Mold Surface Treatment via Inclined Sliding Abrasive Blasting
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Solution Overview
Problem
The existing methods for improving demoldability of molded products, such as mirror-polishing and forming recesses, often require labor-intensive processes and can result in scratches on the workpiece and rapid mold wear due to load concentration on sharp protrusions.
Innovation Solution
A surface treatment method involving three blasting steps: first, removing the hardened layer and adjusting surface roughness; second, creating fine irregularities; and third, flattening peaks of irregularities by sliding abrasives at an inclined angle, using elastic or plate-like abrasives to prevent peak formation and ensure even surface contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface of the mold is mirror-polished by hand, then the surface finish of the workpiece is improved and demoldability is enhanced, but the fabrication time and cost of the mold increase significantly
Solution Approach 1:
The patent replaces manual mechanical polishing with a blasting process using abrasive particles. The blasting apparatus projects abrasive particles onto the mold surface, achieving the desired surface finish through controlled abrasion rather than manual polishing, thereby reducing fabrication time and labor while maintaining surface quality
Solution Approach 2:
The patent controls the surface properties by adjusting blasting parameters such as abrasive particle size, projection pressure, and blasting duration. By optimizing these parameters, the mold surface achieves the appropriate roughness profile that enhances demoldability without requiring time-consuming manual polishing
2Ease of operation
If recesses are formed by blasting to improve demoldability, then the workpiece can be removed more easily, but sharp protrusions are created that concentrate load and cause rapid mold wear
Solution Approach 1:
The patent creates a non-uniform surface structure with localized recesses and rounded peaks rather than a uniform finish. The blasting process generates a profile where recesses provide demoldability while the peaks are rounded through controlled abrasion, distributing contact points and preventing load concentration on sharp protrusions
Solution Approach 2:
The blasting process preliminarily shapes the surface profile before final use, creating rounded peaks and recesses that simultaneously provide demoldability and distribute contact loads. This preliminary surface preparation prevents subsequent mold wear by eliminating sharp protrusions that would otherwise concentrate stress during demolding
3Ease of operation
If irregularities are formed on the mold surface to improve demoldability, then the workpiece can be demolded more easily, but the irregularities are transferred to the workpiece surface creating unwanted roughness
Solution Approach 1:
The patent optimizes the blasting parameters including abrasive particle size distribution, projection velocity, and surface coverage to create a controlled surface profile. The resulting irregularities have specific size ranges and distribution patterns that provide demoldability while being too small or too distributed to create visible defects on the workpiece surface
Solution Approach 2:
The blasting process creates a micro-porous or micro-irregular surface structure that provides demoldability through air pockets and reduced contact area. These micro-scale irregularities are sufficient to prevent sticking but too fine to be transferred as visible roughness to the workpiece during molding
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 enhances demoldability by reducing friction and preventing scratches on the workpiece while minimizing mold wear, allowing for easier demolding and improved productivity without the need for laborious polishing.
Implementation Method 1
a first blasting for removing a hardened layer produced on the surface and/or for adjusting the surface roughness
Implementation Method 2
a second blasting for creating fine irregularities on the surface
Implementation Method 3
a third blasting for flattening peaks of the irregularities created on the surface, the third blasting being performed by causing an ejected abrasive to slide along the surface of the mold
Data Source
AI summary
Provided is a method of treating a surface of a mold to achieve good demoldability and capable of preventing wearing of the mold by avoiding load concentration on one part of the surface of the mold. After a first blasting is performed on the surface of the mold to remove a hardened layer produced on the surface and/or to adjust the surface roughness, a second blasting is performed to create fine irregularities on the surface. Then, an elastic abrasive in which abrasive grains are carried on an elastic body, or a plate-like abrasive having a planar shape with a maximum length that is 1.5 to 100 times the thickness thereof, is ejected onto the surface of the mold at an inclined ejection angle such that the abrasive is caused to slide along the mold surface to flatten peaks of the irregularities created on the mold surface.