The dynamic 3D-printing landscape is a challenge to navigate for industry experts, and even more so for individuals who have no idea of the capabilities, limitations, and idiosyncrasies of the various technologies. Further adding complexity, 3D-printing procedures don’t translate comparably with conventional manufacturing technology always, once the material output is virtually exactly the same even. This is typically because of the dissimilar build parameters, environment, and material delivery methodology. To learn the nuances, you must grasp the basics behind each technologies and know the full spectral range of available material options.
This article can help you determine the technologies and materials that are right for your application. Many 3D-printing processes are in use today, but for the purposes of this article, we will only touch on the most commonly used in design and manufacturing engineering today: photocuring, filament deposition, polymer laser sintering, and direct metal laser beam sintering.
This band of 3D-printing processes employs liquid photopolymer resins which are solidified and cured with ultraviolet (UV) light, to serve as models mostly, light-duty prototypes, and patterns for secondary casting. Photopolymers differ in colour, transparency, and mechanical and thermal attributes, which range from low-temperature soft and versatile elastomers to tough and rigid nanocomposites in a position to withstand elevated temperatures. For example, Somos NanoTool, a composite stereolithography (SL) material, has a heat deflection of up to 437°F at 66 psi.
An advantage of photocuring is the refined quality of the output. Photocuring processes produce parts with smooth surfaces and fine-feature detail-16-micron layer elevation with PolyJet-ideal for aesthetic plus cosmetic applications. However , UV durability and balance falls short for high-efficiency and end-use product applications. Continued contact with UV light causes photocured objects to become brittle and change in appearance. In addition, some materials can lose shape and dimensional accuracy from humidity absorption and sag or creep from prolonged stress.
The two nearly all used photocuring technologies are PolyJet and SL widely. PolyJet deposits tiny droplets of photopolymer and treatments the thin layers with UV lighting simultaneously. This process can print in a very high resolution with layer thicknesses as thin as 16 microns, which minimizes post-processing. Also called multi-jet printing, 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 as well can produce smooth components requiring minimal finishing, but will 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- generated toolpaths, the filament-deposition processes develop 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 durable functional prototypes and end-use parts in a variety of high-performance materials popular in typical machining and molding manufacturing procedures.
Fused deposition modeling (FDM) may be the many mature and widely followed filament deposition process. FDM can maintain dimensional accuracy over length while having the opportunity to save material and weight. Some companies will post a general tolerance of ±0. 008 inches; however , it’s hard to give an exact number or even a range because of this accuracy because it depends upon the machine, material, geometry, and size of the part. In addition, FDM is less prone to warp and curl than laser sintering.
The most significant drawback of filament deposition is the pronounced layer ranges in the surface 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 for example injection molding. Additionally , applications that demand airtight or watertight functionality may necessitate 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 practical processes fuse or melt powdered polymers and composites with a low 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, grommets and seals. Also, low-density polystyrene infiltrated with wax can offer as a low-ash expense casting.
Another benefit of LS is that 3D objects are self-supporting within the construct chamber, enabling three-dimensional nesting. Efficient and affordable production of complex geometries with internal cavities and channels are feasible 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 often exists between your mechanical strength and dimensional precision of the output. Laser energy and build chamber temperature boost 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 temps. 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, encountered LS operators might 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, generally referred to as a YAG-fiber laser, metal laser-sintering systems essentially micro-weld powdered metals and alloys layer upon coating to produce fully dense 3D objects with qualities similar to castings. Through post processes, such as heat-treating and scorching isostatic pushing (HIP), it’s possible to boost metallurgical properties for high-performance programs.
There are several benefits to direct-metal-laser-sintering (DMLS) forms of processes more than conventional manufacturing methodologies, like 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 can consolidate assemblies, reducing the real number of components that may reduce work cost and fasteners, and simplify a product. Benefiting from these features with the DMLS process is ideal for low-volume manufacturing of end-use parts and products, and high-performance functional prototypes.
On the downside, the learning curve to build quality DMLS products and parts is substantial. An educated technician or designer should comprehend how to work with a CAD design to verify a print is economically practical before it would go to print. An experienced operator will have to develop effective build ways of mitigate warping and minimize 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 screen 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 program, and there isn’t usually a clear-cut answer for a customer’s specific needs. Often multiple options could work, each with a different set of pros and cons. The following seven considerations will help you qualify and disqualify procedures and materials for every of your unique projects:
1 . Program: What is the goal of the object?
The intent for 3D-printed objects could range between aesthetic show models and mock-ups, to functional prototypes, R&D test pieces, or end-use production parts and products. The requirements of each of these applications can vary greatly, and therefore are better suited to some processes. It boils down to cosmetic often, dimensional, or performance requirements.
2 . Efficiency: What does the part should do?
A 3D-printed part may should just hold form as a static design or bear a detailed resemblance to a conventionally manufactured product with fine detail and smooth surfaces. In this case, PolyJet or stereolithography may be the ideal process. Hard-working parts that must bear a load or resist impact could be better suitable for the FDM procedure. If the application involves simple fit or long lasting living hinge, LS may be the better option.
3. Stability: In what atmosphere does the part have to function?
The necessity 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 won’t work very well for outdoor environments because they react to UV light. Moisture is another common factor that adversely affects many materials. If biocompatibility is essential for a surgical device, metals then, such as for example titanium Ti-64 for electron or DMLS beam melting may be the best, if not the only real, option.
4. Durability: Just how long does the part have to last?
The number and duration useful cycles can eliminate some processes and materials. For example , a 3D- printed mold or form tool may need to go through hundreds of cycles and withstand prolonged stress and friction, whereas a fit-check prototype may only need to function once. Photopolymer materials are often effective for short-term, low-stress applications and are struggling to withstand prolonged stress typically. Built thermoplastics from the FDM and LS procedures can serve many useful prototyping and end-use reasons for increased cycle life.
5. Aesthetics: How does it have to look and feel?
It is possible to generally expect photocured 3D items to be fairly smooth and also have high resolution right off of the machine, and can easily be hand-finished to a cosmetic state. While thermoplastic and powdered plastic processes such as FDM and LS produce stronger and more durable parts, cosmetically they shall require even more labor and skill to attain a smooth surface, resulting in higher costs and increased prospect time. With the tough alloys and metals 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?
In case you have a firmly capped budget, the decision may be on price rather than other factors. Time and quality come in conflict collectively often; rapid turnaround and high-level aesthetic finishing could be exclusive mutually. However , shortcuts, workarounds, and efficient systems can reduce lead expenses and times while maintaining top quality standards. Efficiencies could be gained from working with something bureau that may creatively batch, nest, strategically section, shell, adjust fill, and modify build orientation to reduce machine time and material usage.
7. Priorities: Of all these aspects, which is the most important?
Ultimately, you must consider all factors and decide on those that are most important to attain the primary objectives and project targets. 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 longevity is the priority, strength may be the determining factor.
Selecting the perfect material and technology for the project is vital to maximizing success. The primary indicate remember is that the “one-size-fits-all” approach doesn’t apply to 3D printing. It is essential that you either invest time to learn the pros, cons, and nuances of the major processes, materials, and post processes, or find a target partner or expert who gets the know-how and experience to provide you with sound guidance.
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