**Part 2**

**Manufacturing Processes and System Analysis** 

156 Mechanical Engineering

common DC bus. Case study 2 deals with gantry cranes that have a large span. Solutions of two problems that occur in these types of cranes are shown as follows: load distribution

This paper is supported by Project Grant III44004 (2011-2014) financed by Ministry of

Backstrand, J.E. (1992). The Application of Adjustable Frequency Drives to Electric

Belmans R., Bisschots F. & Timmer R. (1993). Practical Design Considerations for Braking Problems in Overhead Crane Drives, *Conf. Rec. IEEE-IAS,* Vol.1, pp. 473-479. Busschots F., Belmans R. & Geysen W. (1991). Application of Field Oriented Control in

Hartani, K. & Miloud, Y. (2010). Control Strategy for Three Phase Voltage Source PWM

Jeftenic B., Bebic M. & Statkic S. (2006). Controlled Multi-motor Drives, *Intern. Symp. SPEEDAM* 2006, Taormina (Sicily) - Italy, 23-26 May 2006 , pp. 1392-1398. Jiuhe, W., Hongren, Y., Jinlong Z & Huade, L. (2006). Study on Power Decoupling Control of

Mitrovic N., Petronijevic M., Kostic V. & Bankovic B. (2011). Active Front End Converter in

Mitrovic, N., Kostic, V., Petronijevic, M. & Jeftenić, B. (2010). Practical Implementation of

Odavic M., Jakopovic Z. & Kolonic F. (2005). Sinusoidal Active Front End under the Condition of Supply Distortion, *AUTOMATIKA* 46(2005), 3–4, pp.135–141, 2005. Paul, A. K., Banerje, I., Snatra, B.K. & Neogi, N. (2008). Application of AC Motors and Drives

Petronijevic M., Veselic B., Mitrovic N., Kostic V. & Jeftenic, B. (2011). Comparative Study of

Rockwell Automation (2000), Load Sharing for the 1336 PLUS II AC Drive, *Publication* 

Slutej, A., Kolonic, F. & Jakopovic, Z. (1999). The New Crane Motion Control Concept with

Drives, *Electric Power Applications, IET* , vol.5, no.5, pp.432-442, May 2011

Rashid H., *Power Electronics Handbook*, Academic Press, San Diego, 2001.

*IEEE International Symposium*, Volume 3, 1999, pp.1458 – 1461.

*number* 1336E-WP001A-EN-P, June 2000.

Overhead Cranes, *Industry Applications Society Annual Meeting*, 1992, Conf.

Crane Drives, *Proc. IEEE-IAS, Annual Meeting, Dearborn, Michigan, USA*, September

Rectifier Based on the Space Vector Modulation, *Advances in Electrical and Computer* 

Three Phase Voltage Source PWM Rectifiers, *Power Electronics and Motion Control* 

Common DC Bus Multidrive Application, XLVI *Proc. of Inter. Conf. ICEST* 2011,

Load Sharing and Anti Skew Controllers for Wide Span Gantry Crane Drives",

in Steel Industries, XV *Natinal Power System Conference*, Bombay, Dec.2008, pp.159-

Unsymmetrical Voltage Sag Effects on Adjustable Speed Induction Motor

Integrated Drive Controller for Engineered Crane Application, ISIE'99, *Proc.of the* 

between multiple motor and skew problem as a result of a large span.

Rec.1992 IEEE 4-9 Oct. 1992, vol.2, pp.1986 – 1991.

**8. Acknowledgment** 

**9. References** 

Education and Science, Republic of Serbia.

ABB, Technical guide No.8, Electrical Braking, 2011.

28-October 4, 1991, pp. 347-353.

*Eng*., Vol.10, Issue 3, pp. 61-65.

Serbia, Nis, Vol.3, pp. 989-992, 2011.

*JME*, Vol. 56, no. 3, pp. 207-216, 2010.

*Conference*, 2006.

163.

**7** 

*USA* 

*1Bucknell University, 2Duke University,* 

**Anisotropic Mechanical Properties of ABS Parts** 

Layered manufacturing (LM) methods have traditionally been used for rapid prototyping (RP) purposes, with the primary intention of fabricating models for visualization, design verification, and kinematic functionality testing of developing assemblies during the product realization process (Caulfield et al., 2007). Without any need for tooling or fixturing, LM allows for the computer-controlled fabrication of parts in a single setup directly from a computerized solid model. These characteristics have proven beneficial in regard to the objective of reducing

There are numerous LM processes available in the market today, including stereolithography (SLA), fused deposition modeling (FDM), selective laser sintering (SLS), and three-dimensional printing (3DP), all of which are additive processes sharing important commonalities (Upcraft & Fletcher, 2003). For each of these processes, the object design is first represented as a solid model within a computer aided design (CAD) software package and then exported into tessellated format as an STL file. This faceted model is then imported into the relevant LM machine software where it is mathematically sliced into a series of parallel cross-sections or layers. The software creates a machine traverse path for each slice, including instructions for the creation of any necessary scaffolding to support overhanging slice portions. The physical part is then fabricated, starting with the bottom-most layer, by incrementally building one model slice on top of the previously built layer. This additive layering process is thus capable of fabricating components with complex geometrical shapes

the time needed to complete the product development cycle (Chua et al., 2005).

in a single setup without the need for tooling or human intervention or monitoring.

produced by more traditional manufacturing techniques.

In recent years, layered manufacturing processes have begun to progress from rapid prototyping techniques towards rapid manufacturing methods, where the objective is now to produce finished components for potential end use in a product (Caulfield et al., 2007). LM is especially promising for the fabrication of specific need, low volume products such as replacement parts for larger systems. This trend accentuates the need, however, for a thorough understanding of the associated mechanical properties and the resulting behaviour of parts produced by layered methods. Not only must the base material be durable, but the mechanical properties of the layered components must be sufficient to meet in-service loading and operational requirements, and be reasonably comparable to parts

**1. Introduction** 

**Fabricated by Fused Deposition Modelling** 

Constance Ziemian1, Mala Sharma1 and Sophia Ziemian2
