Bulk temperature still matters
Large-format parts can accumulate heat faster than they release it, especially in thick sections and repeated short tool paths.
Heat accumulation
Heat accumulation in large-format extrusion AM.
Large polymer prints can retain too much heat when paths are short, walls are thick, material flow is high, or the build geometry traps thermal energy.
Problem
Too much retained heat turns productivity into a geometry risk.
Heat accumulation can show up as slumping, sagging, warping, distortion, dimensional instability, or part collapse in severe cases. Slowing the process may help, but it can reduce throughput and still leave the process poorly documented.
The industrial objective is a controlled window: enough heat at the deposition interface for bonding, while the broader part remains stable enough to hold shape.
Instability is a production limit
Slumping and distortion can make a build unusable even when the material bonds well at the interface.
Cooling can be part of the window
When retained heat limits the thermal process window, active cooling and process data can support more repeatable path and speed decisions.
PETG cube process results
Process data shows how cooling, speed, and heating change the build window.
A LEAM internal PETG cube test compared constant layer time, adaptive feed, active cooling, and localized heating on the same 350 mm geometry. The process data shows how speed, cooling, and deposition-interface heating can be coordinated to manage retained heat while supporting bonding conditions at the interface.
Print time is shown as hours:minutes.
Constant layer time
01:29 print time
100% baseline
Adaptive feed
01:21 print time
9.6% shorter print time
Adaptive feed + cooling
00:43 print time
52.2% shorter print time
Cooling + localized heating
00:44 print time
50.1% shorter print time
- Print time: active cooling with adaptive feed shortened the PETG cube print time from 01:29 to 00:43, a 52.2% shorter print time versus constant layer time while managing retained heat.
- Deposition-interface temperature: adding localized heating kept print time at 49.9% of baseline and raised the reported contact temperature from 137 °C to 158 °C, improving bonding conditions at the interface.
Source: LEAM internal PETG cube process-data test, prints from 2025-10-29. These values describe process behavior and print time; mechanical strength and part performance still depend on material- and application-specific validation.
Related resources
Balance part stability with layer adhesion.
Heat accumulation should be reviewed together with interlayer bonding, interface temperature, and build repeatability.