Introduction
DLP (Digital Light Processing) and LCD (Liquid Crystal Display) are both resin 3D printing technologies, which itself is also known as stereolithography. These two 3D printing processes utilize digital methods to control light sources and solidify liquid photosensitive resin layer by layer, thereby creating three-dimensional objects.
In fact, from a perspective of fundamental principles, DLP and LCD technologies have inherent differences. This also results in disparities between DLP and LCD 3D printers in terms of equipment durability and subsequent operating costs.
Comparison of the working principles of DLP and LCD
The DLP printer utilizes a digital light source to directly control the shape of the projected light. The optical system of a DLP printer typically consists of light engine components and refractive components. Taking the Raise3D DF2 printer as an example, its optical system comprises the light engine, reflective glass, and protective glass. The contour shape of the light is instantly controlled by the digital micromirror array (DMD) inside the light engine. When printing each layer, the UV light contour emitted by the light engine is directly projected onto the bottom film of the resin vat, inducing a curing reaction with the resin.
The LCD printer utilizes a liquid crystal display as a mask to indirectly control the contour of the projected light source. The optical system of an LCD printer typically consists of a UV LED light source, an array of lenses, and a liquid crystal screen. The liquid crystal display controls the orientation of liquid crystal molecules through an electric field effect to adjust the brightness of each pixel, thereby creating selective transparent areas. When constructing each layer, the liquid crystal unit allows specific areas of light to pass through and be projected onto the resin vat, forming the contour of each layer of cured resin.
The lifespan advantage of DLP in 3D printing
Overall, DLP printers have a longer lifespan, mainly due to the following factors:
(1) Light Source Lifespan:
Firstly, projector lamps have a longer lifespan, with an extremely low power consumption typically of only a few watts, and a light source utilization rate exceeding 95%. The lifespan of LCD projectors is relatively shorter due to the impact of the number of pixel switching cycles during the lifespan of the liquid crystal panel.
Additionally, UV light sources can accelerate the degradation of organic materials in the LCD screen. This degradation over time can result in a decline in the performance of the LCD screen, thereby affecting the accuracy of 3D printing. With the degradation of organic materials, the LCD screen may experience reduced brightness, weakened contrast, and other issues, thereby affecting the consistency of printing results.
(2) LCD Screens are Prone to Burnout
The LCD display technology, which relies on projecting light from a distance, cannot guarantee pixel accuracy, requiring the LCD screen to be closely attached to the resin vat. When liquid photosensitive resin reacts with UV light, it generates a significant amount of heat. Excessive heat can burn out the LCD screen, so it may need to be replaced frequently during long-term use.
Therefore, despite the higher initial cost of DLP printers compared to LCD printers, the overall cost in the long run may actually be lower for DLP printers.
(3) LCD Screens are Prone to Breaking
Due to the close contact between the LCD screen and the bottom of the resin vat, if the printed part squeezes the release film, it is easy to cause the LCD screen to crack; otherwise, users may need to reduce the peeling speed of the 3D printer. Therefore, this possible occurrence further increases the long-term operating costs of the LCD printer.
Conclusion
In summary, due to differences in components and optical path construction, DLP printers outperform LCD printers in terms of lifespan and long-term maintenance costs, while also exhibiting disparities in imaging quality. The shortcomings of LCD printers lie at the level of technical principles, requiring technological innovation to address.