Characteristics of photosensitive resin

Photosensitive resin is also called light curing resin. As the name suggests, it is a material that can be cured into a certain shape through the irradiation of light. Of course, it can't be any kind of light. Generally, different types of resins have different UV wavelengths for curing, and different types of resins have different requirements for printer wavelengths. Under the irradiation of such wavelengths of light, polymerization reaction is immediately caused to complete curing.

1. High light sensitivity. Because the SLA uses monochromatic light, it requires that the wavelength of the photosensitive resin and the laser must match, that is, the wavelength of the laser should be near the z-large absorption wavelength of the photosensitive resin as much as possible. At the same time, the absorption wavelength range of photosensitive resin should be narrow, so as to ensure that curing occurs only at the point irradiated by laser, so as to improve the manufacturing accuracy of parts.

2. Fast curing rate. Generally, the thickness of each layer is 0.1 ~ 0.2 mm for curing layer by layer during molding, and one part needs to be cured for hundreds to thousands of layers. Therefore, if the solid is to be manufactured in a short time, the curing rate is very important. The exposure time of a laser beam to a point is only in the range of microseconds to milliseconds, which is almost equivalent to the excited state lifetime of the photoinitiator used. Low curing rate not only affects the curing effect, but also directly affects the working efficiency of the molding machine, so it is difficult to be suitable for commercial production.

3. Small swelling. In the process of model forming, the liquid resin has been covered on some cured workpieces, which can penetrate into the cured parts and swell the cured resin, resulting in the increase of part size. Only when the resin swelling is small can the accuracy of the model be guaranteed.