電路板一次銅電鍍生產線吊車控制模擬系統

Simulation System For Crane Control In PCB Electroplating Process

鍾含智(Han-Chih Chung)

指導教授 ： 陳傳生

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

本研究目的在建立印刷電路板製程中，一次銅電鍍系統的模擬器。一次銅電鍍系統是由4~5部吊車在生產線起點吊取空板，依照製程需求，逐序運抵清洗及電鍍槽中，進行往復的清洗和電鍍程序而完成。目前，多數電路板生產廠商採用在個人電腦執行的程式，根據製程需求及設備現況，計算各部吊車的工作指令，再傳送到大型可程式控制器；再由可程式控制器執行順序及其他如藥液容量及滴水盤開關等細節部份的控制。如能藉由電腦動態模擬的方式，模擬包含吊車派遣、可程式控制器和製程所有設備的各種動態狀況，不僅可檢驗控制程式的性能和可靠度；更可據以評估各種新近開發的吊車派遣方法的良窳，進行製程改良，以達到發揮產能，減低設備故障對產能的影響。
為適當地表達控制系統具有的階層(hierarchical)和同時性(concurrent)，作者採用自Finite State Machine理論延伸而來的State Chart理論，以建立模擬系統，以模擬一次銅電鍍生產系統的動態行為。模擬系統分為上層的監控系統及下層的執行系統。前者監控排程的進度與所有的設備狀況;並根據預設的的吊車工作順序，下達命令到執行系統。再由執行系統完成實際的吊車運動控制及吊桿昇降控制等工作。
整個模擬系統是在Matlab/Simulink/StateFlow的軟體環境下完成，模擬的細節包含到最內部的感測器信號和操作人員的輸入和顯示介面。目的在達到充分掌握實際層面的細節與真實的設備狀態，以提供進行控制設計時，便捷的模擬工具，開發更具有生產力的一次銅電鍍控制系統，以及未來直接將現有個人電腦及可程式控制的控制系統，直接換成完全由個人電腦控制的架構。

關鍵字

吊車 ； 排程 ； 有限狀態機 ； 模擬器

並列摘要

This thesis establishes a simulation system for the crane control printed circuit board (PCB) electroplating processes. The crane control system in a PCB electroplating process consists of four to five, which transport board carriers over chemical processing tanks arranged in a line. The cranes load PCB carriers into the electroplating process from the buffer area into tanks, and unload the carriers upon completion of all treatments in a prescribed order.
In today''s PCB manufacturing systems, computer-controlled cranes are commonly used to maximize productivity. The crane control systems use personal computers to compute the dispatching commands for the cranes according to processing specifications and equipment status, and then transfer the commands to a large programmable logic controller (PLC), which executes the commands in sequence. The traditional approach to develop the crane-dispatching schedule relies heavily on the operator to optimize the productivity, which is error-prone and time-consuming. Furthermore, component failures unexpected in the schedule could easily shutdown a massive production line, which results in huge loss. The simulation system for the crane control system can visually inspect the proposed schedule to prevent crane collision, predict production cycle time, and study the impact on performance from simulated fault conditions.
In order to accurately express the hierarchical and concurrent natures of a crane control system in PCB electroplating process, the author adopts the State Chart approach, which is derived from the finite state machine theory. The simulation system consists of two parts, which are the administrative subsystem and the monitoring/control subsystem. The former generates dispatching commands for cranes and the later executes commands from the administrative subsystem and monitors components status, The simulation system is built in Matlab/Simulink/StateFlow environment, incorporating every detail in a real-life crane control system up from man-machine interface down to a single sensor in order to study diversified situations in practices. Applying the simulation to an electroplating process in practice, we observer that the present approach for crane dispatching schedule design underestimates the cycle time without taking into account the opening and closing time for drip trays. Unnecessary steps are often inserted in order to avoid an impossible crane collision. Scenarios of sensor or actuator failure could be accurately simulated, and traced to the underlying control strategy. The simulation system will be used as a tool to develop efficient dispatching algorithm for PCB manufacturing processes and related problems.

並列關鍵字

Crane ； hoist ； scheduling ； finite state machine ； simulator

參考文獻

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4.Arthur Gill,“ Introduction To The Theory Finite State Machines,” New York: McGraw-Hill, 1962.

5.W. C. NG, et al.,“ Determining the Optimal Number of Duplicated Process Tanks In A Single-Hoist Circuit Board Production Line,” Computers & industrial Engineering, vol. 28, no. 4, 1995, pp.681-688.