THE WORLD'S FIRST Macrotextured FEP Film

THE SCIENCE BEHIND 3D PRINTING USING MACROTEXTURED FEP FILM

Our Glimmer FEP Film introduces a macrotextured surface that becomes imprinted onto every printed layer, transforming interlayer bonding from purely chemical adhesion into mechanical interlocking. This, in turn, reduces the interlayer shear compliance and improves the apparent bending stiffness of a 3D-printed part or component.  The improvement in bending stiffness reduces the strain percentage during cyclic bending. Since fatigue failure may occur in a 3D-printed part which repeatedly bends or deflects under cyclic and rapid loading, it's highly preferable to increase the part's apparent bending stiffness which will cause it to deflect less during each loading cycle reducing its overall cyclic strain. In this manner, the

 damage tolerance of our 3D-printed part under high-strain-rate loading conditions can thus be improved.

In conventional resin 3D printing, printed layers are smooth. Under sudden loading, stress localizes or concentrates quickly due to poor 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 our printed structure under dynamic loading conditions.

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

1. How Our Glimmer Macrotexture FEP Film Enhances Stress Transfer

In conventional resin 3D printing, layers are held together mainly by chemical bonding. At low loading rates, this bond provides sufficient retention between layers. However, chemical bonds exist at a very small scale and do not mechanically interlock our 3D-printed layers at the macroscopic scale.

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

High strain-rate-related fracture mechanics are also influenced by the numerous pores or defects present in our 3D-printed structure, which further concentrate internal stresses.

Let us explain why this matters using a simple analogy.

• Our 3D-printed layers may act like gears that either slip or fully engage. Only fully engaged gears transmit torque effectively.

In this context, macro-mechanical interlocking between 3D-printed layers helps transfer stresses smoothly from one layer to the next, just like torque passing through properly meshed gears. Our 3D-printed part then behaves like one solid unit.

• When force increases suddenly, the gears remain well engaged instead of slipping.

But we know that in conventional 3D-printed structures, fast loading causes the micromechanical bonds to slip, leading to rapid stress buildup and crack initiation. However, when we implement an additional level of macro-mechanical interlocking  between our 3D-printed layers, our layers remain engaged, resisting bending and sudden loading without fracturing or delaminating.

So, what does this improve when it comes to the structural behavior of our 3D-printed part or component?

It changes the apparent bending stiffness of our part!  Our macro-mechanical interlocking will not alter the theoretical bending stiffness (EI) of our 3D-printed part, since geometry and material modulus remain unchanged. However, our macro mechanical interlocking will reduce interlayer shear compliance by limiting microscopic slip taking place between the printed layers of our part. As a result, we will see the overall deformation under bending decrease, leading to an increase in the apparent bending stiffness of our 3D-printed part. 

2. Now let us understand what Theoretical Bending Stiffness actually is.

Bending stiffness (EI)theoretical​ : determines how resistant our part is to bending and shear forces.

 It is defined as:

 (EI)theoretical​  = E × I

Where:

(E) is the elastic modulus of our material and (I) is the second moment of area (a geometric property describing cross-sectional distribution relative to the neutral bending axis of our 3D-printed component).

The bottomline:

It's crucial to understand that only when the elastic modulus (E) of our material and/or second moment  of area (I) changes, will there be an improvement in theoretical bending stiffness of our 3D-printed part or structure.

But here is a critical insight to consider..

Since fatigue failure may occur in our 3D-printed part which repeatedly bends or deflects under cyclic and rapid loading, it's highly preferable to increase our part's apparent bending stiffness which will cause it to deflect less during each loading cycle reducing its overall cyclic strain!

Less deflection or bending means our 3D-printed layers are remaining firmly interlocked instead of slipping due to high shear compliance, resulting in lower cyclic strain during each loading cycle.
Lower cyclic strain reduces stress concentrations around internal flaws and porosity within our 3D-printed structure. With reduced stress intensity at these critical regions, crack initiation becomes less likely. As a result, crack growth and propagation are delayed under dynamic and repeated loading conditions experienced by our part.

Now let's see what truly happens when we 3D-print using our Glimmer Macrotextured FEP Film:

3. We improve apparent Bending Stiffness of our part and our part's structural action

We at this point should become clear that by simply introducing a macro-retentive texture pattern in our 3D-printed layers, we are not changing the overall geometry or shape of our 3D-printed part. We do not increase the classical second moment of area (I) of our part, and the elastic modulus (E) of our 3D-printed part also remains the same.

Instead, we allow our Glimmer macro-mechanical interlocking to work for us and suppress interlayer slip taking place. By doing this, we substantially improve the stress coupling across the full thickness of our 3D-printed part or structure. When we reduce the interlayer shear compliance between our printed layers, our 3D-printed part tends to behave more like a unified, monolithic section under dynamic loading conditions.

In other words, we never change the geometric stiffness parameter using our Glimmer macrotexture. We only improve the apparent bending stiffness of our 3D-printed structure to make it more damage tolerant during dynamic and cyclic loading.

Now we are at point where we need to understand that we can also increase the theoretical bending stiffness of our 3D-printed part. This can be done by simply influencing our part's elastic modulus (E) by using porosity free resin to print our 3D-printed part. This is because bending stiffness (EI) is afterall E × I !

We will have to eliminate or reduce resin composite porosity that most certainly decreases elastic modulus (E). For reducing resin nano porosity, we offer our proprietary degassing solution called NETFIL Industrial Processing, which is suitable for all 3D-printed composite resins, including chairside resin composites.

Now let's see how we need to implement our Glimmer FEP Film macrotexture in 3D-Printing

4. Neutral Bending Axis Considerations and Why Macrotexture Matters

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

• When the outermost surface of one side of our part undergoes tension, the opposite surface undergoes compression. Bending stresses are therefore very high on both the Intaglio and Cameo surfaces of our dental 3D-printed part!

• Between our Intaglio and Cameo surfaces in the middle or central plane, lies a neutral bending axis, along which bending stress transitions from compression to tension

• In this central region between our Intaglio and Cameo surfaces, only shear stresses are highest, not bending stresses. The shear compliance or lack of stiffness is also the highest in this region.

Therefore we can clearly tell that  high shear compliance in our 3D-printed part exists because chemical bonding is limited to micro mechanical bonds and microscopic slip can easily occur under bending. 

This slip may initiate along the neutral bending axis of our part, where shear stresses and compliance 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 our 3D-printed part.

This is the reason why it is preferable for our Glimmer retentive macrotexture to run through all the 3D-printed layers, and not just the superficial or deep layers of the 3D-printed part.

Our Glimmer macro-mechanical interlocking improves stress coupling across the entire thickness of our 3D-printed part. It enhances resistance to shear-driven layer delamination along its neutral axis, while also improving  stress transfer and distribution along the outer surfaces of our 3D-printed part where cracks are likely to initiate. 

Again we need to emphasize that our Glimmer macrotexture does not alter part geometry or shift material bulk away from the neutral bending axis of the 3D-printed part in any manner. It only improves how stresses are efficiently transmitted throughout our 3D-printed structure during high strain rates or rapid loading.

5. Why our Glimmer Film Is Transformative for Resin 3D Printing

Traditional Challenges in Layered Resin Printing

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 rates can be high.

Common limitations include:

• Interlayer shear compliance 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 low-strain-rate or quasi-static testing may not fully reveal these vulnerabilities.

How Our Glimmer Macrotextured FEP Film Addresses These Limitations

Our Glimmer macrotextured FEP film introduces a finely controlled macro-mechanical interlocking pattern into every printed layer of our 3D-printed part.

To summarize our Glimmer architecture:

• Suppresses interlayer slip and reduces interlayer shear compliance during bending of the 3D-printed part
• Improves stress coupling across the full thickness of our 3D-printed part
• Reduces the likelihood of planar delamination in our part
• Enhances structural integrity of our 3D-printed part under under dynamic strain rates
• Improves damage tolerance of our 3D-printed part under cyclic loading particularly when a pore-free resins is used to print our part
• By increasing apparent bending stiffness, our printed structure undergoes lower strain for the same applied load during cyclic bending
• Our Glimmer FEP film reduces peel forces while printing bottom layers because of texture relief

Importantly, our Glimmer Film offers so much of flexibility in tailoring the mechanical properties of our 3D-printed part. Our printed part's geometry remains unchanged, and the bending stiffness (EI) of our part can be further improved by simply using our Netfil processed resins.

Combined Advantage with NETFIL Processing

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

• The effective elastic modulus (E), which is an intensive property, improves due to defect reduction and which synergistically improves apparent bending stiffness of our part 

• Stress concentrations from micro- and nano-porosity within our part decrease

• Fracture initiation sites present in our printed part become less defect-driven

• Our part's resistance to  high-strain-rate loading improves further

Together, our NETFIL strategies address:

• Material porosity and structural-level coupling or interlayer mechanical engagement in our printed part or structure

This combined approach improves damage tolerance in our 3D-printed resin structures beyond what chemical bonding alone can achieve.

Final Thoughts In Summary:

 A Structural Shift in Resin 3D Printing

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

By improving interlayer macro mechanical keying, it enhances effective stiffness, durability, and damage tolerance of our printed part under cyclic loading.

Our Netfil approach represents a structural upgrade in how 3D-printed composites perform.

Relevance To Dental and General Resin 3D Printing

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

Easy Demonstration

See the obvious difference yourself. Print a simple bar test specimen using our  Glimmer FEP Film®  and apply bending forces using your hands. Parts printed using Glimmer macrotextured film resist breakage more effectively than conventional parts, demonstrating improved structural engagement without specialized testing equipment.

Mechanical Testing of Our GLIMMER Macrotextured FEP Film

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

This again should not be confused with an increase in flexural modulus. Flexural modulus is an intensive material property, and it remains unchanged without working on the nano- porosity found in resin.

Theoretical bending stiffness of our part 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 our Glimmer macrotextured FEP film. Instead, our macrotextured architecture decreases inter layer shear compliance and material slip and allows our 3D-printed layers to couple stresses and strains more efficiently.

The observed increase in secant modulus therefore represents improved structural action of our printed composite test beam under loading. This need not be purely obtained from a change in the intensive material properties of our material alone , but it can also arise because of enhanced load transfer within our 3D-printed structure.

A note on testing:

It is also important to note that extremely high-strain-rate impact tests, such as Charpy impact testing, operate under loading conditions that are significantly more severe than typical intraoral service environments. At such high strain rates, failure mechanisms can be dominated by rapid crack propagation, making it difficult to clearly distinguish differences in damage tolerance between textured and non-textured specimens.

To more clearly reveal the difference in damage tolerance between textured and non-textured prints, strain rates must reflect realistic service conditions. Quasi-static loading may mask interlayer slip, while extremely high-impact tests can cause rapid failure before structural coupling effects are expressed. The most meaningful evaluation lies in moderate dynamic or cyclic testing using controlled servo-hydraulic systems to assess true damage tolerance under functional loading.