Stationary Print Head for Irregular 3D Objects
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Solution Overview
Problem
Digital printing on three-dimensional objects is challenging due to the need to maintain a fixed distance between the print head and the surface, which is difficult with irregularly shaped items, and requires reprogramming for each unique shape, leading to inefficiencies and potential nozzle blockages.
Innovation Solution
A printing apparatus and method where the object is gripped and moved around a stationary print head using a controllably movable holder, controlled by a dummy object or CAD profile, to maintain a constant distance and orientation, allowing for printing on objects of varying shapes and sizes without reprogramming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed distance is maintained between the print head and the surface, then ink jet exit is enabled and nozzle blockage is prevented, but printing on irregularly shaped three-dimensional objects becomes difficult
Solution Approach 1:
Instead of moving the print head around the object, the object is moved around a stationary print head. The holder rotates and translates the three-dimensional object in multiple directions, allowing the stationary print head to maintain a consistent distance from various surfaces of the irregularly shaped object while printing.
Solution Approach 2:
The holder is designed with multiple degrees of freedom, enabling dynamic adjustment of the object's position and orientation. This allows the system to adapt to irregular shapes by continuously adjusting the object's pose relative to the stationary print head, maintaining optimal printing distance throughout the process.
2Productivity
If a print path is pre-programmed for identical objects, then printing efficiency is improved, but handling objects of different shapes or sizes requires reprogramming
Solution Approach 1:
A physical dummy object with the same shape as the target object is used as a template. The runner follows the contour of this dummy object, automatically generating the correct print path without requiring programming. This copying approach allows the system to handle different shapes by simply replacing the dummy object rather than reprogramming.
Solution Approach 2:
The dummy object itself serves as the guide for the runner's motion path. The geometry of the dummy object directly determines the printing trajectory, eliminating the need for external programming or complex path planning algorithms. The system self-configures based on the physical template provided.
3Manufacturing precision
If ink pressure and spray effectiveness are maintained across all positions, then printing quality is improved, but the print head design becomes more complex when moving
Solution Approach 1:
By making the print head stationary and moving the object instead, the system eliminates the complexity of designing a mobile print head that maintains constant ink pressure and spray effectiveness. The stationary print head operates in a fixed position where pressure and spray characteristics remain consistent, while the object movement handles the adaptability requirements.
Data Source
AI summary
A printing apparatus for printing onto a surface of a previously made three-dimensional article consists of a printing head which is stationary in at least two dimensions, and a controllably movable holder that grips the article and moves the article around the printing head to present parts of the three dimensional possibly contoured surface in a printing order to a preset printing position under the printing head as the printing head prints onto said surface.