Inkjet Forming Shape Accuracy via Layer Contiguity

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Solution Overview

Problem

Conventional inkjet forming methods for three-dimensional objects face shape accuracy issues due to positional inaccuracy of the inkjet head, nozzle discharge angle variability, and airflow effects, causing ink droplets to miss their intended landing positions, resulting in shape errors.

Innovation Solution

The method involves forming three-dimensional objects by vertically stacking layers with a removable or transparent portion in the overhang region, where the outer layers project more outward than the inner layers, ensuring ink droplets land on the intended position by being contiguous with the underlayer, and using a controlled inkjet printer with precise positioning and ultraviolet curing to maintain shape accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional inkjet forming methods are used to manufacture three-dimensional objects, then the manufacturing process can be completed, but shape accuracy deteriorates due to ink droplets missing their intended landing positions

Engineering Contradiction:
Improveshape accuracyVSAvoidink droplet landing accuracy
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The method performs preliminary action by forming a support structure before the target object that prevents ink droplets from falling vertically downward. The support structure is created in advance to provide a foundation that ensures accurate landing positions for subsequent ink droplets, thereby improving shape accuracy of the three-dimensional object.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support structure acts as an intermediary between the inkjet head and the target object. It mediates the ink droplet deposition process by providing a stable base that compensates for positioning inaccuracies and prevents droplets from missing their intended landing positions, thus improving manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the inkjet head is moved horizontally to form layers, then three-dimensional objects can be manufactured, but positional inaccuracy causes ink droplets to miss landing positions

Engineering Contradiction:
Improvemanufacturing capabilityVSAvoidhorizontal positioning accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The support structure is formed in advance before the target object layers. This preliminary formation provides a stable reference surface that compensates for horizontal positioning inaccuracies of the inkjet head, ensuring that subsequent ink droplets land accurately on the intended positions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support structure serves as a cushioning element that absorbs and compensates for horizontal positioning errors. By providing this preliminary cushioning structure, the system tolerates inkjet head positioning variations while maintaining accurate ink droplet landing positions on the target object.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If vertically lower layers project more outward than vertically upper layers in the overhang region, then shape accuracy improves, but the structure requires additional support portions

Engineering Contradiction:
Improveshape accuracyVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The structure is segmented into the target object and the support structure, which are formed at different stages. The support structure is created first as a separate entity, allowing the target object to be formed with accurate shapes without requiring complex integrated support features in the final product.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support structure is extracted as a separate functional element that can be removed after the target object is formed. This extraction allows the target object to achieve high shape accuracy without permanently incorporating the support portions, maintaining simplicity in the final product while enabling complex formation during manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

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 significantly improves the shape accuracy of three-dimensional objects by preventing ink droplets from falling vertically downward, allowing for precise manufacturing of target objects without the need for removing the removable portion, thus enhancing the manufacturing process.

Implementation Method 1

ink droplets discharged by inkjet printing through nozzles of an inkjet head

Methodology Applied
Scientific EffectInkjet printing:

Implementation Method 2

curing the deposited droplets by light irradiation

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3132922B1Inkjet forming method
Publication Date: 2020.05.06 MIMAKI ENGINEERING CO LTD
  • EP3132922B1 patent drawingFigure 1
  • EP3132922B1 patent drawingFigure 2
  • EP3132922B1 patent drawingFigure 3(a)~3(d)

AI summary

An inkjet forming method is provided that manufactures a three-dimensional object by vertically stacking a plurality of horizontally extending layers formed of ink droplets discharged by inkjet printing. The contour of a region in one layer, constituting a target object, in the horizontal direction is contiguous with a region in the layer constituting a removable portion and is vertically contiguous with a region constituting the target object in another layer immediately above and vertically contiguous with the one layer. At least a part of the region constituting the removable portion forms a contour of the layer in the horizontal direction. When a target layer is formed by the inkjet forming method, an entirety of the target layer and an entire contour of the target layer in the horizontal direction are vertically contiguous with an inner part of another layer immediately below the target layer than a contour of the layer immediately below the target layer in the horizontal direction.