One of the manufacturing processes used in the production of intricate dental implants is a method called photochemical or engraving. Photochemical engraving is an unconventional machining method in which the process does not imply cutting tools. Photographic and chemical techniques are used to remove the material from the workpiece to shape the final product. The process implies exposing the work piece to a special chemical and corroer select defined areas. These are those defined through photorers.
1. Preparation for the photo tool.
The pattern used for this process is designed using CAD software that will become the appropriate format necessary for printing. The pattern is printed on a photographic film, in the form of a silver diazo or halide movie, by a specimotter or a laser image system. Common compensation factors affect the dimensions of the photographic tool; These are the engraving factor, temperature and humidity variations.
2. Preparation of the workpiece
The work part will be cut and clean before loading it for the engraving process. It is important to ensure that there are no pollutants on the surface of the metal for the successful adhesion of photor resistance. The pieces can be cleaned by two methods (mechanical and chemical). Mechanical cleaning implies the application of a degree solution and submitting it to a certain form of scrub. On the other hand, in the cleaning of chemicals, the part of the work is suspended in a degrade solution composed of combining soft acids and agents. Most manufacturing stores prefer chemical cleaning methods due to their minimum damage applied to the work part.
3. photorersisister processing
Fotor resistant coating
The photorers are common established on the surface of the work part. These can resist the strong effects of the engraving solution, leaving Beind a masked and defined image. The photographic tool is responsible for protecting and exposing the desired photorers. This exposure composed of UV light makes it solar or insoluble (depending on what will be used) for the developer agent.
Below are the different photorers of photorers:
● Classification according to the type of image produced (positive photor resistance and negative photor resistance)
● Classification according to the chemical structure (photopolymer, photographic composition and photocrosslinking)
● Classification of agreement to form (dry film and liquid or humid film)
Soft bake (90 ° C at 110 ° C)
The next process, after applying the photorersista material, is “soft baking”. This is done to heat, vaporize and release residual solvents. This process must be supervised to avoid high evaporation, causing bubbles and empty within the photorestone. In addition, a low evaporation rate could inhibit the necessary evaporation of residual solvents, which will result in a surface film formation.
Exposure
Before processing with this process, it is vital to guarantee an adequate alignment of photographic tools in a multiple layer pattern. After everything has been established, the work part can now be subject to exposure. The exposure process is where the image of the photo will be transmitted to the work part with the photorers. This is typically done with wavelengths of less than 400 Nm (ultraviolet rays). Different techniques are used to expose photor resistance, and these are through exposure to contact, exposure to proximity, projection, direct laser image and electron beam.
Post Exhibition Bake (110 ° C at 120 ° C)
This process implies thermally catalyze chemical reactions, which completes the photoreaction initiated by exposure to ultraviolet light.
Development
This process is made to eliminate unnecessary parts of the photorestone, leaving behind the desired pattern in the work part.
Hard Bake (120 ° C)
This process adds to the physical stability of the workpiece to resist the engraving process.
4. Clean engraving
This is when unnecessary materials are subtracted from the work part to form it in the desired form. The engraving can be classified into two main types, namely, the Law of Engraving and Dry Engraving.
ETCHING
This method uses liquid chemicals to erode the unprotected part. Start with oxidizing components through hydrogen peroxide or nitric acid. The following is the dissolution of the oxidized part using chemicals such as hydrofluoric acid, phosphoric acid and hydrochloric acid. Finally, the dissolved oxidized substrate is eliminated from the piece, ensuring a homogeneous solution in contact.
Dry engraving
This method is based on high -speed gaseous ions to eliminate and corrode the material. Iron collision with the piece is the answer to eliminate the material in one direction, eliminating the undermining problems that arise from the wet engraving.
5. Disassembly disassembly or elimination
After the desired form has been created, photorestoning materials are eliminated. This process can be carried out with two methods: through the use of solvents and through the use of combustion. Solvents have the ability to break down the structure of the photorersist layer, and oxygen combustion, on the other hand, can deal with materials that are not easy eliminated by chemical agents.
