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1、<p>  Injection molding machine and on the control of it </p><p>  Modern plastic injection molding machine is a set of mechanical, electrical and fluid in one typical system, as this device has form

2、ing complex products, less post-processing, processing characteristics of the plastic variety, since its inception has grown rapidly, the current full Over 80% of the world's products are used plastic injection moldi

3、ng machine for processing.</p><p>  Conventional injection molding machines generally use a simple open-loop control, that is, in accordance with a pre-set value of control. In the device manufacturing proce

4、ss, pre-configured parameter values, such as the clamping force, cycle time, temperature, etc., from the machine in the production process be maintained. For example, by controlling the die temperature can be maintained

5、the temperature of heating fluid, plastic temperature can be outside the heating device by controlling the po</p><p>  At present, more injection molding machine uses a closed-loop control, that is, accordin

6、g to on-line measurement value and set the value of the deviation control. Closed-loop control system uses a negative feedback loop, anti-jamming ability, when the injection speed, injection pressure, mold cavity tempera

7、ture, cavity pressure, melt temperature and oil pressure due to interference in the production process, deviation of the machine through the adaptive control system for automatic correction of</p><p>  Commo

8、nly used injection molding machine control system has three kinds, namely, the traditional relay-based, programmable controllers and computer-based control type. In recent years, programmable logic controller (referred t

9、o as PLC) with its high reliability, high-performance characteristics in injection molding machine control system has been widely used. In order to improve the level of injection molding machine control system and qualit

10、y, a higher level than the PLC, control system design s</p><p>  Control of the contents of the injection molding machine</p><p>  Injection molding machine process control system mainly consist

11、s of two parts: First, the temperature control system in order to right barrel, melt and mold temperature control; second motion control system to the process of injection pressure, velocity and displacement multiple cla

12、ss switching.</p><p>  In the temperature control, its control accuracy has reached a ± 1 ℃. Precise temperature control in precision injection molding that help improve product quality and availability

13、 of raw materials is a very important indicator. In the plastic processing, temperature control include barrel, nozzle and mold temperature control. Barrel temperature of the barrel surface heating temperature, due to re

14、latively thick wall barrel, so the choice of thermocouple detection point is critical, and different </p><p>  Injection speed, packing pressure, back pressure is the injection of part of the sol to control

15、the first of the three variables directly affect the accuracy of its control product quality. Modern more advanced injection molding machine equipped with 5-10 multi-stage injection speed and packing, as well as melt glu

16、e back pressure control. Generally through displacement / velocity sensors, pressure sensors, closed-loop injection control, and high response servo valves used in conjunction to achie</p><p>  Transfer mold

17、 process control variable is the main clamping force, clamping force and time again is stable and the necessary conditions for forming the cycle. Transfer mode control of the process should be another important variable

18、is location. On the one hand, advanced injection molding machine constant pursuit of efficiency, directly affect the speed of transfer mold molding cycle, and quickly transfer to the deceleration control mode in itself h

19、as put forward higher requirements. On the othe</p><p>  PLC and PCC</p><p>  Since the late 20th century, 60 the United States the first programmable logic controller PLC inception, PLC control

20、 technology has gone through a 30-year development process, especially with modern computer technology and microelectronics technology, it has been in the soft hardware technology is far out of the original "sequenc

21、e control" of the prototype stage. Programmable Computer Controller (PCC) is to represent the development trend of this new generation of programmable controllers.</p><p>  PLC compared with conventiona

22、l, PCC is a for motion control, process control and network control of dedicated control system, is a standard PLC, numerical control systems and industrial performance characteristics of the computer in one of the intel

23、ligent controller. PCC is its biggest feature is similar to a large computer time-sharing multi-tasking operating systems and diverse software applications design. Most of the conventional single-task PLC clock scanning

24、or monitoring procedures to dea</p><p>  PCC application modules from the multi-task structure, the development of application software to the project has brought great convenience. Because it can easily con

25、trol the project in accordance with the various parts of the different functional requirements, such as motion control, data acquisition, alarm, PID regulator computing, communications, control, namely the preparation of

26、 a control program module (task), these modules not only operate independently, the data between one another to ma</p><p>  PCC a single task in the preparation of the different modules with a flexible choic

27、e of the characteristics of different programming languages, which means that not only in conventional PLC has been to people familiar ladder, instruction list language can continue to be used on the PCC, but users can b

28、e used more efficient and intuitive high-level language (PL2000), which is a complete text for the control of language, BASIC technical personnel familiar with the syntax it will feel a kind of dej</p><p>  

29、On the hardware structure, PCC is characterized by very significant. In its core computing module inside, PCC for its CPU is equipped with multiple conventional PLC, mass storage unit (100K/16M), this is undoubtedly a po

30、werful system and application software provides a hardware-based monitoring. PCC on the hardware features, but also reflected in its various signals for industrial site designed many dedicated interface module, such as t

31、he high-frequency pulses, incremental encoder, temperature, </p><p>  PCC in the industrial control powerful advantages, and demonstrate the programmable controllers and industrial control computers and DCS

32、(Distributed Industrial Control System) technology, the development trend of convergence, although this is still a relatively young technology, but in its more come more and more application areas, it is increasingly dem

33、onstrating its potential for development can not be underestimated. For the injection molding machine, the current widespread application of th</p><p>  There are many types of materials that may be used in

34、the injection molding process. Most polymers may be used, including all thermoplastics, some thermosets, and some elastomers. When these materials are used in the injection molding process, their raw form is usually smal

35、l pellets or a fine powder. Also, colorants may be added in the process to control the color of the final part. The selection of a material for creating injection molded parts is not solely based upon the desired charact

36、eristi</p><p>  Possible Defects</p><p>  Many of the above defects are caused by a non-uniform cooling rate. A variation in the cooling rate can be caused by non-uniform wall thickness or non-u

37、niform mold temperature</p><p>  Cost Drivers</p><p>  Material cost </p><p>  The material cost is determined by the weight of material that is required and the unit price of that

38、material. The weight of material is clearly a result of the part volume and material density; however, the part's maximum wall thickness can also play a role. The weight of material that is required includes the mate

39、rial that fills the channels of the mold. The size of those channels, and hence the amount of material, is largely determined by the thickness of the part.</p><p>  Production cost </p><p>  The

40、 production cost is primarily calculated from the hourly rate and the cycle time. The hourly rate is proportional to the size of the injection molding machine being used, so it is important to understand how the part des

41、ign affects machine selection. Injection molding machines are typically referred to by the tonnage of the clamping force they provide. The required clamping force is determined by the projected area of the part and the p

42、ressure with which the material is injected. Therefore, a</p><p>  The cycle time can be broken down into the injection time, cooling time, and resetting time. By reducing any of these times, the production

43、cost will be lowered. The injection time can be decreased by reducing the maximum wall thickness of the part and the part volume. The cooling time is also decreased for lower wall thicknesses, as they require less time t

44、o cool all the way through. Several thermodynamic properties of the material also affect the cooling time. Lastly, the resetting time depend</p><p><b>  注塑機(jī)及其的控制 </b></p><p>  現(xiàn)代塑料注塑

45、機(jī)是一個典型的系統(tǒng)集機(jī)械,電氣和流體,此設(shè)備已形成了復(fù)雜的產(chǎn)品,少的后處理,加工各種塑料的特性,自成立以來發(fā)展迅速,目前全過世界上的產(chǎn)品80%用于加工塑料注塑成型機(jī)。</p><p>  傳統(tǒng)的注塑機(jī)一般采用簡單的開環(huán)控制,即按照預(yù)先設(shè)定值的控制。 在設(shè)備制造過程中,預(yù)先設(shè)定的參數(shù)值,如從機(jī)器的鎖模力,循環(huán)時間,溫度等,在生產(chǎn)過程中予以保留。 例如,通過控制模具溫度可以維持加熱流體的溫度,塑料溫度可控制電源,以保

46、持外加熱裝置。 這種結(jié)構(gòu)簡單的控制方法,然而,窮人的抗干擾能力,控制溫度也比較低。</p><p>  目前,更多的注塑機(jī)采用閉環(huán)控制,即根據(jù)上線的測量值和設(shè)定值的偏差控制。 閉環(huán)控制系統(tǒng)采用了負(fù)反饋回路,抗干擾能力強(qiáng),當(dāng)注射速度,注射壓力,模腔溫度,模腔壓力,熔體溫度和壓力油,由于干擾,在生產(chǎn)過程中通過機(jī)器的偏差自適應(yīng)控制系統(tǒng)的干擾進(jìn)行自動修正。 這一控制方法抗干擾能力強(qiáng),控制精度高。 更先進(jìn)的控制方法是應(yīng)用計

47、算機(jī)控制,就是建立一個閉環(huán)實時計算機(jī)控制系統(tǒng)。 它包括直接數(shù)字控制系統(tǒng)(DDC),監(jiān)督計算機(jī)控制系統(tǒng)(SCC),分布式控制系統(tǒng)(DCS)和多層次的幾種類型的控制。</p><p>  常用的注塑機(jī)控制系統(tǒng)有三種,即傳統(tǒng)的基于繼電器,可編程控制器和基于計算機(jī)的控制類型。 近年來,可編程邏輯控制器(簡稱為PLC)以其高可靠性,高性能的特點在注塑機(jī)控制系統(tǒng)已被廣泛使用。 為了提高注塑機(jī)控制系統(tǒng)和質(zhì)量水平更高的水平,比P

48、LC控制系統(tǒng)的設(shè)計專門為中小型可編程計算機(jī)控制器(PCC)的應(yīng)運而生。 政協(xié)集成了一個標(biāo)準(zhǔn)的PLC和工業(yè)控制計算機(jī)的功能,多任務(wù)分時操作系統(tǒng),數(shù)據(jù)計算和處理能力比PLC更強(qiáng)大。 政協(xié)形成了注塑機(jī)控制系統(tǒng),以實現(xiàn)包括位置控制,速度控制,溫度控制,故障控制和實時顯示整個過程中,如注塑成型的各種控制,可以大大提高塑料制品的質(zhì)量有利于提高經(jīng)濟(jì)效益。</p><p><b>  控制注塑機(jī)的內(nèi)容</b>

49、;</p><p>  注塑機(jī)過程控制系統(tǒng)主要由兩部分組成:一是溫度控制系統(tǒng),為了權(quán)利桶,熔體和模具的溫度控制;第二項議案注射壓力,速度和位移的多級交換過程的控制系統(tǒng)。</p><p>  在溫度控制,其控制精度達(dá)到了±1℃。 在精密注塑精確的溫度控制,有助于提高產(chǎn)品質(zhì)量和原料的可用性是非常重要的指標(biāo)。 在塑料加工中,溫度控制主要包括料筒,噴嘴和模具的溫度控制。 料筒溫度,料筒表

50、面加熱溫度,由于料筒的壁比較厚,因此熱電偶檢測點的選擇是至關(guān)重要的,在不同的溫度曲線測試點是一個很大的區(qū)別。 因此,雙點,即表面,在同一時間在每桶深平行檢測設(shè)置熱電偶,將是相對穩(wěn)定的溫度曲線,有利于溫度控制精度。 噴嘴熔融溫度直接影響剪切流的推移,產(chǎn)品的質(zhì)量有重要影響,因此噴嘴溫度的控制精度要求。 模具溫度是在接觸與產(chǎn)品模具型腔表面溫度,它會顯著影響充膜,冷卻和包裝過程。 對于模具溫度控制方法可用于控制熱載體溫度的方法也可以直接控制模具

51、溫度。 前一種方法中,以加熱載體的出口對象的控制溫度,相對簡單,并能滿足一般的溫度控制要求。 當(dāng)溫度控制精度高,一般使用溫度控制的第二種方法。</p><p>  注射速度,保壓壓力,背壓是注射部分溶膠控制的三個變量直接影響其控制產(chǎn)品質(zhì)量的準(zhǔn)確性。 現(xiàn)代更先進(jìn)的注塑機(jī)配備5-10多級注射速度和包裝,以及熔膠背壓控制。 一般通過位移/速度傳感器,壓力傳感器,閉環(huán)注射控制,高響應(yīng)伺服閥配合使用,實現(xiàn)注塑成型工藝,熔膠

52、背壓,注射速度和精確控制的條件下包裝。 另一種比較簡單的方法是采用閉環(huán)比例閥,通過比例閥閥芯自己的閉環(huán)控制的位置,以提高控制精度。 然而,閥芯位置是一個中間變量,因此控制精度稍差。</p><p>  傳輸模過程控制變量是主要的鎖模力,鎖模力和時間,又是穩(wěn)定的成型周期的必要條件。 傳輸模式控制過程應(yīng)該是另一個重要的變量是位置。 一方面,先進(jìn)的注塑機(jī)不斷追求效率,直接影響轉(zhuǎn)移模具成型周期的速度,并迅速轉(zhuǎn)移本身的減速

53、控制模式提出了更高的要求。 另一方面,由于特殊工藝的不斷發(fā)展和推廣的位置控制精密模具的要求越來越高。</p><p><b>  PLC與PCC</b></p><p>  自20世紀(jì)后期以來,60,美國第一臺可編程邏輯控制器PLC以來,PLC控制技術(shù)已走過了30年的發(fā)展過程,尤其是與現(xiàn)代計算機(jī)技術(shù)和微電子技術(shù),在軟,硬件技術(shù)已遠(yuǎn)遠(yuǎn)出原來的“順序控制”的原型階段。 可

54、編程計算機(jī)控制器(PCC)就是代表這新一代可編程控制器的發(fā)展趨勢。</p><p>  與傳統(tǒng)的PLC相比,PCC是一種用于運動控制,過程控制和網(wǎng)絡(luò)控制的專用控制系統(tǒng),是一個標(biāo)準(zhǔn)PLC,數(shù)控系統(tǒng)和工業(yè)計算機(jī)的性能于一體的智能控制器的特點。 PCC是其最大的特點是類似于大型計算機(jī)的分時多任務(wù)操作系統(tǒng)和多樣化的應(yīng)用軟件的設(shè)計。 最傳統(tǒng)的單任務(wù)的PLC時鐘掃描或監(jiān)控程序處理過程本身的邏輯運算指令和外部I / O通道的狀

55、態(tài)收集和刷新。 這種待遇,直接導(dǎo)致“控制速度”,在應(yīng)用程序的大小取決于,這個結(jié)果是毫無疑問的高要求宗教在實時控制I / O通道。 PCC的系統(tǒng)軟件的完美解決方案這個問題,它采用分時機(jī)制構(gòu)建自己的應(yīng)用程序多任務(wù)的軟件操作平臺,使應(yīng)用程序運行周期的長短和無關(guān),但是,在決策周期操作系統(tǒng)。 作為一個結(jié)果,它會掃描應(yīng)用的周期同真正外部的控制周期之間的區(qū)別,以滿足實時控制的實際需求。 當(dāng)然,這在控制循環(huán)的CPU運算能??力允許的前提下,根據(jù)用戶的實

56、際要求,任意更改。</p><p>  PCC的應(yīng)用程序模塊,從多任務(wù)結(jié)構(gòu),應(yīng)用軟件開發(fā)項目帶來了極大的便利。 因為它可以很容易地控制項目按照不同的功能要求的各個部分,如運動控制,數(shù)據(jù)采集,報警,PID調(diào)節(jié)運算,通信,控制,即編制的控制程序模塊(任務(wù)),這些模塊不僅獨立運作,彼此之間的數(shù)據(jù),以保持一定的相互關(guān)聯(lián)的步驟,通過這些模塊后,獨立開發(fā)和調(diào)試的步驟可以下載到該委員會與CPU一起,在調(diào)控和管理多并行運行任務(wù)操

57、作系統(tǒng)下,共同實現(xiàn)項目的控制要求。</p><p>  寶成單個任務(wù)在不同的模塊準(zhǔn)備,用不同的編程語言,這意味著不僅在常規(guī)PLC一直到人們熟悉的階梯的特點靈活選擇,指令表語言委員會可以繼續(xù)使用,但用戶可以使用更加高效和直觀的高級語言(PL2000),這是一個完整的文字語言控制,基本熟悉語法的技術(shù)人員會感到一種似曾相識的感覺,這說明控制要求一個非常簡單的,直觀的。 此外,PCC的應(yīng)用軟件的開發(fā)還具有集成“C”語言程

58、序的能力,從而提供了強(qiáng)大的數(shù)據(jù)計算和處理能力。</p><p>  在硬件結(jié)構(gòu),PCC的特點非常顯著。 在其核心計算模塊內(nèi)部,PCC為其CPU配備有多個傳統(tǒng)的PLC,大容量存儲單元(100K/16M),這無疑是一個強(qiáng)大的系統(tǒng)和應(yīng)用軟件提供了基于硬件的監(jiān)控。 PCC的硬件功能,而且還體現(xiàn)在各種信號設(shè)計了許多專用的接口模塊,如高頻脈沖,增量式編碼器,溫度,稱重信號及超聲波信號接口模塊為工業(yè)用地,。 他們將各種形式的現(xiàn)

59、場信號是很方便的到寶成聯(lián)合成數(shù)字控制系統(tǒng)的核心,用戶可能需要將系統(tǒng)的硬件I / O通道在一個單一的道路,道路或幾十方法比十年作為一個單元模塊進(jìn)行了成千上萬的點對點的擴(kuò)大和網(wǎng)絡(luò)點至數(shù)百數(shù)十家。</p><p>  PCC在工業(yè)控制中強(qiáng)大的優(yōu)勢,并展示了可編程控制器與工業(yè)控制計算機(jī)及DCS(分布式工業(yè)控制系統(tǒng))技術(shù),融合的發(fā)展趨勢,雖然這仍然是一個相對年輕的技術(shù),但在其多來越來越多的應(yīng)用領(lǐng)域,它正日益顯示出其發(fā)展?jié)摿?/p>

60、不可低估。 注塑機(jī),目前的PLC控制系統(tǒng)的廣泛應(yīng)用,但隨著技術(shù)的進(jìn)步,個性化,定制產(chǎn)品,注塑機(jī)的控制要求的日益增長的需求更加復(fù)雜,精度高,寶成更先進(jìn)的控制系統(tǒng),將逐步占據(jù)一定的市場份額。 另一方面,為未來的網(wǎng)絡(luò)為基礎(chǔ)的生產(chǎn)要求,顯然,PCC控制系統(tǒng)更具競爭優(yōu)勢,所以我們有理由相信,PCC控制系統(tǒng)在未來將是發(fā)生在注塑機(jī)領(lǐng)域。</p><p>  注塑成型過程中要使用許多類型的的材料。可以使用大多數(shù)的聚合物,包括所有

61、熱塑性塑料,一些熱固性塑料和一些彈性體。當(dāng)使用這些材料進(jìn)行注塑成型過程時,其原始形式通常是很小的顆粒或粉末。也可以添加著色劑,對最后的顏色進(jìn)行控制。用于創(chuàng)建注塑件的選材不是純粹基于對最后一部分所需的特性。雖然每種材料都有不同的屬性,并會影響部件的強(qiáng)度和最后的的功能,而且這些屬性還要求處理這些材料中使用的參數(shù)。每種材料都需要一組不同的過程,包括注塑溫度、 注射壓力、 模具溫度、 彈射溫度和 時間周期等注塑工藝參數(shù)。</p&

62、gt;<p>  幾種常用材料的比較如下所示 </p><p><b>  。</b></p><p><b>  可能的缺陷</b></p><p>  上述缺陷的很多是由非均勻冷卻造成的。冷卻速度的變化會導(dǎo)致壁厚不均勻或模具溫度不均勻。</p><p>  該材料的成本是由材料重量

63、以及該材料的單位價格決定的。該材料的重量顯然是一個零件的體積和物質(zhì)密度的成績,但是,這部分的最大壁厚也能起到一定的作用。該材料,包括所需材料的重量,填補了模具的渠道。這些通道的大小以及對材料的數(shù)量,在很大程度上取決于該零件的厚度。 </p><p><b>  生產(chǎn)成本 </b></p><p>  生產(chǎn)成本主要是按小時速率和周期時間計算的。每小時的速率是與使用的注塑

64、機(jī)的大小成比例的,所以了解零件的設(shè)計選擇對機(jī)器的影響就顯的很重要。注塑機(jī)通常是指由它們提供的夾緊力噸位。所需的鎖模力是由零件的投影面積,并與該材料注入壓力。因此,較大的部分將需要更大的夾緊力,因此更昂貴的機(jī)器。此外,需要高注射壓力,可能需要更高噸位機(jī)器某些材料。零件的大小也必須符合其他機(jī)器的規(guī)范,如鉗中風(fēng),壓板尺寸和拍攝能力。</p><p>  這個周期時間可細(xì)分為注射時間,冷卻時間,復(fù)位時間。通過減少這些時間

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