膨鬆食材之超音波切割刀具研發

The Design of the Ultrasonice Cutting Tool for Bulking Property Food

蘇建豪(Chien-Hao Su)

指導教授 ： 許坤明

共同指導教授 ： 石煥讓(Hung Rung Shih)

國立虎尾科技大學/工程學院/機械與電腦輔助工程系碩士班/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00112

摘要

傳統切割容易使蛋糕體產生震動，而造成蛋糕失去原本面貌、扁塌、破碎、黏刀、切面不平整、生產速度慢等問題，並且對於切割材料上有諸多限制。因此，藉由超音波高頻率微小振幅的技術，研發一種超音波蛋糕切割刀，使蛋糕不黏刀、切割面乾淨平整。
本研究以郃茂機械公司所提供的聲波焊頭，作為尺寸分析之基礎。切割刀在使用時，刀刃有振幅不均勻現象，造成刃口易發生疲勞破壞，壽命也因此降低。藉由ANSYS有限元素分析軟體，模擬焊頭振幅與應力分佈情形，利用田口望目特性，求得符合設計之自然頻率值，找出聲波焊頭最佳尺寸參數，並進行模擬比對；其結果顯示，模擬值與實際量測值頻率相似，得以證明尺寸設計及模擬數值無誤。如此一來，將取代傳統的經驗法或試誤法進行設計，減少材料成本與設計週期。
影響刀面之沾黏性及加工切面平整性，取決於聲波焊頭表面粗糙度與進給之速度；粗糙度過大或進給太慢，易使材料融化，沾黏於刀面，造成加工切面不平整。在端面振幅均勻性與應力集中方面，已開槽之聲波焊頭，能有效解決輸出端面振幅不均之現象，且有效降低應力集中分佈，因而延長刀具壽命。

關鍵字

田口法 ； Ansys ； 超音波聲波銲頭 ； 模態分析

並列摘要

Traditional cutting methods tend to cause the cake to shift or move, resulting in problems such as damage to the cake appearance, cake collapse, smashing of the cake, cake adhering to the knife, uneven cut surfaces, and slow production. Additionally, the materials used as cake cutting tools are extremely limited. Therefore, we adopted ultrasonic high-frequency low-amplitude technology and developed an ultrasonic cutting horn to achieve a situation in which cakes do not stick to knives and cut surfaces are clean and even.
In this study, a cutting horn provided by He Mao Machinery Co., Ltd., was used as the basis for dimension analysis. When the cutting horn was employed, uneven blade amplitudes occurred, causing wear and tear to the edge and a shorter product life cycle. The ANSYS finite element analysis (FEA) software was used to simulate the distribution of the horn amplitudes and stress. The nominal-the-best (NTB) method proposed by Taguchi was employed to determine the natural frequency value suitable for the design and to identify the optimal dimension parameters of the cutting horn; these data were simulated for comparison. The results showed that the frequency for the simulation values and actual measurement values were similar, verifying the accuracy of the dimension design and the simulation values. Therefore, this method can be used to substitute the traditional experience method or the trial-and-error method for design to reduce material costs and design cycles.
Influences on blade adhesiveness and processed cut surface smoothness are determined by the surface roughness of the sonic horn and the feed speed. Exceedingly high surface roughness or slow feed speeds are likely to cause the material to melt and adhere to the blade, resulting in uneven processed cut surfaces. Regarding the end-face amplitude uniformity and stress concentration, slotted sonic horns can effectively overcome uneven output end-face amplitudes and reduce stress concentration distribution, thereby extending the cutting tool life cycle.

並列關鍵字

Taguchi Method ； Ansys ； Ultrasonic ； Horns ； Model Analysis.

參考文獻

[7]陳聖平，2009，”複雜外型超音波放大器之有限元素分析與最佳化設計“，國立交通大學機械工程系所碩士論文。

[12] 李昱廣，2011，”超音波連續滾焊之變幅桿振動特性模擬與最佳化設計”，國立虎尾科技大學機械與電腦輔助工程系碩士論文。

[1]K.H.W. Seah, Y.S. Wong, L.C. Lee, 1993,"Design of tool holders for ultrasonic machining using FEM", Journal of Materials Processing Technology, Vol. 37, Issues 1-4, pp. 801-816.

[2]S. G. Amin, M. H. M. Ahmed, and H. A. Youssef, 1995,"Computer-aided design of acoustic horns for ultrasonic machining using finite-element analysis",Journal of Materials Processing Technology, Vol. 55, pp. 254-260.

[3]A. Cardoni, M. Lucas,2002,"Enhanced vibration performance of ultrasonic block horns", Ultrasonics, Vol. 40, pp. 365-369.