How do you troubleshoot common layer height issues such as overhangs, gaps, and blobs in 3D printing?

1 What is layer height and how to choose it

Layer height is the distance between two consecutive layers of extruded plastic in your 3D print. It is usually measured in millimeters and can range from 0.05 mm to 0.3 mm or more, depending on your printer and nozzle size. The layer height affects the appearance and performance of your prints in several ways. A lower layer height means more layers, which results in a smoother and more detailed surface, but also a longer printing time and more material consumption. A higher layer height means fewer layers, which results in a faster and cheaper print, but also a rougher and less accurate surface. To choose the optimal layer height for your project, you need to consider the trade-offs between quality, speed, and cost, as well as the geometry and purpose of your model.

2 How to fix overhangs

Overhangs can cause sagging, curling, or drooping of the print if the angle is too steep or the layer height is too high. To fix this, you can reduce the layer height to improve resolution and adhesion, increase the cooling fan speed, add support structures to hold up the overhanging parts, adjust the overhang threshold in your slicer software, or orient your model to minimize the overhangs. Alternatively, you can split it into smaller parts that can be printed separately and assembled later.

3 How to fix gaps

Gaps are holes or spaces between the layers or the perimeters of your print, which can cause weak or brittle prints, poor surface finish, or inaccurate dimensions. These gaps are usually caused by under-extrusion, meaning not enough plastic is coming out of the nozzle. To fix them, you can increase the extrusion multiplier or flow rate in your slicer software, calibrate your extruder to make sure it is feeding the filament correctly and consistently, check your nozzle for clogs, wear, or damage and clean or replace it if necessary, check your filament for moisture, dust, or diameter variations and store it in a dry and sealed container. Additionally, increasing the printing temperature can improve the flow and melt of the plastic.

4 How to fix blobs

Blobs are excess or unwanted plastic that sticks out of the surface of your print, resulting in rough or uneven prints, poor aesthetics, or interference with moving parts. Generally caused by over-extrusion, meaning too much plastic is coming out of the nozzle, blobs can be fixed by decreasing the extrusion multiplier or flow rate in your slicer software to reduce the material. You can also calibrate your extruder to make sure it is not over-feeding the filament, check your nozzle for leaks or oozing, adjust the retraction settings in your slicer software to control the pressure and movement of the filament, check your filament for quality and temperature sensitivity and choose a suitable type and brand for your printer, and decrease the printing temperature to prevent the plastic from being too runny or sticky.

5 Here’s what else to consider

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