De-powdering Nested Additive Objects via Segmentation
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Solution Overview
Problem
In binder jetting additive manufacturing, de-powdering nested objects within a stacked powder bed is complicated due to the substantial volume of unbound powder and inaccessibility of objects buried deep within the stack, making it difficult to remove loose powder effectively.
Innovation Solution
The build box subsystem collaborates with the de-powdering subsystem to isolate each nested object by inserting a separating blade into the print bed stack, creating an artificial floor and using air jets and vacuum devices to agitate and remove unbound powder, while also employing separation plates between layers to simplify the de-powdering process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If objects are vertically stacked to form a print bed stack of nested objects, then productivity is improved by fabricating multiple objects in one build box, but de-powdering complexity increases due to substantial volume of unbound powder and inaccessibility of buried objects
Solution Approach 1:
The patent divides the nested object stack into separate de-powdering zones by inserting a separating blade between layers. This segmentation allows each object or layer to be de-powdered independently, reducing the complexity of removing powder from deeply buried objects while maintaining high productivity through multi-object fabrication
2Ease of operation
If a separating blade is inserted into the print bed stack to isolate nested objects, then ease of operation is improved by making loose powder more accessible, but device complexity increases due to additional separating mechanisms
Solution Approach 1:
The separating blade acts as an intermediary element that temporarily divides the powder bed stack during de-powdering. This simple blade structure provides effective powder accessibility without requiring complex mechanisms, as it can be easily inserted and removed between printing cycles
3Device complexity
If separation plates are stacked on top of the build area between different object levels, then device complexity is reduced by eliminating the need for inserting separating blades, but manufacturing precision may be affected by irregularities in plate planarity
Solution Approach 1:
The separation plates are pre-positioned on the build area before printing begins, establishing a uniform powder surface in advance. This preliminary action eliminates the need for post-printing surface re-establishment, compensating for any plate irregularities and maintaining manufacturing precision while reducing overall device complexity
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 allows for efficient de-powdering of nested objects individually, reducing the complexity of powder removal and improving accessibility, thereby facilitating a more straightforward and effective de-powdering process.
Implementation Method 1
a controlled pattern of the liquid binder is applied to successive layers of the powder in a powder bed such that the layers of the material adhere to one another
Implementation Method 2
air jets and vacuum devices to agitate and remove unbound powder
Implementation Method 3
air jets and vacuum devices to agitate and remove unbound powder
Data Source
AI summary
According to some aspects, a de-powdering subsystem for an additive fabrication system is described. The de-powdering subsystem may comprise a bath subsystem. The bath subsystem may comprise a reservoir configured to contain a liquid and to accept objects to be de-powdered into the liquid, and an agitation facility configured to cause currents within the liquid. The agitator facility may be at least one of (i) a pump configured to circulate the liquid within the reservoir, (ii) a heating element configured to generate convection currents in the liquid, and (iii) a stirrer driven through a linkage to a motor. The bath subsystem may comprise at least one ultrasonic transducer configured to apply ultrasonic vibrations to the liquid within the reservoir.