W. van Wijck

Investigating the achievable accuracy of three dimensional printing

Purpose – The research was undertaken to characterise the three dimensional printing (3DP) process in term of the achievable dimensional and geometric accuracy.Design/methodology/approach – New benchmark models were developed that represent characteristics needing to be investigated. The parts were fabricated in different materials. A program was written to measure the features on a numerically controlled coordinate measurement machine. Finally, a statistical analysis was done. The results are reported in terms of statistical parameters and international tolerance (IT) grades.Findings – The paper provides general IT grades of the 3DP process for parts printed using different materials (powders).Research limitations/implications – The research is limited to specific materials and equipment.Practical implications – The data is very useful for designing products to be manufactured on 3DP machines applying either direct or indirect methods.Originality/value – 3DP is more and more used for rapid prototyping wi...

Development, evaluation, and selection of rapid tooling process chains for sand casting of functional prototypes

Abstract This paper discusses the results obtained from studies on different rapid tooling process chains for improved design and manufacture of foundry equipment for sand casting of prototypes in final material for functional and pre-production tests of vehicles, using the three-dimensional printing process as core technology. Subsequently, while considering aspects such as time, cost, quality (accuracy and surface roughness), and tool life, a framework for evaluation and selection of the most suitable process chain in accordance to specific requirements is presented. Apart from only using these process chains for prototype manufacturing, initial results from a study to apply one of these process chains in automated sand casting full production is also presented. This research builds on an in-depth characterization of the accuracy and repeatability of a three-dimensional printing process.

An Investigation of the Capability Profile of the Three Dimensional Printing Process with an Emphasis on the Achievable Accuracy

Abstract A benchmark procedure has been designed to assess the dimensional as well as the geometric accuracy of currently one of the most widely used rapid prototyping processes - the Three Dimensional Printing. It tests not only linear accuracy but also precision, and repeatability of the process, as well as its ability to create manufacturing features such as fillets and draft angles. The presented research results reflect the necessity to adequately respond to engineering requirements for clearly meeting dimensional and geometric tolerances and root on several in-house case studies proving the comparison with established high-end RP processes.

An introduction to rapid casting : development and investigation of process chains for sand casting of functional prototypes

This paper discusses the results obtained from studies on different Rapid Tooling process chains in order to improve the design and manufacture of foundry equipment that is used for sand casting of prototypes in final material. These prototypes are intended for functional and pre-production tests of vehicles. The Three Dimensional Printing process is used as core technology. Subsequently, while considering aspects such as time, cost, quality (accuracy and surface roughness), and tool life, a framework is presented for the evaluation and selection of the most suitable process chain in accordance with specific requirements. This research builds on an in-depth characterisation of the accuracy and repeatability of a 3D printing process. OPSOMMING Hierdie artikel bespreek die resultate wat verkry is tydens studies op verskillende Snel-Gereedskapvervaardigingproseskettings wat ondersoek is teneinde die ontwerp en vervaardiging van sandgietgereedskap, om prototipes in finale materiaal te vervaardig, te verbeter. Die prototipes is bestem vir gebruik in funksionele- en voorproduksietoetse van voertuie. Die sogenaamde Driedimensionele Drukproses (3DP) is as kerntegnologie aangewend. Gevolglik, na oorweging van aspekte soos tyd, koste, kwaliteit (akkuraatheid en oppervlakafwerking), en gereedskapleeftyd, is ’n raamwerk ontwikkel vir die evaluering en seleksie van die mees geskikte prosesketting met inagname van spesifieke vereistes. Hierdie navorsing bou op ’n diepgaande karakterisering van die akkuraatheids- en herhaalbaarheidsvermoe van ’n 3D drukproses.

CONSTRAINT PROGRAMMING AND UNIVERSITY TIMETABLING

CITATION: Groves, G. W. & Van Wijck, W. 2002. Constraint programming and university timetabling. South African Journal of Industrial Engineering, 13(1):1-12, doi:10.7166/13-1-314.

An effective scheduling scheme for lift clubs

CITATION: Van Wijck, W. 1998. An efective scheduling scheme for lift clubs. South African Journal of Industrial Engineering, 9(1): 135-145, doi: http://dx.doi.org/10.7166/9-1-388.

A ZERO SAMPLING PLAN FOR THE MODERATION OF EXAMINATION PAPERS

CITATION: Van Wijck, W. & Dirkse Van Schalkwyk, T. 2005. A zero sampling plan for the moderation of examination papers. South African Journal of Industrial Engineering, 16(2):69-80, doi:http://dx.doi.org/10.7166/16-2-167.