Substrate Conveying Device Stop Position Accuracy
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Solution Overview
Problem
Existing substrate conveying devices face challenges in accurately stopping belt conveyors, leading to potential interference and reduced detection efficiency due to deviations in substrate positioning, especially when relative displacement occurs between the substrate and the conveyor belt.
Innovation Solution
A substrate conveying device equipped with upstream and downstream substrate sensors, a first operation control unit that operates the belt conveyor by a set amount and stops it upon detecting the substrate ends, and a second operation control unit that stops the conveyor based on downstream end detection, along with an operation control selection unit to choose between these controls, allowing for precise stop position adjustment and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the belt conveyor is operated by a set operation amount and stopped after detecting the substrate ends, then the substrate can be conveyed to a predetermined position, but the stop position accuracy deteriorates due to relative displacement between the substrate and conveyor belt
Solution Approach 1:
The patent employs feedback control by detecting the actual stop position of the substrate and comparing it with the target position. When a deviation is detected, the system automatically adjusts the conveyor operation in subsequent cycles to compensate for the positioning error, thereby improving stop position accuracy despite relative displacement between substrate and belt
Solution Approach 2:
The patent replaces pure mechanical positioning with a combination of mechanical conveyance and optical/electronic detection. By using sensors to detect substrate position and controlling the conveyor based on detection results rather than solely on mechanical operation amounts, the system achieves higher positioning accuracy
2Manufacturing precision
If the downstream side end detection method is used to stop the conveyor, then the substrate stop position accuracy is improved, but the device complexity increases due to multiple sensors and control units
Solution Approach 1:
The patent makes the upstream side substrate sensor serve multiple functions: it detects both the upstream side end and downstream side end of the substrate by detecting different edges of the same object. This reduces the need for separate sensors while maintaining high positioning accuracy
Solution Approach 2:
The patent combines the detection functions of upstream and downstream sensors into a unified control logic. The control unit integrates signals from both sensors to determine the precise stop position, merging multiple detection functions into a single coordinated system that improves accuracy without proportionally increasing complexity
3Ease of operation
If the belt conveyor stops at a position determined by set operation amount, then the operation control is simplified, but the detection efficiency deteriorates due to potential interference from inaccurate substrate positioning
Solution Approach 1:
The system maintains simple operation control by keeping the basic set operation amount functionality while adding feedback-based corrections. The feedback mechanism automatically adjusts for positioning errors without complicating the operator's interface or control logic, thus preserving ease of operation while improving detection efficiency through accurate positioning
Data Source
Figure 1
Figure 2(a)~2(b)
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AI summary
An aim is to improve the practical use of operation stop control of a belt conveyor of a substrate conveying device. Substrate sensors are provided at the upstream side end and the central position of a main conveyor in a conveyance direction. Second operation control is selected when a substrate length is equal to or less than a set length, and the main conveyor is stopped when a downstream side substrate sensor, which is provided at the central position, detects a substrate downstream side end (S7). When the substrate length is greater than the set length and a high position accuracy is not required, first operation control without correction is selected and the main conveyor is operated by a set operation amount and then stopped after an substrate upstream side end is detected by an upstream side substrate sensor so that the circuit substrate is stopped at a position where the middle point of the circuit substrate in the conveyance direction corresponds to the downstream side substrate sensor (S3). When the high position accuracy is required, first operation control with correction is selected, the number of output pulses is counted from when the substrate downstream side end is detected, stop position errors are obtained in comparison with a logical operation amount, the main conveyor is operated again and position errors are corrected after the stopping (S5, S6).