A design that is quite easy using one type of software can become very complex if another one is used. For example, to design a model with recurrent geometric patterns, like a bangle adorned with fretwork, then a true CAD, that is a solid modelling system, is preferable. In contrast, if you want to design an artistically very elaborate object, a CAID system, that is a surface modelling system, is preferable. Consequently, software selection should be carefully considered and should be based on production characteristics and potential of the company. It must be remembered that CAD design is definitely not automatic and always man is the “thinking” subject. A wrong choice can cause big problems in the use of the system and, in some cases, can make it completely useless.There is a wide range of modelling systems offered in the market and an inexperienced company can have great difficulties in making the correct choice.

After this premise, we can consider the step that comes after CAD modelling, by CAM. CAM is a computer directed and controlled production activity. CAM technology not only allows direct control of machines and of a company’s functions, but can also enable production planning, in order to reach the following objectives:

• automatic diagnostics of production process,
  
• product quality analysis,
  
• collection, organization and recording of data on process stages and work progress,
  
• and, principally, production control.

To gain a better understanding of the above topics, we will examine a practical application of CAD/CAM in jewellery manufacturing. The task of the jewellery designer and of the goldsmith can be divided into two phases. The first phase concerns CAD modelling: The designer’s idea (usually a sketch drawn on paper) is the starting point. The next stage is the realisation of the drawing with the CAD program.

The mathematical model is analyzed with the same program to verify the surfaces and control any possible errors. Finally, to get a better understanding, the finished object is simulated. This phase is named “rendering” by the technicians, but is not essential for the production of the model. It is used only to check the aesthetic characteristics of a jewellery piece. Now comes the second phase, CAM manufacturing, where the machining route is planned.

Obviously, the material machined is not necessarily gold but, more commonly, a cheap material is used, such as wax, plastic or a base metal. When tool type and machining technique have been defined, simulation of machining can begin. Now, once the machining route is ready and it can be sent to numerically controlled machines for the manufacture of the real object.

 
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To sum up, what does a CAD/CAM system mean today?

A CAD/CAM system is able to carry out the development, control and preparation of the model, or of the tools required for model manufacturing, such as moulds or templates, setting of machine tools. Above all, it enables a clear integration of the above phases in an integrated 3-dimensional modeling environment.

CAD/CAM in the factory :

Now the next question to be answered is ‘how can these technologies be introduced in the jewellery factory?’
Introduction of these new technologies in a company, or to arrange for the company to utilize them by means of new specialized design companies, can give substantial advantages in terms of cost and time required for making a model, but it is not exempt from problems.

In particular, it has been observed that, generally, the introduction of these new technologies can lead to one of two opposite reactions, either the company totally refuses to consider the new technology or takes a liking to it and tries to use it at all stages of the production process, possibly fully in-house. In the

First case, the refusal generally comes from the fear of change. At the start, some manufacturing operations will require changes that will result in some unavoidable opposition inside the factory by the operators who will see it, wrongly, as a challenge to their work or to their position. I stress “wrongly” because these new technologies absolutely do not aim to reduce or limit the tasks of designers or model makers. On the contrary, when these new systems are integrated into the factory production process, they will have much wider freedom of action and a stronger stimulus to imagination.

There is also the second case, when these techniques are not only accepted, but even extolled, when the first results are achieved. At this moment a new problem arises that is exactly opposite to the first case:

The entrepreneur tries to do every thing with the computer, even the operations that can still be made more easily, logically and economically by hand.