PUR Adhesive Green Strength for Door Assembly
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Solution Overview
Problem
The door manufacturing process faces challenges such as warping of skins due to temperature or humidity, inaccurate application of components, and incomplete bonding, leading to defects and quality issues in assembled doors.
Innovation Solution
The use of a polyurethane reactive (PUR) adhesive with controlled application and timing to achieve green strength quickly, preventing movement of door components during assembly, and ensuring precise positioning and bonding through automated systems and methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional adhesives are used with standard application timing, then the bonding process is simple, but the door components shift and warp during assembly and transportation
Solution Approach 1:
The patent changes the parameters of the adhesive system by using a PUR adhesive with specifically controlled open time (1-4 minutes) and application temperature (265-285°F), allowing the adhesive to achieve green strength quickly enough to prevent component shifting during assembly and transportation while maintaining manageable process complexity
Solution Approach 2:
The adhesive is applied to the frame surface before the door skin is positioned, and the assembly is immediately conveyed to a press that applies pressure within 30-35 seconds of adhesive application, ensuring the adhesive achieves sufficient bond strength before the door leaves the assembly line
2Adaptability or versatility
If prefabricated solid cores are used, then the core provides structural integrity, but the cores cannot be universally applied to wide variety of door designs
Solution Approach 1:
Instead of using a single prefabricated core, the patent divides the core into multiple insert pieces that can be selectively placed in the cavity, allowing the same basic core structure to be adapted to different door designs by varying the number, size, and placement of insert pieces
Solution Approach 2:
The core system is designed to be universal by using a standardized cavity structure that can accommodate different combinations of insert pieces, enabling the same core framework to serve multiple door designs while maintaining the ability to customize for specific requirements
3Manufacturing precision
If expanding foam is injected through holes in the frame, then the core fills the entire internal cavity, but the process requires drilling holes and allows foam expansion variability
Solution Approach 1:
The patent extracts the foam injection step from the assembly process by using pre-formed foam cores or insert pieces that are placed in the cavity before assembly, eliminating the need to drill holes in the frame and allowing for more controlled foam placement and expansion
4Reliability
If adhesive is applied with standard timing, then the bonding is sufficient, but warping occurs due to temperature or humidity delays
Solution Approach 1:
The patent changes the timing parameter of adhesive application by using a PUR adhesive with a 1-4 minute open time, which provides sufficient time for precise component positioning and assembly while the adhesive reaches green strength quickly enough to prevent warping during subsequent transportation and handling
Solution Approach 2:
The assembly process is designed to be continuous, with the door conveyed immediately from the adhesive application point to the pressing point within 30-35 seconds, eliminating delays that would allow warping to occur while maintaining continuous adhesive bonding action
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 minimizes defects and ensures quality construction by maintaining component positionality during transportation and assembly, allowing for efficient and defect-free door assembly.
Implementation Method 1
The use of a polyurethane reactive (PUR) adhesive with controlled application and timing to achieve green strength quickly, preventing movement of door components during assembly
Data Source
AI summary
Doors, half doors, systems and methods of making the same are described, including use of an adhesive that is capable of achieving green strength in a predetermined time, including for exemplary automated embodiments, to prevent movement of the components relative to each other.