Sensor Unit for Selective Laser Melting Build Platform
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Solution Overview
Problem
The challenge in selective laser melting is achieving an exact thickness of the first powder layer on a build platform, which is complicated by high temperatures causing thermal expansions and manual adjustments are difficult due to the risk of collision and height errors.
Innovation Solution
A method using a sensor unit with a sensor assembly that detects an intermediate position and adjusts the build platform's starting position by lowering it by the exact thickness of the powder layer, coupled with a levelling assembly, to ensure precise layer thickness regardless of thermal expansions, allowing for automatic adjustment and increased process safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment of the build platform is used to achieve exact powder layer thickness, then adjustment flexibility is maintained, but adjustment precision deteriorates due to thermal expansions at high temperatures
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated drive system that electronically positions the build platform. The drive receives control signals to move the build platform to a precisely defined starting position, eliminating manual intervention and its associated imprecision under thermal conditions.
Solution Approach 2:
The system uses a sensor assembly to automatically detect the intermediate position of the build platform and triggers the drive to automatically adjust the platform position. This self-service mechanism eliminates the need for operator intervention and maintains consistent precision regardless of thermal expansion.
2Reliability
If the build platform is preheated to high temperatures to prevent internal stresses, then component quality is improved, but positioning accuracy deteriorates due to thermal expansions
Solution Approach 1:
The patent defines an intermediate position for the build platform that is determined before the actual powder layer application. The drive automatically adjusts the platform from this intermediate position to the exact starting position, compensating for thermal expansions that occur during preheating.
Solution Approach 2:
The sensor assembly detects the intermediate position of the build platform and provides feedback to the control system. Based on this feedback, the drive calculates and executes the precise adjustment needed to reach the starting position, compensating for thermal effects.
3Stability of the object's composition
If a rigid levelling assembly is used to apply powder layers, then structural stability is maintained, but collision risk increases with thermal expansions
Solution Approach 1:
The patent employs a levelling assembly with levelling elements that can adapt their position. These elements can move or flex to accommodate thermal expansions of the build platform, maintaining contact with the platform surface without causing collisions, thus combining stability with adaptability.
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 adjustment of the first powder layer thickness, compensating for thermal elongations and ensuring secure adhesion to the build platform, thereby enhancing process safety and enabling automated production.
Implementation Method 1
The build platform or the base plate mounted on the build platform is heated to temperatures in excess of 250 degrees C.
Implementation Method 2
This heating process causes considerable thermal expansions which also affect the position of the build platform.
Implementation Method 3
The invention relates to a method for the manufacture of a molding, in particular through selective laser melting
Implementation Method 4
method for the manufacture of a molding, in particular through selective laser melting
Data Source
AI summary
The invention relates to a method for the manufacture of a molding through generative processing methods, in particular through selective laser melting, wherein a model of a molding is built from a powder material according to CAD data, wherein an application unit is used to apply a powder layer and the powder layer applied is fixed to a layer arranged there under or a base plate by means of radiation, characterized in that prior to applying a first layer onto a build platform or a base plate, a sensor assembly having a sensor level which is located in relation to the levelling level of a levelling assembly for the applied powder layer is allocated to the build platform or the base plate, the build platform or the base plate is moved in relation to the sensor assembly until the sensor assembly emits a signal for stopping the build platform to a drive in an intermediate position, and starting from the intermediate position, the build platform or the base plate is moved by a distance to adjust the layer thickness of the first powder layer and is positioned in a starting position.