Diffusion Bonded Insertion Block for Injection Moulding
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Solution Overview
Problem
Existing moulding insertion blocks for forming hook fields in moulded objects often result in burrs due to separation under injection pressure, making the hook fields unusable and requiring costly repairs, and are difficult to produce with small thicknesses, occupying excessive space.
Innovation Solution
The use of diffusion bonding to securely attach plates without a liquid interface, incorporating aeration channels with stepped or flared cross-sections to prevent thermoplastic infiltration and burr formation, allowing for thin, space-efficient hook fields with smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If plates are clamped together or welded together at their ends to form an insertion block, then the plates are held together during injection moulding, but the plates might slightly separate from each other under the effect of the injection pressure, resulting in burr formation
Solution Approach 1:
The patent replaces mechanical fastening systems (clamps, welds) with a diffusion bonding process that creates a monolithic structure. The plates are bonded together through diffusion bonding to form a single integrated insertion block without mechanical joints, eliminating the separation issue under injection pressure that causes burrs.
Solution Approach 2:
The patent merges multiple plates into a single integrated structure through diffusion bonding. The individual plates lose their independent identity and become part of a unified insertion block, eliminating interfaces where separation and burr formation could occur.
2Strength
If a combination of clamping and welding methods is used to attach plates, then the plates are securely held together, but the insertion block requires significant space for clamping devices, resulting in a used surface area much greater than the hook field area
Solution Approach 1:
The patent merges the attachment function into the bonding process itself, eliminating the need for separate clamping devices. The diffusion bonding creates internal bonds between plates without requiring external clamping mechanisms, dramatically reducing the space required in the mould.
Solution Approach 2:
The patent extracts the clamping function from the final structure. Instead of requiring permanent clamping devices that occupy space, the clamping action is temporary and only present during the bonding process, after which no clamping elements remain in the insertion block.
3Strength
If plates are clamped together to form an insertion block, then the plates remain attached during moulding, but it becomes difficult to produce inserts with small thicknesses, e.g., less than 10 mm
Solution Approach 1:
The patent replaces mechanical fastening with diffusion bonding, which can effectively join plates of any thickness. The bonding process works at the material level rather than relying on mechanical interlocking, making it suitable for thin plates where mechanical fasteners would be impractical.
Solution Approach 2:
The patent changes the bonding mechanism from mechanical to thermal/diffusion-based, allowing effective joining of thin plates. The diffusion bonding process parameters (temperature, pressure, time) can be adjusted to accommodate various plate thicknesses, including very thin plates less than 10 mm.
4Reliability
If the insertion block is repaired by better clamping the plates, then the hook field can be made usable, but the production process must be stopped, resulting in costs in terms of time, personnel and productivity
Solution Approach 1:
The patent replaces mechanical fastening with diffusion bonding to create a defect-free monolithic structure that requires no repair. The bonding process ensures complete fusion between plates, eliminating the need for post-production clamping repairs and maintaining continuous production.
Solution Approach 2:
The patent performs the bonding action preliminarily, before the insertion block is used in production. The diffusion bonding is completed during manufacturing, ensuring the structure is ready for use without requiring any corrective clamping actions during ongoing production.
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 solution effectively prevents burr formation, enables the production of thin, space-efficient hook fields, and ensures the hooks have smooth, curved shapes suitable for fixation, improving productivity and reducing scrap rates.
Implementation Method 1
By attaching the plates to each other by this process, which is a piece-joining process for forming a solid piece, which does not require a liquid interface as in brazing, and which does not produce a porous connection by melting and re-solidification as in conventional fusion welding.
Data Source
AI summary
Object molded in thermoplastic material in any shape having an outer surface from which protrudes at least one hook in one piece with the molded object, in particular a hook field, the molded object and the hook(s) having been formed by injection molding, each hook comprising a base part and a head or hooking part protruding from the base part and being delimited by first and second lateral surfaces each extending on the outer surface of the molded object, being separated from each other by an intermediate surface forming the edge of the hook, the curve sections, defined by the intersections of at least one of the first and/or second lateral surfaces with planes which are in parallel with the base plane from which the hook protrudes and which are at given distances h from this base plane, have a curvature which varies as a function of the distance h, the curvature of the curve section for h=0 (the base plane and said parallel plane merging) being greater than the curvature of at least one curve section for a distance h substantially corresponding to a level of the head of the hook.