3D LASER FORMING OF SADDLE SHAPES
3D LASER FORMING OF SADDLE SHAPES
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鞍形 3D 激光成型
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
J. Magee
中科院分区：
文献类型：
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作者：
S. Edwardson;K. Watkins;G. Dearden;J. Magee
在二维激光成形方面已经进行了大量的工作，使用多通道直线扫描策略在包括航空航天合金在内的多种材料中产生合理控制的弯曲角度。然而，为了进一步推进该工艺以实现实际成形应用以及制造业中的矫直和对准操作，有必要考虑更大规模的 3D 激光成形。本次研究的目的是建立受控 3D 激光从矩形板材形成对称马鞍形状所需的照射线的定位和排序规则。选择马鞍形状是因为其 3D 几何形状更复杂，双曲率提供了有用的案例研究，可用于建立此类 3D 形状的设计规则。研究包括使用 CO2 激光源对 400mm x 200mm 1.5mm 规格低碳钢 CR4 板材进行激光成型。测试的扫描策略包括直线、径向线和同心圆图案。所使用的主动激光成形机制从温度梯度到镦锻机制各不相同，具体取决于所使用的光束参数和移动速度。使用坐标测量机验证并呈现所形成零件的最终几何形状。使用同心跑道策略，在板材中心采用镦锻机构，从而缩短中心材料，板材自然成为鞍形，从而可以生产受控的可重复鞍形。然而研究结果表明，3D激光成形的问题极其复杂。人们发现，一旦发现成功的扫描策略，由于成形过程本身的不对称性质，对称性就很难实现，因为不可能同时成形整个板材。
There has been a considerable amount of work carried out on two-dimensional laser forming, using multi-pass straight line scan strategies to produce a reasonably controlled bend angle in a number of materials, including aerospace alloys. However in order to advance the process further for realistic forming applications and for straightening and aligning operations in a manufacturing industry it is necessary to consider larger scale 3D laser forming. The objective of this investigation is to establish rules for the positioning and sequencing of the irradiation lines required for the controlled 3D-laser forming of a symmetrical saddle shape from rectangular sheet material. The saddle shape was chosen due to its more complex 3D geometry, the double curvature providing a useful case study with which to build up the design rules for such 3D shapes. The investigation consisted of the laser forming of 400mm x 200mm 1.5mm gauge Mild Steel CR4 sheet using a CO2 laser source. The scan strategies tested consist of straight and radial lines and concentric circular patterns. The active laser forming mechanism used varied from the temperature gradient to the upsetting mechanism depending on beam parameters and traverse speed used. The final geometries of the parts formed were verified using a coordinate measuring machine and are presented. It was possible to produce a controlled repeatable saddle shape using a concentric race-track strategy, employing the upsetting mechanism at the centre of the sheet, thus shortening the material at the centre and the plate naturally saddles. However the results of the investigation show that the problem of 3D laser forming is extremely complex. It was found that once a successful scan strategy was discovered symmetry was difficult to achieve due to the asymmetrical nature of the forming process itself, in that it was not possible to form the whole sheet at the same time.