Ink Density Compensation for 3D Substrate Deformation
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Solution Overview
Problem
Ink density variations occur when a pre-decorated two-dimensional substrate is transformed into a three-dimensional shape, leading to undesirable changes in the appearance of the image or coating due to stretching or shrinking, causing uneven thickness and color shifts.
Innovation Solution
A method involving the application of calculated additional ink or coating and color correction to the substrate, using a grid pattern printed on a thermally transformable polymer web, which is then digitized and used to create a mask that compensates for ink-density irregularities by adjusting ink density and color in the final formed substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a pre-decorated two-dimensional substrate is transformed into a three-dimensional shape, then the substrate takes on a desired 3D form, but the printed ink density becomes non-uniform due to stretching or shrinking
Solution Approach 1:
The patent applies preliminary action by pre-calculating and applying compensation values to the ink density before the substrate is transformed into its three-dimensional shape. The system determines compensation values based on the expected deformation and applies them in advance to the graphic image or coating density, ensuring that after transformation, the ink density remains uniform despite the shape change.
2Manufacturing precision
If additional ink is applied to compensate for ink thinning in stretched areas, then uniformity is improved, but the process complexity increases
Solution Approach 1:
The patent applies local quality by varying the ink density compensation locally across different areas of the substrate. The system divides the substrate into multiple regions and applies different compensation values to each region based on the local deformation characteristics. This allows precise control of ink density uniformity while managing process complexity through localized adjustments rather than global changes.
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
The method ensures a uniform image or coating on three-dimensional parts by compensating for ink-density fluctuations, maintaining desired shading and color intensity, and preventing unwanted darkening or lightening effects.
Implementation Method 1
the heated plastic web stretches as it is formed
Implementation Method 2
when the plastic substrate makes contact with the mold, it 'freezes off' at that point and ceases stretching
Implementation Method 3
when the substrate is shrunk in a heat tunnel or similar, the substrate will undergo a shrink in surface area making the printed ink more dense
Data Source
AI summary
Herein is disclosed a method for ink or coating density compensation by means of applying calculated additional ink/coating to the pre-decorated substrate or film, and by additionally, if needed, apply colour-correction to pre-decoration print files to compensate for higher-than-desired ink density colour shifts. The method includes the steps of providing a flat polymer web having a uniform grid pattern of grid markers printed thereon, and then thermally transforming the web to form a three-dimensional target grid. The target grid is then digitized and the change in the spacing of the grid markers is measured and recorded. The recorded transformed spacing for each grid marker is then used to modify the initial graphics file to compensate for ink-density irregularities resulting from the shrinking and stretching deformations of the substrate during thermal transformation.