端銑刀動態切削力及抵抗係數估測方法之研究

Study of Cutting Force in End Milling and Cutting Resistance Coefficients Estimation

蕭順德(Shun-Te Hsiao)

指導教授 ： 康淵

中原大學/工學院/機械工程研究所/碩士(2001年)

https://doi.org/10.6840/cycu200100477

摘要

切削抵抗係數影響切削力預測值甚大，因此本研究主要探討準確取得切削抵抗係數(cutting resistance coefficients)的估測方法。影響切削力之因素很多，如刀具幾何形狀、切削條件、刀具材質、工件材質、工具機結構動態特性、切削液等。從數學模型中可知，不同材料與切削條件，會引起不同的切削抵抗係數。
本研究針對螺旋端銑刀提出二種取得材料切削抵抗係數的估測方法：包括（1）將螺旋刃端銑刀假設為直刃端銑刀，求解出每刃元素之切削力（cutting force）、推擠力（thrust force）及側向力（lateral force），取其每切削循環之平均極大值，以線性擬合（linear fitting）得單一轉速取樣值之切削抵抗係數(cutting stiffness)，再以多項式擬合（polynomial fitting）得到以轉速為函數之切削抵抗係數之數學式；（2）根據瞬時剪切平面面積（instantaneous shear plane area）觀念，發展端銑刀動態三軸向切削力的數學模型，以不同的切削條件，經由計算各切刃元素之瞬時剪切平面面積、實際切削力量測與Matlab程式分析及模擬求得切削抵抗係數，以預測各種切削條件之動態三維切削力。
為驗證所推導之數學模型、比較切削抵抗係數之估測方法與電腦模擬結果的準確度，本研究也針對鋁（Al6061）及鈦（Ti6A14V）二種材料進行實際切削測試，以驗證所提出的動態切削力預測方法對各種不同切削條件的適用性。
關鍵詞：端銑刀、切削力、切削抵抗係數

關鍵字

端銑刀 ； 切削抵抗係數 ； 切削力

並列摘要

Many factors affect cutting force, including geometric shape of cutter, cutting conditions, material of cutter, material of workpicec, dynamics characteristics of machine structure, coolant of cutting. From mathematical model’s prediction, it is known that different material and conditions cause the cutting resistance coefficients. Since the cutting resistance coefficients will affect the cutting force extremely, finding methods for accuracy estimating it is the purpose of the study.
This study proposes two methods to estimate the cutting resistance coefficients for end milling cutter : (1) Assuming the blade is straight first, solve the cutting force, thrust force, and lateral force of each blade element. Average the maximum value of each cutting cycle. Using the linear fitting method, estimate the cutting resistance coefficients under single rotational speed based on the values as the samples. Then, using the polynomial fitting method for formulating the equations of cutting resistance coefficients, which is functioned by rotational speed; (2) According to the concept of instantaneous shear plane area, develop a mathematical model for milling cutter with 3-axial cutting force. By calculating the instantaneous shear plane area for each blade element, a mathematic model is developed and incorporated with measure cutting forces to estimate the cutting resistance coefficients, to effectively execute the estimation, a compute-aided system was developed is this research.
To verify the two proposed methods, experiments on cutting Al6061 and Ti6Al4v were conducted,comparison of the two methods were addressed.

Keywords：End Milling、Cutting Force、Cutting Resistance Coefficients

並列關鍵字

Cutting Resistance Coefficients ； End Milling ； Cutting Force

參考文獻

[23] Chu-Hsiang Chiou, 1997, “A Computational Model for End Milling Operations”, Ph. D. thesis, Northwestern University.

[1] M. C. Merchant, ”Basic mechanics of the metal cutting process”, Journal of Applied Mechanics, Trans. ASME, Vol.66, 1944, pp.168-175

[5] M. E. Merchant, “Basic Mechanics of the Metal –Cutting Process,”Journal of Applied Mechanics, TRANS. ASME, Vol.66, 1944, pp.A-168-175.

[9] P. K. Venu Vinod and W. Lau, “On a new model of oblique cutting”, Trans. ASME, Vol.100, 1978, pp.287-292.

[10] F. Koenigsberger, and A. J. P. Sabberwal, “An investigation into the cutting force pulsations during milling operations, “Int. J. Mach. Tool. Des. Res. 1961, 1, 15.