Error compensation for tool-tip trace during cutting of laminated paper for rapid prototyping

Abstract

Laminated object manufacturing (LOM) is one of the commercialized rapid prototyping (RP) processes, where a focused laser is usually used to cut the cross-section contours of a 3 D part and the grid hatchings of the part-exterior region on a sheet paper stack-wise. Using a laser beam as a cutter can be costly, and the thermal burning of a sheet paper along a laser scanning path can also cause an environment-polluting smoke. This paper presents a paper laminating RP system using a knife as the paper cutter instead of a laser beam. The knife holder is mounted through a radial bearing on the X-Y positioning mechanism in such a way that the knife tip is eccentric to the bearing axis by a small distance (so-called offset). Therefore, the knife tip, which engages into the sheet paper during cutting, tends to follow the path of the XY-driven bearing axis by the error that depends on the path tangential and the eccentricity of the knife tip. A tractrix model is applied to describe the kinetic motion of the knife tip and a method is formulated to compensate for the tracing error of the eccentric knife tip by modifying the original cross-section contours of the part for each layer based on the tractrix equation. A study has also been performed regarding the effect of the knife tip geometry on the cutting notch of the sheet paper and on the roughness of the finished part.

Keywords

rapid prototyping / laminated object manufacturing / knife-cutting / tracing error

References

[1] Wohlers T. Wohlersβreportβ2002βexecutiveβsummary. http://www.wohlersassociates.com/

[2] Chua C K, Leong K F. Rapid Prototyping: Principles and Applications in Manufacturing. Singapore: World Scientific Publishing Co Pte Ltd, 2000

[3] Helisys Inc, LOM-1015plus System, Helisys Inc. 24015 Garnier Street, Torrance, CA 90505, 1997

[4] Shi Y S, Muo J H, Huang S H, Zhou Z D. Convenient rapid prototyping systems and selection principle. Duan Ya Ji Xie, 2001, 2: 1–6 (in Chinese)

[5] Mueller B, Kochan D. Laminated object manufacturing for rapid tooling and patternmaking in foundry industry. Computers in Industry, 1999, 39: 47–53

[6] Pham D T,Gault R S. A comparison of rapid prototyping technologies. International Journal of Machine Tools & Manufacture, 1998, 38: 1257-1287

[7] Kira Corporation. http://www.kiracorp.co.jp

[8] 3D Systems, Inc. Stereolithography Interface Specification. <patent>P/n 50065-S01-00</patent>, 1989

[9] Hairer E, Nørestt S P, Wanner G. Solving Ordinary Differential Equations I. Berlin: Springer-Verlag, 1987

[10] Compiling group. Mathematics Handbook. Beijing: Higher Education Press, 1979 (in Chinese)

[11] ISO 4287:1997, Geometrical product specifications (GPS) – surface texture: profile method – terms, definitions and surface texture parameters, ISO, 1997

Acknowledgements

The research was financially supported by Taishang Scholar Program of Shandong Province. Thanks are also due to Dr. Wanhua Zhao (Xi’an Jiaotong University) for the help provided in designing and building the experimental setup.

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg