Why Do My 3D Prints Suddenly Fail After Hours of Printing?

3D Printing
1

I’ve been wondering if anyone else has experienced this.

Sometimes a 3D print looks completely fine for the first few hours, and then suddenly the model comes loose from the build plate. After that, the printer just keeps moving and creates a big mess of filament.

What confuses me is that the first few layers usually look perfect.

I’ve been checking a few things when this happens:

  • Build plate cleanliness

  • Bed temperature

  • First-layer adhesion

  • Z-offset

  • Print speed

  • Whether the model has enough contact with the build plate

  • Cooling settings

So far, I’ve noticed that larger or taller models seem to be more likely to fail. I’m also wondering if the problem could be related to warping or small changes in the first layer that become more noticeable as the print gets taller.

For those who have been 3D printing for a while, what’s usually the first thing you check when a print suddenly detaches several hours into the job?

Is it usually the build plate, temperature, model design, or something else?

Would be interested to hear what has worked for you.

2

The level of the bed, the build plate temp and adhesion.

3

Brims. About 2mm have helped my tall prints more than anything else with PLA. Printing the first five layers 5°c higher with other filaments.

4

With recommendations in the forum, I add a cover around the printer which keeps the project temp stable from start to finish. Also, you can add an Adhesive spray. There are many brands, but I use Filaform. Spray it on the bed before start printing. It should not lift.

5

Without details of the machine and filament you’re just guessing.
Machine make/model will give us the machine type( CoreXY, H-bot, BedSlinger, Delta, etc )
hotend nozzle diameter and your setting in the slicer for layer height, width. Also did you calibrate the extruder?
Filament: which filament(ABS, PLA, etc).

Is the room temperature managed and held steady throughout the duration of the print?

6

It could be also missed steps by stepper motors, if you have good build plate adhesion and have ruled that out. That would mean that print head kicks object off build plate.

That could happen also for smaller objects, but its not obvious. It can happen at bigger accelerations and is object/slicer depended.

Other thing, depending on printer of course, is that first level is well calibrated, but head positional accuracy changes with print height, but that would mean that you got issue above certain height.

7

I’ll keep the enclosure and adhesive spray in mind for future prints!

8

That’s a good point! I hadn’t considered missed steps or the print head hitting the model. I’ll keep an eye on acceleration settings and check whether the problem happens at a consistent height. Thanks for sharing these possibilities!

9

Thanks for the tip! Brims sound like a simple but effective way to improve bed adhesion, especially for tall PLA prints. I’ll give a 2 mm brim a try and see if it helps with stability!

10

Absolutely