In the past, the research of laser cleaning technology in developed countries was earlier, making some areas of cleaning has been industrialized. China's laser cleaning technology research started late, basically following the development of foreign countries. With the continuous efforts of the majority of researchers, some achievements have been made.
As a kind of cultural relics protection and restoration technology and equipment, laser cleaning technology has been widely used in the international community, especially in ancient architecture and its various construction surface cleaning protection and restoration, with many successful cases.
Cultural relics due to a variety of environmental and storage time and other reasons. The surface will have a lot of dirt, such as: soil spots, rust spots, oil, water, sweat stains, etc., due to the artifacts of many kinds of different textures, in the cleaning process taken by different methods. This brings a lot of inconvenience to the cleaning of cultural relics. Here we look at what are the traditional ways of cleaning cultural relics?
Traditional cleaning treatment generally have the following ways:
First, water washing
For general solid texture, not afraid of water immersion artifacts, the surface attached or stained dirt can be washed with distilled water. The solidified material on the excavated artifacts is more hard, not easy to wash off at one time, do not use metal or hard objects in the cleaning, so as not to damage the artifacts.
Second, dry cleaning
Textile artifacts such as stains, washing may fade, should use gasoline and other things to scrub, you can also use dry cleaning agent directly sprayed in the stains, dry cleaning agent should be used before making a test.
Third, dry rubbing
Some objects afraid of water and some unearthed items, in order to maintain the original object due to the erosion of the ground over the years and the appearance of the natural color, should not be rinsed with water and drugs. For this type of artifacts with a soft texture of the damp cloth gently wipe can be.
Four, wind drying
For the paper articles and part of the fabric should not be washed or dry rubbed, should choose the wind drying method, the surface of the dust and moisture blown away. Avoid exposure to strong sunlight, avoid strong wind blowing, avoid smoke pollution, avoid pollen staining.
Fifth, mechanical dust removal
Larger, bulky and irregular objects, vacuum cleaners and other mechanical dust; larger stone carvings, sculptures, etc., in the vacuum at the same time you can also use high-pressure air pumps, vacuum cleaners are not easy to remove the dust blown off.
Six, drug cleaning
Mainly used in various types of harsh environment to preserve the antiques and excavated artifacts. Because of the excavated material in different places in the mixture, so in the use of self-mixing liquid should be done when the experiment, the choice of different drugs and the use of different methods.
The above six means of cleaning will cause irreversible damage to cultural relics, just how much damage is the problem. The laser cultural relics cleaning is different, laser cleaning uses the characteristics of the laser beam, through the focusing system can make the laser beam gathered into different sizes of spot diameter, in the laser energy under the same conditions, different spots of the laser beam, the resulting energy density or power density is different, so that you can easily control the cleaning of the laser energy required. The laser can achieve a high degree of concentration in time and space. Laser cleaning utilizes these characteristics to effectively remove contaminants. The contaminants are instantly stripped from the surface of the artifacts, thus realizing the cleaning of the artifacts.
Another important aspect: it is a harmless cleaning method - the material of the surface of the cultural relics and the pollutants attached to it on the absorption of the laser beam is different, this difference makes it possible to distinguish between the pollutants and the material of the surface of the cultural relics, so as to accurately control the cleaning of the laser energy required to do not harm the cultural relics, but also clear off the pollutants. At present, this technology has been widely used in stone cultural relics, paintings and other fields.
At present, the pace of development of the global laser industry more and more quickly, promoting the rapid development of laser cleaning. Although now the laser cleaning technology can not replace the traditional cleaning technology, and even not yet towards the mature stage. But many research institutions of laser cleaning, studied the conditions of the laser process and the complex interaction of rising gas flow and mechanical factors, although these interactions have not yet been fully applied in practice. However, with the advancement of process knowledge in theoretical modeling control strategies, as well as the continued development of laser cleaning technology, the laser process will overcome the disadvantages of conventional operations and provide increasingly effective potential value in industrial development.
It is foreseeable that laser cleaning with its super adaptability, its application will continue to be extended to new areas, for the cleaning industry to bring a green revolution.
