Additive Manufacturing Temperature Control via Sacrificial Object
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Solution Overview
Problem
In additive manufacturing, precise control of surface temperature during the fabrication process is challenging due to non-uniform temperature distribution and thermal stress, leading to defects such as warpage and inadequate material properties, especially when using low-resolution thermal sensors that struggle to accurately measure temperatures of small objects.
Innovation Solution
The implementation of a sacrificial object within the build chamber, which is discarded after completion, allows for accurate thermal feedback to adjust the power level of the thermal energy source, ensuring consistent temperature control and improved build quality by forming sacrificial layers that can be measured by thermal sensors to stabilize and monitor the build object's temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If low-resolution thermal sensors are used to measure temperature during additive manufacturing, then device complexity is reduced, but measurement precision deteriorates leading to inaccurate temperature readings of small objects
Solution Approach 1:
A sacrificial object is introduced as an intermediary medium between the thermal energy source and the actual build object. This sacrificial object serves as a temperature reference that can be accurately measured by low-resolution thermal sensors, allowing indirect temperature control of the build object without requiring high-resolution sensors.
Solution Approach 2:
The sacrificial object acts as a thermal copy or surrogate of the build object. By measuring the temperature of this copy instead of the original build object directly, the system achieves accurate temperature monitoring despite sensor limitations. The sacrificial object replicates the thermal characteristics needed for measurement purposes.
2Productivity
If thermal energy is applied to build material to fuse layers, then manufacturing progress is achieved, but non-uniform temperature distribution occurs causing warpage and defects
Solution Approach 1:
The system implements a feedback loop where thermal sensors continuously monitor the temperature of the sacrificial object, and this temperature information is used to adjust the power level of the thermal energy source in real-time. This closed-loop control ensures uniform temperature distribution and prevents warpage while maintaining build productivity.
Solution Approach 2:
The system dynamically changes the power level parameter of the thermal energy source based on measured temperature conditions. By adjusting this parameter in response to feedback, the system maintains optimal temperature uniformity across the build area, preventing dimensional inaccuracies while sustaining manufacturing progress.
3Manufacturing precision
If temperature control is tightened to prevent warpage and defects, then manufacturing precision improves, but device complexity and control difficulty increase
Solution Approach 1:
The sacrificial object serves as a simplified intermediary that provides a single, measurable temperature reference point. This approach simplifies the control system compared to attempting to directly measure and control temperatures at multiple points on the build object, while still achieving the precision needed to prevent warpage and defects.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables precise temperature control and improved dimensional accuracy and material properties by using the sacrificial object's temperature measurements to adjust the thermal energy application, reducing defects and enhancing the overall quality of the build object.
Implementation Method 1
A thermal energy source can also be mounted on the carriage system and moved across a build surface. In an example additive manufacturing process, energy may then be applied to the layer of build material to solidify those portions of the layer on which fusing agent was deposited
Implementation Method 2
The thermal sensor can measure a thermal temperature of the sacrificial object and provide thermal feedback to the controller for controlling the thermal energy source
Implementation Method 3
The sensed thermal temperature of the sacrificial object can be used as feedback to control the thermal energy source
Data Source
AI summary
Some examples include a method of operating an additive manufacturing machine including forming a layer of a build material, selectively applying a fusing agent onto the formed layer of build material, applying fusing energy to the build material and fusing agent with a thermal energy source to form an object layer of a three dimensional object and a sacrificial layer of a sacrificial object at the selectively applied fusing agent, sensing a thermal temperature of the sacrificial layer, comparing the sensed thermal temperature of the sacrificial layer to a target temperature, and adjusting a power level of the thermal energy source based on the compared temperatures.