Circuits Assembly - December 2007 - (Page 42) Eastern Advances SMT生产中的可识别性 北京柏瑞安科技 蔡三强 杨威 Ed.: For the full version, visit circuitsassembly.com. 二、MARK与可识别性 2、MARK的防呆设计－－不对 称性 我们在生产（如图1）的Ｐ板 时，最初采用对称MARK :A和C, 由于来料Ｐ板标识油墨方向反， 人工上板时未发现，而导致大量 料损（该Ｐ板的PAD对称）。后 采取选用不对称的MARK如图B、C 点作为贴片机的识别点，杜绝了 此类现象的发生，当设计具有对 称性的Ｐ板时，应考虑不对称的 MARK。对于阴阳板的防呆设计（ 防止先行面未翻面而损坏网板） 在编制印刷程序时要采用多点识 别，其中一点采用一个必贴元件 的焊盘，当已贴装面被再次印刷，设备在识别MARK 时会自动停止从而达到防呆的目的，对于手工印刷 或老式丝印机没有视觉的识别功能，可借助工艺边 上的不对称设计的孔(如图2中A、B、C、D)，用光 传感器或行程开关达到识别的目的。 3、MARK组－－独立性 图2是一块阴阳板，其MARK组如图2中E。MARK组 的好处是在丝印时如图2中E点要在网板上要开口， 它的特点是有利于X 、Y 、θ偏差的识别，而其 余的MARK留给贴片机用，这对于手工印刷或非视觉 识别的印刷机，特别是在红胶的刷胶工艺中其重要 性更为突出。 三、Ｐ板设计中的可识别性实例 1、由于相当数量的Ｐ板在制作过程中客观存在 边、孔与焊盘的相对的偏差，为了简单的识别和 判定，定位孔及设在工艺边上的工艺孔设计上要 和铜箔保持一定的相对关系如图 2－2.2中的F。由于人在相对小 的范围内对对称图型的识别十分 敏感，使0.1㎜或0.05㎜的偏差 都可被察觉，这样可快速判定Ｐ 板大概的精度。对不太规范的P 板做筛选。在采用边或孔定位的 Ｐ板印刷，自动插件时都大有好 处。 2、如图2－2.2中的G，设计者 把一些与Ｐ板制造品质相关的识 别点做在工艺边上，可以让人方 便地甚至是破坏性认定过孔的品 质及PAD的附着力和可焊性，用 以识别Ｐ板制程的品质，我们也 曾见过设计十数个金属化孔串联，方便使用者用毫 欧计判定金属化孔凹蚀可能带来的电阻增大或断路 等缺陷。 3、标识油墨首先是对ISO9000中的可追溯性的 体现，图3A是组装信息：月、日、班及Ｐ板生产日 期的体现。以保证先入先出及正常的报废（可焊性 保证）。并应设盖印章处，以作为板级合格品及版 本号的识别 。 由图2可看出，该阴阳板设计A、B 面的标识油墨采用不同的颜色，黄与白的使用（当 AOI被使用时，黑色被推荐采用）方便了生产过程 中操作，对缺陷的解析及追溯都是有利的。标识油 墨的另一种作用是对元件的极性、安装位置做简单 明了的指示。 ■ Cai San Qiang is senior engineer at Beijing Brio Technology (brio-tech.ca). 42 Circuits Assembly DECEMBER 2007 circuitsassembly.com http://circuitsassembly.com http://brio-tech.ca http://circuitsassembly.com
Table of Contents Feed for the Digital Edition of Circuits Assembly - December 2007 Circuits Assembly - December 2007 Contents Caveat Lector Industry News Market Watch Talking Heads Global Sourcing Screen Printing Better Manufacturing Metalization Options for COB Assembly A Test Comparison of SAC and Non-SAC Pb-Free Solders An A-to-Z Guide to X-Ray Inspection BEST: A ‘Funky Chicken’ with an EMS Niche Tech Tips Wave Soldering Process Doctor Pb-Free Lessons Learned Getting Lean Eastern Approaches Product Spotlight Ad Index Assembly Insider Technical Abstracts Circuits Assembly - December 2007 Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page Cover1) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page Cover2) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page 1) Circuits Assembly - December 2007 - Circuits Assembly - December 2007 (Page 2) Circuits Assembly - December 2007 - Contents (Page 3) Circuits Assembly - December 2007 - Caveat Lector (Page 4) Circuits Assembly - December 2007 - Caveat Lector (Page 5) Circuits Assembly - December 2007 - Industry News (Page 6) Circuits Assembly - December 2007 - Industry News (Page 7) Circuits Assembly - December 2007 - Industry News (Page 8) Circuits Assembly - December 2007 - Industry News (Page 9) Circuits Assembly - December 2007 - Industry News (Page 10) Circuits Assembly - December 2007 - Industry News (Page 11) Circuits Assembly - December 2007 - Market Watch (Page 12) Circuits Assembly - December 2007 - Market Watch (Page 13) Circuits Assembly - December 2007 - Market Watch (Page 14) Circuits Assembly - December 2007 - Market Watch (Page 15) Circuits Assembly - December 2007 - Talking Heads (Page 16) Circuits Assembly - December 2007 - Talking Heads (Page 17) Circuits Assembly - December 2007 - Global Sourcing (Page 18) Circuits Assembly - December 2007 - Global Sourcing (Page 19) Circuits Assembly - December 2007 - Screen Printing (Page 20) Circuits Assembly - December 2007 - Better Manufacturing (Page 21) Circuits Assembly - December 2007 - Metalization Options for COB Assembly (Page 22) Circuits Assembly - December 2007 - Metalization Options for COB Assembly (Page 23) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 24) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 25) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 26) Circuits Assembly - December 2007 - A Test Comparison of SAC and Non-SAC Pb-Free Solders (Page 27) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 28) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 29) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 30) Circuits Assembly - December 2007 - An A-to-Z Guide to X-Ray Inspection (Page 31) Circuits Assembly - December 2007 - BEST: A ‘Funky Chicken’ with an EMS Niche (Page 32) Circuits Assembly - December 2007 - BEST: A ‘Funky Chicken’ with an EMS Niche (Page 33) Circuits Assembly - December 2007 - Tech Tips (Page 34) Circuits Assembly - December 2007 - Tech Tips (Page 35) Circuits Assembly - December 2007 - Wave Soldering (Page 36) Circuits Assembly - December 2007 - Process Doctor (Page 37) Circuits Assembly - December 2007 - Pb-Free Lessons Learned (Page 38) Circuits Assembly - December 2007 - Pb-Free Lessons Learned (Page 39) Circuits Assembly - December 2007 - Getting Lean (Page 40) Circuits Assembly - December 2007 - Getting Lean (Page 41) Circuits Assembly - December 2007 - Eastern Approaches (Page 42) Circuits Assembly - December 2007 - Eastern Approaches (Page 43) Circuits Assembly - December 2007 - Eastern Approaches (Page 44) Circuits Assembly - December 2007 - Product Spotlight (Page 45) Circuits Assembly - December 2007 - Ad Index (Page 46) Circuits Assembly - December 2007 - Assembly Insider (Page 47) Circuits Assembly - December 2007 - Technical Abstracts (Page 48) Circuits Assembly - December 2007 - Technical Abstracts (Page Cover3) Circuits Assembly - December 2007 - Technical Abstracts (Page Cover4)
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