鑄鐵平臺精度修復(fù)方法

時間：2016/1/25 8:54:36 瀏覽量：464

一般通過刮研來恢復(fù)鑄鐵平臺的精度。所謂“刮研”，是刮削和研磨兩個工序的結(jié)合。即平面刮削——研磨顯示，再平面刮削——再研磨顯示，如此往復(fù)，交替循環(huán)，不斷運作。使鑄鐵平板的表面粗糙度值和形位誤差逐步降低；接觸精度、幾何精度在運作中逐步提高，直到達到規(guī)定要求為止。

1、刀跡成形與受力分析

鉗工在刮研鑄鐵平板操作時，將平面刮刀刀柄頂住胯骨，雙手握住刀具，使平面刮刀與鑄鐵平板被刮表面形成一定的切削角度并對刀頭施加壓力，使平面刮刀刀刃吃緊平面。這時當(dāng)人的胯骨和腰部給刀柄以推力，使刀刃切入鑄鐵平板金屬表面并使刀刃在深入向前中切去研磨的黑點，然后將雙手壓力立即轉(zhuǎn)換提升力，把刀頭快速提起離開鑄鐵平板表面。完成了挖掘式的刀跡成形切削過程，并刮去一層極薄的金屬刀跡運作有3種方法，即直推法、直推加扭轉(zhuǎn)法、左右扭轉(zhuǎn)法。直推法產(chǎn)生長方塊、三角塊。表面呈現(xiàn)微波形，表面質(zhì)量較差，適宜粗刮；直推加扭轉(zhuǎn)法產(chǎn)生反“6”塊、正“6”塊形，表面呈細微波形，表面質(zhì)量光滑適宜細刮。左右扭轉(zhuǎn)法產(chǎn)生正鱗塊、反鱗塊、燕翼塊、燕身塊等，表面呈細曲紋波形，表面質(zhì)量光亮光滑，宜精刮或刮花（圖2所示）。從刮削過程看，刮削是合力作用的過程，操作熟練程度決定了刮削質(zhì)量的優(yōu)劣。

2、黑點規(guī)律

研具與鑄鐵平板經(jīng)過研磨以后，凸起部分的鑄鐵平板表面顯示的全是黑點，黑點分亮點、濃黑點、淡黑點。這些黑點在刮研中是一個變量。經(jīng)過連續(xù)的交替循環(huán)不斷地運作不斷地刮研，黑點由稀少變稠密，由不均勻分布變?yōu)榫鶆蚍植肌：邳c的演變過程，也是表面光潔度、表面接觸精度、表面幾何精度逐步提高的過程。

對研磨顯示出來的黑點要區(qū)分對待。對于濃黑點刮削的刀跡大小應(yīng)同按粗、細、精3個階段規(guī)定大小刮削，其刀跡方向應(yīng)同方向排列，逐步刮削到黑點全數(shù)刮完。經(jīng)研磨顯示后，第二遍以交錯方向刮削也將黑點全數(shù)刮完。必須指出，每輪刮削，刀跡必須交錯，否則將影響表面光潔度。在刮削中對黑點按亮、濃、淡在用力上應(yīng)有輕重之分，對亮點、大濃黑點用力要大，對大多數(shù)的濃黑點用力要適中，對淡黑點，則保留不刮，待下輪顯示后變黑時再刮，必須強調(diào)指出，對于分布在鑄鐵平板平面邊緣、角落的亮點。因隱布稀少，極易為人眼所忽略，極易漏刮。因為漏刮點在研磨時往往頂起研磨平板，妨礙黑點的正常顯示，會形成黑點越刮越少的現(xiàn)象。

3、刮研3階段

在刮研全過程中，一般都要經(jīng)歷粗刮、細刮、精刮3個階段。

粗刮階段：粗刮的首要任務(wù)應(yīng)先解決形位誤差問題。比如車床溜板燕尾導(dǎo)軌的兩端平行度，如不先解決好，留到粗刮好后再解決平行度，不但費工費時而且延誤工期。粗刮刀跡要寬大、要大刀闊斧地進行。對每個點只刮一次不刮第二次。刀跡方向是同方向順次排列，每輪變換一次。經(jīng)過反復(fù)循環(huán)不斷刮研，黑點由稀少變稠密，由不均勻分布至均勻分布，當(dāng)任意刮方（25mm×25mm）達到4～6點時，表面粗糙度達到Ra2.5～Ra3.2時即告粗刮階段中止。

細刮階段：細刮在粗刮基礎(chǔ)上進行。細刮的任務(wù)主要解決表面質(zhì)量問題，即接觸精度、幾何精度（平面度達到0.01mm/500mm2）、表面粗糙度（Ra1.6～Ra3.2），同時還要兼顧到形位誤差。細刮的刀跡寬為6～8mm，長10～12mm，刀跡建議采用直推加扭轉(zhuǎn)法，正“6”塊反“6”塊刀跡較好，當(dāng)任意刮方達到10～12點時細刮階段即告中止。

精刮階段：精刮是在細刮基礎(chǔ)上進行的，精刮的任務(wù)是進行提高刮研表面質(zhì)量，兼顧、核定形位誤差。精刮要磨好平面刮刀，要鋒利，落刀要穩(wěn)要輕，特別要避免刀角劃傷表面，精刮刀跡寬5～７mm，甚至更窄更短，視刮削平面大小而變化。刀跡建議采用左扭轉(zhuǎn)法或右扭轉(zhuǎn)法，刮削時用力宜小，刮花則例外。當(dāng)黑點增加到每任意方20～25點時，即精刮結(jié)束，其鑄鐵平板平面度應(yīng)為0.01mm/500mm2以下，表面粗糙度為Ra0.8～Ra1.6。

Cast iron platform precision repair method

The accuracy of the cast iron platform is generally restored by scraping.The so-called "scraping" is a combination of two processes of scraping and grinding. That is, plane scraping - grinding display, then plane scraping - re-grinding display, so reciprocating, alternating cycle, continuous operation. The surface roughness value and shape error of the cast iron plate are gradually reduced; the contact accuracy and geometric accuracy are gradually increased during operation until the specified requirements are met.

1、Tool path forming and force analysis

When the fitter is working on the cast iron plate, the flat scraper handle is placed against the tibia, and the cutter is held by both hands, so that the plane scraper and the cast iron plate are cut to a certain cutting angle and pressure is applied to the cutter head, so that the flat scraper blade is tightly flat. . At this time, when the human shinbone and the waist give the shank a thrust, the cutting edge cuts into the metal surface of the cast iron plate and the blade cuts the black point of the grinding in the deep forward direction, and then the pressure of the hands is immediately converted into the lifting force, and the blade is quickly lifted. Leave the cast iron plate surface. The excavation-type cutting process is completed, and a very thin metal blade is scraped off. There are three methods, namely, direct push method, direct push plus twist method, and left and right twist method. The straight push method produces long squares and triangular blocks. The surface is micro-waveform, the surface quality is poor, suitable for rough scraping; the direct push plus twist method produces anti-"6" block, positive "6" block shape, the surface is fine waveform, the surface quality is smooth and suitable for fine scraping. The left and right torsion method produces positive scales, anti-scales, swallow wing blocks, swallow body blocks, etc. The surface has a fine curved waveform, and the surface quality is bright and smooth, which should be finely scraped or scratched (shown in Figure 2). From the scraping process, scraping is the process of synergy, and the proficiency of the operation determines the quality of the scraping.

2、black dot law

After the lap and the cast iron plate are ground, the surface of the cast iron plate on the convex part is all black spots, and the black dots are bright, dark, and black. These black spots are a variable in scraping. After successive alternating cycles, the black spots are dilute from dense to dense, and from uneven distribution to uniform distribution. The evolution of black spots is also a process of gradually improving surface finish, surface contact accuracy, and surface geometric accuracy.

The black spots displayed by the grinding should be treated differently. For the thick black point scraping, the size of the knife should be scraped according to the size specified in the coarse, fine and fine stages. The direction of the tool path should be arranged in the same direction, and the scraping should be scraped until the black spots are completely scraped. After the grinding is displayed, the second pass is scraped in the staggered direction and the black spots are also completely scraped. It must be pointed out that for each round of scraping, the marks must be staggered, otherwise the surface finish will be affected. In the scraping, the black points should be light, thick, and light, and should be light and heavy. For the bright spots and large dark spots, the force should be large. For most of the dark spots, the force should be moderate. For the dark spots, keep it. Do not scrape, wait until the next round shows black and then scrape. It must be emphasized that for the bright spots distributed on the edge and corner of the plane of the cast iron plate. Because the hidden cloth is rare, it is easily overlooked by the human eye and is extremely easy to slip. Because the scratch point often pushes up the grinding plate during grinding, hindering the normal display of the black spots, the phenomenon that the black spots are less scratched.

3、scraping 3 stages

In the whole process of scraping, it is generally necessary to undergo three stages of rough scraping, fine scraping and fine scraping.

Rough scraping stage: The primary task of rough scraping should first solve the problem of shape and position error. For example, the parallelism of the two ends of the lathe tail of the lathe slide, if not solved first, to solve the parallelism after the rough scraping, not only labor and time and delay the construction period. The rough scraper should be large and must be carried out drastically. Only scratch once for each point and do not scrape the second time. The direction of the tool path is arranged in the same direction in sequence, and each round is changed once. After repeated cycles of continuous scraping, the black spots become dense from rare to dense, from uneven distribution to uniform distribution. When any scraping square (25mm × 25mm) reaches 4-6 points, the surface roughness reaches Ra2.5～Ra3.2. That is to say, the rough scraping stage is suspended.

Fine scraping stage: Fine scraping is carried out on a rough scraping basis. The task of fine scraping mainly solves the surface quality problem, namely contact precision, geometric precision (flatness of 0.01mm/500mm2), surface roughness (Ra1.6~Ra3.2), and also takes into account the shape and position error. The blade width of the fine scraping is 6~8mm and the length is 10~12mm. It is recommended to use the straight push and twist method. The "6" block is opposite to the "6" block. When the scraping reaches 10~12 points The fine scraping phase is aborted.

Fine scraping stage: Fine scraping is carried out on the basis of fine scraping. The task of fine scraping is to improve the surface quality of scraping, and to balance and verify the shape and position errors. Fine scraping should be ground flat scraper, to be sharp, the knife should be stable and light, especially to avoid scratching the surface of the knife corner, the fine scraping knife width is 5 ~ 7mm, even narrower and shorter, depending on the size of the scraping plane. It is recommended to use the left torsion method or the right torsion method. The force should be small when scraping, except for scratching. When the black point is increased to 20 to 25 points per arbitrary side, that is, the finish is finished, the flatness of the cast iron plate should be 0.01 mm/500 mm 2 or less, and the surface roughness is Ra 0.8 to Ra 1.6.

Company name: botou zhuoyuan mechanical equipment manufacturing co.,LTD
Registered address: jiaohe development zone, botou city, hebei province
Fax number: 0317-8031093
Contact information: 15369812793 (WeChat with the same number)  liansheng chu
Postcode: 062151
Enterprise email:1358827475@qq.com
Account Opening Bank: Botou Branch of Bank of China
Account number: 100399943203
Agricultural bank account number: 6228481739059615270

http://zhuoyuanjixie.com