A novel approach for batch production of micro holes by micro EDM - PowerPoint PPT Presentation

A novel approach for batch production of micro holes by micro EDM Shun-Tong Chen a , Yunn-Shiuan Liao b a Dept. of Mechatronic Technology, National Taiwan Normal University, Taiwan chenst@ntnu.edu.tw b Dept. of Mechanical Engineering, National Taiwan University liaoys@ntu.edu.tw 2007/11/12 4M2007 1

Outline � Introduction (background and objective) � Hardware � Approach � Experiment � Conclusions 2007/11/12 4M2007 2

Background Micro holes can be applied widely to various fields such as � aerostatic air bearing � Ink-jet nozzle � Micro-jet cooling device 2007/11/12 4M2007 3

Background (cont.) Various micro machining techniques have been developed to fabricate micro holes. � Costly → → MEMS and LASER → → � Difficult → → micro drilling and punching → → 2007/11/12 4M2007 4

Objective To develop an approach for batch production of micro holes by micro EDM. 2007/11/12 4M2007 5

The multi-function tabletop machine tool � Micro Milling � Micro Hi-Speed Milling � Micro EDM � Micro Wire-EDM � Micro on-line Measurement 2007/11/12 4M2007 6

A novel micro Wire-EDM Mechanism Machining region 2007/11/12 4M2007 7

Partial magnification of the micro Wire-EDM 2007/11/12 4M2007 8

The mechanism design of reverse micro Wire-EDM 2007/11/12 4M2007 9

The proposed approach (Batch production of mass micro holes) Positioned directly � Material ： ： SUS304 ： ： 2007/11/12 4M2007 10

Experiment Finished micro electrodes array by reverse micro Wire-EDM � 100 pillars � 21 µ µ m width µ µ � Over 700 µ µ m height µ µ � More than 33 aspect ratio 2007/11/12 4M2007 11

The machining of the batch mode micro EDM. . � Material ： ： SUS304 ： ： 2007/11/12 4M2007 12

Finished 900 micro holes array � Material ： ： SUS304 ： ： 2007/11/12 4M2007 13

Finished holes array by pyramid tip electrode machining 2007/11/12 4M2007 14

Finished holes array by flat end electrode machining 2007/11/12 4M2007 15

Surface roughness on the hole-wall 2007/11/12 4M2007 16

The average consumption of the electrode Have consumed → → 150 µ µ m µ µ → → Before processing ： ： 360 µ µ m After processing ： ： 210 µ µ m µ µ µ µ ： ： ： ： 2007/11/12 4M2007 17

The average consumption of the electrode Have consumed → → 540 µ µ m µ µ → → Before processing ： ： 700 µ µ m After processing ： ： 160 µ µ m µ µ µ µ ： ： ： ： 2007/11/12 4M2007 18

Machining time for single hole Average drilling time : 66.2 (sec) for each hole. 2007/11/12 4M2007 19

Machining time for holes array Average drilling time : 19.5 (sec) for each hole. 2007/11/12 4M2007 20

Conclusions � An approach for batch production of micro holes is successful developed. � A good positional accuracy, dimensional accuracy, and surface roughness of the drilled holes are achieved. � Compared with single hole machining, the holes array machining can be saved about two-third time. 2007/11/12 4M2007 21

Thank you very much for your kind attention! 2007/11/12 4M2007 22

Machining time for holes array Average drilling time : 19.5 (sec) for each hole. 2007/11/12 4M2007 23

Machining time for holes array Average drilling time : 19.5 (sec) for each hole. 2007/11/12 4M2007 24

Tension control of the micro wire (Patent pending) Basic idea Top view of the mechanism 2007/11/12 4M2007 25