Release film is a critical component in resin-based 3D printing, specifically designed to prevent the cured resin layers from adhering permanently to the bottom of the resin vat during the printing process.
Understanding Release Film
In many resin 3D printing technologies, such as Stereolithography (SLA), Digital Light Processing (DLP), and LCD-based printers, a build platform lowers into a vat of liquid photopolymer resin. A light source (like a UV laser or an LCD screen projecting UV light) cures a layer of resin onto the build platform or the previous layer.
The bottom of the resin vat is lined with a clear film. This release film acts as a non-stick barrier. After each layer of resin is cured, the build platform lifts slightly. Because the cured resin is stuck to both the platform (or previous layer) and initially the bottom of the vat, the film allows the cured layer to gently peel away from the vat bottom with minimal force. This peeling or separation step is crucial for the printing process to continue successfully layer by layer.
Common Types: FEP Film
A widely used type of release film is FEP film. According to the reference provided, FEP Film or FEP Tape consists of optically clear Teflon™ film made with Teflon® fluoropolymers.
FEP film is particularly suitable for this application because it is:
- Optically Clear: It allows the UV light source to pass through unimpeded to cure the resin.
- Non-Stick: The fluoropolymer material provides excellent release properties, preventing the resin from bonding strongly to the film.
- Chemically Resistant: It withstands exposure to various photopolymer resins.
As noted in the reference, FEP is used in Stereolithography (SLA), a special form of 3D Printing that works by focusing an ultraviolet (UV) laser onto a vat of photopolymer resin. Similar films are also used in other vat polymerization methods.
Why Release Film is Essential
The release film is vital for reliable resin 3D printing. Without it, the cured resin layer would strongly adhere to the vat, making it impossible for the build platform to lift and separate the layer. This would cause print failures, damage to the printer components, or warping of the printed part.
Key benefits include:
- Enabling Layer Separation: The primary function, allowing prints to detach easily.
- Protecting the Vat: Shields the underlying glass or screen of the vat from resin spills and damage.
- Improving Print Reliability: Reduces the chance of print failures caused by adhesion issues.
- Extending Component Lifespan: Less stress is placed on the printer's mechanics during the layer separation (peeling) process.
Key Characteristics
Here are some essential characteristics of 3D printer release film:
| Characteristic | Description |
|---|---|
| Material | Often FEP (Fluorinated Ethylene Propylene), PFA, or similar non-stick polymers |
| Transparency | Optically clear to allow UV light passage |
| Function | Provides a non-stick surface for cured resin to detach from |
| Location | Forms the flexible bottom window of the resin vat |
| Application | Primarily used in Stereolithography (SLA) and other resin 3D printing types |
Over time, release films can become cloudy, scratched, or damaged by repeated peeling forces or accidental contact with sharp objects. A degraded film can lead to print failures (e.g., layers not sticking, holes in the print) and reduced print quality. Therefore, it is considered a consumable part that needs periodic replacement.
