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畢業(yè)設(shè)計
文獻(xiàn)翻譯
院(系)名稱
工學(xué)院機(jī)械系
專業(yè)名稱
機(jī)械設(shè)計制造及其自動化
學(xué)生姓名
指導(dǎo)教師
2012年 03月 10 日
黃河科技學(xué)院畢業(yè)設(shè)計(文獻(xiàn)翻譯) 第 7 頁
Abrasive belt grinding technology in the machinery industry
Abstract
Situation and characteristics of the abrasive belt grinding technology, discusses the development trends of the abrasive belt grinding technology. In the construction machinery industry, some of the higher parts of the long axis of traditional processing technology is generally a coarse grinding and a grinding a few processes of roughing a fine car, parts machining surface finishing rely mainly on a cylindrical grinder with a grinding wheel grinding to achieve. For some of the aspect ratio of a slender rod, such as various types of hydraulic cylinder piston rod, ordinary wheel grinding will be the limit of the range of processing, abrasive belt grinding with its significant advantages, and reveal the head and feet .
Keywords: abrasive belt grinding, development, processing
1 Overview
Abrasive belt grinding process, is the ring of abrasive belt on the cylindrical contact roller and the tension pulley, tension in the state, so that the processing of high-speed rotation of the abrasive belt surface and the workpiece surface in contact, and in certain under pressure, a grinding process on the workpiece surface relative friction movement (cutting motion). Abrasive belt grinding into a round of compression with pressure are two ways shown in Figure 1.
Wheel pressure grinding method, the contact roller to put pressure on the surface of metal in the contact wheel and the workpiece axis spacing A = 1/2 (D + d) such grinding method due to contact pressure, the unit of time removal capacity, high efficiency, and thus applicable to the coarse and fine grinding of the inner cylindrical surface and plane. Put pressure on the workpiece grinding surface pressure grinding method using abrasive belt, due to tensioner pulley bracket to the workpiece direction tilted at an angle α, contact wheel and the workpiece axis spacing interaction A '> 1/2 ( D + d). Compared with round pressure grinding method, the smaller the contact pressure with the pressure method, the amount of metal removed per unit time is also small, mainly used for grinding circular surface, conical and other shaped surface, in particular, to the finishing polish based.
Belt and grinding wheel belong to a multi-tooth micro-edge cutting tool, its processing characteristics are basically the same, the only difference shapes.
2 the current state of development
In foreign countries, some industrial countries due to the rapid development of various types of abrasive belt grinding machine, the function of the abrasive belt grinding has gone far beyond the range for rust, rough grinding, polishing, etc., the processing efficiency of grinding wheel ~ 20 times the processing quality can be comparable to conventional grinding, machining accuracy is close to or reach the same level with the grinding wheel, while the utilization of the machine power than any metal cutting machine tools are high, and its range of applications throughout the various industries, almost all materials (eg, timber, rubber, all kinds of metal) can wear g the Shuai 0 workers. According to the information, the United States each year of the grinding wheel and abrasive belt production ratio of approximately 1: 1. In the famous engineering machinery enterprises CaterPiller, abrasive belt grinding occupies an important position.
Following the introduction of the new technology of high voltage electrostatic plant sand in the country to ensure that the abrasive in the abrasive belt surface of the "orientation", so that the sand, some belt manufacturers, such as Zhengzhou White Dove Group (grinding wheels), the Shanghai wheel plant so with a good sharp. With the development of the binder, water-resistant oil-resistant resin strong belt of the emergence of the abrasive belt grinding performance is significantly improved. Although the models of all kinds of abrasive belt grinding machine is not yet complete, but the development and use of abrasive belt grinding device is feasible.
3 Characteristics of three abrasive belt grinding
(1)The abrasive belt grinding "cutting" said. Abrasive belt grinding, high efficiency, up to 10 times the milling, 5 to 20 times the normal grinding wheel.
(2)The abrasive belt grinding also has a "cold state" grinding said. Friction and heat due to the processing time is less and due to the abrasive cooling time interval, can effectively reduce the deformation of the workpiece and burns, machining accuracy is generally ordinary wheel grinder machining accuracy can be achieved, some of the dimensional accuracy of ± 0. 005 mm, a maximum of ± 0. 0012mm.
(3)The abrasive belt grinding with the grinding of said "flexibility". The abrasive belt grinding workpiece flexible contacts, running and polishing the role of the surface roughness up to Ra0.8 ~ 0.2μm.
(4)Abrasive belt grinding device structure is simple, low cost, minimal wear contact wheel, abrasive belt can maintain constant speed, short transmission chain, the machine power up to 85% utilization.
(5)Auxiliary time. Positioning of the workpiece clamping, multiple replacement of the abrasive belt to complete all processing, do not need to like the wheel as balance and trim work.
(6) adaptability, simple operation, safe and reliable.
4 The main structure and the grinding amount of abrasive belt grinding device
There are several different structure of abrasive belt grinding unit. A device from the motor output shaft direct drive abrasive belt, the other is by the device of the motor by grinding spindle drive belt, a device for grinding.
For the first device, which is characterized by the contact wheel mounted directly on and fixed with 1:5 taper in the motor output shaft, the device has the abrasive belt tensioner and quick-change control mechanism, see Figure 2. Grinding device can make use of the clamping frame installed in a variety of metal cutting machine tools, grinding, so called general-purpose abrasive belt grinding device.
In such a device, the tension wheel and contact wheel should adopt a uniform texture nylon material. Contact roller and tensioner pulley are high-speed rotating parts, the tension wheel speed up to more than 5 000 r / min, the response to these two parts after processing in order to ensure safety and improve the smoothness of the entire device, dynamic balance unbalanced weight trials, and strive to minimize.
The belt line speed by the maximum allowable limit restrictions, generally selected as 25 m / s,. Workpiece per revolution abrasive belt along the workpiece axis vertical feed the general control of finishing in less than half of the abrasive belt width may be appropriate to reduce the number of In addition, the granularity of the abrasive grinding surface roughness has a direct relationship, the smaller the particle size, the lower the value of the surface roughness after grinding. When used, should ensure that there is plenty of coolant and dust removal equipment.
5 direction of development of abrasive belt grinding
Compared with the conventional processing method, the abrasive belt grinding is indeed a high-quality, high efficiency, low consumption of novel processing methods. At the same time, the long axis of the less rigid or thin wall sleeve parts, design and manufacture of some simple structure, easy to manufacture, easy to operate abrasive belt grinding device, installed in the general machine instead of grinding machines to carry out efficient finishing is feasible the.
In other countries, the belt grinding to the following direction:
(1) machine power continued to grow. The abrasive belt grinding machine (kw) for more than 200 have emerged.
(2) increase the belt speed. 100 m / s and above the development of high-speed abrasive belt grinding machine is in progress.
(3) increase the width of the belt, to improve processing efficiency, the widest reached 4.9m.
(4) to extend the life of the belt. From the initial 2 ~ 4h to 8 - 12h.
(5) with the amount of grinding of abrasive belt grinding, the grinding unit time have been able to reach general metal cutting machine tools unit time cutting, abrasive belt grinding finishing push strong mill cutting stage, and to grind on behalf of the car to the mill on behalf of the milling and planing to grind on behalf of the trend.
With the belt grinding process used in the continuous promotion of the domestic construction machinery industry, and the abrasive belt manufacturing process of continuous improvement and development is bound to a wider range of abrasive belt grinding machines and devices. It can be expected that the abrasive belt grinding process in the construction machinery manufacturing industry is bound to receive due attention and further development.
砂帶磨削技術(shù)在工程機(jī)械行業(yè)的應(yīng)用
摘要
介紹砂帶磨削技術(shù)的概況和特點(diǎn),論述砂帶磨削技術(shù)的展趨勢。在工程機(jī)械行業(yè)中,一些要求較高的長軸類零件傳統(tǒng)的加工工藝一般為粗車一精車一粗磨一精磨幾道工序,零件加工表面的精加工主要依靠在外圓磨床上用砂輪磨削來實(shí)現(xiàn)。而對于一些長徑比很大的細(xì)長桿件,如各類液壓缸的活塞桿,采用普通砂輪磨削就會受到加工范圍的限制,砂帶磨削正以其顯著的優(yōu)勢而嶄露頭腳。
關(guān)鍵詞:砂帶磨削,發(fā)展,加工
1 概述
砂帶磨削工藝,就是將環(huán)形砂帶套在接觸輪和張緊輪的外圓上,在張緊的狀態(tài)下,使高速旋轉(zhuǎn)的砂帶表面與工件的加工表面相接觸,并在一定的壓力作用下,以產(chǎn)生的相對摩擦運(yùn)動(切削運(yùn)動)對工件表面進(jìn)行磨削加工的一種工藝方法。砂帶磨削分為輪壓式和帶壓式兩種方法.
對于輪壓式磨削法,即接觸輪施壓于工件表面上,此時接觸輪與工件的軸間距A=1/2(D+d)此種磨削方式由于接觸壓力大,單位時間內(nèi)金屬的去除量大,效率高,因而適用于內(nèi)、外圓表面和平面的粗、精磨削。對于帶壓式磨削法,即用砂帶施壓于工件磨削表面,此時因張緊輪支架向工件方向傾斜了一個角度α,接觸輪與工件軸間距互A′>1/2(D+ d)。與輪壓式磨削法相比,帶壓法的接觸壓力較小,單位時間內(nèi)去除的金屬量亦小,主要用于磨削圓弧面、圓錐面和其它異形表面,尤其以精加工拋光為主。
砂帶和砂輪一樣,同屬于一種多齒微刃型切削工具,其加工特性基本相同,所不同的只是形狀各異而已。
2 目前的發(fā)展?fàn)顩r
在國外,一些工業(yè)發(fā)達(dá)國家由于各種類型砂帶磨床的迅速發(fā)展,砂帶磨削的功能已遠(yuǎn)遠(yuǎn)超出了用于除銹、粗磨、拋光等范圍,其加工效率為砂輪磨削的5~20倍,加工質(zhì)量可與一般常規(guī)的磨削方法相媲美,加工精度已接近或達(dá)到與砂輪磨削相同的水平,而機(jī)床功率的利用率卻比任何金屬切削機(jī)床都高,其應(yīng)用范圍遍及各個行業(yè),幾乎對所有材料(如木材、橡膠、各種金屬)都可進(jìn)行磨g帥0工。據(jù)有關(guān)資料介紹,美國每年的砂輪與砂帶產(chǎn)量之比約為 1: 1。在著名的工程機(jī)械企業(yè)CaterPiller公司,砂帶磨削就占有重要的地位。
在國內(nèi)繼引進(jìn)了高壓靜電植砂新工藝,保證了磨粒在砂帶表面的“定向排列”,使砂,一些砂帶生產(chǎn)廠家如鄭州白鴿集團(tuán)(即中國第二砂輪廠)、上海砂輪廠等都相帶具有良好的鋒利性。同時,隨著粘結(jié)劑的發(fā)展,耐水耐油的全樹脂強(qiáng)力砂帶的出現(xiàn),使砂帶的磨削性能得到顯著提高。雖然目前我國各類砂帶磨床的型號尚不完備,但研制和使用一些砂帶磨削裝置是切實(shí)可行的。
3? 砂帶磨削的特點(diǎn)
(1) 砂帶磨削具有“快削法”之稱。砂帶磨削效率高,已達(dá)到銑削的10倍,普通砂輪磨削的5~20倍。
(2) 砂帶磨削還具有“冷態(tài)”磨削之稱。由于加工時摩擦生熱少,且因磨粒散熱時間間隔長,可有效地減少工件變形和燒傷,加工精度一般可達(dá)到普通砂輪磨床的加工精度,有的尺寸精度已達(dá)到±0. 005 mm,最高可達(dá)到±0. 0012mm。
(3) 砂帶磨削具有“彈性”磨削之稱。由于砂帶磨削與工件是柔性接觸,具有較好的跑合和拋光作用,工件表面粗糙度可達(dá)Ra0.8~0.2μm。
(4) 砂帶磨削設(shè)備結(jié)構(gòu)簡單,制造成本低,接觸輪極少磨損,可使砂帶保持恒速,傳動鏈短,機(jī)床功率利用率可達(dá) 85%。
(5) 輔助時間少。工件裝夾一次定位后,可多次更換砂帶完成全部加工,無需象砂輪那樣進(jìn)行平衡及修整工。
(6)適應(yīng)性強(qiáng),操作簡單,安全可靠。
4 砂帶磨削裝置的主要結(jié)構(gòu)及磨削用量
砂帶磨削裝置有幾種不同的結(jié)構(gòu)。一種是由電機(jī)輸出軸直接傳動砂帶的裝置,另一種是由電機(jī)經(jīng)磨削主軸傳動砂帶的裝置,還有一種是供內(nèi)圓磨削使用的裝置。
對于第一種裝置,它的特點(diǎn)是接觸輪直接安裝并固定在具有1:5錐度的電機(jī)輸出軸上,該裝置具有砂帶張緊及快換操縱機(jī)構(gòu).因為這種磨削裝置可以借助夾持架安裝在多種金屬切削機(jī)床上進(jìn)行磨削加工,故稱其為通用砂帶磨削裝置。
在這種裝置中,張緊輪和接觸輪宜采用質(zhì)地均勻的尼龍材料制成。由于接觸輪和張緊輪都是高速旋轉(zhuǎn)的零件,張緊輪的轉(zhuǎn)速可達(dá) 5 000 r/ min以上,為保證安全并提高整個裝置的工作平穩(wěn)性,加工后應(yīng)對這兩種零件進(jìn)行動平衡試驗,力求將不平衡重減到最小。
砂帶的線速度受允許的最大極限限制,一般選為 25 m/s。工件每轉(zhuǎn)砂帶沿工件軸線的縱向進(jìn)給量一般控制在砂帶寬度的一半以內(nèi),精加工時可適當(dāng)減少一些。另外,磨粒的粒度與磨削的表面粗糙度有直接關(guān)系,粒度越小,磨削后的表面粗糙度數(shù)值越低。使用時,應(yīng)保證有充足的冷卻潤滑液和相應(yīng)的除塵設(shè)備。
5 砂帶磨削的發(fā)展方向
與一般常規(guī)的加工方法相比較,砂帶磨削的確是一種優(yōu)質(zhì)、高效、低消耗的新穎的加工方法。同時,對于剛性較差的長軸或薄壁套筒零件,設(shè)計制造一些結(jié)構(gòu)簡單、制造容易、操作方便的砂帶磨削裝置,安裝在通用機(jī)床上代替磨床來進(jìn)行高效的精加工是切實(shí)可行的。
在國外,砂帶磨削技術(shù)正在向以下方向發(fā)展:
(1)機(jī)床功率不斷增大。 200 kw 以上的砂帶磨床已經(jīng)出現(xiàn)。
(2)提高砂帶速度。正在進(jìn)行 100 m/s以上高速砂帶磨床的研制。
(3)則增大砂帶的寬度,提高加工效率,最寬已達(dá)4.9m以上。
(4)延長砂帶的使用壽命。已從初期的2~4h提高到目前的 8— 12h。
(5)隨著砂帶磨削的磨削用量不斷提高,單位時間內(nèi)的磨削量已能夠達(dá)到通用金屬切削機(jī)床單位時間內(nèi)的切削量,從而把砂帶磨削由精加工推向強(qiáng)力磨削的階段,并出現(xiàn)了以磨代車,以磨代銑和以磨代刨的趨勢。
隨著砂帶磨削工藝在國內(nèi)工程機(jī)械行業(yè)的不斷推廣使用,以及砂帶制造工藝的不斷完善和發(fā)展,必將出現(xiàn)種類更多的砂帶磨床和裝置。可以預(yù)料,砂帶磨削工藝在工程機(jī)械制造業(yè)中必將得到應(yīng)有的重視和進(jìn)一步的發(fā)展。