4130钢的CO2激光切割质量

研究了在CO2激光切割系统上切割的4130钢试样,以及功率和进给率对切缝宽度、表面粗糙度、条带频率和热影响区大小的组合影响.用回归分析研制了能描述独立工艺过程参数对激光切割质量影响的模型.对于试验的工作条件范围,观察到主要是功率影响切缝宽度和热影响区大小,而进给速率的影响是次要的.另一方面,表面粗糙度和条纹出现率受进给速率的影响最大.在低功率级时,可获得最小的切缝宽度和热影响区,并且进给速率的影响为中等.低进给速率可获得良好的表面粗糙度和低条纹出现频率.为了得到最佳的切割质量,切缝宽度、热影响区和表面粗糙度应保持最小.但是,在保持高生产率时不能满足符合这些要求的工作条件.     

4130钢的CO2激光切割质量

研究了在CO2激光切割系统上切割的4130钢试样，以及功率和进给率对切缝宽度、表面粗糙度、条带频率和热影响区大小的组合影响。用回归分析研制了能描述独立工艺过程参数对激光切割质量影响的模型。对于试验的工作条件范围，观察到主要是功率影响切缝宽度和热影响区大小，而进给速率的影响是次要的。另一方面，表面粗糙度和条纹出现率受进给速率的影响最大。在低功率级时，可获得最小的切缝宽度和热影响区，并且进给速率的影响为中等。低进给速率可获得良好的表面粗糙度和低条纹出现频率。为了得到最佳的切割质量，切缝宽度、热影响区和表面粗糙度应保持最小。但是，在保持高生产率时不能满足符合这些要求的工作条件。     

不锈钢板材激光切割工艺分析

研究了不锈钢板材激光切割工艺中重要因素对切割质量的影响,即激光功率、切割速度对割缝表面粗糙度、割缝宽度、割缝挂渣情况以及割缝热影响区宽度的影响情况,确定了最佳的切割工艺参数,为不锈钢板材激光切割提供参考,具有一定的实用价值。     

钛合金的激光切割

研究了不同辅助气体和工艺参数对激光切割钛合金板的影响，分析了激光切割切缝的断面特征和热影响区特点。试验结果表明，用氩气作辅助气体，切割质量最好；激光功率和切割速度对切缝宽度和热影响区宽度有一定影响；切缝断面可分为形貌不同的两个区，两区之间有明显界线；切缝上表面和下表面热影响区宽度不同，特点为上窄下宽。     

基于响应面法的水导激光加工碳纤维复合材料工艺参数优化

为了更好地采用水导激光加工碳纤维复合材料，基于响应面法设计实验，研究了工艺参数对切割质量指标的影响规律和切割质量对工艺参数的敏感性，并以热影响区、锥度、有效切割速度为目标进行了优化。结果表明：激光峰值功率对热影响区和锥度的影响显著，而切割速度和切割次数对有效切割速度的影响显著；当在切割速度2.35 mm/s、激光峰值功率324.45 W、切割次数6次时，水导激光切割碳纤维复合材料表面质量较好。     

基于正交试验的MS-WEDM第二次切割工艺参数优化

研究MS-WEDM多次切割中第二次切割参数对表面质量和切割速度的影响规律,寻求最优参数组合,有利于提高多次切割的加工质量。采用单因素试验研究第二次切割参数的脉宽、脉间、功放、丝速等参数对表面粗糙度和切割速度的影响规律,选取4水平4因素进行正交试验,用综合评分法将表面粗糙度和切割速度的多目标优化问题转化为加权综合评分的单目标问题。结果表明:更优的加工参数方案为脉冲宽度6μs、脉冲间隔5μs、功放1个、丝速6 m/s,并通过试验验证,其表面粗糙度为1. 54μm,切割速度为149. 43 mm~2/min,加权综合评分为0. 26。     

光纤激光切割对医用金属L605管切面质量的影响

采用不同的光纤激光切割工艺参数(功率、频率、脉宽、切割速度、氧气压力、喷嘴距离)对?1.8 mm(壁厚0.1 mm)的L605管材进行了切割。将切割试样酸洗处理后,用3D共聚焦显微镜测量切缝宽度和切面粗糙度,用扫描电镜(SEM)观察切面的微观形貌。结果表明:激光功率增大,切缝宽度增大,切面粗糙度先减小后增大;激光频率、脉宽增大,切缝宽度和切面粗糙度都增大;切割速度增大,切缝宽度减小,切面粗糙度增大;氧气压力提高,切缝宽度增大,切面粗糙度降低;喷嘴距离为0.25 mm时,切缝宽度和切面粗糙度均最小。激光功率、频率、脉宽、切割速度、氧气压力、喷嘴距离改变使切面上的切割条纹发生改变以及出现残渣、金属屑、重铸层等。     

基于Cr12MoV模具钢水雾中电火花线切割工艺研究

为探讨超声水雾中第二次切割的加工参数对模具钢Cr12MoV表面粗糙度和切割速度的影响规律,在往复走丝线切割加工中,计划采用一种多介质的多次切割新工艺,即第一次切割在乳化液中进行,第二次切割在超声水雾中,第三次切割在大气中。实验采用单因素法,分析了脉冲宽度、峰值电流、工件厚度、偏移量、水雾量和工作台进给速度对表面粗糙度和切割速度的影响规律;借助中心复合法的建模优势及Design-Expert软件绘制三维响应曲面图的功能,建立了精度较高的线切割精加工表面粗糙度和切割速度的回归模型公式,经过实验验证表面粗糙度的实测值和预测值的相对误差最高为3.56%,切割速度的实测值和预测值的相对误差最高为-8.68%;由回归方程方差分析结果可知,工作台进给速度和脉冲宽度对表面粗糙度的影响非常显著,工作台进给速度对切割速度的影响非常显著。     

前混合磨料水射流切割参数对表面粗糙度的影响

采用前混合磨料水射流对Q235碳素结构钢进行切割实验,测量样品切口表面粗糙度;研究前混合磨料水射流的切割压力、喷嘴出口直径、切割靶距、切割速度和切割深度对样品切口表面粗糙度的影响规律;结合实验数据,建立表面粗糙度二次非线性回归预测方程。研究结果表明：前混合磨料水射流的切割压力、喷嘴出口直径与表面粗糙度呈负相关关系;切割靶距、切割速度、切割深度与表面粗糙度呈正相关关系;各因素的影响权重大小依次为：喷嘴出口直径、切割深度、切割压力、切割速度、切割靶距;影响表面粗糙度的实质因素为磨料流量和磨料能量;建立的表面粗糙度二次非线性回归预测方程的平均偏差为7.99%。     

气中电火花线切割精加工Cr12MoV实验研究

本文采用单向走丝线切割机,针对Cr12MoV模具钢,设计一种新的多次切割实验,前三次切割在去离子水中,第四次切割在大气和去离子水中进行。对比实验结果表明,气中精加工的表面粗糙度优于去离子水中,去离子水中加工表面有许多腐蚀形成的微孔,同时去离子水中的切割速度较高。第四次切割采用大气介质更容易获得较好的表面质量。为研究主要加工参数(脉冲宽度、脉冲间隔、峰值电流、伺服电压、主电源电压、伺服速度、电极丝的速度、偏移量)对工件表面粗糙度和加工切割速度的影响,进行了大气中的第四次切割实验。单因素实验结果表明,与去离子水中的精加工相比,大气中精加工时各加工参数对工艺指标的影响规律曲线有不同之处。本文对气中精加工实验结果进行了分析,并在实验取值范围内,通过比较获得了表面粗糙度和切割速度俱佳的几个主要参数取值。     

Evaluation of cut quality of fibre-reinforced plastics-A review

This paper presents an overview of the development in laser cutting of fibre-reinforced plastics materials. Important aspects of laser cutting process are identified and discussed. Analytical and experimental findings are cited and critically assessed. This paper suggests that simulation of laser cutting parameters is required not only to reduce the heat-affected zone but also to improve the laser cut quality with respect to surface quality and dimensional accuracy. It is recommended that research effort be directed towards contour cutting and sharp comer cutting to make the laser more applicable in industries.     

CO2 laser cut quality of 4130 steel

Samples of 4130 steel were cut on a CO₂ laser cutting system and the combined effects of power and feed rate on kerf width, surface roughness, striation frequency and the size of heat affected zone (HAZ) have been studied. Regression analysis was used to develop models that describe the effect of the independent process parameters on laser cut quality. For the range of operation conditions tested, it was observed that power had a major effect on kerf width and size of HAZ, while feed rate affects were secondary. On the other hand, surface roughness and striation frequency were affected most by feed rate. At low power levels, the smallest kerf width and HAZ are obtained and the effect of feed rate is moderate. Low feed rates gave good surface roughness and low striation frequency. For optimum cut quality, kerf width, HAZ and surface roughness are kept at a minimum. However, operating conditions that satisfy these requirements while maintaining high productivity could not be identified.     

水下50 m激光切割30 mm厚钢板特性

在模拟50 m水深环境下进行中厚板激光切割,通过切割的宽度和断面粗糙度研究了氧气压力、喷嘴到工件的距离、切割速度等对切割质量的影响.结果表明,氧气压力较低时,切缝底部无法割透,下半部分有较多熔渣相连.随着氧气压力增加,切缝背面排渣能力明显增强,切缝平直度增加.与大气中切割不同的是氧气压力增大,切缝壁面反而光洁.喷嘴到工件的距离对切缝各部位尺寸影响均不明显,文中取平直度最佳的范围2~4 mm.随着切割速度增加,切缝下部宽度减小最明显,切割断面纹理线发生弯曲,在水下50 m环境中,切割30 mm厚钢板,最快切割速度可达到2.0 m/min.     

Striation-free Laser Cutting of Mild Steel Sheets

Striation, i.e. periodic lines appearing on the cut surface, is one of the most important quality factors in laser cutting. It affects the surface roughness, appearances and geometry precision of laser cut products. Despite various efforts over the last 30 years to understand striation formation mechanisms and to optimise laser parameters, no reported work has so far shown striation-free cutting. This paper reports an investigation into achieving striation-free laser cutting of EN43 mild steel sheets of 2 mm thickness. A 1 kW single mode fibre laser was used in this work. Specific operating conditions have been determined which enable high-speed, striation-free laser cutting. A theoretical model is proposed to predict the critical cutting speed at which striation-free cutting occurs. It is also observed that at cutting speeds above the critical cutting speed, striation reappears and surface roughness increases with the cutting speed, a phenomenon not observed before.     

Experimental analysis of irregularities of metallic surfaces generated by abrasive waterjet

Experimental study of the surface quality produced by abrasive waterjet (AWJ) on metallic materials has been performed. The surface roughness/waviness was quantitatively evaluated by using the contactless optical measurement. In order to characterize the cut surface qualities, a single-parameter criterion has been proposed. Based on root mean square (RMS) roughness evaluation of the worst cut surface zone, the dimensionless statistical parameter C can be calculated as a basic quantity for AWJ surface cut characterization. As it was approved, besides its dependency on depth of AWJ trace, the value of C-parameter for the specific material is noticeably related also to the traverse speed of the cutting head. Such a relationship can be potentially used for adjusting the cutting speed of the machining process.     

Scaling laws for the laser-oxygen cutting of thick-sheet mild steel

The laws of scaling the laser-oxygen cutting of mild steel based on experimental optimization are proposed. The sheets from 5 to 25 mm are cut with the aid of CO₂ laser.It has been established that the minimal surface roughness is reached within the whole thickness range if the laser energy value per unit of the removed material and the power per sheet thickness unit are held constant. The results permit to determine the laser power and cutting speed values optimal for a certain sheet thickness. Within the range of large thicknesses, the conditions of cutting with minimal roughness are written as ratios between dimensionless variables. Evaluation of the maximum thickness of the sheet, at which the high-quality cutting is realizable, has been made.     

微沟槽织构对切削力和表面粗糙度的影响

为研究微织构对切削过程中产生的切削力和已加工表面粗糙度的影响,在聚晶立方氮化硼(PCBN)刀片前刀面制备与主切削刃平行的宽度为32.6μm的微沟槽织构。分别用微沟槽刀具和无织构刀具在主轴转速为450、500、600 r/min的条件下切削淬硬钢GCr15,分析切削力和已加工表面粗糙度。试验结果表明:微沟槽改善了刀具的切削性能,主切削力、进给力和切深力均小于无织构刀具;进给力、切深力随着主轴转速的增加均变大,主切削力表现为先减小再增大;用微沟槽织构刀具切削的已加工表面粗糙度大于无织构刀具,表明微沟槽不利于获得表面质量较好的工件;随着主轴转速增加,微沟槽刀具和无织构刀具切削的表面粗糙度均减小。     

药芯割丝水下湿式电弧切割割口成形及热影响区组织分析

针对水下作业发展的需要,利用药芯割丝进行了水下湿式电弧切割试验,分析了水下电弧切割过程中切割电压、电流及切割速度对割口成形的影响规律,并研究了割口热影响区的显微组织.结果表明,药芯割丝水下电弧切割过程中电弧长度、割丝伸出长度在不停变化;割口下口基本较上口宽;随切割电压或电流的增大,割口上下宽度均有所增加;随切割速度的增大,割口下口宽度逐渐变小.同时发现,由于水下冷却速度较快,割口热影响区较窄,可分为重熔区、过热区、完全再结晶区与不完全再结晶区等区域.     

CVD金刚石膜激光平整化效率和粗糙度

对化学气相沉积(CVD)多晶金刚石膜进行激光平整化的正交试验,使用场发射环境扫描电子显微镜(SEM)进行形貌分析,激光共聚焦扫描显微镜测量线粗糙度Ra、面粗糙度S_a和切缝锥度,分析激光参数对CVD膜平整化的影响。结果表明：影响切缝锥度的因素依次为脉冲宽度、脉冲频率、进给速度和激光电流,影响线粗糙度Ra的因素依次为进给速度、激光电流、脉冲频率、脉冲宽度。正交试验优化后,当激光电流为64 A、脉冲宽度为400μs、脉冲频率为275 Hz、进给速度为100 mm/min时,可获得最佳的切槽表面形貌。采用该优化参数进行面扫描,测得面粗糙度S_a为11.7μm;进一步增加入射角度至75°时,面粗糙度S_a降低至1.9μm,实际去除效率达到1.1 mm³/min。