Introduction to Jewellery CAD/CAM :

Today I will explain how production techniques developed in fields quite different from goldsmithing can be adapted perfectly to jewellery manufacture. In this presentation, the following topics are discussed:

• what is CAD/CAM
• what opportunities this new technology can offer to jewellery   factories
• when use of CAD/CAM can be profitable
• how can CAD/CAM be utilized to the best
  

At the threshold of the new century, technology can offer substantial support to all the activities of the goldsmith. Particularly in recent years, much research work has been carried out in the field of jewellery production and new sophisticated technology for jewellery manufacturing has been developed. Unhappily, the goldsmith does not always readily accept new technology. To give an example, investment casting was introduced in the late 1940s, but it was not accepted by the industry until the late fifties. Ten years elapsed before it was used in factories.

Consequently, in spite of active research work for end product quality improvement, there are some production steps that seem unaffected by the lapse of time. In particular, there is a step in the production process where, even today, the goldsmith is still unwilling to accept new technology. This step is design or, more precisely, the intercommunication between the designer and the goldsmith - that is, between creativity and practical realization. It has always been believed that a compromise between aesthetic and production technology requirements is difficult to reach, but this has not actually been true for a long while, a statement proved by many examples of industrial design, such as Pininfarina design for the automotive industry. These demonstrate how creativity and imagination can perfectly be harmonized with computer calculations.

The instrument enabling this small miracle is named CAD/CAM. These acronyms denote all systems that assist design (CAD = Computer Aided Design) and manufacturing (CAM = Computer Aided Manufacturing) through a computer.

 
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What is CAD/CAM?

Let us first analyze design. Traditionally, CAD denotes programs that replace the pencil and assist the designer in the representation of his ideas. These programs aid in the achievement of a quick development of the design and allow an immediate control. Moreover, they enable the transmission of the designed geometric patterns to other programs for machining. I have said “traditionally”, because unceasing evolution has somewhat changed the original characteristics of these systems. Initially, this software was mainly used for mechanical design. Later they underwent a true transformation and gave birth to two distinct branches:

The first one led to the development of programs named CAE (Computer Aided Engineering), and
The second one led to CAID (Computer Aided Industrial Design), both softwares for model development and study of style.

The programs of the first kind are of a more technical in nature. CAID programs don’t require operations like dimensioning and patterning and give more emphasis to the creative phase. They enable a perfect simulation of the reality and give immediate concreteness to ideas.

Consequently, different kinds of CAD systems have been developed that are devoted to different design and modelling types, such as:

• Polygonal modelling
• Surface modelling
• Solid-parametric modelling
• Hybrid modelling.

 
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Let us briefly describe the above types :

Polygonal modelling : This is the most common CAD modeling software: all models are created as a combination of small squares and triangles.

Surface modelling : This CAD software shapes the surface, ie. the “skin” of the designed object, and enables the achievement of very complex shapes.

Solid parametric modelling : This software is based on the geometric parameters defining the object. The ability to modify the design whilst keeping some parameters constant is typical of this kind of modelling.

Hybrid modelling : These are CAD systems that combine surface and solid modelling, and enable the creation of complex patterns, starting from simple models. These classifications do not have a commercial purpose, like classifying the products from different software houses; each type denotes a specialization, with a completely different approach to design, and has advantages and drawbacks.