The dynamic 3D-printing landscape is a challenge to navigate for industry experts, and even more so for those who have no idea of the capabilities, limitations, and idiosyncrasies of the different technologies. Further adding complexity, 3D-printing processes don’t translate comparably with conventional manufacturing technology always, even though the material output is practically the same. This is typically due to the dissimilar build parameters, environment, and material delivery methodology. To learn the nuances, you must grasp the basics behind each technology and know the full spectrum of available material options.
This article will help you determine the materials and technologies that are right for your application. Today many 3D-printing processes come in use, but for the reasons of this article, we shall only touch on probably the most commonly used in style and manufacturing engineering nowadays: photocuring, filament deposition, polymer laser beam sintering, and direct metal laser beam sintering.
This group of 3D-printing processes employs liquid photopolymer resins that are solidified and cured with ultraviolet (UV) light, mostly to serve as models, light-duty prototypes, and patterns for secondary casting. Photopolymers vary in color, transparency, and mechanical and thermal qualities, which range from low-temperature flexible plus soft elastomers to hard plus rigid nanocomposites in a position to withstand elevated temperatures. For instance, Somos NanoTool, a composite stereolithography (SL) material, includes a heat deflection as high as 437°F at 66 psi.
An advantage of photocuring is the refined quality of the output. Photocuring functions produce parts with smooth floors and fine-feature details-16-micron layer elevation with PolyJet-ideal for aesthetic plus cosmetic applications. However , UV balance and durability falls brief for high-performance and end-use product applications. Continued exposure to UV light causes photocured objects to become brittle and change in appearance. In addition, some materials can lose shape and dimensional accuracy from moisture absorption and sag or creep from prolonged pressure.
The two most used photocuring technologies are PolyJet and SL widely. PolyJet deposits tiny droplets of photopolymer and remedies the thin layers with UV lighting simultaneously. This process can printing in a very high res with layer thicknesses as slim as 16 microns, which minimizes post-processing. Called multi-jet printing also, PolyJet is one of the only technologies with the ability to print multiple materials in one print with varying durometers.
On the other hand, SL builds 3D objects layer upon layer by using an UV laser to draw and solidify cross-sectional slices in a vat of liquid resin. It too can produce smooth parts requiring minimal finishing, but does not offer multi-material printing. Multi-jetting and SL have minimal shrink-associated deformation typically. Finally, both processes are perfect for producing casting patterns targeted at silicone urethane and tooling casting, and sacrificial patterns for expense casting.
Guided by software- produced toolpaths, the filament-deposition processes build 3D objects by drawing cross-sectional slices of parts one upon another via a heated extruder head. One chief advantage of filament deposition is the ability to produce strong and long lasting functional prototypes and end-use components in a number of high-performance materials popular in regular machining and molding manufacturing procedures.
Fused deposition modeling (FDM) may be the the majority of mature and widely adopted filament deposition process. FDM can maintain dimensional accuracy over distance while having the ability to save weight and material. Some companies will post an over-all tolerance of ±0. 008 inches; however , it’s hard to give an exact number or even a range for this accuracy because it depends on the machine, material, geometry, and size of the part. In addition, FDM is less susceptible to warp and curl than laser beam sintering.
The most important drawback of filament deposition may be the pronounced layer outlines in the top of its output. It necessitates even more effort than various other 3D-printing technologies to even the areas and create aesthetic qualities much like conventional manufacturing procedures, such as injection molding. Additionally , applications that call for airtight or watertight functionality may require a denser build style, which increases build time and material consumption, and/or software of a sealant to alleviate surface porosity.
Polymer Laser Sintering
These useful processes fuse or melt powdered polymers and composites with a minimal wattage CO2 laser that sinters cross-sections of 3D objects layer upon layer. Polymer laser-sintering (LS) materials mainly have bases of Nylon 12 and Nylon 11, with a number of filler options such as for example glass beads, mineral fibers, and carbon fiber, which supply substantial durability and strength for useful prototyping and end-use part creation.
Other specialty materials that assist niche applications include thermoplastic elastomer, which can have rubber-like qualities for prototype hoses, seals and grommets. Also, low-density polystyrene infiltrated with wax can assist as a low-ash investment casting.
Another advantage of LS is that 3D objects are self-supporting within the build chamber, enabling three-dimensional nesting. Efficient and affordable production of complex geometries with internal cavities and channels are possible with LS without the need to remove supports.
The thermal nature of the process and absence of supports to anchor laser-sintered objects makes them more prone to warp during the build or cool- down cycle. In addition, an inverse relationship frequently exists between the mechanical strength and dimensional accuracy of the output. Laser strength and build chamber temperature raise to optimize particle adhesion, and create a stronger part. However , increased temperatures and power could cause expansion; the walls and top features of a right part may become oversized, warp, and curl. Generally, dimensional problems arise with higher laser-power and powder-bed temperatures. That’s because more of the surrounding powder sticks to the sintered/melted part, which causes the surfaces to grow and walls to thicken.
This commonly results in fitment problems with mating parts. Yet, experienced LS operators may be able to adjust laser offsets, adjust build orientation, and change the design to work much better with the process.
Direct Metal Laser Sintering
Using an yttrium-aluminum-garnet-fiber laser, known as a YAG-fiber laser commonly, metal laser-sintering systems basically micro-weld powdered metals plus alloys layer upon level to produce completely dense 3D objects with properties similar to castings. Through post processes, such as heat-treating and very hot isostatic pressing (HIP), it’s possible to improve metallurgical properties for high-performance applications.
There are several advantages to direct-metal-laser-sintering (DMLS) types of processes over conventional manufacturing methodologies, including their ability to produce complicated contoured geometries without too much tooling or programming costs. The additive nature of 3D printing saves weight and materials , and offers greener manufacturing in comparison to casting and deductive processes.
In addition , 3D printing has the capacity to consolidate assemblies, reducing the amount of components that can reduce work cost and fasteners, and simplify a product. Taking advantage of these features with the DMLS process is ideal for low-volume producing of end-use parts and products, and high-performance functional prototypes.
On the downside, the learning curve to build quality DMLS parts and items is substantial. A knowledgeable technician or designer should understand how to use a CAD model to verify that a print is economically viable before it would go to print. An experienced operator will have to develop effective build ways of mitigate minimize and warping assistance structures. Furthermore, for optimal dimensional accuracy, smooth surface finishing, and tiny features, DMLS users often have to utilize more sophisticated post-processing and finishing systems, such as CNC machining, wire EDM, chemical etching, liquid honing, tumbling, media blasting or coating.
A trained staff can display and qualify the very best materials and processes for every customer’s specific programs and needs. There isn’t an individual technology well-suited for every software, and there isn’t always a clear-cut solution for a customer’s specific needs. Often multiple options could work, each with a different set of pros and cons. The following seven considerations can help you qualify and disqualify processes and materials for each of your unique projects:
1 . Software: What is the goal of the object?
The intent for 3D-printed objects could range between cosmetic show mock-ups and models, to functional prototypes, R&D test pieces, or end-use production items and parts. The requirements of every of these applications may differ greatly, and they are better suitable for some processes. It often comes down to cosmetic, dimensional, or performance requirements.
2 . Functionality: What does the part need to do?
A 3D-printed part may simply need to hold shape as a static model or bear a close resemblance to a conventionally manufactured product with details and smooth areas. In this case, Stereolithography or polyjet could be the ideal process. Hard-working parts that has to bear lots or resist impact could possibly be better suited to the FDM process. If the application involves a snap fit or durable living hinge, LS may be the better option.
3. Stability: In what environment does the part need to function?
The need to maintain properties and function in higher temperatures rules out some 3D-printing processes and materials. In addition , outdoor applications need an UV-stable material such as for example acrylonitrile styrene acrylate (ASA) or durable laser-sintered nylon with an UV-inhibitive coating. Photopolymers shall not work very well for outdoor environments since they react to UV light. Moisture is another common aspect that affects many components adversely. If biocompatibility is necessary for a surgical device, then metals, such as titanium Ti-64 for DMLS or electron beam melting could be the best, if not the only, option.
4. Durability: How long does the part need to last?
The true number and duration useful cycles can eliminate some processes and materials. For example , a 3D- published mold or form tool might need to go through a huge selection of cycles and endure prolonged stress and friction, whereas a new fit-check prototype might just need to function once. Photopolymer materials tend to be effective for short-term, low-stress applications and are typically unable to withstand prolonged stress. Manufactured thermoplastics from the FDM and LS processes can serve many practical prototyping and end-use purposes for increased cycle life.
5. Aesthetics: How does it need to look and feel?
You can generally expect photocured 3D objects to be fairly smooth and also have high resolution quickly of the machine, and will be hand-finished to a beauty state easily. While thermoplastic and powdered plastic material processes such as for example FDM and LS produce more powerful and more durable parts, cosmetically they shall require even more labor and skill to accomplish a smooth surface, resulting in higher costs and increased business lead time. With the durable metals and alloys of DMLS, it takes much more time, effort, and expertise to produce a polished look.
6. Economics: What is your budget, timeline, and quality expectation?
If you have a capped budget firmly, the decision could be on price instead of other factors. Time and quality are often in conflict with one another; rapid turnaround and high-level cosmetic finishing can be mutually exclusive. However , shortcuts, workarounds, and efficient systems can reduce lead expenses and times while maintaining top quality standards. Efficiencies could be gained from dealing with an ongoing service bureau that may creatively batch, nest, section strategically, shell, adjust fill, and modify build orientation to reduce machine time and material consumption.
7. Priorities: Of all these factors, which is the most important?
Ultimately, you must consider all factors and decide on those that are most important to achieve the primary objectives and project goals. There are many competing requirements often, however your main priorities should drive your choice and filter the 3D-publishing material and technology options. If you have a brief timeline, economics may be the determining factor. If long life is the priority, durability may be the determining factor.
Selecting the optimal technology and material for a project is imperative to maximizing success. The primary point to remember is certainly that the “one-size-fits-all” approach doesn’t connect with 3D printing. It is important that you either invest time and energy to learn the pros, disadvantages, and nuances of the main processes, materials, and post procedures, or find a target partner or expert who gets the experience and know-how to provide you with sound guidance.
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