Cold Fabrication Research Articles

皮秒激光微制造As 2 Se 3 玻璃红外增透性表面

采用紫外皮秒激光在As2Se3玻璃表面以线扫描形式快速制备大面积周期性点阵式增透微结构，获得了红外透光性能提高的硫系玻璃样品。研究确定了As2Se3玻璃的激光刻蚀阈值，并研究设计了合适线扫描工艺方法。所制样品相对于原样在波长11.0 μm~12.4 μm范围内，透过率平均提高10.0 %；波长13.0 μm~14.2 μm范围内，透过率平均提高5.2 %。激光扫描制备方法没有破坏样品表面原有的浸润性，整个制备过程均在空气开放环境下进行，成本低，工艺可控性强，效率高，制备8 mm×8 mm的表面微结构，仅用时3.65 s，且表面微结构单元尺寸及间距可按材料应用需求调控。分析表明，当激光能量较低时，对该硫系玻璃的去除以“冷加工”为主，不会有明显的热效应，得到微结构的硫系玻璃表面元素组成未发生改变；激光能量较高时，会存在一定的热效应，使得刻蚀点出现熔融态，在微坑边缘出现凸起或翻边。

Study on Fabricated Toolpost Shaft Efficiency for Cold Cutting Machine

The study discussed on the fabrication of Cold Cutting Machine (CCM) toolpost shaft and the optimization of the fabricated toolpost shaft efficiency. CCM has been used in oil and gas industry for cutting on-site, thus it has to be mobile and spark free. The CCM toolpost shaft is functioning as the holder for the cutting tool and it is adjustable as the cutting process takes place. Thus the study is to re-design, fabricate and testing the new toolpost shaft for its cutting efficiency. The existing toolpost shaft was made as a reference for the fabrication of the new one. The shaft was fabricated in two new different sizes of cutting clearance and the original size of thread M10 as a constant. The pitch was altered in a range between 1 mm and 1.25 mm. Design of Experiment (DOE) Taguchi L9 orthogonal array was used to study the optimization process for toolpost shaft efficiency. The parameters include cutting clearance, coolant types and rotation speed at three different levels. It was found that for both depth of cut and machining time yields were strongly affected by the rotation speed and followed by cutting clearance. Background/Objectives: In industry, standardizing the toolpost shaft clearance is a major issue since their usage varies by different sizes of clearance. Hence, the study investigates the variety of clearance at toolpost shaft for its cutting efficiency in CCM. The re-design toolpost are fabricated by referring to the industry requirement. Methods/Statistical Analysis: The toolpost of CCM was fabricated by machining process. Then, the optimization of fabricated toolpost efficiency was done by using Design of Experiment Taguchi method and analyzed by using Analysis of Variance (ANOVA) analytical tool in MINITAB 15. Findings: CCM toolpost was successfully fabricated in two new sizes and fully functioning. The optimization of toolpost efficiency process yields were depth of cut and machining time. It shows that both of these efficiency yields were strongly affected by the rotation speed and cutting clearance. Applications/Improvements: Results from this study showed that the optimum of overall efficiency was found in the depth of cut for higher number of cutting in less time. This will increase productivity at the production line for the next pipe cutting.