It's Not Magic, It's Variables
When a print fails, we tend to blame "bad luck." As engineers, we know luck isn't a variable. Failure is simply a misalignment of parameters. I've spent hundreds of hours tuning my Anycubic Kobra and Photon Mono, and I've learned that 90% of failures come down to three things: Adhesion, Moisture, and Temperature.
The Myth of the "Perfect" Z-Offset
The first layer is the only layer that matters. If you are getting "spaghetti" (a pile of loose filament), your nozzle is too high. If your extruder is clicking and grinding, your nozzle is too low.
The "Paper Test" is not accurate enough. I use a live Z-offset calibration print. I adjust the offset by 0.05mm increments while the skirt is printing until the lines fuse perfectly.
Hydroscopy: The Invisible Enemy
I live in Bogota (and previously Miami). Humidity is the silent killer of TPU and PETG. Wet filament boils in the hotend, creating steam bubbles that pop and leave gaps in your walls.
If you hear popping sounds while printing, your filament is wet. I now print TPU strictly from a heated dry box running at 50°C. It's not optional.
Thermal Runaway & Warping
Why do corners lift off the bed? Differential cooling. The plastic cools and contracts faster than the heated bed can hold it. To fix this for ABS or ASA:
- Enclosure: Keep the ambient temp stable.
- Brims: Increase surface area contact.
- No Drafts: Even a door opening can warp a large print.
SLA: The Chemical Variable
Resin printing fails differently. Usually, it's a "suction force" issue. If your FEP film is too loose, or your lift speed is too high, the print rips off the supports and sticks to the vat bottom.
My fix: PTFE Lubricant on the FEP film and slowing the lift speed to 1mm/s for the first 5mm of the print.
Document Your Failures
Every time a print fails, I write down the settings in a logbook. This turns a waste of plastic into a data point. Stop guessing, start measuring.