自由喷嘴式接触引弧空气等子割炬及其应用

提出了一种轻便简易的接触引弧空气等离子割炬，介绍了其结构和工作原理及其在逆变式空气等离子切割机中的应用和相应的控制方法。试验表明，该割炬具有优良的工艺性能。     

数控火焰和等离子高低调节器的原理及应用

由于切割机在工作过程中不能准确探知切割割炬与钢板的距离,影响焊接质量,提出了一种数控火焰和等离子调高闭环自动控制系统.详细介绍了控制系统中的电容传感器、高频滤波电路、差分运算放大器、比较器、霍尔传感器、触发器、断弧提升器、模拟开关手动/自动转换器、定位起弧电路、手动/自动振荡器、光电藕合与电机驱动电路等的组成和原理.经实际应用证明,该控制系统切割后工件质量好,能达到切割精度要求,同时还能减轻操作者劳动强度.     

焊接与切割设备的使用和维修(六十七)——空气等离子弧切割机的使用与维修

介绍了空气等离子弧切割机切割前的准备、手工切割程序、自动切割程序、注意事项、割炬的安装维护及零件的更换、故障原因及其排除方法.同时列举了日本A-70等离子弧焊机的故障实例和解决方法.     

气焊及切割工艺与设备

水下自动套料切割定位系统,等离子弧切割装置的改进[英],径向基神经网络在三维激光切割中的应用，激光冲击加工表面涂层厚度的优选,CO2激光用于船体型线放样切割的研究及应用,[编者按]     

FastCAM套料软件在数控切割机上的应用

针对火焰、等离子、激光和水射流数控切割机在下料切割过程中套料生产效率低和钢板浪费严重的问题，重点介绍如何使用好FastCAM套料软件，以提高套料效率和钢材利用率。     

一种简单手动切割机动架

在钢板下料以及切割坡口时,一般都要采用手动切割。这是由于半自动切割机用起来较麻烦,而自动切割机的价格又昂贵。然而用手动割炬割出的钢板毛坯以及坡口面都很粗     

数控火焰切割机套料系统

个绍了火焰切割机自动套料切割系统、电容传感器自动调高系统是如何在工控机配合下自动完成套料和穿孔切割的全过程,解决了传统技术在厚板切割中的难题。     

水再压缩等离子弧切割的研究

本文研究设计的新型水再压缩等离子弧割炬,也可以作为浅水下等离子弧割炬,还可以作为一般等离子弧割炬。文中较详细地介绍了该割炬喷嘴的结构,列举了切割2.5～60mm厚不锈钢和10～23mm厚铝板的一些技术数据。本文还对等离子弧切割时产生的有害气体、粉尘及经济效果进行了分析。     

空气等离子切割电极可批量生产

该电极系装在空气等离子切割机的割炬上,能发射电子电离空气形成等离子弧焰束,可切割普通钢、不锈钢、铜、铝等材。具有切缝窄、切口不挂渣、热影响与变形均小等特点,是氧-乙炔气割所不能比拟的;     

PC—20X30型数控等离子切割机常见故障分析

１概述我厂购买的ＰＣ－２０Ｘ３０型数控等离子切割机，由济南铸锻研究所生产。其框图如图１所示。图１ＮＣ－ＰＣ数控等离子切割机框图该机床主要由ＦＡＧ０Ｒ８０２５－ＭＡ和可编程控制器组成的控制系统、受控的切割机本体以及与自动套料排料功能相配套的ＡＳＴ－３８...     

焊接与切割设备的使用和维修(六十五)——空气等离子弧切割机的使用与维修

分析了LGK系列空气等离子弧切割机的使用方法,例举了其引弧故障、主电路故障、气路故障、割枪故障产生的原因和解决方法.同时也讲述了晶闸管式等离子弧切割机的操作原理和使用方法.     

Analysis of acoustic characteristics for plasma arc cutting

Abstract

The sound emitted during plasma arc cutting is closely related to the cutting conditions including cutting speed, arc current, operating gas flowrate, torch standoff height, nozzle shape, etc., and it therefore contains useful information for the evaluation of the plasma arc cutting process. The present work investigates the characteristics of the sound emitted during plasma arc cutting under various cutting conditions, using fast Fourier transformation and probability statistical analyses. An acoustic model of plasma arc cutting, having two jet sound sources, is proposed to interpret this sound. The sensitive frequency band of the cutting sound and the relationship between the cutting sound and the conditions are then revealed. It is shown that the cutting sound is a random signal readily affected by cutting conditions, and its energy is concentrated in the high frequency field and originates mainly from the mixing region of the first sound source and the mixing and transition regions of the second sound source. Experimental results also suggest the possibility of developing an acoustically based monitor system for this plasma arc process, and of reducing the acoustic exposure level, thereby improving working conditions.     

Improvement of Plasma Spray Torch Stability by Controlling Pressure and Voltage Dynamic Coupling

The development of coating formation processes involving electric arcs depends on process stability and the capacity to ensure a constant reproducibility of coating properties. This is particularly important when considering suspension plasma spraying or solution precursor plasma spraying. Submicron particles closely follow plasma instabilities and have nonhomogeneous plasma treatment. Recently, it has been shown that arc voltage fluctuations in direct-current (dc) plasma torches, showing dominant fluctuation frequencies between 4 and 6 kHz, are linked to pressure oscillations in the cathode cavity of the plasma torch. In this study, first, a method to isolate the different oscillation modes in arc voltage and pressure signals using signal processing methods is presented. Second, correlations between the different modes of oscillations are analyzed following the plasma torch operating parameters. Lastly, it is shown that the use of an acoustic stub, mounted on the torch body, decreases the amplitude of arc voltage fluctuations and slightly increases the mean voltage.     

Effect of plasma spray operating conditions on plasma jet characteristics and coating properties

Using statistical design of experiments, the arc current, total gas flow rate, percent secondary gas (He), and powder feed rate have been varied to assess the torch behavior and establish its correlation to coating properties. The torch response includes arc voltage drop, torch efficiency, and plasma jet geometry. High-speed images of the luminous plasma jet for each operating condition have been acquired with a LaserStrobeℳ videocamera, and image analysis has been used to quantify the jet length and jet fluctuations as additional torch responses. Porosity and unmelted particles, which are determined using image analysis of a micrograph of a NiAl coating cross section, were selected as principal coating characteristics. These findings are expected to be useful for optimization of new spray processes and for evaluation of new torch designs.     

一种基于等离子弧的水蒸气割炬

介绍了一种用水蒸气作为工作气体的等离子割炬，它具有体积小、质量轻、污染小、使用方便等特点。     

Effects of Anode Arc Root Fluctuation on Coating Quality During Plasma Spraying

To obtain a coating of high quality, a new type of plasma torch was designed and constructed to increase the stability of the plasma arc and reduce the air entrainment into the plasma jet. The torch, called bi-anode torch, generates an elongated arc with comparatively high arc voltage and low arc fluctuation. Spraying experiments were carried out to compare the quality of coatings deposited by a conventional torch and a bi-anode torch. Alumina coatings and tungsten carbide coatings were prepared to appraise the heating of the sprayed particles in the plasma jets and the entrainment of the surrounding air into the plasma jets, respectively. The results show that anode arc root fluctuation has only a small effect on the melting rate of alumina particles. On the other hand, reduced air entrainment into the plasma jet of the bi-anode torch will drastically reduce the decarbonization of tungsten carbide coatings.     

切割用等离子弧的数值分析

以转移型直流电弧等离子体切割炬为研究对象,根据局部热力学平衡假设和磁流体动力学理论构建了电弧数学模型,采用数值模拟方法分析了等离子体炬内等离子体的传热和流动特性,阴极形状、锥角、内缩量和喷嘴形状对切割气流的速度和等离子温度分布的影响.并对五种常用形状阴极和两种不同内缩量的割炬内等离子流体速度场和温度场进行了比较.从数值分析的角度验证了阴极斑点较小的阴极能产生较大的焰流速度和热量,以及内缩量的增加对电弧的压缩具有显著作用.     

Electric Characteristics of Plasma Arc Produced by Bi-Anode Torch

In order to improve the voltage control and stability of a plasma arc, a new-type plasma torch was designed and constructed. The torch, called bi-anode torch, has two anodes that were inter-insulated and have different distances from the cathode tip. The position of the arc root can be controlled to attach to either anode surface during operation to obtain a low-voltage and high-fluctuation arc or a high-voltage and low-fluctuation arc. The paper discussed the occurrence of the double-arc phenomenon and its prevention. Experimental work has been carried out to compare voltage-current (U-I) characteristic of the arc when using different plasma gases and anode arc root attaching to different anode surfaces. The results show that the U-I characteristic of the plasma arc is affected by the position of the anode arc root attachment and the composition of the plasma gas, which was explained by a simplified arc model.     

Plasma arc cutting torch tracking control

Abstract

The present paper is concerned with a tracking system for cutting torch height in the plasma arc process. The computer based control system consists of the sensing and detection unit, controller, and servo actuator. The use of arc and laser sensors to detect the torch height is presented, and their applied characteristics are investigated in detail. A feedforward compensation of workpiece position is introduced to improve tracking properties. Moreover, to address the non-linear characteristics of the arc sensor, deviation classification and adaptive control approaches are also proposed. Tracking experimental results show acceptable tracking precision and strong noise restraining capability for the system. These demonstrate the effectiveness of the sensing and detection, and the proposed control algorithms. It is also shown that the arc sensing approach is more attractive, owing to its merits of synchronous sensing, high reliability, and low cost.