Most "printer problems" are actually material problems
It's a natural instinct to assume a failed print means something is wrong with the machine. In practice, a large share of common print failures trace back to the filament itself, either the wrong material for the application, old or poorly stored filament, or print settings that don't match what the material actually needs. Find your symptom below.
Symptom: Your print is warping or lifting off the bed
Likely cause: this is a classic sign of a material that's more heat-sensitive than your settings account for, or insufficient bed adhesion for the material in use. PETG and ABS-style materials are more prone to warping than PLA if bed temperature isn't dialled in correctly.
Fix: if you're using PETG, double-check your bed temperature is in the recommended range for that specific filament, and make sure your build surface is genuinely clean. If warping persists with PLA specifically, it's worth checking for draughts or inconsistent ambient temperature near your printer.
Symptom: Thin, hair-like strings between parts of your print
Likely cause: stringing happens when filament oozes from the nozzle during travel moves rather than only during active printing. PETG is particularly prone to this compared to PLA, due to its different viscosity when molten.
Fix: retraction settings tuned specifically for your filament type usually solve this. If you've recently switched from PLA to PETG and started seeing stringing that wasn't there before, your retraction settings likely need adjusting for the new material rather than the old default.
Symptom: Your finished part snaps or cracks under light pressure
Likely cause: this is almost always a material mismatch rather than a printer fault. Standard PLA is rigid but genuinely brittle under sudden impact or repeated flexing, a limitation of the material itself rather than a printing error.
Fix: if a part needs to survive impact, flexing, or repeated mechanical stress, the fix isn't a setting, it's a material swap. PETG offers significantly better impact resistance for functional parts, and TPU is the right choice entirely if the part needs to flex rather than just survive stress.
Symptom: Your TPU print won't extrude consistently
Likely cause: TPU is considerably more demanding on your extruder than PLA or PETG, and a setup that handles those materials fine can struggle with TPU's flexibility, particularly with certain extruder designs.
Fix: slow your print speed down specifically for TPU prints, and double check your filament path for unnecessary bends or tight turns where flexible filament can buckle rather than feed smoothly.
Symptom: Your print looks fine, but feels weirdly weak after a few weeks
Likely cause: this often points to filament that's absorbed moisture from the air during storage. PLA and especially more hygroscopic materials can degrade in print quality and final part strength if the spool has been stored in humid conditions for an extended period.
Fix: store opened filament spools in a sealed container with a desiccant pack, particularly relevant in coastal or humid parts of South Africa, and consider this the cause first if older, previously fine filament suddenly starts producing weaker or rougher prints.
Quick reference: matching the material to the failure you're trying to avoid
| If you need... | Choose | Watch out for |
|---|---|---|
| Easy, reliable everyday prints | PLA | Brittleness under impact, heat sensitivity |
| Durable, functional parts | PETG | Stringing, needs tuned retraction |
| Flexible, bendable parts | TPU | Slower printing, extruder sensitivity |
Before you troubleshoot your printer settings further: ask whether the material itself is actually suited to what you're trying to build. A surprising number of "my printer is broken" support questions turn out to be "my filament was never going to work for this part."
Ready to rule out filament as the problem? Toner and Ink stocks PLA, PETG and TPU filament suited to ELEGOO Neptune and other popular FDM printers, with guidance available if you're not sure which to choose.