Abstract
M.Sc.
Layered Manufacturing (LM), also known as "Rapid Prototyping", is that process in
terms of which a computer-designed model is created layer by layer with the aid of
specific LM hardware. Telemanufacturing constitutes an extension of this technology
that allows remote submission of manufacturing jobs or assignments across a
communication medium, typically the Internet, to be built at the manufacturing bureau
concerned. The de facto standard of LM is the STL file. Simply put, this file consists of a number of triangles that are used to describe an object in its entirety. This file format has
several advantages over other known formats and allows easy 2D rendering. Unfortunately, however, the limitations of the latter format outweigh its advantages.
Since the entire model is described in terms of a collection of triangles, the original
geometry of the model is lost. As a result, a certain level of degradation will occur,
especially around curvatures in the model. Although an increase in the number of
triangles around such areas will enhance precision, it will also result in a much larger
STL file. Triangles that get lost somewhere inside the file could also give rise to holes,
orphaned surfaces and zero-width walls in the projected object. It is vital, therefore,
that the manufacturing bureau verify the correctness of the entire file before it is built
in order to prevent machine time and materials from being wasted. Instead of transmitting the entire file again, the bureau could attempt automatically to correct and repair less critical errors, thereby saving valuable resources and time.