Investigation on shape precision of surface exposure selective laser melting
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摘要: 主要研究面曝光选区激光熔化单层成形时,激光光斑搭接率和电流对形状精度的影响。实验通过控制变量法研究搭接率、曝光时间、电流等工艺参数对激光光斑、熔道、圆环、尖角等成形形状精度的影响。实验结果表明:一定范围内,电流越大,激光光斑更均匀,成形一致性更好;搭接率38.4%能够获得最低的形状误差的熔道;搭接率一定,圆环成形误差随电流的增加而增加;尖角成形误差随着电流增加,呈现先增后减的趋势;搭接率为46.1%、38.4%时,零级衍射带来的形状误差降低。Abstract: Having a new generation of selective laser melting process, surface exposure selective laser melting technology has the advantages of high forming efficiency and uniform temperature field, and is becoming a research focus in additive manufacturing field. The influence of laser spot overlap rate and electric current on the shape accuracy of single-layer laser melting with surface exposure was investigated. The effects of overlap rate, exposure time and electric current on the forming of laser spot, track, circular ring and sharp angle were studied by the control variable method. The experimental results show that: within a certain range, the larger the electric current is, the more uniform the laser spot is, and the more conducive to forming; The lowest shape error can be obtained with overlap rate of 38.4%. The forming error of the circular ring increases with the increase of electric current. The forming error of sharp angle increases first and then decreases with the increase of electric current. The shape error caused by zero-order diffraction can be reduced when the overlap rate is 46.1% and 38.4%.
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表 1 激光光斑形状精度实验表
Table 1. Experimental scheme of laser spot size accuracy test table
exposure time/s current/A 0.1 0.05 0.2 0.10 0.3 0.15 0.4 0.20 0.5 0.25 0.6 0.30 表 2 激光功率、搭接率对熔道影响
Table 2. Influence of laser power and overlap rate on track
current/A 53.8% 46.1% 38.4% 30.7% 23% 1
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4表 3 圆环成形实验结果
Table 3. Experimental results of circular ring forming
current/A 92.3% 53.8% 46.1% 38.4% 2 3 4 5 6 表 4 成形角度实验结果
Table 4. Experimenta results of forming sharp angle
current/A 92.3% 53.8% 46.1% 38.4% 1 2 3 4 5 6 表 5 线框成形实验
Table 5. Results of wireframe forming experiments
current/A 92.3% 53.8% 46.1% 38.4% 6
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8zero-order diffraction light spot -
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