Our Glimmer FEP Film introduces a macrotextured surface that becomes imprinted onto every printed layer. This geometric imprinting transforms interlayer bonding from purely chemical adhesion into mechanical interlocking, significantly improving damage tolerance under higher strain-rate loading.

In conventional resin printing, layers behave like smooth plates stacked together and bonded, but they can shear easily under rapid force. Under sudden loading, stress localizes and cracks propagate quickly due to weak interlayer stress transfer.

Our Glimmer FEP macrotexture changes this behavior. The imprinted surface acts like intermeshing gear teeth between layers, creating macro-mechanical keys that resist material slip. This effectively enhances the mechanical response of the printed structure under dynamic loading.

To understand why, let us break it down step by step.

In conventional resin 3D-printing, layers are held together mainly by chemical bonding. At low rates of loading, this bond provides sufficient retention between layers. However, chemical bonds exist at a very small scale and do not create strong macro-mechanical interlocking.

When loading becomes fast, dynamic, or highly variable, chemical bonds are no longer sufficient to keep the layers firmly engaged together. Instead of transferring stresses smoothly from one layer to the next, stress concentrations or pile ups may occur within the structure, making it prone to sudden fracture during service.

High strain-rate fracture mechanics is also influenced by the numerous pores or defects present in the printed structure, which further concentrate internal stresses.

Let us explain why this matters using a simple analogy.

• The printed layers may act like gears that can slip or fully engaged gears that transmit torque well.

Macro-mechanical interlocking  between printed layers helps transfer stresses smoothly from one layer to the next, just like torque passing through properly meshed gears. The printed part behaves like one solid unit.

• When force increases suddenly, the gears stay locked-in instead of slipping.

In a conventional 3D-printed structure, fast loading causes the micromechanical bonds to slip, leading to rapid stress buildup and crack initiation. But when additional macro-mechanical interlocking is present between the layers, the layers remain engaged, resisting bending and sudden forces without separating.

So, what does this improved macro- mechanical interlocking change when it comes to the structural behavior of the 3D-printed part or component ? 

It changes the bending stiffness of the part.

Bending stiffness (EI) determines how resistant a part is to bending and shear forces. It is defined as:

EI = E × I

Where:

E is the elastic modulus of the material.

And I is the second moment of area (a geometric property describing cross-sectional distribution relative to the neutral bending axis of the component).

Fatigue failure may occur when the part repeatedly bends or deflects under cyclic and rapid loading. By increasing bending stiffness, the structure deflects less during each cycle, reducing the overall cyclic strain experienced by the part or component.

When printed layers of a part remain firmly interlocked instead of slipping, crack formation is delayed under dynamic and repeated loading conditions of the part.

By introducing macro-retentive texture in the layers, the overall geometry or shape of the printed part remains unchanged. The classical second moment of area (I) is not increased and the elastic modulus (E) of the part also remains the same.

Instead, macro-mechanical interlocking suppresses interlayer slip and improves stress-coupling across the full thickness of the part or structure. This allows the printed part to behave more like a unified, monolithic section under load.

In other words, the macrotexture does not change geometric stiffness parameters. It improves how effectively the structure realizes its inherent bending stiffness during dynamic and cyclic loading.

For eliminating material porosity that decreases elastic modulus (E), we offer our proprietary degassing solution known as NETFIL Industrial Processing for all 3D-printed composite resins, including chairside resin composites.

When a 3D-printed part or component undergoes bending, different regions experience different stresses:

• The outermost surface on one side undergoes tension where bending stresses are high

• The opposite outer surface undergoes compression where again, bending stresses are high

• Between them in the middle, lies a neutral axis, where bending stress transitions from tension to compression

• In this central region, only shear stresses are their highest and not bending stresses

In resin 3D-printed structures, the material is added layer by layer. If interlayer bonding is limited to small-scale chemical adhesion, microscopic slip can occur under bending. This slip may initiate along the neutral bending axis of the part, where shear stresses are high and may propagate outward during high strain-rate loading. Simultaneously, tensile stresses at the outer surface can initiate cracks that grow through the thickness of the part.

This is why retentive macrotexture must run through all printed layers, not just surfaces or central regions of the part.

The Glimmer macro-mechanical interlocking improves stress-coupling across the entire thickness. It enhances resistance to shear-driven layer delamination near the neutral axis, while also improving tensile and compressive load transfer at the outer surfaces.

The macrotexture would not alter part geometry or shift the neutral axis. It substantially improves how bending and shear stresses are transmitted throughout the 3D-printed structure during fast loading scenarios.

Layered resin 3D-printing inherently produces structures built from sequential laminas or layers. While chemical adhesion may be sufficient under low or quasi-static loading, structural behavior changes under real service conditions where material strain-rate can be high.

Common limitations include:

❌ Interlayer shear weakness under dynamic or high strain rate loading
❌ Crack initiation along planar layer interfaces
❌ Reduced performance under cyclic bending
❌ Stress concentrations or amplification due to porosity

Conventional slow strain-rate or quasi-static testing may not fully reveal these vulnerabilities.

The Glimmer macrotextured FEP film introduces a controlled macro-mechanical interlocking pattern into every printed layer.

This architecture:

✅ Suppresses interlayer slip during bending of the 3D-printed part
✅ Improves stress coupling across the full thickness
✅ Reduces the likelihood of planar delamination
✅ Enhances structural integrity under dynamic strain-rates
✅ Improves damage tolerance under cyclic loading

 ✅ By increasing effective bending stiffness, the structure undergoes lower strain for the same applied load during cyclic bending

Importantly, this improvement is structural. Part geometry remains unchanged, and intrinsic material modulus or flexural modulus (E) does not increase due to macro- texturing alone. Instead, the layered structure behaves more like a unified section during service.

When macro-mechanical interlocking is combined with NETFIL Industrial Processing (porosity reduction):

• Effective elastic modulus (E) which is an intensive property improves due to defect reduction
• Stress concentration from micro and nano-porosity decreases.
• Fracture initiation becomes less defect-driven.
• Resistance to moderate high strain-rate loading improves further.

Together, our Netfil strategies address:

• Material-level integrity (porosity control)
• Structural-level coupling (interlayer mechanical engagement)

This combined approach improves damage tolerance in layered resin structures beyond what chemical bonding alone can achieve

Glimmer FEP Film does not alter resin chemistry. It strengthens mechanical engagement between layers.

By improving interlayer locking, it enhances effective stiffness, durability, and damage tolerance to cyclic loading.

This represents a structural upgrade in how 3D-printed composites perform.

The structural advantage becomes even more significant in long-span appliances or prostheses such as splints, full-arch bridges, and all-on-X prostheses, where bending and deflection are inherently greater. While single-unit crowns experience limited flexure, larger prostheses benefit substantially from improved interlayer stiffness and resistance to deformation.

✅ See the difference yourself. Print a simple test specimen and apply rapid bending by hand. Parts produced with Glimmer macrotextured film resist sudden breakage more effectively than conventional prints, demonstrating improved structural engagement without specialized equipment.

Mechanical testing of parts printed using our macrotextured FEP film demonstrated an increase in secant modulus during bending evaluation. This reflects improved effective bending stiffness of the laminated structure.

This should not be confused with an increase in flexural modulus. Flexural modulus is an intensive material property, and it remains unchanged.

Bending stiffness depends on elastic modulus and cross-sectional geometry. In this case, neither the elastic modulus nor the geometric second moment of area is altered by the macrotextured film. Instead, the macrotextured architecture improves interlayer stress-coupling and suppresses internal slip, allowing the layered structure to carry bending and shear stresses more efficiently.

The observed increase in secant modulus therefore represents improved structural action of the printed part or component under load. This is not a change in intensive material properties, but enhanced load transfer within the laminated structure.