Drilling Burr Minimization and Energy Saving for PCB Production Funding Sources: Korea Institute of Industrial Technology Yu-Chu Huang © 2011 LMAS contact email: [email protected] Motivation Information Flow Diagram ■ The hole drilling step is important in the manufacturing of Printed Circuit Boards (PCB). It influences the shape of burrs and the deburring process. Minimizing drilling burr can reduce effort and time for deburring, and therefore decrease energy consumption for the whole process. Inter Layer Image Transfer Circuit Design Photoresist Coating Pro-clean Photoresist Coating UV Exposure Resist Develop Copper Etch Resist Strip Electroless Copper Deburr and Scrub Hole Desmear Hole Drilling Laminate inner Layers Oxide Treatment Resist Develop UV Exposure Pattern Plate Copper Pattern Plate Etch Resist Photoresist Strip Copper Etch Etch Resist Strip Final Fabrication Nickel Gold Plating Hot Air Solder Level Process Solder Mark Application Outer Layer Image Transfer - What we are focusing on The process flow diagram for manufacturing PCB ■ The general goal of the project is to develop a energy-saving manufacturing process for information technology (IT). ■ The research consortium: Design Tech for PCB Process SNU/UCB Optimization and Fusion Process Tech for Forging U of Ulsan/U of Hannover Quality Management, Simulation and Process Optimization KITECH/CAU Quantification and Optimization Based on LCA KAIST/NIST PMU Diagram and Configurable EMS KITECH/U-Bot INC PMU Diagram and Configurable EMS KITECH/U-Bot INC Demo Site1 BM Korea Co., Ltd Information exchanged with SNU Surface Finish Background Energy Saving ■ What is a printed circuit board (PCB)? n Common drilling tool ■ Energy flow in PCB drilling machine f400 mm PCB - What we are focusing on Energy lost at heating step Energy lost due to electrical motor Drilling stack Cu Entry board GFRP Demo Site2 KOFCO Cu Energy lost due to standby mode Energy lost due to friction Bakelite PCB Energy input for the drilling machine PCB Epoxy Energy transferred to final product Backup board PCB n The importance of PCB drilling process The global market size of PCB products in 2009 was $44.4 billion and is projected to register about $76.2 billion by the year 2015. If we can reduce the energy consumption in PCB drilling process, the global PCB market and our environment will be benefited. Experiment Setup Types of Drilling Burr ■ Process parameters Accelerometer • Bit diameter: 400µm • Spindle speed: 90000 rpm • In-feed speed: 40 mm/sec • Hits: 790 hits (2000hits) • Sampling frequency: 20 kHz (low 9 kHz) • Sampling time: 5 sec (x3) • Sensors: 3-axis dynamometer, 3-axis accelerometer • Stacks: 3 layer (recommended by Axis) • Entry board: Al • Backup board: wood ■ Tool wear in PCB drilling X 500 New bit ■ To achieve energy saving, our strategy are: - Minimizing the size of drilling burrs - Reducing tool wear - Reducing PCB drilling lead time Spindle ■ Three types of drilling burr were defined Type I – uniform burr with smaller burr height. Type II – uniform burr but with a relatively large burr height. Type III – crown burr which has no drill cap. Material: Aluminum alloy Dynamometer Drilling experiment setup X 500 After 790th hit Drilling Burr Control Chart ■ A DBCC is proposed as a tool to assist prediction and control of drilling burr under given drilling conditions. ■ Here is an example for one material and driller combination. Type 1 Type 2 Type 3 ■ Based on the definition, we aim to develop the Drilling Burr control chart (DBCC) for PCB by varying the drilling conditions. Picture Source: Kim J, Min S, Dornfeld D (2001) Optimization and Control of Drilling Burr Formation of AISI 304L and AISI 4118 Based on Drilling Burr Control Charts. International Journal of Machine Tools & Manufacture 41(7):923–936. Future Work ■ Developing the drilling burr control chart for PCB ■ Analyzing relationships among process parameters and energy ■ Reducing PCB drilling lead time ■ Constructing energy saving knowledge ■ Increasing the energy efficiency for drilling ■ Constructing information database of PCB drilling ■ Type 1 burr is smallest and preferred. To minimize the drilling burr, the rectangle points out the generally recommended ranges of cutting parameters. Picture Source: Min S, Kim J, Dornfeld DA (2001) Development of a Drilling Burr Control Chart for Alloy Steel AISI 4118. Journal of Materials Processing Technology 113(1–3):4–9. Berkeley / UNIVERSITY OF CALIFORNIA
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