In-Mould Welding Injection Mould Device
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Solution Overview
Problem
Conventional injection moulding methods require separate welding processes and equipment, increasing manufacturing time and costs due to the need for additional machinery and operator intervention to join injection-moulded plastic parts.
Innovation Solution
An injection moulding device with integrated moulding and ejection sides, featuring mirror-image cavities and welding-gate-forming patterns that allow for in-mould welding of plastic parts, eliminating the need for a separate welding process by rotating the mould portions to position parts for internal welding within the same device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate welding machines and operator intervention are used to join injection-moulded parts, then welding can be performed, but manufacturing time increases and equipment expenses increase
Solution Approach 1:
The patent combines the injection moulding process and welding process into a single integrated device. The mould portion includes both injection-side and ejection-side cavities that can simultaneously form multiple parts and position them for welding. The welding material is injected through the same device through welding gates, eliminating the need for separate welding machines and operator intervention, thus reducing manufacturing time while maintaining welding capability.
Solution Approach 2:
The injection moulding device is designed to perform multiple functions: it can inject different materials (first and second plastics) into different cavities, position the resulting parts in specific orientations, and inject welding material through welding gates. This multi-functional capability allows the single device to replace both injection moulding machines and welding machines, reducing equipment expenses and streamlining the manufacturing process.
2Reliability
If separate welding machines and operator intervention are used to join injection-moulded parts, then welding can be performed, but equipment expenses increase
Solution Approach 1:
The patent merges the functions of injection moulding and welding into a single integrated device. The mould portion contains both injection-side and ejection-side cavities for forming parts, and welding gates for injecting welding material. This consolidation eliminates the need for separate welding machines and reduces equipment expenses while maintaining full welding capability.
Solution Approach 2:
The device is designed as a universal system that can perform injection moulding of multiple different parts and subsequently perform welding operations on those parts without requiring operator intervention or additional equipment. This multi-functionality reduces the overall number of machines needed in the production line, thereby reducing equipment expenses.
3Productivity
If mirror-image cavities and in-mould welding are used, then manufacturing efficiency improves, but mould complexity increases
Solution Approach 1:
The mould is segmented into distinct injection-side and ejection-side portions, each with specific cavities for different functions. The injection-side has cavities for forming outer surfaces of parts, while the ejection-side has cavities for forming inner surfaces and positioning parts for welding. This segmentation allows for systematic organization of the complex mould structure, making it manageable and efficient for production.
Solution Approach 2:
The patent employs asymmetric cavity design where the injection-side and ejection-side cavities are not identical but are specifically configured for their respective functions. The injection-side cavities are optimized for forming outer surfaces, while the ejection-side cavities are optimized for positioning and welding. This asymmetric design, including the specific arrangement of welding gates, optimizes the mould for its dual function of moulding and welding, improving manufacturing efficiency despite the increased complexity.
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
Enables the direct welding of injection-moulded parts within the moulding device, reducing manufacturing time and equipment needs, and enhancing the structural integrity of the finished articles through reinforcement ribs and channels.
Implementation Method 1
a first plastic part and a second plastic part are made by injection moulding
Implementation Method 2
welding gates on the inner surface of one injection-moulded part become welded to the inner surface of the other injection-moulded part
Data Source
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AI summary
An injection moulding device for making articles from at least two injection-moulded parts, comprising an injection-side mould portion (10) with two equal first injection-side moulding cavities (11a, 11b) for moulding an outer surface of a first part (2) a second injection-side moulding cavity (11c) for moulding an inner surface (1a) of a second part (1) and a void cavity (11d) these latter cavities being rotary by 180º; the ejection-side mould portion (12) rotary by 180º and with two first equal ejection-side moulding cavities (13a) for moulding an inner surface (2a) of said first part (2), and two second equal ejection-side cavities (13b) for moulding an outer surface of said second part (1), welding-gate-forming patterns (14) in the second injection-side moulding cavity (11c), in each first equal ejection-side moulding cavities (13a) or in both said second injection-side moulding cavity (11c) and each of the first equal ejection-side moulding cavities (13a), the welding-gate-forming patterns (14) being designed to form injection-moulded welding gates (15) so that, when a welding material (6) has been injected into the welding gates (15), the welding gates (15) on the inner surface (1a, 2a) of one injection-moulded part (1, 2) become welded to the inner surface (2a, 1a) of the other injection-moulded part (2, 1).