibrate the Z-offset of your 3D printer.
Another thing you shouldn’t overlook is having your bed level. An uneven bed can easily be the downfall of your 3D printing success, so it needs to be parallel to the X-axis and the same distance away from the bed to the nozzle throughout the platform.
Make sure you adjust your Z endstop so that the nozzle is close to your build platform, while your bed leveling screws are properly tightened.
Once this is completed, you’d need to do the normal bed leveling process at each corner of your bed, using the paper method to get the correct distance throughout your bed.
During this process, you need to ensure that your printbed is heated. This is because, your heatbed can contract or expand during heating, causing the measurements taken to be invalid if the bed is cold.
Double-check your slicer settings and make sure you aren’t using a Z-offset unless it’s for a specific reason such as printing on top of another object or doing more complicated prints.
The M120 G-code enables endstop detection, and some slicers don’t actually enable this before a print starts.
If your printer doesn’t detect the endstop, that’s where you can run into your nozzle hitting your print bed. You definitely want this to be detected before starting a print or doing auto-home.
One user recently got the SV06 3D printer and tried assembling it. After assembling and calibration, it worked fine.
However, as soon as he started to print the Benchy model that came along on the SD card, the extruder descended into the print bed, pushing it down and actually bending it down. This caused the build plate’s coating to have dents.
To fix this, he had to move the extruder to the Z = 0 position in the “Prepare menu” before starting the “Probe Z offset calibration”. Apparently, the Home Position for the 3D Printer was at Z = 5mm and not at Z = 0mm, causing any calibration to move down by another 5mm.
