3C電子產品落地試驗之分析驗證

Simulation and Validation of Drop Test for 3C Electronic Products

黃世欽(Shis-Chin Huang)

指導教授 ： 楊哲化

國立臺北科技大學/機電學院/精密機構設計產業研發碩士專班/碩士(2007年)

摘要

隨著越來越多可攜式電子產品，諸如筆記型電腦、個人資料助理（PDA）、電視、電腦螢幕、手機等產品，皆須具備輕、薄、短、小等考量，便利性成為了電子產品在選購上的重要指標之ㄧ。然而，在產品越做越薄的條件下，設計者與製造商為維持產品本身一定的品質，對於產品出貨前的品質管控也更加嚴苛。而多項的品管檢驗中，落摔測試（Drop Test）為評估該產品品質的重要指標，但對於產品設計者而言，並無法藉由落摔測試的結果，獲得產品失效（Failure），諸如外殼破裂、內部結構斷裂、銲錫破裂及電子元件剝落等，的發生原因。另ㄧ方面，在現今微利的時代裡，落摔測試所耗費的時間與成本儼然成了各公司的另一項負擔。
近年來利用有限元素法的數值理論進行分析模擬瞬時、非線性、大變形、接觸等問題的技術，除了在學術研究中使用外，有普及於工業產品設計開發的趨勢。對於落摔測試數值分析而言，其優勢在於可獲得產品各局部的物理特性，諸如內的結構變形及瞬時應力分佈等，不用受限於產品內部空間不足，而造成現有量測設備，如應力規（Strain Gauge）及加速規（Acceleration Gauge）等，只能應用在特定範圍內。本研究為了評估落摔實驗與模擬結果之相符性，利用滑鼠作為實驗樣本，針對量測與模擬之結果做相互比對，以確保數值模擬之正確性。
本研究利用數值模擬滑鼠在不同落摔高度和落摔方向之瞬時應力分佈及碰撞接觸力關係，並針對滑鼠在落摔測試後所產生的功能失效機制分析探討。以下是本研究的結論：（一）在相同高度的落地試驗中，撞擊於不同的測試平台上，會有不同的作用時間與衝擊力大小。（二）落摔方向對滑鼠各元件之應力分佈及數值，具有重要的影響。（三）落摔發生時，結構破壞處不侷限在產品表面發生，產品內部也可能有結構破壞行為。（四）最大應力發生的時間點不一定在產品碰撞地面時，有時會在碰撞地面後反彈的過程中。（五）在整個落摔模擬過程中，因IC本身受到導光元件的衝擊，造成剝落現象，而導致產品功能失效（六）針對滑鼠整體產品模型，以PC及ABS兩種材質落摔模擬得知，PC材質對於防撞能力比ABS來的優越。

關鍵字

落摔測試 ； 數值模擬

並列摘要

As more portable electronic products like notebook, PDA, monitor, TV, and mobile phone, etc., become small sized and lighted weight, Product manufacturers have to pay more attention to the robustness and reliability especially in drop/impact performance. Because of the small size and compact design of these electronics devices, it is very expensive, time-consuming and difficult to conduct experimental drop tests and achieve directly detection for the failure mechanism and drop
behaviors.
An alternative of conducting drop tests is to perform numerical simulation. Numerical simulation allows critical drop heights and orientations to be identified so that selective experimental drop test can be performed to determine the actual physical robustness of those products. Quantities those are difficult to obtain experimentally like stress distribution in the product during drop can now be obtained with greater ease. This research examines the feasibility of studying the drop response of an electronic mouse using finite element method. Experimental drop test results are then conducted to verify the numerical simulations. Comparisons
show good agreement between experimental and simulation results.
Numerical simulation of the drop impact of an electronic mouse was performed. The mouse was subjected to drop heights ranging from 700 mm to 1200 mm and six impact orientations. It is found that first; the variations of the impact force with time during drop are largely dependent on the drop orientations. Second, the variations of transient strain distribution with time during drop are affected largely by the drop orientations. Third, physical damage may happen on the external housing but also internal structure. Forth, the maximum strain does not necessarily occur when mouse impacts on the ground, sometimes it occurs after impacting. Fifth, IC component was flaking off the printed circuit board because it was collided with lens which conduces to functional failure. Sixth, compare with two different materials, PC and
ABS, the maximum stress of PC is smaller than ABS.

並列關鍵字

Drop test ； Finite Element(FE) Simulation ； Portable Electronic Product

參考文獻

[3] Courant, R., “Variational Methods for the Solution of Problems of Equilibrium and Vibrations, ”Bulletin of the American Mathematical Society, vol. 49, 1943, pp. 1-23.

[4] Levy, S., “Structural Analysis and Influence Cofficients for Delta Wings ,”Journal of Aeronautical Sciences, vol. 20, no. 20,July 1953, pp. 449-454.

[5] Turner, M.J., Clough, R.W., Martin, H.C., and Topp, L.J., “Stiffness and Deflection Analysis of Complex Structures, ”Journal of Aeronautical Sciences, vol. 23, no. 9,Sept. 1954, pp. 805-824

[7] Low, K.H., Yang,Aiqiang., Hoon, K.H., Xinwei Zhang , Judy, K.T., Lim and Lim,K.L.,“Initial Study on The Drop-Impact Behavior of Mini Hi-Fi Audio Product ,”Advances in Engineering Software ,2001, pp. 683-693.

[8] Lim, C. T. and Low, Y. J., "Investigation the Drop Impact of Portable Electronic Products, " Electronic Components and Technology Conference, 2002, pp. 1270-1274.