C620-3型普通車床數控化改造（橫向與縱向進給系統）含開題及5張CAD圖
C620-3型普通車床數控化改造（橫向與縱向進給系統）含開題及5張CAD圖,c620,普通,車床,數控,改造,橫向,縱向,進給,系統,開題,cad
附 錄
Analysis on the economic CNC transformation of machine system of C620 machine tool
Li Ye
This paper briefly introduces the design scheme of nc transformation of machine system of C620 lathe. Compared with the purchase of new machine tools, the modified C620 lathe saves a lot of money and shortens the delivery time.
Keywords: C620 lathe; Numerical control transformation
Just now, China's machine tool equipment nc manufacturing equipment rate of less than 30%, and a large part of the structure problems, such as aging, idle or eliminated, all depend on the purchase of new CNC machine, and it can take huge sums of money to buy for the old machine is not reasonable use is also a kind of resource waste, this is obviously not conform to China's national conditions. Therefore, using digital technology to transform existing machine tools is a national need, industrial policy and feasible way. This paper makes a brief discussion on the economic CNC transformation of the machine system of C620 lathe.
1. Modification scheme of mechanical system
1.1 modification scheme of the main drive system
The main role of spindle is to be responsible for the accuracy of nc machine tools, is a very important component. The frequency conversion speed of ac asynchronous motor is increased on the spindle, and the machining precision is improved. CNC lathe modification with different shaft installation, in the numerical control lathe spindle is installed on a spindle pulse encoder, for in the thread machining, prevent coaxial when machining parts can't wear a lathe spindle hole. Due to the different axis installation will show the location of the main shaft signal, so, when install, pay special attention to the main shaft axis and the derivation of the lathe spindle pulse encoder to achieve zero clearance between flexible coupling transmission (the ratio of 1:1), synchronous tooth profile can be very good to do this. The spindle of a lathe is limited in the process of using it. The maximum speed of a driving shaft pulse generator is subject to the highest speed limit, which cannot exceed its maximum speed.
Pulse encoder connection way, complete the following steps: ac spindle motor through the pulley movement to the spindle, the spindle movement through synchronous pulley and synchronous belt wheel 2 and 1 synchronous belt drive pulse encoder, with spindle speed operation, pulse encoder on the spindle box body with screws.
Generally, in the transformation of horizontal lathe numerical control, the amount of work of mechanical transformation is large, and the main drive and variable speed control mechanism on the machine tool can be retained, which can greatly reduce the amount of work. The forward and reverse rotation and stop functions of the spindle can be controlled by a numerical control system. Single-speed motor can be replaced by 2-4 speed multi-speed motor. The control of multi-speed motor can be realized by using ac inverter by spindle motor, which can meet the requirement of stepless variable speed. Through actual operation, it is proved that in the process of operating the converter, if the operating frequency of the original motor is below 70HZ, no replacement is required, but the power of the converter is greater than that of the motor.
The above example, when to have a variable can use the YD series level 7.5 kw variable multispeed three-phase asynchronous motor, this machine produced by zhejiang chaoli motor co., LTD.) for 2 ~ 4 block variable speed; The precondition of adopting the stepless variable speed is to install ac frequency converter. It is recommended to use the model f1000-g0075t3b produced by yantai huifeng electronics co., LTD., with a 7.5kw motor.
1.2 replace the automatic rotary tool holder
Can help to improve nc machining precision machine tool and can be done a one-time multi-channel working procedure, its model for LD4B - CK6140 four station vertical electric tool rest is a good equipment and the choice, the device production and changzhou hongda nc equipment co., LTD., can be very good to complete the manual tool post transfer automatic rotary tool rest. And the nc system can help the automatic tool change when the circuit configuration requirements.
1.3 installation scheme of screw encoder
Screw encoder, also known as spindle pulse generator or circular grating. When threading, the CNC lathe should install the spindle pulse generator to feedback the position of the spindle of the lathe and rotate synchronously with the spindle of the lathe. Examples are given below.
Reformed lathe, can lead most no more than 24 mm thread processing, Z to feed is 0.01 mm/pulse, each thread encoder, cannot be less than 24 mm (0.01 mm pulse - 1) = 2400 pulse output. Because the output of the encoder is different (phase difference is 900 A, B believe signal), A and B can be logically different or obtain 2,400 pulses. In this way, the number of lines in the pulse encoder can be reduced to 1200 lines (A and B signals). Also note that the encoder also needs to output a zero - bit pulse Z for each turn to repeat the same spiral groove.
According to the above requirements, the following examples are selected as the screw encoder of model zlf-1200z-05v0-150ct, which is from changchun optical machine digital display technology co., LTD. The power supply voltage is +5V, with 1200 A/B pulses and 1 Z pulse for each output. The signal is voltage output and the shaft head diameter is 15mm.
In threaded code installation, common installation methods are coaxial and cross-axis installation. Coaxial installation means that the encoder is installed directly on the spindle and coaxial with the spindle. Although this method is fast and simple, it has the disadvantage of easily causing the blockage of the main shaft through hole. Off-axis installation, namely in the back of the spindle box installed encoder, best location on the main shaft synchronous rotating output shaft, such as there is no synchronous spindle axis, you can use synchronous cog belt and spindle joins (rotation ratio is 1:1). At this time, the shaft head of the encoder must be connected with the installation shaft without clearance, which is a point needing attention, and the maximum speed of the spindle should be controlled within the maximum allowable speed of the encoder.
1.4 modification and design scheme of feed system
The pulse instructions issued by the nc system are received and amplified and converted by the feed system of the nc machine tool. The lateral (X axis) movement of the tool holder is driven by the horizontal feed drive system, which controls the radial dimension of the workpiece. The axial (Z axis) motion is driven by the longitudinal feed device, which controls the axial dimensions of the workpiece.
1.4.1 feed drive chain
Transverse feed (X axis) consists of stepper motor and reducer drive (stepper motor is installed behind the bed saddle), feed drive system include: stepper motor, vertical screw pair, synchronous belt, horizontal screw pair.
1.4.2 selection of ball screw nut pairs
To ensure the machining accuracy of nc machine tools high, the requirements of the feed drive system with high transmission precision, high sensitivity, fast response), stable work, have a high stiffness of components and service life, small friction and inertia, and can remove the transmission clearance.
1.4.3 design scheme process
(1) remove all the gears on the hanging wheel, find out the synchronous shaft of the spindle, and install the screw encoder.
(2) first remove the feed box assembly, and install the longitudinal stepping motor and synchronous belt reducer assembly (to be installed in the original position).
(3) first remove the quick tool gear rack and slide box assembly, and then install the nut holder bracket of the longitudinal ball screw (to be installed under the bed saddle).
(4) first remove the square tool holder and small skateboard assembly, and then install the four-station vertical electric knife holder above the middle skateboard.
(5) to dismantle the skateboard sliding screw nut pair, sawing the roller screw in dial a long (216 mm) and reserves, will the handles on the dial down, while retaining the dial nearby two thrust bearing, finally the ball screw pair of change.
(6) install the horizontal feed stepping motor on the bed saddle at the back of the middle skateboard through the flange seat and connect it with the shaft head of the ball screw.
(7) remove the parallel bars (screw, light bar and joystick) and replace the right bearing of the parallel bars.
2. Conclusion
We compared the mechanical system of a C620 lathe used in the production training with the newly purchased machine tool after the numerical control transformation, and the transformation cost was reduced by 60% to 80%, which was very economical. Especially in large, special machine tools especially prominent. The cost of large-scale machine tool transformation is only 1/3 of the total cost of newly purchased machine tool, and the delivery time is short.
reference
[1] Chen weidong, machinery processing equipment [M], Beijing university press, 2010.
This article is from Silicon Valley, article number: 1671-7597 (2014) 15-0146-01
C620機床機械系統的經濟型數控化改造探析
李燁
摘要 簡要介紹C620車床的機械系統進行數控化改造的設計方案。改造后的C620車床與同購置新機床相比大大節(jié)省了費用，縮短了交貨期。
關鍵詞 C620車床；數控化改造
就現在來看，中國機床設備數控制造裝備率小于30%，而且很大一部分結構存在問題，如：機構老化、閑置或淘汰，全部都依賴于購買新的數控機床代替，而購買則需要巨額資金，對于舊機器不合理的利用也是一種資源的浪費，這顯然是不符合中國國情。因此，利用數字技術對現有機床進行改造，是一個國家的需要和行業(yè)政策和可行的途徑。本文對C620車床機械系統進行的經濟型數控化改造這一課題來做一簡要探討。
1、機械系統的改造方案
1.1主傳動系統的改造方案
主軸的主要作用是負責數控機床精度的準確性，是十分重要的組成部分。在主軸上增加交流異步電動機變頻調速，加工精度提高的同時也實現了主軸自動無極變速，從而省去了機械換擋的麻煩。數控車床的改造采用異軸安裝，在數控車床主軸上安裝一個主軸脈沖編碼器，是為了在加工螺紋時，防止同軸裝時的加工零件無法穿出車床主軸孔。由于異軸安裝會顯示出主軸的位置信號，所以，在進行安裝時，要特別留意主軸脈沖編碼器的引出軸與車床主軸之間要達到無間隙柔性聯接傳動（其比例為1：1），同步齒形可以很好的做到這一點。車床主軸在使用過程中是具有限制的，一主動軸脈沖發(fā)生器的最高限速為準，不能超過其最高轉速。
脈沖編碼器聯接方式的步驟如下：交流主軸電動機通過帶輪把運動傳給主軸，主軸的運動經過同步帶輪1和同步帶輪2以及同步帶帶動脈沖編碼器，使其與主軸同速運轉，脈沖編碼器用螺釘固定在主軸箱體上。
一般在改造臥式車床數控化時，機械改造的工作量大，保留機床上的主傳動和變速操縱機構，可以大大的減少齊工作量。主軸的正反轉和停止功能，可以通過數控系統來控制。單速電機可以使用2~4速的多速電動機來替代；多速電動機的控制可通過主軸電動機利用交流變頻器來實現，可滿足其要求最終達到無級變速的目的。通過實際操縱，證明變頻器在工作的過程中，如原有電動機工作的頻率在70HZ以下，就無需更換，但前提是變頻器的功率大于電動機。
上述例子中，在進行有級變速的時候可以用YD系列7.5kw變級多速三相異步電動機（此款機器由浙江超力電機有限公司而產）來實現2~4擋變速；采用無級變速的前提是加裝交流變頻器，推薦使用煙臺惠豐電子有限公司生產的F1000-G0075T3B這個型號的，在配以7.5kw電動機。
1.2換裝自動回轉刀架
能幫助數控提高機床加工精度并可以一次性的完成多道工序，其型號為LD4B-CK6140的四工位立式電動刀架是一款比較好的設備和選擇，這款設備生產與常州市宏達數控設備有限公司，可以很好的完成手動刀架轉換自動回轉刀架。而數控系統可以幫助自動換刀時電路配置的要求。
1.3螺紋編碼器的安裝方案
螺紋編碼器，也可稱為主軸脈沖發(fā)生器或圓光柵。在進行螺紋加工時，數控車床要安裝主軸脈沖發(fā)生器來反饋車床主軸的位置，且與車床主軸同步轉動。以下舉例說明。
改造后的車床，可加工導程最大不超過24mm的螺紋，Z向的進給脈沖當量是0.01mm/脈沖，螺紋編碼器每一轉，都不能少于24mm（0.01mm·脈沖-1）=2400脈沖的輸出量。因編碼器的輸出有出入（相位差為900的A、B相信號），可將A、B經邏輯異或后獲得2400個脈沖?？蓪、B經邏輯異或后獲得2400個脈沖（一轉內），這樣脈沖編碼器的線數可降到1200線（A、B信號）。還要注意，要重復車削同一螺旋槽時正常工作，編碼器還需要輸出每轉一個的零位脈沖Z。
按照以上的要求，以下舉例選擇的是型號ZLF-1200Z-05V0-150CT的螺紋編碼器，來自于長春光機數顯技術有限公司。電源電壓＋5V，每輸出1200個A/B脈沖與1個Z脈沖，信號為電壓輸出，軸頭直徑15mm。
在螺紋編碼安裝中，常見的安裝方法分同軸和異軸安裝。同軸安裝，即指在主軸上直接安裝上編碼器，與主軸同軸，雖然這種方式快速簡單，但缺點卻是很容易造成主軸通孔的堵塞。異軸安裝，即指在主軸箱的后面安裝編碼器，位置最好在主軸同步旋轉的輸出軸上，如主軸上沒有同步軸，則可以使用同步齒形帶和主軸進行聯接（轉動比為1：1）。此時的編碼器軸頭必須要無間隙柔性聯接安裝軸，這是需要注意的一點，并且主軸的最高轉速要控制在編碼器的最高許用轉速內。
1.4進給系統的改造與設計方案
數控系統發(fā)出的脈沖指令由數控機床的進給系統接受并放大和轉換后驅動機床運動支星件完成預期的運動。刀架橫向（X軸）移動由橫向進給傳動系統帶動，它控制工件的徑向尺寸；軸向（Z軸）運動由縱向進給裝置帶動，它控制工件的軸向尺寸。
1.4.1進給傳動鏈
橫向進給（即X向）是由步進電動機及其減速箱傳動的（步進電動機裝在床鞍后面），進給傳動系統包含：步進電動機、縱向絲杠副、同步帶、橫向絲杠副。
1.4.2滾珠絲杠螺母副的選用
為保證數控機床高的加工精度，其進給傳動系統要求有高的傳動精度、高的靈敏度（響應速度快）、工作穩(wěn)定、有高的構件剛度及使用壽命、小的摩擦及運動慣量，并能清除傳動間隙。
1.4.3設計方案的過程
（1）將掛輪上的齒輪全部拆除，找出主軸的同步軸再進行螺紋編碼器安裝。
（2）先拆除進給箱總成，再安裝縱向步進電動機和同步帶減速箱總成（須在原來的位置上安裝）。
（3）先拆除快走刀齒輪條和溜板箱總成，然后安裝縱向滾珠絲杠的螺母座托架（須安裝在床鞍下面）。
（4）先拆除四方刀架和小滑板總成，然后在中滑板上方安裝四工位立式電動刀架。
（5）先拆除中滑板下的滑動絲杠螺母副，在鋸斷滑輪絲杠靠刻度盤一段（長216mm）并保留，將刻度盤上的手柄拆掉，同時保留刻度盤附近的兩個推力軸承，最后將滾珠絲杠副換上。
（6）將橫向進給步進電動機通過法蘭座安裝到中滑板后部的床鞍上，并與滾珠絲杠的軸頭相聯。
（7）將三杠（絲杠、光杠和操縱桿）拆除，更換絲杠的右軸承。
2、結束語
我們將生產實訓中使用的一臺C620車床機械系統通過數控化改造后與新購置的機床進行比較，改造費用方面減少60%到80%，十分節(jié)省。尤其在大型、特殊機床尤為突出。大型機床改造的費用，只需新購機床總費用的1/3，且交貨時間短。
參考文獻
[1]陳偉棟.機械加工設備[M]，北京大學出版社，2010.
文章摘自Silicon Valley，文章編號：1671-7597（2014）15-0146-01
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