A Six-sigma approach for benchmarking of RP&M processes

  • M. Mahesh
  • Y. S. Wong
  • J. Y. H. Fuh
  • H. T. Loh


This paper presents a methodology of using six-sigma quality tools for benchmarking of rapid prototyping & manufacturing (RP&M) processes. It involves the fabrication of a geometric benchmark part and a methodology to control and identify the best performance of the process to reduce the variablity in the fabricated parts. The approach is demonstrated with a case study based on the direct laser sintering (DLS) process for prototyping using plastic powder. In the case study an identified set of six-sigma/ statistical process control tools is employed to determine and best tune factors affecting the desired outcomes of the built parts.


Benchmarking Decision support Process characterization Process optimization Six-sigma 



Geometric benchmark part


Mechanical benchmark part










Cylindrical holes


Flat beam




Free-form features


Hollow cylinders


Hollow squares


Square base


Solid cylinders


Small holes






Thin cylinders


Thin slots


Thin walls

RP&M quality characteristics GA

Geometric accuracy (deviation measured in mm)


Surface roughness, Ra in μm

Control factors: LP

Laser Power in W


Layer thickness in mm


Part bed temperature in ° C


Scan speed in mm/s


linear dimension (length, breadth or height in mm)


actual design dimension of STL file in mm


measured dimension on fabricated GBP in mm


scaling factor


laser beam offset factor in mm


shrinkage in mm


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Copyright information

© Springer-Verlag London Limited 2006

Authors and Affiliations

  • M. Mahesh
    • 1
  • Y. S. Wong
    • 1
  • J. Y. H. Fuh
    • 1
  • H. T. Loh
    • 1
  1. 1.Department of Mechanical EngineeringNational University of SingaporeSingaporeSingapore

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