Electronic Middle Frame Casting Layout for Fewer Sand Holes
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Solution Overview
Problem
The middle frames of electronic devices formed through die casting suffer from numerous sand holes, leading to poor quality and low strength, which compromises the overall strength and reliability of the electronic device.
Innovation Solution
The design of the middle frame includes a drainage material section located between the top and bottom surfaces of the middle plate region in the die casting mold, allowing the casting liquid to flow parallel to these surfaces, reducing flow rate loss and maintaining a stable flow state, and incorporates machined surfaces and through holes formed post-casting to minimize flow resistance, thereby improving filling quality and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the middle frame is formed through die casting, then the manufacturing efficiency is high, but the filling quality is poor resulting in numerous sand holes
Solution Approach 1:
The patent positions the runner outlet at the middle plate region rather than at the edge, and orientates it parallel to the top and bottom surfaces. This dimensional repositioning allows the casting liquid to flow horizontally through the middle plate region without needing to overcome vertical height differences, transforming the flow path from a multi-directional complex flow to a simplified horizontal flow, thereby improving filling quality while maintaining die casting efficiency
Solution Approach 2:
The patent changes the orientation parameter of the runner outlet from vertical or edge-parallel to horizontal (parallel to top and bottom surfaces). This parameter change enables the casting liquid to flow in a direction that minimizes resistance and avoids turbulence, directly improving the filling quality and reducing sand holes while maintaining the high productivity of die casting
2Weight of moving object
If the middle plate region is made thinner to reduce weight, then the weight decreases, but the filling quality deteriorates due to insufficient liquid flow
Solution Approach 1:
The patent changes the flow direction parameter to be parallel to the top and bottom surfaces of the middle plate region. This parameter change allows the casting liquid to flow horizontally through the thin middle plate region without needing to overcome vertical height differences, enabling adequate filling quality even when the middle plate is made thinner for weight reduction
3Device complexity
If the runner outlet is positioned at the edge of the mold cavity, then the device complexity is low, but the flow rate loss is high resulting in poor filling quality
Solution Approach 1:
The patent repositions the runner outlet from the edge to the middle plate region, and changes its orientation to be parallel to the top and bottom surfaces. This spatial repositioning and orientating reduces the flow path length and eliminates the need for the casting liquid to overcome vertical height differences or make sharp turns, significantly reducing flow rate loss while maintaining simple mold structure
Solution Approach 2:
By positioning the runner outlet parallel to the top and bottom surfaces at the middle plate region, the patent creates an equipotential flow path where the casting liquid flows horizontally without needing to overcome gravitational potential differences. This eliminates energy loss associated with vertical flow and turbulence, reducing overall flow rate loss
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 results in a middle frame with fewer sand holes, better quality, and higher strength, enabling a lightweight design with larger accommodation space for components and facilitating automatic assembly and enhanced reliability.
Implementation Method 1
at least a part of casting liquid does not flow in the thickness direction of the mold cavity after flowing out of the outlet of the runner, but directly flows into the first middle plate region mold cavity in a direction substantially parallel to the top wall and the bottom wall of the first middle plate region mold cavity
Implementation Method 2
there is no height difference from the first middle plate region mold cavity in a thickness direction of the mold cavity. In this case, at least a part of casting liquid does not flow in the thickness direction of the mold cavity after flowing out of the outlet of the runner, but directly flows into the first middle plate region mold cavity in a direction substantially parallel to the top wall and the bottom wall of the first middle plate region mold cavity, and does not need to overcome a height difference or need to turn. Therefore, there is a small flow rate loss and a stable flow state
Data Source
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Figure 3
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AI summary
Embodiments of this application disclose a middle frame of an electronic device, a middle frame assembly, and an electronic device. The embodiments of this application may be applied to a terminal product that includes a screen, for example, a mobile phone, a tablet computer, a handheld computer, a walkie-talkie, a POS machine, an event data recorder, a wearable device, a virtual reality device, or a vehicle-mounted front loading apparatus. The middle frame assembly includes a middle frame and a plastic part injection-molded on a surface of the middle frame. The middle frame includes a middle plate and a first accommodation chamber configured to accommodate a battery of the electronic device. There is a drainage material section on an outer side surface of the middle frame. The middle plate includes a first middle plate region for forming a bottom wall of the first accommodation chamber. The drainage material section is at least partially located between surfaces on which a top surface and a bottom surface of the first middle plate region are located. The middle frame has few sand holes, good quality, and high strength, to resolve a problem that overall strength and reliability of the electronic device are low due to poor forming quality and low strength of the middle frame.