Print quality guide

Looking to improve the quality of your 3D printed models? We have compiled a list of some of the common issues you may have faced, along with a short explanation and how to solve them. Use the images below to identify the picture that best represents the issue that you are experiencing and click on the thumbnail to jump that that portion of the guide for immediate recommendations on how to resolve the issue. If the issue you are experiencing is not shown below, feel free to raise a support request at support@me3d.com.au.
Your printer produces incomplete first layers or does not extrude plastic at all.
The first layer doesn't stick properly and gets caught in the extruder as it continues to print.
Strings or hairs are produced between different sections of your model.
The extruder is visibly blocked and is unable to push plastic through.
The rate of extrusion fluctuates when you print, causing problems when you print.
Edges/corners are lifting from the bed during a print, sometimes causing the print to fail.
Some parts of the model have not been printed, even though they are there in the preview.
The printer stops extruding plastic in the middle of a print.

Not extruding on first layer

Z-Offset is too low
If your printer is producing incomplete first layers or isn't printing at all on the first layer, your Z-Offset may need calibrating. You may also hear the extruder nozzle scrape against the print or a 'clunking' noise coming from the extruder motor. Read the How To: Calibrate your Z-Offset article for how to fix this issue.
The extruder is blocked
Little to no extrusion can be a result of a blockage somewhere in the extruder. It may be as simple as a piece of filament getting snapped off inside, or retrograde extrusion as a result of a low Z-Offset. For steps on how to fix this problem, take a look at our Remedy a serious blockage article.
Filament has not been loaded properly
There will be little to no extrusion at the start of the print if the filament hasn't been pulled in far enough by the extruder motor. This is because the filament may have come out or hasn't reached the area in the extruder where it gets melted yet. When loading filament, make sure you can feel the extruder motor 'grab' the filament and pull it through.
The feed tube grub screw is loose
The feed tube assembly of the extruder is fixed in place using a grub screw. Repeated accidents such as print head collisions may loosen this grub screw. This can cause the action of extruding plastic to push the hot end down and away from the extruder body, which will affect your Z-Offset calibration. If your Z-Offset is constantly too low, check out this article on diagnosing a loose feed tube grub screw: How To: Tighten the Feed Tube Grub Screw.

Not sticking to the print bed

Z-Offset is too high
If your prints are not sticking to the bed and getting caught in the extruder nozzle, your Z-Offset may need calibrating. Whether your print fails halfway through or turns into clumps of plastic at the start, read the How To: Calibrate your Z-Offset article for how to fix this issue.
You may need to tweak your print settings
The shape of the model you're trying to print may require support material and/or a raft to stick to the bed properly. In BuildFlow, this can be done after you choose your material in the model preset section.

Stringing

You may need to tweak your print settings
You may have the wrong material preset chosen for the filament you are using, or the material itself is the issue (flexible material is prone to stringing). Experiment with different model presets as well to see what works best for your model and material.
It may be unavoidable with this particular model
Stringing may simply be unavoidable in the model you are printing. Models with small gaps between structures such as the one pictures are most susceptible because the filament can't retract fast enough. Making the model slightly larger may reduce the amount of stringing in the finished product.

Blocked extruder

Z-Offset is too low
If your printer is producing incomplete layers or isn't extruding at all, there may be a blockage within the extruder and is most commonly a result of the Z-Offset being to low. You may also see plastic built up around the exterior of the extruder nozzle or hear a 'clunking' noise coming from the extruder motor. To remove the blockage, refer to the Remedy a serious blockage article. Once the blockage has been removed, read the How To: Calibrate your Z-Offset article for how to recalibrate the Z-Offset and prevent other issues.
Your extruder has retrograde extrusion
If you've been experiencing issues with your Z-Offset being too low and don't fix it straight away, your printer will be susceptible to retrograde extrusion. This happens when plastic cannot be pushed out onto the print bed and travels back up the feed tube and can either get baked on or overflow into the insulation. For more information on correct nozzle height and how to diagnose the issue, read our Nozzle height article.
The feed tube grub screw is loose
The feed tube assembly of the extruder is fixed in place using a grub screw. Repeated accidents such as print head collisions may loosen this grub screw. This can cause the action of extruding plastic to push the hot end down and away from the extruder body, which will affect your Z-Offset calibration. If your Z-Offset is constantly too low, blockages are more likely to occur and cause retrograde extrusion. Check out this article on diagnosing a loose feed tube grub screw: How To: Tighten the Feed Tube Grub Screw

Inconsistent extrusion

There may be a blockage in the extruder
Inconsistent extrusion can be a result of a blockage somewhere in the extruder. It may be as simple as some filament stuck to the outside of the extruder nozzle, or retrograde extrusion as a result of a low Z-Offset. For steps on how to fix this problem, take a look at our Remedy a serious blockage article.
Filament is not heating evenly
Filament not heating evenly may be caused by baked on residue on or in the extruder nozzle. More commonly, the filament you are using may have taken in moisture from its surroundings, as PLA is a hygroscopic material. The water will turn into pockets of steam which affect the flow of plastic when printing. To prevent this, we recommend not leaving your filament out for extended periods of time and storing it in the ziplock bag it came in.

Curling/Warping

This particular model may be prone to curling/warping
When the plastic cools it will shrink a little bit, which can cause it to come away from the bed. Models that are considerably wide are prone to curling away from the print bed because the shrinking factor of the plastic is exaggerated in larger models. To help reduce the effect, use a BuildFlow preset that includes a raft to give your model more surface area to stick to the print bed. If possible, you may also like to reduce the size of the model before printing.
One or more of you axes may be loose
Each axis uses an eccentric spacer to tighten the wheels into the grooves along each axis arm to square them up and make sure they are level. These wheels can become loose through vibration or heavy knocks caused in transport, which will result in poor bed adhesion, amongst other problems. To diagnose a loose axis, check out our Check and tighten a loose axis article.
You may need to tweak your print settings
The shape of the model you're trying to print may require a raft to stick to the bed properly. In BuildFlow, this can be done after you choose your material in the model preset section. You may also like to check that you have chosen the correct material preset, as each setting changes how the printer heats, cools and moves for each type of filament (it may be cooling too quickly and therefore not sticking to the print bed).

Small features not printed

The design has features that are too small to print
Whether you designed the model yourself or downloaded it from the Internet, if a model has features that are smaller than the diameter of your printers extruder nozzle (0.5mm), they will not be printed. You will have to increase the size of the model or redesign it to include larger features.

Stops extruding mid-print

The filament may have snapped or come out during the print
In the case that the filament breaks during a print, you can follow up the broken piece with a fresh piece of filament mid-print if you catch it soon enough. To avoid this happening in the first place, we recommend proper filament storage to preserve its strength and the use of a spool to allow the roll of filament unravel itself easily. Here is our design of a spool for you to print yourself: Me3D Desk Spooler.
Your BuildFlow unit has lost power or USB connection
If the USB connection or power cable is disconnected during a print, your BuildFlow unit can no longer send information to the printer, therefore halting the print. To avoid this, make sure both USB and power cables are securely plugged in at both ends and refrain from moving the hardware around during a print.
Your printer has lost power
If power is lost whilst printing, your printer will lose all functionality and halt the print. To avoid this, make sure the power cable is securely plugged into a working powerpoint and refrain from moving the hardware around during a print to avoid the cable coming out of the printer.