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Archaeological findings and the creation of accurate copies without touching the prototype

The aim is to develop innovative procedures to create
accurate copies of archaeological findings without touching
them. It includes procedures such as computer tomographies,
thermojet printing, rapid prototyping, coatings/mouldings.

Nowadays, the creation of accurate copies of objects with high emotional or actual value is an interesting but very sophisticated procedure. Especially when the accurate reproduction concerns archaeological findings, the most commonly used procedures currently incorporate disassembly or direct moulding of the prototype, which may harm it. The registration of the solid geometry is the first and most crucial step in the creation of an accurate copy. A commonly used method for this purpose is laser scanning. Although this is a highly accurate method, there are many restrictions regarding the geometry of the specimen, since the laser beam scans only the outer surface geometry of the object and does not detect potential overlaps of external object details. In addition to the laser scanning method, in the frame of the present project, an innovative procedure with industrial computer tomographies will also be applied to extract the object geometry with a high accuracy (several micrometers). This method overcomes the restrictions of laser scanning, as proved by experiments already conducted. Using this method the prototype is scanned through an industrial computer-tomography and a union of points, comprising the geometry of the prototype, are defined. A special software, which will be further developed and optimised for the purposes of the present project, processes the points obtained from the tomography and provides the CAD (Computer Aided Design) solid model of the prototype with a very high accuracy. Considering the described defined solid geometry, the next step in the project is the manufacture of an accurate object copy. This project will use a manufacturing technique that produces an accurate copy, in terms of the material used for the copy. Through this procedure, an accurate temporary model is created by means of thermojet printing. Thermojet printing is a modern technique that enables the production of accurate waxworks from a CAD solid model. The herewith-produced temporary model is then used to create an appropriate mould of the desired model. This procedure is very complicated, since the waxwork has to be specially treated. For this reason, a special software for the mould creation procedure will be used and the moulding process will be simulated and optimised using a computer beforehand. The last phase is the casting of the true copy. Investigations regarding the appropriate properties of the casting material will be conducted, in order to achieve an unobstructed casting result and a good resemblance of the copy of the prototype. After the creation of the accurate copy, it undergoes a relevant final treatment, in terms of the desired properties and colour of the external surface. For this reason, a number of modern techniques will be investigated, for example the deposition, physically or chemically, of thin, hard coatings on the external surface. Using this procedure, the accurate copies are coated with various coatings of several micrometers that appear identical to the original in mechanical and thermal properties as well as colour. These methods are commonly used nowadays for different purposes such as coating of tools, machine parts, etc. which are usually of a small size and simple geometry. Among others, appropriate investigations will be conducted during this project in order to apply these procedures in creating objects of a bigger size and more complex geometry. The aforementioned manufacturing procedures, as well as the treatment of final copies, may result in various production costs which will also be taken into account. The final phase of the project deals with the control of the accuracy of the produced copies as far as concerns their shape and dimensions as well as the properties and the colour of their external surface. In order to control accuracy in shape and dimensions, the geometry of the copies will be extracted in the way that has been described concerning the prototype, and a comparison of the two geometries will be conducted with the aid of a computer. During this phase of the project, appropriate stands will be also designed and manufactured to support and exhibit the accurate copies produced. Keywords: tomography, rapid prototyping, casting.
Acronym: 
ARCHAEOCOP
Project ID: 
2 740
Start date: 
01-01-2004
Project Duration: 
27months
Project costs: 
540 000.00€
Technological Area: 
Imaging, Image Processing, Pattern Recognition
Market Area: 

Raising the productivity and competitiveness of European businesses through technology. Boosting national economies on the international market, and strengthening the basis for sustainable prosperity and employment.