Movable Load Port Buffer for OHT Track Gridlock Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automated material handling systems (AMHS) in semiconductor fabrication facilities face gridlock issues due to limited buffer capacity at fixed load ports, leading to reduced throughput and efficiency when OHT vehicles cannot unload additional wafer carriers, causing traffic stoppages on tracks.
Innovation Solution
Implementing rotational, retractable, or expandable load ports that provide additional buffer by moving away from or expanding to accommodate more loads, allowing continuous OHT operations by rotating, retracting, or unfolding to engage storage locations and tracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed load ports are used with limited buffer capacity, then device complexity is reduced, but traffic stoppages occur on OHT tracks when buffer is full
Solution Approach 1:
The load port is designed with a movable platform that can dynamically change its position between a first position (for receiving loads from OHT vehicles) and a second position (for storing loads in buffer). This dynamic repositioning allows the load port to adapt between active loading and buffer storage modes, preventing traffic stoppages while maintaining manageable device complexity through controlled movement mechanisms.
Solution Approach 2:
The buffer storage function is achieved by adding a spatial dimension to the load port design. The platform can move between two distinct positions along a track, creating an additional spatial dimension for buffer storage. This dimensional approach increases storage capacity without significantly complicating the overall device structure, as the movement follows a simple linear path.
2Reliability
If buffer capacity is increased to prevent gridlock, then OHT track efficiency improves, but load port structure becomes more complex
Solution Approach 1:
The load port employs a movable platform that dynamically transitions between loading position and buffer position, enabling continuous operation by preventing gridlock. The dynamic nature allows the system to maintain reliability by adapting to varying load conditions without requiring complex multi-component buffer structures.
Solution Approach 2:
The movable platform acts as an intermediary between the OHT vehicle interface and the storage locations. It mediates the transfer of loads by temporarily holding them at the first position before moving to the second position for storage, or vice versa. This intermediary approach ensures continuous OHT operation while keeping the mechanical structure relatively simple.
3Productivity
If multiple storage locations are added to increase buffer, then gridlock is prevented, but device complexity and space requirements increase
Solution Approach 1:
Instead of expanding buffer capacity horizontally with multiple adjacent storage locations, the invention utilizes a vertical or linear dimensional approach. The single platform moves between two positions along a track, effectively creating buffer capacity in the direction of movement rather than requiring additional lateral space. This maintains high throughput while minimizing the load port's footprint.
Solution Approach 2:
The system achieves multiple storage capabilities through dynamic repositioning of a single platform rather than static multiple locations. The platform can hold loads at the first position, move to the second position for buffer storage, and return when needed. This dynamic approach provides equivalent functionality to multiple storage locations while requiring significantly less space.
Data Source
AI summary
Storage systems and method of using the same are provided. An exemplary storage system according to the present disclosure includes a storage device including a plurality of storage locations arranged in an upright stadium shape and a plurality of load ports each movable to engage any of the plurality of storage locations.