Abstract :
Influence of tool geometry on the quality of surface produced is well known and hence any attempt to assess the performance of end milling should include the tool geometry. In the present work, experimental studies have been conducted to see the effect of tool geometry (radial rake angle and nose radius) and cutting conditions (cutting speed and feed rate) on the machining performance during end milling of medium carbon steel. The first and second order mathematical models, in terms of machining parameters, were developed for surface roughness prediction using response surface methodology (RSM) on the basis of experimental results. The model selected for optimization has been validated with the Chi square test. The significance of these parameters on surface roughness has been established with analysis of variance. An attempt has also been made to optimize the surface roughness prediction model using genetic algorithms (GA). The GA program gives minimum values of surface roughness and their respective optimal conditions.
1、Introduction
End milling is one of the most commonly used metal removal operations in industry because of its ability to remove material faster giving reasonably good surface quality. It is used in a variety of manufacturing industries including aerospace and automotive sectors, where quality is an important factor in the production of slots, pockets, precision and dies. Greater attention is given to dimensional accuracy and surface roughness of products by the industry these days. Moreover, surface finish influences mechanical properties such as fatigue behaviour, wear, corrosion, lubrication and electrical conductivity. Thus, measuring and characterizing surface finish can be considered for predicting machining performance.



摘要： 刀具幾何形狀對(duì)工件表面質(zhì)量產(chǎn)生的影響是人所共知的，因此，任何成型面端銑設(shè)計(jì)應(yīng)包括刀具的幾何形狀。在當(dāng)前的工作中，實(shí)驗(yàn)性研究的進(jìn)行已看到刀具幾何（徑向前角和刀尖半徑）和切削條件（切削速度和進(jìn)給速度） ，對(duì)加工性能，和端銑中碳鋼影響效果。第一次和第二次為建立數(shù)學(xué)模型，從加工參數(shù)方面，制訂了表面粗糙度預(yù)測(cè)響應(yīng)面方法（丹參） ，在此基礎(chǔ)上的實(shí)驗(yàn)結(jié)果。該模型取得的優(yōu)化效果已得到證實(shí)，并通過了卡方檢驗(yàn)。這些參數(shù)對(duì)表面粗糙度的建立，方差分析極具意義。通過嘗試也取得了優(yōu)化表面粗糙度預(yù)測(cè)模型，采用遺傳算法（ GA ） 。在加文的程式中實(shí)現(xiàn)了最低值，表面粗糙度及各自的值都達(dá)到了最佳條件。

1 導(dǎo)言
端銑是最常用的金屬去除作業(yè)方式，因?yàn)樗軌蚋焖偃コ镔|(zhì)并達(dá)到合理良好的表面質(zhì)量。它可用于各種各樣的制造工業(yè)，包括航空航天和汽車這些以質(zhì)量為首要因素的行業(yè)，以及在生產(chǎn)階段，槽孔，精密模具和模具這些更加注重尺寸精度和表面粗糙度產(chǎn)品的行業(yè)內(nèi)。此外，表面光潔度還影響到機(jī)械性能，如疲勞性能，磨損，腐蝕，潤(rùn)滑和導(dǎo)電性。因此，測(cè)量表面光潔度，可預(yù)測(cè)加工性能。
車削過程對(duì)表面光潔度造成的影響歷來倍受研究關(guān)注，對(duì)于加工過程采用多刀，用機(jī)器制造處理，都是研究員需要注意的。由于這些過程涉及大量的參數(shù)，使得難以將關(guān)聯(lián)表面光潔度與其他參數(shù)進(jìn)行實(shí)驗(yàn)。在這個(gè)過程中建模有助于更好的理解。在過去，雖然通過許多人的大量工作，已開發(fā)并建立了表面光潔度預(yù)測(cè)模型，但影響刀具幾何方面受到很少注意。然而，除了切向和徑向力量，徑向前角對(duì)電力的消費(fèi)有著重大的影響。它也影響著芯片冰壺和修改芯片方向人流。此外，研究人員[ 1 ]也指出，在不影響表面光潔度情況下，刀尖半徑發(fā)揮著重要作用。因此，發(fā)展一個(gè)很好的模式應(yīng)當(dāng)包含徑向前角和刀尖半徑連同其他相關(guān)因素。
對(duì)于制造業(yè)，建立高效率的加工參數(shù)幾乎是將近一個(gè)世紀(jì)的問題，并且仍然是許多研究的主題。獲得最佳切削參數(shù)，是在制造業(yè)是非常關(guān)心的，而經(jīng)濟(jì)的加工操作中及競(jìng)爭(zhēng)激烈的市場(chǎng)中發(fā)揮了關(guān)鍵作用。在材料去除過程中，不當(dāng)?shù)倪x擇切削條件造成的表面粗糙度