Gaps in Thin Walls


Generally speaking, a strong model contains thick walls and solid infill. However, sometimes there will be gaps between the thin walls, which cannot be firmly bonded together. This will make the model soft and weak that can’t reach the ideal hardness.


∙ Nozzle Diameter and Wall Thickness do Not Match

∙ Under-Extrusion

∙ Printer Losing Alignment


Nozzle Diameter and Wall Thickness Not Fit

When printing the walls, the nozzle prints one wall after another, which requires the wall thickness to be an integral multiple of the nozzle diameter. Otherwise, some walls will be missing and cause gaps.

Adjust the wall Thickness

Check whether the wall thickness is an integral multiple of the nozzle diameter, and adjust it if not. For example, if the diameter of the nozzle is 0.4mm, the wall thickness should be set to 0.8mm, 1.2mm, etc.

Change the nozzle

If you don’t want to adjust the wall thickness, you can change a nozzle of other diameters to achieve wall thickness is an integral multiple of the nozzle diameter. For example, a 0.5 mm diameter nozzle can be used to print 1.0 mm thick walls.

Setting the thin wall printing

Some slicing software has printing setting options for thin walls. Enable these settings can fill gaps in thin walls. For example, Simply3D has a function called “gap fill”, which can fill the gap by printing back and forth. You can also use the “Allow single extrusion fill” option to dynamically adjust the amount of extrusion to fill the gap at one time.

Change the extrusion width of the nozzle

You can try to change the extrusion width to get the wall thickness better. For example, if you want to use a 0.4mm nozzle to print a 1.0mm wall, you can try to extrude excess filament by adjusting the extrusion width, so that every extrusion reaches a thickness of 0.5mm and the wall thickness reaches 1.0mm.


Insufficient extrusion will make the wall thickness of each layer thinner than needed, resulting in gaps appearing between layers of the walls.

Go to the Under-Extrusion section for more details on troubleshooting this issue.

Printer Losing Alignment

Check the state of the external wall gap. If there are gaps on the external wall in one direction but not in the other, it may be caused by the printer losing alignment so that sizes in different directions change and produces the gaps.

Tighten the Belt

Check whether the timing belts of the motors on each axis are tightened, if not, adjust and tighten the belts.

Check the Pulley

Check the pulleys of each axis to see if there is any looseness. Tighten the eccentric spacers on the pulleys until they are just tight. Note that if is too tight, it may cause movement blocked and increase pulley wear.

Lubricate the Rods

Adding lubricating oil can reduce the movement resistance, making the movement smoother and not easy to miss location.

Date:2022-9-5 Author:admin