Research on roller size modeling of sand bed laying in 3DP process
-
摘要: 为探究影响粉末粘结类3D打印工艺成型质量的因素,文章在砂型打印的砂床铺设阶段,基于固体力学进行辊子半径和铺砂质量之间的规律进行分析,得到铺砂质量随辊子半径的变化趋势,给出了砂床规模给定的情况下辊子半径大小的取值范围。采用离散元仿真软件建立了铺砂阶段的数值仿真模型,完成了不同尺寸辊子铺砂后砂床质量评价,通过仿真给出了铺设较高质量砂床的辊子半径取值范围,其结果与理论计算一致性较高,证实了理论分析的有效性。Abstract: In order to explore the factors affecting the forming quality of powder-bonded 3D printing process, this paper uses the sand bed laying stage of sand mold printing to analyze the law between the roll radius and the sand laying quality based on solid mechanics, and obtains the change of the sand laying quality with the roller radius trend. Through the derived formula, the value range of the roller radius under the specified sand bed scale is given. The discrete element simulation software EDEM is used to establish the numerical simulation model of the sand laying stage, and the quality measurement of the sand bed after sand laying with rollers of different sizes is completed on the constructed sand bed. The results are in good agreement with the calculation results of the proposed theoretical formula, and the validity of the theoretical formula is verified by simulation.
-
Key words:
- 3DP technology /
- sand laying process /
- roller /
- DEM
-
表 1 材料间相互作用参数
材料 平均粒径/µm 密度/(kg/m3) 恢复系数 钢-砂粒静摩擦系数 砂粒-砂粒静摩擦系数 砂粒 175 2 650 0.5 0.3 0.4 表 2 铺砂过程的工艺参数
参数 数值 辊子平移速度$ {v} $/(m/s) 0.1 辊子半径$ {{R}}_{{\rm{{r}{o}{l}{l}}}} $/mm 5 辊子旋转速度$ {\omega } $/(rad/s) 40 层厚$ h $/mm 0.3 供料箱长度$ {{l}}_{1} $/mm 20 供料箱的宽度$ W $/mm 20 高出供料箱砂层的厚度$ {{h}}_{1} $/mm 1 成型箱长度$ {{l}}_{2} $/mm 30 表 3 辊子半径与自转速度设置
组号 辊子半径$ {{R}}_{\mathrm{r}\mathrm{o}\mathrm{l}\mathrm{l}} $/mm 自转速度$ \mathrm{\omega } $/(rad/s) 1 2.50 80.00 2 4.00 50.00 3 5.00 40.00. 4 6.25 32.00 5 7.00 28.50 6 12.50 16.00 7 25.00 8.00 8 40.00 5.00 9 50.00 4.00 10 62.50 3.20 11 70.00 2.85 12 80.00 2.50 表 4 不同辊子半径仿真数据
辊子半径
$ {{R}}_{\mathrm{r}\mathrm{o}\mathrm{l}\mathrm{l}} $/mm表层致密度/
(g/cm3)中间层致密度/
(g/cm3)平均致密度/
(g/cm3)2.50 0.864 1 2.090 0 1.477 1 4.00 0.875 0 2.087 9 1.481 5 5.00 0.944 2 2.065 5 1.504 9 6.25 1.008 1 2.094 8 1.551 5 7.00 1.025 0 2.091 4 1.558 2 12.50 1.107 0 2.101 7 1.604 4 25.00 1.174 4 2.140 4 1.657 4 40.00 1.267 6 2.169 4 1.718 5 50.00 1.291 4 2.162 5 1.727 0 62.50 1.362 5 2.174 8 1.768 7 70.00 1.364 9 2.124 0 1.744 5 80.00 1.365 4 2.177 0 1.771 2 -
[1] Kevin J. H, John A. N, Rick J. C. Process limitations of 3D printing model rock[J]. Progress in Additive Manufacturing, 2018, 3(3): 173-182. doi: 10.1007/s40964-018-0042-6 [2] 张江涛, 谭援强, 纪财源, 等. 增材制造中滚筒铺粉工艺参数对尼龙粉体铺展性的影响研究[J]. 力学学报, 2021, 53(9): 2416-2426. doi: 10.6052/0459-1879-21-240 [3] 王君, 楼光宇, 曾顺麒, 等. 选择性激光烧结铺粉辊运动参数分析[J]. 机械设计与制造, 2022(2): 247-251. doi: 10.3969/j.issn.1001-3997.2022.02.053 [4] 郑军辉. 尼龙粉末选择性激光烧结铺粉工艺数值模拟研究[D]. 湘潭: 湘潭大学, 2016. [5] 王媛媛. 微滴喷射砂型三维打印成型机理研究[D]. 天津: 河北工业大学, 2018. [6] Kruggel-emden H, Wirtz H, Scherer V. A study on tangential laws applicable to the discrete element method(DEM)for materials with viscoelastic or plastic behavior[J]. Chemical Engineering Science, 2008, 63: 1523-1541. doi: 10.1016/j.ces.2007.11.025 [7] 谭援强, 郑军辉, 张浩, 等. 基于离散元法的锥形筒仓中颗粒流体的数学模拟[J]. 过程工程学报, 2015, 15(6): 916-922. doi: 10.12034/j.issn.1009-606X.215277 [8] 胡国明. 颗粒系统的离散元素法分析仿真[M]. 武汉: 武汉理工大学出版社, 2010: 34-42. [9] Michele M, Edmund H. S. Discrete element method (DEM) for industrial applications: comments on calibration and validation for the modelling of cylindrical pellets[J]. KONA Powder and Particle Journal,2015, 32 : 236-252 [10] Zhang X K, Xu J, Sun J, et al. Segregation behavior of sinter in vertically arrange cooler with high performance GPU simulation[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(1): 64-73. [11] Tan Y Q, Xiao X W, Zhang J T, et al. Determination of discrete element model contact parameters of nylon powder at SLS preheating temperature and its flow characteristics[J]. Chinese Journal of Theoretical and Applied Mechanics, 2019, 51(1): 56-63. [12] Johnson K L, Greenwood J A. An approximate JKR theory for elliptical contacts[J]. Journal of Physics D:Applied Physics, 2005, 38(7): 1042-1046. doi: 10.1088/0022-3727/38/7/012 [13] Chen H, Wei Q S, Wen S F, et al. Flow behavior of powder particles in layering process of selective laser melting: Numerical modeling and 29 experimental verification based on discrete element method[J]. International Journal of Machine Tools & Manufacture, 2017, 123: 146-159. [14] 王媛媛, 张思祥, 杨伟东. 3DP工艺中铺粉过程建模与仿真研究[J]. 河北工业大学学报, 2018, 47(6): 37-43. [15] Kruggel-emden H , Rickelt S , Wirtz S. A study on the validity of the multi-sphere discrete element method [J]. Powder Technology. 2008 , 188 : 153 – 165.