CONFERENCES
- Publications -
Raino Ranta
Interaction In Ceramics - Art, Design and Research, A. Valkonen (ed.), ISBN 951-9384-56-1, ISSN 0782-1778, UIAH, Helsinki 1993 

CAD/CAM IN CERAMIC DESIGN

In the early '60s the first interactive computer graphic systems came into existence In the early '60s the first interactive computer graphic systems came into existence and at the same time parametric surfaces were introduced to computer aided design (CAD). The first applications of CAD systems were released to be used in the car industry. Around 1970 Bezier had implemented his UNISURF system at the Renault car company that became a benchmark for many other modeling systems.The development of CAD programs got extremely speed in the '80s. Simultaneously the hardware prices started to go lower and the capacity of computers started to rise. That development has been continued in the '90s with increasing speed so that the three-dimensional CAD applications can be found at almost any levels and for any one's purposes. 

The computer aided manufacturing systems (CAM) were first designed for the machine engineering. The manufacturing of precise machine tools and equipment became much easier and quicker when complex form making was supervised by the computer. 

In the ceramic industry models and molds can be made from nylon and if decried even from plaster. The most recent technique, developed in the late '80s, is called stereo lithography. In that technique the model is built up from polymeric liquid and hardened by an ultra violet light beam. 

WHY CAD/CAM IN CERAMICS
It is known that in the ceramic industry the product developments and manufacturing are complex and time consuming processes involving much manual labor. After the designer's visualisations, many skillful people and time are needed until we have, for example, a prototype of a teapot, and this is just a beginning of a long way to the final product and production. In the following chapter I will shortly describe to you a common product development process in ceramic industry. 

When the designer has visualised his ideas by drawings and the first prototype has been made the discussions between the designer, the client and the product and marketing departments will be held. Corrections and changes will be made so that every party can agree how to continue. When the correct new prototype is finished and decisions of new corrections made, the third prototype is needed. It is usually that this process, making a proto - making corrections - making a new proto, must be done at least one or twice before the model making can be started. When the fired sample of the model is criticised the whole process can be returned to the designer's drawing board or the decision of tools manufacturing can be done. Manufacturing the tools is also a time and skills demanding process because all the molds and metallic rollers that are needed for the test production must be made and copied.

After the testing period the final product decision can be done. If everything works properly the production can be started. This description of product development is the traditional way and is still used in many factories. However, nowadays many ceramic factories and design studios all over the world are starting to use CAD systems in their designing processes and CAM systems in model and mold making. We can now take a view to the same product development process and see how it could be handled by using the CAD/CAM technology. 

DESCRIPTION OF THE CAD/CAM PROCESS IN CERAMICS
When the client first describeshisideasofthenewproducttothe designer, the designing process will be started by launching the three-dimensional CAD program. The designer can use his hand made scetches as a starting point for his modeling session by scanning them onto the background of the screen and starts to input projection and crossection curves on that image. He can create the three-dimensional surface from two-dimensional curves by rotating, sweeping or skinning them. If the form of the surface does not look acceptable he can make corrections to it by returning to the curve level and editing curves as helikes. Rotating or skinning the surface again will show him the result of the curve manipulation. If he wants to view the object with shadows he can now use a qu ick shading program. Rotating and moving the shaded object i n real time on the screen is possible with most of the CAD programs. 

When designing a larger concept, like a whole tea set, he makes the same operations to each single object so that every part will fit together with forms and sizes. When the geometry has been finished he can define the surface material by given the physical characters, like color, hardness, reflectance, transparency, etc. He can also build an actual scene where all his objects will be presented with background, floor and light sources just like in real life. Lightsource's directions can be defined and images can be scanned to the composition's background. If decorations are wanted the designer does not need to wait for the first fired prototype because there is a possibility in many CAD systems to place textures, designed with a paint program, onto the object's surface. 

It is now time to launch the ray-tracing program that produces photo realistic images from the scene. Instead of manufacturing prototypes and showing photographs taken of them, the designer will print out images direct from thecomputer screen and show then to the client. The designer makes the client's decision easier by producing a selection of images with different forms and glazes. All kinds of material effects and form changing are possible until the prototype is made. When the product's geometry has been done with the CAD system it can be translated into a data that supervises mechanical tool manufacturing. Models and molds that are needed for the test production will now be made with CAM system. After the testing period the final production can start. 

TOOLS FOR DESIGNING
As artists and designers we do not know and fortunately we are not even expected to know much of the mathematics behind the computer programs. Despite the theoretical and technological innovations, most of the available CAD systems have support engineers rather than artists and designers. Luckily the very recent development in CAD system's user interfaces seems to have improved that situation. 

The problems of numeric and text based data input has lead to so called graphic user interfaces. Instead of using the keyboard the user points icons, little graphic symbols on the screen, with the mouse when he wants that certain function to happen. That liberates the user from the specifics of computerisation. Most of the available programs are nowadays based on that method. The newest user interface that is under development is based on voice control. The mouse has been the most common device since the graphic interfaces were released but it is not a very good drawing tool. Digital tablets that are pressure sensitive with a pen that behaves and feels just as a normal one have been developed to offer a possibility for the artist and designer to have a very powerful electronic drawing tool. The development of computer hardware, programs and user interfaces in the '80s and '90s has been unexpectly fast. In every coming year more capacity and qualities can be bought with less money. That trend has made it possible for designers to supply their studios with CAD/CAM systems also. Personal computers (PC) are nowadays powerful enough to be used almost in any kind of three dimensional designing. 

A LOOK INTO THE FUTURE
We live in the world where computers are applied to solve scientific problems, control the traffic in the cities, make prognoses of the daily weather, pay our bills automatically from the bank account and have charge of the missiles in their silos. There is nothing new about that, but when the new technology comes suddenly so cheaply and easily to use by any man it will certainly cause confusion in a field where everything has been based on human touch. Many artists and designers are afraid of the invasion of computers into their area and there is indeed a danger in designing process that the computer guides us to make too simple decisions if we can not master the software effectively enough. CAD programs become day by day more user-friendly and if I could take a climb to the future I think that I would see artists and designers using computers as they use any other equipment to express their creativity. 
REFERENCES
- Raija Siikamäki, CAD - Computer Aided Design or Computer Against Designer, Ceramic Bulletin, Vol. 71, No. 31992, US ISSN 0002-7812
- Charles Woodward, Method for computer aided design of free form objects, Acta Polytechnica Scandinavica, Mathematics and Computer Science Series No. 56, Helsinki 1990, ISBN 951-666313-5. ISSN 0355-2713
- Charles Woodward, Panu Rekola, Maria Nordgren, An Implementation of CAD/CAM System in Ceramic Industry, Computer Applications in Production and Engineering, F. Kimura and A. Rolstadas (Editors), Elsevier Science Publishers B.V. (North-Holland), IFIP 1989 

Publications


Info:

Raino Ranta, @, http://art.net/~raino

University of Art and Design Helsinki UIAH
Department of Ceramics and Glass
Hämeentie 135 C 
FIN-00560 Helsinki, Finland 
phone: +358 9 75630249, fax: +358 9 75630373