Midplate Attachment Structures for Electronic Device Rework
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The alignment inaccuracies introduced by relying on holes and screws for mounting midplates in electronic device housings can lead to performance issues over the device's lifetime, as they allow for movement and misalignment, complicating rework and repair operations.
Innovation Solution
The use of welded tabs, welded and screwed nuts, overmolded plastic heat stakes, and adhesive connections for accurately assembling and reattaching midplates within electronic device housings, allowing for precise placement and facilitating rework and repair by removable connections such as cutting, solvent dissolution, or unscrewing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If holes and screws are used to mount midplates, then rework and repair operations can be performed, but alignment inaccuracies and movement occur over the device lifetime
Solution Approach 1:
The mounting system is divided into separate functional elements: alignment features (precision-machined surfaces, pins, or fixtures) and attachment features (weld tabs, nuts, or other fastening mechanisms). This segmentation allows the alignment function to be precisely defined during assembly while the attachment function provides secure, permanent fixation that prevents movement over time.
Solution Approach 2:
Alignment features are pre-configured into the midplate or housing structure before the actual attachment process. These preliminary alignment elements (such as precision-machined surfaces, locating pins, or registration features) ensure accurate positioning is achieved before the permanent attachment is made, eliminating the need for holes and screws that compromise alignment.
2Manufacturing precision
If permanent connections such as welds are used, then accurate placement is achieved, but rework operations become difficult
Solution Approach 1:
The connection system is segmented into alignment features (which ensure precision) and attachment features (which enable rework). Alignment features such as precision-machined surfaces or locating pins establish accurate positioning, while separate attachment features like weld tabs, nuts, or mechanically removable connectors provide the permanent yet reworkable connection.
Solution Approach 2:
Intermediary attachment features serve as mediators between the midplate and housing structure. These intermediaries (such as weld tabs that can be cut, nuts that can be unscrewed, or mechanically removable connectors) allow the permanent connection to be made with high precision while maintaining the capability for future rework through controlled removal methods.
3Strength
If welded tabs or adhesive connections are used, then structural strength is improved, but rework operations require specialized equipment
Solution Approach 1:
The attachment system is segmented into different functional zones: areas with high-strength permanent connections (welded tabs or adhesive-bonded regions) and areas with controlled-release features (such as tabs designed for cutting, nuts for unscrewing, or heat-stake structures for removal). This segmentation allows the overall assembly to achieve high structural strength while maintaining rework capability through targeted removal of specific attachment features.
Solution Approach 2:
The attachment features are designed with parameters that allow controlled changes in connection strength. For example, weld tabs can be designed with specific geometries that provide strong welding but easy cutting; adhesive bonds can be designed with specific shear strengths that allow controlled failure; heat-stake structures can be designed to release at specific temperature thresholds. These parameter changes enable the transition from strong attachment to removable states.
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 ensures accurate and secure attachment of midplates, maintaining mechanical rigidity and strength while enabling efficient rework and repair operations by allowing for the removal and reinstallation of midplates without compromising the device's structural integrity.
Implementation Method 1
The housing midplate may be accurately assembled to the display frame using connections formed using welded tabs
Implementation Method 2
overmolded plastic heat stake structures
Implementation Method 3
overmolded plastic structures and adhesive
Implementation Method 4
by using solvent to dissolve adhesive
Data Source
AI summary
An electronic device may be provided with a display mounted in a display frame assembly that includes a plastic structure overmolded over a display frame. A housing midplate may be used to provide the electronic device with mechanical rigidity and strength, and may also be used as a sensor plane. For sensor plane applications, accurate placement and assembly of the midplate in the housing can be critical. The housing midplate may be accurately assembled to the display frame using connections formed using welded tabs, welded and screwed nuts, overmolded plastic heat stake structures, or overmolded plastic structures and adhesive. Rework and repair operations may be performed by disconnecting connections such as welds using cutting equipment, by using solvent to dissolve adhesive, by unscrewing welded nuts, or by removing heat stake structures. Following rework or repair, a fresh midplate and associated components may be attached to the display frame.