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數(shù)控機(jī)床潤滑系統(tǒng)控制的改進(jìn)
機(jī)床潤滑系統(tǒng)的設(shè)計(jì)、調(diào)試和維修保養(yǎng)，對于提高機(jī)床加工精度、延長機(jī)床使用壽命等都有著十分重要的作用。但是在潤滑系統(tǒng)的電氣控制方面，仍存在以下問題：一是潤滑系統(tǒng)工作狀態(tài)的監(jiān)控。數(shù)控機(jī)床控制系統(tǒng)中一般僅設(shè)油箱油面監(jiān)控，以防供油不足，而對潤滑系統(tǒng)易出現(xiàn)的漏油、油路堵塞等現(xiàn)象，不能及時做出反應(yīng)。二是設(shè)置的潤滑循環(huán)和給油時間單一，容易造成浪費(fèi)。數(shù)控機(jī)床在不同的工作狀態(tài)下，需要的潤滑劑量是不一樣的，如在機(jī)床暫停階段就比加工階段所需要的潤滑油量要少。針對上述情況，在數(shù)控機(jī)床電氣控制系統(tǒng)中，對潤滑控制部分進(jìn)行了改進(jìn)設(shè)計(jì)，時刻監(jiān)控潤滑系統(tǒng)的工作狀況，以保證機(jī)床機(jī)械部件得到良好潤滑，并且還可以根據(jù)機(jī)床的工作狀態(tài)，自動調(diào)整供油、循環(huán)時間，以節(jié)約潤滑油。
1 潤滑系統(tǒng)工作狀態(tài)的監(jiān)控
潤滑系統(tǒng)中除了因油料消耗，油箱油過少而使?jié)櫥到y(tǒng)供油不足外，常見的故障還有油泵失效、供油管路堵塞、分流器工作不正常、漏油嚴(yán)重等。因此，在潤滑系統(tǒng)中設(shè)置了下述檢測裝置，用于對潤滑泵的工作狀態(tài)實(shí)施監(jiān)控，避免機(jī)床在缺油狀態(tài)下工作，影響機(jī)床性能和使用壽命。
1) 過載檢測 在潤滑泵的供電回路中使用過載保護(hù)元件，并將其熱過載觸點(diǎn)作為PMC系統(tǒng)的輸入信號，一旦潤滑泵出現(xiàn)過載，PMC系統(tǒng)即可檢測到并加以處理，使機(jī)床立即停止運(yùn)行。
2) 油面檢測 潤滑油為消耗品，因此機(jī)床工作一段時間后，潤滑泵油箱內(nèi)潤滑油會逐漸減少。如果操作人員沒有及時添加，當(dāng)油箱內(nèi)潤滑油到達(dá)最低油位，油面檢測開關(guān)隨即動作，并將此信號傳送給PMC系統(tǒng)進(jìn)行處理。
3) 壓力檢測 機(jī)床采用遞進(jìn)式集中潤滑系統(tǒng)，只要系統(tǒng)工作正常，每個潤滑點(diǎn)都能保證得到預(yù)定的潤滑劑。一旦潤滑泵本身工作不正常、失效，或者是供油回路中有一處出現(xiàn)供油管路堵塞、漏油等情況，系統(tǒng)中的壓力就會顯現(xiàn)異常。根據(jù)這個特點(diǎn)，設(shè)計(jì)時在潤滑泵出口處安裝壓力檢測開關(guān)，并將此開關(guān)信號輸入PMC系統(tǒng)，在每次潤滑泵工作后，檢查系統(tǒng)內(nèi)的壓力，一旦發(fā)現(xiàn)異常則立即停止機(jī)床工作，并產(chǎn)生報(bào)警信號。
2 潤滑時間及潤滑次數(shù)的控制
為了要使機(jī)床運(yùn)動副的磨損減小，必須在運(yùn)動副表面保持適當(dāng)?shù)那鍧嵉臐櫥湍ぃ淳S持摩擦表面之間恒量供油以形成油膜。但是數(shù)控機(jī)床運(yùn)動副需要的潤滑油量不是太多時，采用連續(xù)供油方式既不經(jīng)濟(jì)也不合理。因?yàn)檫^量供油與供油不足同樣是有害的、會產(chǎn)生附加熱量、污染和浪費(fèi)。因此，潤滑系統(tǒng)均采用定期、定量的周期工作方式。
集中潤滑系統(tǒng)本身可以配置微處理器，專門用于設(shè)定潤滑泵停止的時間和每次供油時間，以控制潤滑泵間隙工作，設(shè)計(jì)人員往往也借此來簡化自己的PMC程序。
但機(jī)床在不同的工作狀態(tài)下，如剛剛通電初始工作階段、加工運(yùn)行和因調(diào)整、檢測工件而使機(jī)床暫停運(yùn)行時，機(jī)床對潤滑油的需求量各不相同。在配置FANUC數(shù)控系統(tǒng)的機(jī)床中，通常通過控制潤滑泵工作的時間來調(diào)節(jié)提供的潤滑油量，但是，習(xí)慣考慮的是潤滑系統(tǒng)在機(jī)床加工運(yùn)行狀態(tài)下的供油方式，而沒有顧及其它工作狀態(tài)，這樣，當(dāng)機(jī)床處于其它工作狀態(tài)時，潤滑系統(tǒng)所提供的潤滑油量要么不夠，要么過多。
機(jī)床導(dǎo)軌需要的潤滑油量近似可用下面公式計(jì)算：(長度+移動行程)×寬度×K。從公式中可以看出，機(jī)床導(dǎo)軌需要的潤滑油量與該導(dǎo)軌上的軸的移動距離有關(guān)。歐美生產(chǎn)的數(shù)控系統(tǒng)大多以行程量作為依據(jù)，來控制潤滑泵工作，間隙供油，并在系統(tǒng)中提供了相應(yīng)的參數(shù)，便于機(jī)床制造商通過PMC程序?qū)櫥眠M(jìn)行電氣控制。而在FANUC 0i系統(tǒng)中沒有類似的控制方法，為了能在配置FANUC 0i的數(shù)控機(jī)床上，采用近似的供油方式控制潤滑泵工作，我們改進(jìn)了潤滑控制部分的電氣設(shè)計(jì)，讓控制系統(tǒng)能根據(jù)機(jī)床的具體工作情況自動調(diào)整潤滑泵工作頻率和每次的工作時間，在機(jī)床暫停時適當(dāng)減少供油量，而機(jī)床初始工作時適當(dāng)增加。
現(xiàn)將潤滑泵的工作狀態(tài)分成三類，分別設(shè)置潤滑泵工作時間和頻率。
1) 開機(jī)初始階段 機(jī)床開機(jī)，潤滑泵即刻開始工作，連續(xù)供油一段時間，此時潤滑泵工作的時間T1比正常狀態(tài)下的要長，以便在短時間內(nèi)提供足夠潤滑油，使機(jī)床導(dǎo)軌上迅速形成一層油膜。潤滑泵運(yùn)行時間由PMC程序中的TMRB指令設(shè)定。與TMR指令不同，由TMRB設(shè)定的時間，用戶不能隨意修改調(diào)整。
2) 加工運(yùn)行階段 機(jī)床開機(jī)以后，經(jīng)過空載運(yùn)行預(yù)熱后，進(jìn)入穩(wěn)定工作狀態(tài)。此后，控制系統(tǒng)控制潤滑泵間歇工作，以保證機(jī)床導(dǎo)軌能夠得到定期、定量的潤滑。潤滑泵每次工作的時間和其停止的時間由PMC程序中的TMR指令設(shè)定。TMR設(shè)定的時間參數(shù)，用戶可以在PMC數(shù)據(jù)窗口中根據(jù)需要適當(dāng)調(diào)整。
3) 暫停階段 工件待加工或加工完畢時，機(jī)床往往處于暫停工作狀態(tài)，潤滑油的需求量相應(yīng)減少，因此，需要及時調(diào)整控制方式，適當(dāng)延長潤滑泵停止工作的時間，以減少其工作頻率，從而減少油品消耗。實(shí)現(xiàn)的關(guān)鍵是機(jī)床處于暫停狀態(tài)時，系統(tǒng)如何獲知。FANUC 0i數(shù)控系統(tǒng)中提供了信號MVX(F102.0)、MVY(F102.1)、MVZ(F102.3)，用于反映機(jī)床各軸的移動狀態(tài)。如果該信號狀態(tài)為“0”，表明相應(yīng)機(jī)床軸靜止不動，如果所有移動軸均靜止不動，則表明機(jī)床此時處于暫停工作狀態(tài)。所以，只要上述所有信號狀態(tài)都為“0”，通過設(shè)計(jì)，PMC程序自動改變潤滑泵工作及停止時間。此時，潤滑泵工作的時間T2和停止的時間T3均使用TMRB指令設(shè)定，同樣，用戶不可以隨意修改這兩個時間參數(shù)。
3 潤滑報(bào)警信號的處理
1) 壓力異常 數(shù)控機(jī)床中潤滑系統(tǒng)為間歇供油工作方式。因此，潤滑系統(tǒng)中的壓力采用定期檢查方式，即在潤滑泵每次工作以后檢查。如果出現(xiàn)故障，如漏油、油泵失效、油路堵塞，潤滑系統(tǒng)內(nèi)的壓力就會突然下降或升高，此時應(yīng)立即強(qiáng)制機(jī)床停止運(yùn)行，進(jìn)行檢查，以免事態(tài)擴(kuò)大。
2) 油面過低 以往習(xí)慣的處理方法是將“ 油面過低”信號與“ 壓力異常”報(bào)警信號歸為一類，作為緊急停止信號。一旦PMC系統(tǒng)接收到上述信號，機(jī)床立即進(jìn)入緊急停止?fàn)顟B(tài)，同時讓伺服系統(tǒng)斷電。但是，與潤滑系統(tǒng)因油路堵塞或漏油現(xiàn)象而造成“ 壓力異常”的情況不同，如果潤滑泵油箱內(nèi)油不夠，短時間不至于影響機(jī)床的性能，無需立即使機(jī)床停止工作。但是，出現(xiàn)此現(xiàn)象后，控制系統(tǒng)應(yīng)及時顯示相應(yīng)的信息，提醒操作人員及時添加潤滑油。如果操作人員沒有在規(guī)定時間內(nèi)予以補(bǔ)充，系統(tǒng)就會控制機(jī)床立即進(jìn)入暫停狀態(tài)。只有及時補(bǔ)給潤滑油后，才允許操作人員運(yùn)行機(jī)床，繼續(xù)中斷的工作。針對“油面過低”信號，這樣的處理方法可以避免發(fā)生不必要的停機(jī)，減少輔助加工時間，特別是在加工大型模具的時候。在設(shè)計(jì)時，我們將“ 油面過低”信號歸為電氣控制系統(tǒng)“ 進(jìn)給暫?！鳖愋盘?，采用“提醒——警告——暫停，禁止自動運(yùn)行”的報(bào)警處理方式。一旦油箱內(nèi)油過少，不僅在操作面板上有紅色指示燈提示，在屏幕上也同時顯示警告信息，提醒操作人員。如果該信號在規(guī)定的時間內(nèi)沒有消失，則讓機(jī)床迅速進(jìn)入進(jìn)給暫停狀態(tài)，此時暫停機(jī)床進(jìn)行任何自動操作。操作人員往油箱內(nèi)添加足夠的潤滑油后，只需要按“循環(huán)啟動”按鈕，就可以解除此狀態(tài)，讓機(jī)床繼續(xù)暫停前的加工操作。
4 結(jié)語
數(shù)控機(jī)床電氣控制設(shè)計(jì)過程中，潤滑系統(tǒng)的處理若被忽視，對于機(jī)床的使用者而言，機(jī)床各部件能否定期定量得到潤滑，卻是十分重要的問題。應(yīng)不斷改進(jìn)、完善產(chǎn)品的設(shè)計(jì)，減少機(jī)床出現(xiàn)故障的次數(shù)，提高產(chǎn)品的可靠性。
The number controls the improvement that machine bed lubricate the system the control
The machine bed lubricates the design of the system and adjust to try with maintain to maintain, having got increases machine bed process accuracy, extension machine bed service life etc. very much the very important function.But in the aspects of electricity control that lubricate the system, still exsits below problem:An is to lubricate the system work appearance supervise and control.Number control the machine bed control system inside to establish generally and only the fuel tank oil supervise and control, the in order to prevent provides the oil the shortage, but to lubricate the system appear easily of leak the oil, oil road stop to wait the phenomenon, can't on time do the reaction.Two is a lubrication to establishes circulation with give oil time one, result in easily wasted.The number under the different work appearance control the machine bed, the amount of lubricant of the demand is different, such as in stage in pause in bed in machine compare an amount of lubricant for needing that process the stage want to be little.Aim at the above circumstance, in count control machine bed electricity control system, to lubricate to control the part proceeded the improvement designs, supervising and control the work condition of the lubrication system every moment, toing guarantee the machine bed machine parts get the good lubrication, and can also according to the work appearance of the machine bed, automatic adjust to provide the oil, circulation time, to economize the lubricant.
1 Lubricate the system the work the appearance supervise and control
Lubricate the system inside in addition to making the lubrication system provide the oil shortage because of the oil anticipates the depletion, fuel tank oil over little, familiar breakdown still contain oil pump expiration, provide the pipeline road stop, divide to flow the machine work falsely often, leak the oil to wait seriously.Therefore, establishes to descend to say the examination device in lubricate system, used for the work to pump to lubrication appearance puts supervise and control into practice to, avoiding the machine bed the work while lacking the oil appearance, affect the machine bed function with the service life.
1) Over carry to examine to used to carry to protect a dollar an importation for, combining its heat over carrying the order to be used as the system of PMC signal in power supply back track that lubrication pump, once lubricate the pump appeared to carry, the system of PMC can immediately examine and put paid to, make machine bed stopped the movement immediately.
2) The oil examines lubricant as the expendable goods, for this reason machine bed work after a period of time, lubricating pump lubricant inside the fuel tank will reduce gradually.If operate the personnel have no on time increase, be the lubricant inside the fuel tank arrive lowest oil, oil examination the switch acts immediately, combining to deliver this signal to PMC system the proceeding handles.
3) Pressure examination machine bed the adoption passes into the type concentrates lubrication system, only system work normal, each lubrication orders it can guarantee to get the pre-arranged lubricant.Once lubricate to pump oneself the work falsely often, lose efficacy, or is to provide to have in the oil back track a the place appears to provide the pipeline road stop, leak oil etc. circumstance, pressure in the system will present the abnormality.According to this characteristics, design at lubricate the pump to install the pressure examination switch exit, combine to input this switch signal into the PMC system, after every time lubricate pump work, check pressure in the system, once discover the abnormality then stop immediately the machine bed works, combining the creation report to the police the signal.
2 Lubricate the control between time and lubrication number of times
The in order to makes the machine bed exercise the vice- wear and tear lets up, must at exercise vice- surface keep appropriate and detergent lubricant , then maintain the friction surface an amount of provides the oil to become oil .But the number control the lubricant that machine bed exercise vice- demand the deal is not too many, adoption continue provide the oil method since uneconomical too not reasonable.Because too many to provide the oil with provide the oil the shortage similarly harmful, will produce the additional calories, pollution with wasted.Therefore, lubricate the system to all adopt the periodical and quantitative period the work the method.
Concentrate lubrication system oneself can install the microprocessor, used for exclusively the enactment lubricates to pump time of the ceasing with every provide oil time, lubricate pump cleft to work with the control, design the personnel to usually also borrow this to simplify own the procedure of PMC.
But the machine bed is under the different work appearance, such as just switch on electricity the beginning start the stage in work and process the movement similar to made machine bed pause circulated because of adjust, examination work piece, machine bed to lubricate the oily demand eachly not.In install FANUC number control the machine bed of the system, usually pass the control lubricates time that pump the work to provide to the amount of lubricant that regulate, but, what habit consider is to lubricates the system to process in the machine bed the movement appearance descend of provide the oil method, but did not have regard for the other the work the appearance, like this, crash the bed be placed in other work appearance, lubricate the system an amount of lubricant for providing want the 么 not enough, wanting the 么 excessive.
The machine bed leads the amount of lubricant of the demand look like and can use underneath formula calculation:( length+ move the route of travel) × width × K.Can see from the formula inside, the machine bed leads the lubricant of the demand measures to have something to do with should leading the axial ambulation distance of the 軌 .The number that Europe and America produce controls the system to measures with the route of travel mostly conduct and actions according to, control lubrication pump work, the cleft provides the oil, and provided the homologous parameter in system, the easy to machine bed manufactory pass the procedure of PMC to the lubrication pump proceed electricity control.But has no similar control method in FANUC a system, for the sake of can in installing a the 0 is of FANUCly the number controls machine bed, the adoption looks like of provide the oil method the control to lubricate to pump the work, we improved the lubrication the control part of electricity designs, letting control system can according to machine bed of concrete work the circumstance adjusts automatically lubrication pump work frequency with every work time, at machine bed pause hour appropriate the decrease provides the amount of oil, but appropriate increment for machine bed beginning to start work.
Will lubricate now the work appearance of the pump be divided into three type, establishes respectively lubrication pump work time with frequency.
1) The machine beginning that open the machine bed starts the stage opens the machine, lubricating the pump to begin to work right away, continuing to provide oil a period of time, lubricating at this time the time T1 that pump the work compares the normal appearance descends of want long, in order to provide the enough lubricant in the in a short time, make the machine bed lead the. the top become quickly a layer oil .Lubricate pump circulate time be set up by PMC TMRB in the procedure instruction.Different from the instruction of TMR, from time that TMRB set up, the customer can't modify the adjustment as one's pleases.
2) Processing the stage in movement machine bed opens the machine hereafter, passing by to get empty to transport the line prepare the hot empress, entering the stable work appearance.Henceforth, control system control lubricate the pump intermittent work, to guarantee the machine bed lead the can get periodical, quantitative lubrication.Lubricate time of the every work in pump to be set up by PMC TMR in the procedure instruction with time of its ceasing.Time parameter that TMR set up, customer can in PMC data window way according to need the appropriate adjustment.
3) Stage in pause a time for treating processing or processing completing, machine bed usually being placed in pause working appearance, lubricating oily demand cowgirl reducing, therefore, needing on time adjusting controling way, appropriate extension lubricating pumping stopping work, to reduce its work frequency, from but reduce the oil article the depletion.When key of realizing is a machine bed to be placed in the pause appearance, the system how to have learned that.The number of FANUC controled to provide the signal MVX( F102.0), MVY( F102.1), MVZ( F102.3) in the system, useding for reflecting machine bed each axial ambulation appearance.If the signal's appearance is a "0", express cowgirl machine bed stalk static motionless, if all ambulation stalk all static motionless, then express the machine bed to be placed in at this time pause work appearance.So, above only all signal appearance all for"0", pass the design, the procedure of PMC changes automatically lubrication pump work and stop time.This time, lubricate the time T2 that pump the work to use with the time T3 of the ceasing all the instruction of TMRB set up, same, customer must not modify these two time parameter as one's pleases.
3 Lubricate to report to the police the signal handles
1) Pressure excrescent the number controls to lubricate system as in the machine bed intermittent provide oil work method.Therefore, lubricate pressure in the system adoption periodical check method, at lubricate the pump the every work later on check.If appear the breakdown, if leaks oil, oil pump expiration, the oil road stops, lubricate the pressure in the system and then will descend or go up suddenly, this time should immediately compulsory the machine bed stops the movement, proceeding the check, in order to prevent the circumstances extends.
2) Oil over low handles habitually before the method is to report to the police with" pressure abnormality" the " oil over low" signal to signal to classify a type, be used as the urgent ceasing signal.Once the system of PMC receives the above signal, the machine bed enters the urgent ceasing appearance immediately, let servo system cut the power at the same time.But, with lubricate the system make the circumstance of the " pressure abnormality" different because the oil road stops or leaks the oil phenomenon, if lubricate to pump the oil inside the fuel tank not enough, short time affects the function of the machine bed not to the extent of, having no to need to make the machine bed stop the work immediately.But, after appearing this phenomenon, control system should on time show the homologous information, remind to operate the personnel on time increase the lubricant.If operate the personnel did not give complement in rule time, system will control the machine bed to enter the pause appearance immediately.Only have on time after supplying the lubricant, just allow to operate the personnel circulate the machine bed, continuing the work of the interruption.Aim at the " oil over low" signal, handles like this the method can avoid the occurrence the otiose shutting down, reducing the assistance processes time, especially at the time of processing the large molding tool.While designing, we classify the " oil over low" signal to electricity control system" enter to the pause" a signal, adoption" remind the —— the warning the —— pause, prohibition against auto circulate" of reporting to the police and handling way.Once oil inside the fuel tank over little, not only there is red instructioning in operating front-panel the light hint, in holding act but also show to warn the information at the same time, remind to operate the personnel.If that signal did not disappear in prescriptive time, then let machine bed entered in to give the pause appearance quickly, this time pause machine bed proceed any automatic operation.Operate the personnel toward fuel tank inside to increase the enough lubricant empress, a demand presses" circulate to start" button, can relieve this appearance, before letting the machine bed continue the pause process the operation.
4 Conclusion
Number control in the machine bed electricity control design process, lubricate the system handles if is neglected, for the user of the machine bed but speech, machine each parts of bed can periodical the fixed amount gets the lubrication, is a very important problem however.Should improve continuously, the design of the perfect product, reduce the number of times that machine bed appear breakdown, increase the dependable of the product.
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