Generally spoken: a 3D printer can be used to replicate any figure of any size with high accuracy. The fact it might take several hours to produce one single design (depending on the size), it consumes much less time and is much more cost efficient compared to e.g. prototyping carried out by engineers or product designers. This is due to the fact that 3d prints can be created from a vast selection of materials such as polymers, resins and diverse metals.
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A 3D printer works with building up layer by layer of a desired compound (resin, polymer or metal). Until the layers merge into the desired 3d shape. Major preparations have to be done before the printing can be started as the printer relies on a computational generated 3D model.
There are mainly four printing methods: fused deposition modelling (FDM), stereolithography (SLA), carbon CLIP technology (CLIP stands for continuous liquid interface production), and selective laser sintering (SLS). Depending on the type of compound used, the type of drying or curing will be different. From the mentioned techniques, the SLA and CLIP are the ones where photosensitive resins are employed. Generally, lasers or UV-LED lamps are used. Lasers can be used for all materials, while UV-LED lamps are applied for resins, gels and special polymers.
To look into the UV process in more detail: One of the most important factors to have in mind when working with a 3D printer is the curing of the compound, since it is not possible to continue applying raw material if the work’s surface has not dried yet. By irradiating the composite with UV light, the composite hardens as it polymerizes, allowing more material to be applier in further layers.
Depending on the wavelength and the material properties, the UV exposure time determines directly the polymerization process or the curing of the resin. It is also important to consider which resin is the best fit to the printer. The most common polymeric resins used in the UV-curing are thermoplastic polymers, such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyamide (PA) and polycarbonate (PC), and thermosetting polymers such as epoxy resins, which requires thermal or UV-assisted curing to complete its polymerization process.
Metal materials usually cannot be cured by UV light sources due to their requirement of a more focused power source which fall upon one small area. Hence, laser technology is more frequent used when working with metals.
Besides the already mentioned curing of the resin while printing, UV is further used in the post-processing of the formed shape. This procedure is carried out to improve the material performance and mechanical properties, minimize shrinkage, increase of resistance or resilience, among others.
But why should an LED be used as a light source in the 3D industry? As it was mentioned before, a LED lamp requires a lower energy source to operate and in the present days where in the industry the price of electricity represents a big share in the operational costs, it is a factor that must be considered. Further LED light sources are very compact and therefore easy to place especially in the smaller set-ups of desktop 3D printing machines.
References:
Wang, X., Jiang, M., Zhou, Z. Gou, J., & Hui, D. (). 3D printing of polymer matrix composites: A review and prospective. Composites Part B: Engineering, 110, 442-458; Stansbury, J. W., & Idacavage, M. J. (). 3D printing with polymers: Challenges among expanding options and opportunities. Dental Materials, 32(1), 54-64
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#1
Having just got my mars printer today, I've only just discovered that it is necessary to bathe the resin model in ultraviolet light as part of the curing process. I'm trying to figure out which UV lights are best for curing, I believe that they should be in the 405nm wavelength to be effective but I don't know what the number of watts should be.
I have a couple of light boxes (lage and small) and turn tables (large and small) already.
For smaller 28mm resin miniatures like say warhammer sized minis I think a ladies nail varnish uv box my be of use but a larger light for the light boxes (with maybe tin foil on the inside) will be required, again, I don't know the ideal, make, model or number of watts that would be ideal to cure or even the length of time to cure under UV light.
Anyone point me in the right direction ?
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NullARCJunior Member
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#23D Printer UV Resin Curing Light for SLA DLP 3D Printer Solidify Photosensitive Resin 405nm UV Resin Affect, DIY Curing Enclosue https://www.amazon.com/dp/B07XJZK4R6/ref...KEbMBC2EXB
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zemerickJunior Member
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#3
20-40w is vaguely where you want to be, but it doesn't matter much: and it's a good thing too, because there is no consistency. This isn't that surprising, because most of the UV lamps are LED, so it's actually listing the "equivalent" rating, and there's a lot of variation going on.
The big thing is if you are not using a water washable resin: Submerge your parts in water during post-cure. This dramatically improves curing. It can take a print from 2 hours and failing to fully cure, to just 15 mins and being perfectly cured.
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PolyJet is one of the mainstream 3D printing technologies today. The PolyJet 3D printer sprays photosensitive resin material layer by layer onto the print tray until the parts are completed. Each layer of material is cured with ultraviolet light while being sprayed and can be taken out and used immediately without secondary curing. It can realize the combination of color and multi-materials in a single printing to produce a prototype close to the real product. It can also be used to print quick molds and verify product designs. Full-color multi-material 3D printer can mix six materials at the same time to achieve 500,000 colors, different textures, transparency, and softness. Products are widely used in medicine, education, engineering models.
Using the Phoseon FireEdge™ FE400 air-cooled curing light source, end customers can run stably for a long time (the model printing cycle of the model is more than 48 hours). The printing process with highest efficiency, printing accuracy and yield can fulfill end customer’s stringent requirements. Compared with domestic and foreign LED light source manufacturers, the key advantages of Phoseon LED light source include:
1. Small and compact structure: Very suitable for the limited space and complicated installation structure of the printer. And there are basically no wearing parts, eliminating the need for replacement and maintenance.
2. Stable performance: With Phoseon’s TargetCure™ technology (https://phoseon.com/industrial-curing/technology/targetcure/) the continuous stable and reliable output of the light source ensures the quality consistency of the printed objects. UV-LED provides fast, consistent and reliable curing every time, minimizing waste.
3. High-power air-cooled design: Air-cooled heat dissipation and exhaust prevent water pipes from occupying the internal space. High intensity UV irradiation can improve the surface drying performance of each layer of the resin, thereby ensures the printing accuracy of the model.
4. Instant on/off: It can be used immediately without preheating and can seamlessly match the response time of the inkjet nozzle. It is especially suitable for scanning high-speed printing. Utilizing UV-LED technology, UV-sensitive properties enable rapid layering and curing using low energy UV light. The instant on/off function of LED lamps enables 3D printers to cure as quickly and constantly per the need of the printing process therefore optimizing production - something not easily achieved using traditional UV lamps. Phoseon Technology’s UV LED cures to print super-size lightweight objects at a remarkable speed.
5. Customizable and user-ready: Phoseon Technology’s UV-LED curing speed delivers “ready” objects right off the printer; no post-curing or post processing is required. The final printed object is very receptive to multiple types of finishes. That allows the 3D object to be painted or decorated to create complex and eye-catching designs. The LED technology also allows to create multiple shapes and designs that meet end customer needs.
6. Energy saving and environmental protection: Safe and stable UV-A products without mercury, ozone, or radiation. Phoseon Technology’s UV-LED lights are an environmentally friendly alternative to traditional UV arc lamps, which contain mercury. In addition, UV-LED lamps last longer and use less energy than traditional curing methods, which reduces operational costs and increases energy savings as much as ninety percent.
For more information, please visit UV LEDs for 3D Printing.
3D printing, also known as additive manufacturing, has emerged as one of the most transformative technologies of the 21st century. By enabling the layer-by-layer construction of objects from digital designs, 3D printing offers unprecedented flexibility in manufacturing, prototyping, and even customized consumer products.
The true power of 3D printing lies in its ability to turn complex digital models into tangible physical objects. This has revolutionized industries ranging from aerospace and automotive to healthcare and fashion. Whether it’s creating intricate engine components, prosthetic limbs tailored to individual patients, or avant-garde clothing designs, 3D printing has opened new horizons for innovation and efficiency. But beyond its initial printing stage, the journey of a 3D-printed object often involves a critical step known as post-curing, a process that ensures optimal mechanical properties and aesthetics.
In the realm of 3D printing, the post-curing stage is a vital step that often follows the initial printing of an object. But what exactly is post-curing, and why is it so critical? Post-curing refers to the process of exposing a freshly 3D-printed item to additional light and heat treatment. This treatment enhances the polymerization process, ensuring that the resin or other material used in the printing fully cures, hardens, and attains its desired mechanical properties. In essence, post-curing is a finishing touch that helps the 3D printed object reach its full potential in terms of strength, durability, and appearance. Without proper post-curing, a 3D printed object may remain soft or weak in certain areas, compromising its functionality and longevity. The post-curing stage not only perfects the final product but also ensures consistency, a factor paramount in both industrial applications and consumer products. Whether it’s a critical aerospace component or an artistic sculpture, post-curing helps to deliver a product that meets or exceeds the intended specifications.
Ultraviolet (UV) curing represents a cutting-edge solution in the post-curing stage of 3D printing, bringing a unique blend of efficiency and precision to the process. But what is UV curing, and how does it play such a pivotal role in post-curing? UV curing is a technology that uses ultraviolet light to initiate a chemical reaction that leads to the rapid hardening or drying of a material, such as the resins commonly used in 3D printing. Unlike traditional drying methods that rely on heat and air, UV curing employs specific wavelengths of UV light to achieve rapid and controlled polymerization. This enables the material to reach its desired mechanical properties in a fraction of the time that other methods might require.
In the context of 3D printing’s post-curing stage, UV curing offers several compelling advantages. The process can be finely tuned to match the specific material and design characteristics of the printed object. This results in a more uniform cure, reducing defects and enhancing structural integrity. Furthermore, UV curing is often more energy-efficient and environmentally friendly than other curing methods, aligning with sustainable manufacturing practices. The application of UV curing in 3D printing’s post-curing stage is more than a mere technological enhancement; it represents a fusion of science and innovation that directly translates into better products and more streamlined production processes. Whether in small-scale prototyping or large-scale industrial manufacturing, UV curing is helping to redefine what’s possible in 3D printing, contributing to a future where quality and speed go hand in hand.
Post-curing in 3D printing is a crucial stage that focuses on the cross-linking of polymer chains within the printed material, particularly in the case of photopolymers that are common in various 3D printing applications. The underlying science of post-curing is complex, involving precise control over various factors that shape the final characteristics of the material.
In the broader context of 3D printing, the post-curing process’s control, particularly through UV curing, serves as a linchpin for quality and efficiency. This section explores the nuances that make UV curing pivotal for maintaining stringent quality control while enhancing operational efficiency.
Wavelength Sensitivity: Wavelength sensitivity plays a critical role in UV curing, as different photopolymers are sensitive to particular UV wavelengths. A mismatch in wavelength can lead to insufficient cross-linking, resulting in under-cured parts with reduced mechanical strength. Moreover, the control of UV intensity and exposure time must be finely tuned to the specific material’s needs. Both over-curing and under-curing can compromise the final properties of the product, potentially causing brittleness or reduced tensile strength. The interplay between wavelength, intensity, and exposure time underscores the complexity of UV curing and the need for precise control to achieve optimal results.
Calibration and Alignment of UV Sources: The calibration and alignment of UV sources, including UV lamps and LEDs, are fundamental aspects of the curing process. The spatial alignment of UV lamps or LEDs is crucial for uniform exposure across the entire surface of the material. Misalignment can create hotspots or shadows, leading to an uneven cure that affects not only the appearance but also the function of the part. This intricacy extends to regular calibration and maintenance of UV sources, which are necessary to ensure consistent output over time. Even slight drifts in UV intensity or changes in the spectral output can cause variations in the curing process, highlighting the importance of meticulous attention to detail in both the setup and ongoing operation of UV curing systems.
Inconsistent UV Exposure: Inconsistent UV exposure presents unique challenges, particularly when dealing with complex geometries or variations in material thickness. For parts with intricate surface geometry, the design of the UV curing system is paramount. This design must consider factors like reflector configuration and light guides to ensure uniform exposure. Complex geometries may obstruct UV light, leading to uneven exposure, and overcoming this obstacle requires a carefully designed system. Similarly, differences in material thickness can lead to variations in cure depth. Achieving a consistent cure throughout the part is no small feat and requires sophisticated control over exposure time and intensity. These considerations exemplify the multifaceted nature of UV curing and underline the importance of specialized knowledge and technology in achieving uniform and high-quality results.
Environmental Regulations and Sustainability: Environmental regulations and sustainability considerations are vital aspects of UV curing processes. The choice of materials and additives must be carefully made to align with environmental regulations. This alignment is especially pertinent in industries like healthcare and food processing, where considerations regarding biocompatibility and toxicity are paramount. Equally important is the management and disposal of uncured resins and associated waste products. Compliance with local environmental regulations is essential, and this includes ensuring the responsible recycling or proper disposal of contaminated containers and cleaning solvents. These considerations reinforce the need for a thoughtful and comprehensive approach to UV curing that prioritizes not only product quality and efficiency but also environmental stewardship and regulatory compliance.
Integration with Other Processes: Integration with other processes within a broader manufacturing chain adds another layer of complexity to post-curing in 3D printing. The alignment of the post-curing stage with preceding and subsequent stages is vital to maintaining an efficient and seamless workflow. This synchronization must be precisely managed to ensure that the workflow progresses smoothly without compromising the quality of the final product. Consideration must also be given to factors such as timing, material handling, and coordination between different process stages. The integration must account for variations in materials, part geometries, and production volumes, making it a complex and multifaceted challenge. This complexity highlights the importance of expertise and robust systems in successfully integrating post-curing with other stages of manufacturing, ensuring efficiency, quality, and consistency throughout the entire process chain.
Cost Considerations: Cost considerations are an ever-present concern in the world of manufacturing, and UV curing systems are no exception. High-precision UV curing equipment, often required for exacting applications, can come with substantial initial investment and operational costs. The associated maintenance, calibration, and alignment to ensure consistent performance further contribute to ongoing expenses. Balancing these quality requirements with cost constraints becomes a continuous challenge for many manufacturers. Making informed decisions on the types of UV curing systems, including choices between LED and mercury lamps, can help in optimizing costs without compromising on quality. This economic balancing act requires careful planning, understanding of the specific application needs, and a consideration of both short-term and long-term financial factors. The goal is to find a solution that delivers the desired performance and quality while aligning with budgetary constraints, underscoring the multifaceted nature of decision-making in UV curing processes.
Understanding UV curing requires delving into the chemistry and physics that govern this fascinating process. Though often employed in various applications, its role in 3D printing post-curing is particularly crucial, where it transforms a liquid photopolymer resin into a solid structure. Below, we break down this complex process into fundamental stages:
Initiation: The initiation stage is a pivotal part of the UV curing process, particularly in the context of 3D printing post-curing. At this stage, specialized molecules known as photoinitiators, which are found within the resin, play a critical role. When these photoinitiators absorb UV light, they break apart into highly reactive components. In free-radical polymerization, these reactive components are called free radicals, whereas in cationic polymerization, they are referred to as cations. This absorption of UV photons triggers an energy transfer that activates these molecules, causing them to enter an excited state. The energy in this excited state is then transferred to other components within the resin, initiating the polymerization reaction that transforms the liquid resin into a solid polymer.
The sensitivity of photoinitiators to various UV wavelengths adds another layer of complexity to this process. Different photoinitiators are sensitive to different UV wavelengths, meaning that the UV source must be carefully matched to the resin to ensure effective initiation. A mismatch in wavelength can lead to insufficient cross-linking and under-cured parts with reduced mechanical strength. Consequently, this requires precise selection and calibration of UV sources to align with the specific photoinitiators used in a given resin formulation. This initiation stage exemplifies the scientific precision and technical intricacy inherent in UV curing, highlighting the need for specialized knowledge, equipment, and attention to detail to achieve desired outcomes in the final product.
Propagation: The propagation stage is the heart of the UV curing process, where the actual transformation of the resin takes place. During this stage, the reactive components formed during initiation, such as free radicals or cations, interact with the monomers in the resin. Monomers are single molecular units that have reactive sites, allowing them to link together. This linking forms a polymer chain, a continuous sequence of interconnected monomers. As the polymer chains grow, they start to cross-link with other chains. This cross-linking is not merely a linear connection; instead, it forms a complex three-dimensional network. The three-dimensional structure is what gives the final material its strength, rigidity, and other desired properties. The process is akin to weaving a tightly-knit fabric where each strand is interwoven with the others, creating a robust and unified structure.
However, the propagation stage is not a simple or self-driving process. It requires careful control and understanding of various factors that can influence the polymerization rate and the final properties of the cured material. The concentration of photoinitiators in the resin must be balanced, as too few can slow down the reaction, while too many can cause premature curing. The strength of the UV light, or UV intensity, affects how quickly the reaction occurs, with too intense light possibly curing the surface too rapidly and leaving the inside uncured, while too weak light may lead to incomplete or prolonged curing. The duration the resin is exposed to UV light, known as exposure time, must be precisely timed to achieve complete curing without over-curing, leading to brittleness. Additionally, the temperature of the reaction must be controlled, as it can affect the reaction speed and the final properties of the material. The propagation stage illustrates the delicate balance and intricate control needed in UV curing. It’s a dynamic process where every variable must be finely tuned to produce a material with the desired characteristics. This complexity underscores the need for expert knowledge and precision equipment in UV curing, highlighting the importance of choosing a reliable and experienced UV curing manufacturer.
Termination: The termination stage signifies the conclusion of the polymerization process, marking the end of the UV curing journey. During this phase, the reaction naturally halts as no more links can be formed. This cessation can occur for several reasons, including the exhaustion of reactive sites on the monomers, interaction between reactive components that neutralize each other, or stabilization of the reactive components through other chemical mechanisms. The termination stage is not merely an arbitrary endpoint. It defines the final structure of the polymer network, solidifying the three-dimensional configuration that was being constructed during the propagation stage. This final structure dictates the material’s ultimate properties, such as tensile strength, hardness, and elasticity. If the termination occurs too early or too late, these properties can vary, leading to inconsistencies in the material’s performance.
In the specialized field of UV curing, particularly within the context of 3D printing, the choice of UV source is a critical decision. Two primary technologies dominate the industry: Mercury Lamps and LED-based UV Curing systems. Both have unique characteristics, benefits, and applications that cater to various needs:
Mercury Lamps
LED UV Curing
In 3D printing and manufacturing, ultraviolet (UV) curing has emerged as a sophisticated technology offering remarkable advantages. UV curing’s effectiveness can be attributed to the science behind the photopolymerization process. Utilizing specific wavelengths of UV light, the liquid resin’s molecules are cross-linked in a polymerization reaction, converting into a solidified structure within seconds to minutes.
The speed of UV curing is not only a time-efficient asset but also a result of the photoinitiator’s precise reaction with the UV light. Depending on the photoinitiator’s concentration and the light source’s intensity, manufacturers can achieve an ideal degree of conversion (DoC), optimizing the polymer’s mechanical properties.
Efficiency in UV curing is marked by meticulous control over variables such as wavelength, exposure time, and intensity. Both mercury vapor lamps and LED-based UV systems play distinct roles here. Mercury lamps offer a broad spectrum of UV light, suitable for various resins, while LED systems provide specific wavelengths, aligning with certain photoinitiators. The energy utilization in both systems contributes to cost reduction, with LEDs often providing higher energy efficiency due to their narrow spectral output.
Quality control in UV curing is a scientific endeavor, with the ability to adjust variables ensuring each part meets specific tolerances and quality standards. The choice between mercury lamps and LEDs, along with the control over exposure parameters, impacts the final product’s tensile strength, flexural modulus, hardness, and surface finish. This fine-tuned process aligns with the rigorous requirements of industries that demand precision, reliability, and aesthetics.
Sustainability in UV curing is manifested through the energy-efficient nature of the process, especially with LED UV curing systems. The narrow spectral emission of LEDs minimizes energy wastage, contributing to a more eco-friendly manufacturing approach. Waste reduction is achieved through uniform curing, minimizing defects, and the need for rework.
Versatility in UV curing is evident in its adaptability to different materials and applications. The wide spectrum of mercury lamps versus the specific wavelengths of LEDs allows manufacturers to align the UV curing process with different resins’ requirements. The calibration of UV sources in accordance with material needs offers flexibility without sacrificing speed, quality, or sustainability.
Celebrating 30 years of innovation and excellence in , Uvitron International has been a trusted name in UV curing technology since . With thousands of systems in operation across the globe, we have tailored our offerings to various materials and industrial applications, reflecting the ever-changing demands of different industries. Our technical expertise in UV curing is comprehensive and includes both traditional mercury vapor lamps and innovative LED systems. We have adapted to the needs of sectors ranging from aerospace and automotive to medical devices and consumer goods, demonstrating our wide-reaching capabilities and alignment with global industry trends.
Reliability is a core value at Uvitron, evident in our UV curing systems, which undergo meticulous testing and calibration. We ensure that our products consistently meet the highest standards of uniform and efficient curing, providing quality and performance that our customers have come to rely on. We also take pride in our customer service and technical support, offering personalized assistance tailored to each client’s unique needs. Our experienced team is dedicated to ensuring customer satisfaction, providing continuous support from initial consultation to post-installation.
As we celebrate our 30th anniversary in , we reflect on our journey as a leading figure in UV curing technology. Our robust global presence, reputation for reliability, and focus on customer service, innovation, and sustainability have contributed to our success and continued growth. Here at Uvitron International, we’re not only celebrating three decades in business but also a legacy of excellence and dedication to our clients. Our products, attention to quality, commitment to sustainable practices, and adaptability illustrate why we’ve been a trusted partner to manufacturers for so many years. Here’s to many more years of collaboration, innovation, and shared success in the field of UV curing.
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