Additive Manufacturing Using Heat-Curable Adhesive and Laser Curing
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Solution Overview
Problem
Existing additive manufacturing methods, such as binder jetting and selective laser sintering, face limitations in manufacturing speed and energy consumption, with binder jetting being slow due to curing times and selective laser sintering requiring high energy to heat metallic materials to their melting point.
Innovation Solution
A method using a heat-curable adhesive applied layer by layer, which is selectively activated and cured using controlled thermal energy, such as a laser, to fuse powder grains at a lower temperature, reducing energy consumption and increasing manufacturing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If binder jetting is used to fuse powder grains with a binder, then the manufacturing process can be implemented, but the manufacturing speed is limited due to curing time requirements
Solution Approach 1:
The invention uses phase transition of the binder material from uncured to cured state through thermal energy input. The binder is applied in an uncured state and then rapidly cured by heating to its curing temperature, enabling fast phase transition and eliminating long curing times. This resolves the contradiction by using controlled phase change to achieve both complete binder curing and high manufacturing speed.
Solution Approach 2:
The invention employs periodic application of thermal energy to cure the binder in a controlled manner. Instead of continuous heating, thermal energy is applied in periodic pulses or cycles, allowing the binder to cure completely while maintaining high processing speed. This periodic action enables the system to achieve both thorough curing and rapid manufacturing.
2Strength
If selective laser sintering is used to directly sinter metallic particles, then the particles can be fused without binder, but substantial energy must be used to heat particles to their melting point
Solution Approach 1:
The invention introduces a binder as an intermediary material between the laser energy and the metallic powder particles. Instead of directly heating and melting the metal particles (which requires very high energy), the binder acts as a mediator that absorbs thermal energy at lower temperatures and transfers it to fuse the particles. This intermediary approach achieves strong bonding with significantly reduced energy consumption compared to direct laser sintering.
Solution Approach 2:
The invention changes the temperature parameter from the melting point of metals (1,000°C or above) to the much lower curing temperature of the binder material. By selecting a binder with appropriate curing temperature well below metal melting points, the process achieves particle fusion at reduced temperatures, thereby dramatically lowering energy consumption while maintaining binding strength.
3Manufacturing precision
If a binder is applied selectively layer by layer, then the workpiece can be built up precisely, but the manufacturing speed is limited by the printing speed of the print head
Solution Approach 1:
The invention inverts the conventional approach by applying the binder in a non-selective manner over the entire powder bed surface, then using selective thermal energy input to cure the binder only in regions where the workpiece should be formed. This inversion eliminates the limitation of print head speed while maintaining precise workpiece definition through selective curing, thereby resolving the contradiction between precision and manufacturing speed.
Solution Approach 2:
The invention replaces the mechanical printing system (print head moving layer by layer) with a thermal field-based selective curing system. Instead of mechanically depositing binder selectively, the system applies binder universally and uses controlled thermal energy to selectively cure it. This substitution of mechanical deposition with thermal field control eliminates mechanical speed limitations while preserving precision through selective energy application.
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 approach allows for high-speed additive manufacturing with lower energy usage by curing the adhesive at a temperature lower than the melting point of metals, enabling efficient and rapid production while conserving energy.
Implementation Method 1
the adhesive used is not applied selectively as in the prior art, but over a larger surface, i.e., without exception on the entire surface of the powder bed, and it is cured, in particular thermally cured, only selectively
Implementation Method 2
A method using a heat-curable adhesive applied layer by layer, which is selectively activated and cured using controlled thermal energy, such as a laser
Implementation Method 3
the energy input in/on the heat-curable adhesive or the hot-melt adhesive takes place by means of waves, in particular by means of electromagnetic waves, for example by means of microwaves, UV radiation, light, polarized light, monochromatic light, or the like. Since the adhesive according to the invention cures as a result of a heat input, high-energy radiation is generally to be preferred here, for example infrared rays.
Data Source
AI summary
The invention is directed to a method and an apparatus for building up a workpiece layer by layer in the course of an additive manufacturing process, in particular in the form of a powder-bed process, wherein grains of a powder are fused to one another by using a binder, wherein the binder used is a heat-curable adhesive which is not applied selectively but layer by layer and which is activated and cured by a controlled energy source, in particular a laser with a controlled laser beam, and thereby fuses respectively adjacent grains of the powder.