What are the steps in the three-dimensional printing process
The process of three-dimensional printing is generally divided into four steps.
Step 1: Stereo Photography
There are two commonly used methods for photographing three-dimensional printed originals:
(1) Arc stereo photography method: take a cylindrical lens plate in front of the photosensitive film to take a picture, the optical axis of the camera is aligned with the center of the object to perform a circular arc with an angle of 3 to 10 degrees, and the grating plate in front of the photosensitive plate of the camera and the The photosensitive film moves randomly and synchronously. After exposure, it is focused into one pixel under each half cylinder of the grating plate. When the camera finishes shooting at a predetermined distance, the pixels are covered with the entire grating distance, and a stereo photograph can be obtained after processing.
(2) Shutter movement method: When shooting, the shutter movement distance is approximately equivalent to the distance between two eyes (60mm), and at the same time, the grid plate is moved accordingly, and the movement distance is a grid distance (0.6mm).
Step 2: Plate making
The following points need to be paid attention to in the three-dimensional printing process:
(1) Stereo photos are usually made by offset printing. Considering the delicate pixels of the stereo image and the magnification of the cylindrical grating, the density of the network lines must not be less than 300 lines / inch.
(2) Since the three-dimensional original is composed of closely-spaced pixels, and a lenticular lens plate is required after plate-making and printing, the three-dimensional printing is different from the ordinary color printing screen angle. In order to avoid moire, different grids The three-dimensional printing with different distances must have different angles of the combination of the yellow, magenta, cyan, and black colors. Among them, the cyan and black colors can have the same angle. The error caused by four overprints eliminates the need to print a black plate.
Step 3: Printing
The paper used for three-dimensional printing must be compact, smooth, flat, with low flexibility, and not fade after printing.
Generally, a high-precision four-color printing machine is used, and the workshop must have constant temperature and humidity conditions.
Step 4: Composite cylinder lens plate
After printing, the surface needs to be covered with a lenticular sheet to have a three-dimensional effect. There are two types of cylindrical lens grids: hard plastic and soft plastic. When the format is large, hard plastic is used.
Three-dimensional printing has the following characteristics:
1. The image has a strong three-dimensional effect.
2. The three-dimensional printed manuscript can be made by modeling design or scene photography. The ink printing is high temperature resistant.
3. The surface of the printed product is covered with a layer of concave-convex mirror-like grating plate, which can directly view the three-dimensional effect of the panoramic picture.
4. Overprint printing must be carried out as planned to avoid paper expansion and contraction.
The elements of three-dimensional printing include:
(1) Paper: Three-dimensional printing paper is required to be compact, smooth, flat, and has low flexibility. Coated paper and cardboard are more commonly used.
(2) Grating material: hard plastic stereo grating and soft plastic stereo grating.
Hard plastic stereo gratings have high refractive index and good gloss.
Soft plastic stereo gratings have good chemical resistance, but poor thermal stability and light resistance.
(3) Ink: Because any visible degree of foaming will affect the clarity and three-dimensional effect, the three-dimensional printing ink is not a foaming ink. The curing temperature of the three-dimensional three-dimensional printing ink conforms to the curing range of the plastic ink. After the ink layer is cured, the three-dimensional ink has the same elasticity as the standard plastic ink. The image printed with this ink has sharp subtle levels and sharp edges, and the subtle levels and screen quality are suitable.
(4) Adhesive: The role of the adhesive is to make the printed matter and the grating film firmly adhere together, and can protect the ink layer from discoloring at high temperature.