How do LCD Resin Printers Work?

LCD resin printers create 3D objects by selectively curing liquid resin using light projected through an LCD screen. Let's break down the process:

The Key Components

• Resin Vat: A container holding the liquid resin, a photopolymer that solidifies when exposed to specific wavelengths of light.
• LCD Screen: This acts as a mask. It selectively allows light to pass through in the shape of each layer of the 3D model. Pixels on the LCD screen either block or transmit light.
• Light Source: Typically an array of LEDs located underneath the LCD screen. These LEDs emit the specific wavelength of light needed to cure the resin.
• Build Plate: A platform that is lowered into the resin vat. The first layer adheres to this plate, and subsequent layers are built upon it.
• Z-Axis Movement: A mechanism that precisely raises the build plate after each layer is cured, creating space for fresh resin to flow between the build plate and the vat floor.

The Printing Process, Step-by-Step

1. Preparation: The 3D model is sliced into thin, 2D layers by software. These sliced images are then displayed sequentially on the LCD screen.
2. First Layer: The build plate is lowered into the resin vat, leaving a thin gap (the layer height) between the build plate and the bottom of the vat.
3. Layer Curing: The LED array illuminates the LCD screen, which displays the first layer's shape. The light passes through the transparent portions of the LCD screen and cures the resin directly above it, forming the first solid layer adhered to the build plate.
4. Z-Axis Movement: The build plate is raised slightly, allowing fresh liquid resin to flow into the space between the cured layer and the bottom of the vat.
5. Repeating the Process: Steps 3 and 4 are repeated for each layer of the 3D model. The LCD screen displays a new layer image, the light cures the resin, and the build plate is raised.
6. Completion: Once all layers are cured, the build plate is raised completely out of the resin vat.
7. Post-Processing: The printed object is removed from the build plate, washed to remove any uncured resin, and often further cured under UV light to fully harden the material.

Advantages of LCD Resin Printing

• High Resolution: LCD printers are known for their ability to produce parts with fine details and smooth surfaces due to the high resolution of the LCD screen.
• Accuracy: The LCD screen precisely controls the shape of each layer, resulting in accurate prints.
• Faster Print Speeds: Compared to SLA (Stereolithography) printers, LCD printers can often cure an entire layer at once, leading to faster overall print times.

In Summary

LCD resin printers use an LCD screen as a dynamic mask to selectively cure layers of liquid resin with UV light, building up a 3D object layer by layer. The accuracy and resolution of the LCD screen are key to the printer's ability to create highly detailed and precise parts.