压焊设备

20093186斩波式交流点焊电源信号的频谱分析/胡姜文…//电焊机.-2008,38(12):80~82设计了斩波式交流点焊电源的主电路,并讨论了其工作过程及原理。利用离散傅立叶变换对采样的斩波电源信号进行了频谱分析。分析了占空比、斩波频率与谐波幅值和频率之间的关系,通过对比得出了占空比及斩波频率的合理取值范围。图3表3参320093187一种提高晶闸管触发电路抗干扰的改进方法/成海晖…//电焊机.-2008,38(12):93~94介绍了一种应用于电阻焊机的、基于脉冲变压器的传统晶闸管触发电路;描述了电路的组成以及各个组成部分的功能;分析了干扰对电路的影响,提出了一种提高电路抗干扰能力的改进方法;对改进后的电路进行了原理分析并给出了应用情况。图2参220093188基于PIC单片机的电容储能点焊机电路设计/徐向前…//热加工工艺.-2008,37(21):126~128介绍了以PIC单片机为控制核心芯片的电容储能点焊机的电路系统设计。充分利用PIC单片机,完成了对储能电容组的恒流充电。将高频脉冲电流点焊理论应用于储能电容组的放电中,成功地解决了焊接强度和飞溅之间的矛盾,使焊接飞溅大大减少。所研制的焊机已成...     

压焊设备

20093186斩波式交流点焊电源信号的频谱分析/胡姜文…//电焊机.-2008,38(12):80~82设计了斩波式交流点焊电源的主电路,并讨论了其工作过程及原理。利用离散傅立叶变换对采样的斩波电源信号进行了频谱分析。分析了占空比、斩波频率与谐波幅值和频率之间的关系,通过对比得出了占空比及斩波频率的合理取值范围。图3表3参320093187一种提高晶闸管触发电路抗干扰的改进方法/成海晖…//电焊机.-2008,38(12):93~94介绍了一种应用于电阻焊机的、基于脉冲变压器的传统晶闸管触发电路;描述了电路的组成以及各个组成部分的功能;分析了干扰对电路的影响,提出了一种提高电路抗干扰能力的改进方法;对改进后的电路进行了原理分析并给出了应用情况。图2参220093188基于PIC单片机的电容储能点焊机电路设计/徐向前…//热加工工艺.-2008,37(21):126~128介绍了以PIC单片机为控制核心芯片的电容储能点焊机的电路系统设计。充分利用PIC单片机,完成了对储能电容组的恒流充电。将高频脉冲电流点焊理论应用于储能电容组的放电中,成功地解决了焊接强度和飞溅之间的矛盾,使焊接飞溅大大减少。所研制的焊机已成...     

大功率低纹波等离子喷涂斩波电源研制

等离子喷涂电源通常采用可控硅整流电源或逆变电源,存在效率低、输出电流纹波大等问题,难以满足等离子喷涂工艺的特殊要求.文中提出了一种基于八相交错并联Buck变换器的大功率等离子喷涂斩波电源.首先设计了斩波电源的电路拓扑,分析了斩波电源的工作原理和电流纹波产生机理,阐明了并联相数、占空比对电流纹波的影响规律,并进行了仿真验证.然后,基于等离子喷涂工艺对电源特性的要求,设计出功率为40 kW的四相交错并联模块,在CAN总线协同控制下,组成80 kW的八相交错并联斩波式等离子喷涂电源.最后,搭建了等离子喷涂斩波电源样机,进行了喷涂试验,测试了电源的输出纹波和效率.试验结果表明,与传统的可控硅整流电源和逆变电源相比,斩波电源的电流纹波率降低50%以上,电源效率最高达到94.5%.     

斩波式中频点焊电源的PLC控制系统

设计的斩波式中频点焊电源主电路由一对反向串联的IGBT及其保护电路组成,两个IGBT在设定的占空比通断信号控制下轮流导通,从而实现了焊接变压器次级交流斩波波形的输出,线路简单、工作稳定可靠.以S7-200PLC为核心,设计开发了电源及焊接过程控制系统.其中,斩波控制信号由基于TL494的PWM信号发生电路产生,该电路还...     

高频脉冲电子束偏压电源设计

为了实现具有陡峭上升沿和下降沿的高频脉冲偏压,改善高频脉冲电子束束流品质,提出了基值偏压直流电源、脉冲偏压直流电源和高压斩波主电路串联的主电路结构。高压斩波主电路通过MOSFET功率开关管导通和关断将脉冲偏压直流电源变换为高频脉冲偏压输出,使脉冲偏压具有快速变化的上升沿和下降沿;基于调制解调工作原理,设计了高压隔离通讯电源,实现了脉冲频率、占空比等高频脉冲偏压参数及命令从低压电路向高压斩波电路的可靠传输并生成PWM波形;设计了专门的高压隔离供电电源,实现了高压端高压斩波电路的可靠供电与驱动。基于上述技术,研制出高频脉冲电子束偏压电源,获得了具有陡峭上升沿和下降沿的高频脉冲偏压输出,20 kHz时脉冲偏压上升沿≤1μs。     

大功率微弧氧化电源的研制--主电路的设计

微孤氧化是一种新型的表面处理方法,需要可输出双端不时称的高压脉冲电源,且电源的脉冲幅值、频率、占空比均在一定范围内连续可调。为此设计了三相半控整流和IGBT斩波相组合的主电路．重点介绍了三相整流同步触发电路及保护电路的实现,控制系统采用以80C196KC单片机为核心．通过对可编程定时器82C54编程,控制晶闸管的导通角,目的是为斩波电路提供输出电压连续可调的直流源。通过波形分析和对产品的微弧氧化性能测试,证明了该电源设计合理．完全可满足微弧氧化工艺的需求。     

大功率脉冲电化学光整加工电源的研制

脉冲电化学光整加工技术是近年来新发展的一种高效的光整加工方法,需要用高频窄脉宽大功率的脉冲电源.该电源的设计采用了单片机AT89s52作为主控部分,通过8254-2可编程定时器/计数器输出频率和占空比可调的脉冲方波,并使用M57962AL来驱动和保护IGBT,实现了把直流电压信号斩波成脉冲电压信号输出.     

晶体管斩波宽调压电源及应用

斩波式可调稳压电源具有调压范围宽、功耗小、效率高、体积小、重量轻等优点使它得到了广泛应用。在该电源中主电路采用大功率晶体管模块（GTR），耐压1600V电流35A、控制电路只采用了一片集成电路TL494，电路十分简单。在斩波频率不变的情况下，改变斩波器的占空比即可改变电源的输出电压，这一功能由TL494控制，电压反馈调节及电流保护也由TL494实现。在图1的控制电路中，TL494的第5脚，第6脚所接电容C1和电阻R1决定斩波频TM94内部有两只晶体管输出，工作电压可达4OV，输出电流250InA，13脚与14脚（5伏）相接时两只晶体管推挽工…     

高频脉冲TIG焊电源

采用两套斩波电路输出端并联的方式,设计了一台高频直流脉冲TIG焊电源。该电源可以输出不同频率、不同占空比、具有陡峭上升沿和下降沿的脉冲电流,并且基值电流和峰值电流可以独立调节。对比了常规直流TIG焊和高频直流脉冲TIG焊电弧的挺直度,结果表明,在电流平均值相同的情况下,无论在高速焊接还是V型坡口焊接中,高频电弧都具有良好的挺直度,焊接工艺性能明显优于普通直流TIG焊。     

新型超窄脉宽脉冲电源的设计与实现

脉冲电源的脉宽及占空比对电化学加工的精度有着重要的影响。传统的脉冲电源一般采用开关斩波形式,对开关器件的开关速度要求很严格,且对开关器件的驱动也有很高的要求。对于电化学微细精加工,常用的开关器件很难达到超窄脉宽的要求。利用DDS信号电路产生基本信号,结合脉冲调理电路,设计一种新型超窄脉宽脉冲电源。实践表明:该超窄脉宽脉冲电源的脉宽最低可达10 ns,占空比可调,输出信号稳定性强,被成功应用于光学码板的加工。     

The effect of additives on the pulsed electrodeposition of copper

Abstract

The pulsed electrodepostion of copper has been systematically investigated from a copper sulphate bath. Pulse duty cycles of 5–80%, at frequencies from 10 to 100 Hz with current densities ranging from 2·5 to 7·5 A dm^?2 were employed. The influences of pulsed current duty cycle, peak current density and frequency on the thickness and hardness of the copper deposit, current efficiency and throwing power of the plating process were studied. The effect of additives, polyethylene glycol and di-sodium EDTA on the properties of deposit were investigated.     

脉冲参数对等离子电沉积镍镀层结构和性能的影响

采用高频脉冲电源在纯铜基材上以等离子电沉积技术制备出了金属镍镀层,研究了高频脉冲频率以及占空比变化对等离子镀镍层结构和性能的影响。对镀层进行了SEM,显微硬度以及划痕结合力的表征。结果表明,随着高频脉冲频率和占空比的增加,镀层表面的熔融态形貌逐渐减少,镀层逐渐变得致密,表面硬度与结合力值也相应提高。通过讨论脉冲电源的能量作用方式,分析了频率及占空比对等离子电沉积镍层表面结构及性能的影响规律。     

Controlling the output power of soft switching arc welding inverter by two-stage continuous PWM method

The full bridge zero voltage zero current switching( FB-ZVZCS) , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of parallel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.     

Effects of pulsing frequencies on macro-particle contamination during pulsed vacuum arc deposition

Offering high deposition rates and being suitable for thin film fabrication, vacuum arc deposition (VAD) has been investigated extensively. However, macro-particles (MPs) emitted from the vacuum arc degrade the properties of the deposited samples and various types of magnetic filters have been proposed to mitigate macro-particle contamination. Unfortunately, the resulting deposition efficiency is inevitably compromised. In this work, we used a direct current (DC) based pulsed vacuum arc to deposit copper on a glass substrate. DC ensures continuous arc burning to achieve better stability, and the pulsed power provides high instantaneous and discontinuous energy that affects the generation of MPs. Four sets of experiments were done, and the relationship between the pulsing frequencies and MPs deposited on the substrate was studied. Our results show that the MPs tend to be smaller when the pulsing frequency increases, and the MP ratios vary with the pulsing frequencies in a different way than duty cycles. Several factors related to this phenomenon are discussed.     

整体翅片管的劈切—挤压加工

提出了一种新的本翅片管的机械加工方法,即劈切－挤压加工,实验观察发现,翅片的形成包括切入、挤压和成形3个阶段,实验结果表明,影响翅片形成的主要有刀具几何参数、挤压深度,进给量和劈切－挤压速度;对某一刀具,在选定挤压速度时,一定的挤压深度对应一个极限进人量,一定的进给量对应一个极限挤压深度。选择合理的参数可保证翅片加工的连续性和获得接近最佳形状的翅片。劈切－挤坟加工在普通车床上进行,设备简单易,翅片一次成形,材料利用率高,是一种能降低加工技术,提高生产率的加工方式。     

Effects of pulse parameters on macro-particle production in pulsed cathodic vacuum arc deposition

The effects of the pulse parameters on the production of macro-particles in vacuum arc deposition are studied. A power supply that can provide either direct current or pulsed power is used and the influence of the current and duty cycle are independently investigated. Copper is used as the cathode and glass is used as the substrate. Optical microscopy and scanning electron microscopy with image processing software are used to analyze the macro-particles deposited on the substrate. Our results show the general trend that the density of macro-particles increases with the direct current but there is no obvious correlation with the duty cycles. The lowest degree of macro-particle contamination is observed at a duty cycle of about 40.5%.     

提高大功率可控硅等离子切割机暂载率的有效途径

由于大功率可控硅空气等离子面所需空载电压较高,而切割时的电弧电压仅为空载电压的1／2－1／3,导致目前的大功率可控硅等离子切割机均存在暂载率低的现象。其实质因大的移相角,导致功率因素下降。为了保证额定的输出,电路中流过较大的电流,产生大量的无用功,线圈发热严重,暂载率下降。本文通过改变主电路的拓扑结构,在部分初级线圈中串接电容,对无功功率进行补偿,提高功率因素,克服了以往只对网络功率因素补偿,而不对负载功率因素补偿的缺点,减少额定功率输出时流过变压器原边的输入电流,提高了暂载率,使变压器工作在最佳状态,     

重载齿轮热处理及应用

重载齿轮是指传递功率大、承载大、低速、受冲击载荷大的齿轮,技术要求其具有优良的耐磨性能、较高的接触疲劳强度和弯曲疲劳强度等,同时具有较高的抗冲击和承载能力,所以需要对其进行强化热处理,以提高综合力学性能及使用寿命。重载齿轮常用的强化热处理工艺有渗碳淬火、渗氮以及感应淬火等。本文综述了重载齿轮上述3种热处理技术的应用情况及进展,并提出重载齿轮真空低压渗碳的应用前景。     

Effects of pulse reverse electroforming parameters on the thickness uniformity of electroformed copper foil

The non-uniformity of electroformed layers directly affects the mechanical properties and application requirements of micro devices. Therefore, uniformity of electroformed copper foil is significant in ensuring or improving the mechanical properties of micro devices. The influences of duty cycle, current density, power source, and electroforming time on the thickness uniformity of electroformed copper layers were studied, and these parameters were optimised by using the orthogonal experiment method. The thickness distribution rule of electroformed copper foil was also determined. Duty cycle had the largest influence on the uniformity; the uniformity of electroformed layers prepared with pulse reverse current power source was superior to those prepared with direct current power source and pulse current power source. Increasing current density enhanced uniformity. The optimal technical process suggested by this orthogonal experiment adopts pulse reverse current power, 30% of positive duty cycle, 10% of negative duty cycle, 2?A?dm^?2 of current density, and 92?minutes of electroforming time. The minimum coefficient of variation reached 1.54%. The thickness of electroformed copper foil varied directionally.