Unit 45A

UNIT 45-A

3Dプリントはとても良いです(Not latin this time!)

What is additive manufacturing?

"In layman's terms, additive manufacturing is the production process of adding material to a workpiece gradually, as opposed to removing it."

- Floyd Rayner, 2023

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Why additive?

Since the industrial age, engineers have searched for more efficient machining methods than traditional milling, drilling and turning. Thanks to the technological developments of the modern computer age, the level of precision necessary to manufacture components additively is now commonly within the grasp of even small businesses or individuals. Additive manufacturing reduces material waste, for no material is unecessarily taken away.

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Why additive, in detail?

Monetary Savings

Small Batch Benefits

Rapid Prototyping

Design prototypes used to require extensive machining timeframes. Now, an additive design may be produced in several days or even a few hours. Subsequently, designers can evaluate initial flaws with their design choices at greater pace, increasing the efficiency of design iterations.

Smaller manufacturing companies can produce intricate designs without the startup cost of multiple machines. In addition, only a single trained operator is required, as opposed to employing a full staff team of qualified technicians.

As minimal material is wasted through additive production, material throughput costs are reduced. Furthermore, additive manufacturing implements require minimal additional tooling, eliminating the cost of items like bespoke cutting bits and molding dies.

VAT PHOTOPOLYMERIZATION

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• Definitely underrated!
• Looks awesome!

What is Vat Photopolymerization?

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Vat Photopolymerization is the process of curing (solidifying) a liquid polymer or resin layer by layer to produce a solid object. The workbed of a VP printer will move vertically away from the vat, as opposed to an extruder moving vertically away from a workbed in an extrusion printer. Vat Photopolymerization printers often have greatly superior detail to extrusion printers at the cost of durability.

Categories Of Vat Photopolymerization

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Applications of Vat Photopolymerization

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Specific Applications of VP:

Commercially available Vat Photopolymerization printers typically have smaller maximum build areas than similarly priced Extrusion systems - this is due to the volume of photopolymer resin needed to fill one and the difficulty of recycling the remaining resin to avoid waste and expenditure. For these reasons, Vat Photopolymerisation is best suited to smaller, intricate designs where detail is paramount, such as: - Custom bone structure replacements, which can be produced immediately after an operation, thus reducing hospital waiting times. - Personalised manufacture of small-scale detailed models - a number of companies already exist who produce bespoke, made to order models of people's designs for tabletop games and scale models. - Tool-free rapid prototyping - as VP manufacturing produces its own support structure, no custom toolings are needed to produce prototypes, also reducing manufacturing time.

Material Extrusion

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What is Material Extrusion?

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Material extrusion:

Material extrusion is the process of forcing liquid material through a small opening, then cooling the liquid into a solid object. By moving the opening (the extrusion head) along programmed vectors, material can be laid into a path, gradually forming a layer. Because the extrusion head has a limited traversal speed, material extrusion is seldom used for solid objects, and most extrusion designs make use of internal hollow bracings known as "infill".

However, even with a limited maximum traversal rate, material extrusion is still commonly used for rapid prototyping of mechanical systems wherein internal strength is an essential property. Material extrusion is one of the most versatile additive manufacturing methods, as myriad materials of varied can be heated and extruded.

Categories Of Material Extrusion

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Applications of Material Extrusion

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Material extrusion is not itself particularly accurate, with most commercial devices sporting a tolerance of 0.2mm, and that's on a perfect print. For this reason, material extrusion is better suited towards larger components which need to absorb mechanical interference. 100% infill prints are especially tough, allowing near-functional prototypes of mechanical systems to be manufactured within hours.

Not all extrusion printers are inaccurate, mind - some have especially low tolerances, and are used for the specialist task of "medical bioprinting", wherein biological matter (known as bioink) is extruded rather than solid matter. It is hoped that bioprinting will allow hospitals to print compatible replacement organs on demand, rather than waiting for a donor and risking organ rejection.

Applications of Additive Manufacturing

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Safety Considerations of Additive Manufacturing

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How To Ensure Safe Additive Production:

Additive manufacturing brings its own host of potential safety concerns, especially with more specialist forms.For example, when using DLP VP manufacturing, it is essential that a UV filtering cover is installed over the print vat to avoid burns or long term complications from intense UV exposure. In addition, it is advisable to wear insoluble gloves to avoid skin contact with any solvents in photopolymer resin. In terms of more conventional methods like material extrusion, it is adviseable to install personnel warning signs indicating the presence of hot extruders and moving components to avoid burns or harm to appendages. Finally, as is the case with all additive processes, it is essential ento use additive production machinery in well ventilated areas. In some configurations where excessive quantities of harmful gases are released, masks/respirators may be a necessary addition to PPE.

The Sustainability of Additive Manufacturing

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Is Additive Sustainable?

The short answer: yes and no.

Whilst additive manufacturing requires, on the whole, substantially less material use than traditional subtractive manufacturing, there are more factors to consider than merely material throughput - for example, extrusion-based systems require vast sums of electrical energy to run - the same is true of methods like SLS, DMLS and EBM.However, almost every material used in subtractive manufacturing on mass is either non-recyclable or finite, and as such will bring its own energy toll through refining and distributing. Overall, depending how mankind chooses to generate its power, additive manufacturing could very well be the most ecological manufacturing method for years to come.

Conclusion

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Conclusion

In conclusion, additive manufacturing is an exciting new avenue for product manufacturing that allows a designer to directly turn their computer models into an almost exact prototype in a short period of time. With greater development, it's possible that many consumer products in the future could be manufactured to much tighter tolerances using additive processes. Similarly, additive manufacturing already allows engineers to produce vastly superior designs which would have been previously inachievable in a significantly smaller timeframe. Many businesses may benefit from the development of additive manufacturing, especially small to medium scale developers.

Bibliography

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(Various sources are embedded throughout the text for in-text citation)Image credits: Fast Radius Manufacturing guide Protolabs Thomasnet Mashable Additive Manufacturing Media HiSoUR 3Faktur Geeetech 3D Printing Industry 3Dnatives Liqcreate Fusion3 WhiteClouds

Stereolithography

Lithography in both speakers!

Stereolithography is similar to 3SP, in that it uses a versatile laser to cure a photopolymer resin. However, stereolithography printers are unable to scan existing objects as they lack the head drum of a 3SP printer. Subsequently, only computer designed CAD files may be printed. Stereolithography printers are capable of manufacturing to tolerances of just 0.07mm, a remarkable accuracy for VP manufacturing.

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Digital Light Projection

(DLP)

DLP is the most common method of Vat Photopolymerization. Unlike SLA and 3SP, DLP printers cure an entire layer from a singular light emitting screen. DLP is relatively affordable compared to SLA and 3SP, but can lose accuracy on larger prints. DLP is also relatively fast, making it ideal for rapidly prototyping more intricate models than extrusion can handle.

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Fused Deposition (FDM)

Fused Deposition Manufacturing

FDM (Fused Deposition Manufacturing) is functionally similar to FFF, except that FDM employs a heated workbed/work area to gradually relieve internal stresses in the workpiece. Subsequently, layers in FDM prints adhere to one another better, increasing the durability and accuracy of the final model. Excluding the additional energy cost, many consider FDM to be the superior material extrusion method.

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Continuous Liquid Interface

(CLIP)

CLIP is best described as continuous DLP - that is to say, the object being produced is continually moved through the photopolymer liquid and is continually cured. CLIP-manufactured components have no layer seams, and therefore have a smooth texture and vastly superior mechanical properties to most additive processes. However, CLIP requires costly specialised polymers.

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Rapid Prototyping

Faster realisation

A key benefit of additive manufacturing is its capability to recreate a digital model physically within the space of mere hours. For this reason, many businesses have found uses for additive manufacturing: in the case of the cover image, some real estate developers are now using additive modelling through both ME and VP to produce small-scale models of new structures before construction. Other uses may include: to gain customer feedback from initial designs faster, to demonstrate design choices to shareholders on demand and to visualise flaws with a physical model.

Fused Filament (FFF)

Fabrication with filaments!

FFF (Fused Filament Fabrication) is considered by many to be the original method of material extrusion manufacturing. In FFF, a material filament (similar to a welding cord) is fed into a heating element in the head, causing the material to melt. When the molten material hits the workbed/workpiece, it cools and solidifies. FFF is arguably the most energy efficient method of extrusion as only one heating element is needed.

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Bespoke Products

Manufacturing on commission

As additive manufacturing requires no external toolings or moulds, it is significantly better adapted towards one-off scale production, or limited runs for a client. Using additive manufacturing enables smaller companies to produce bespoke models to suit an individual client's needs, with a fraction of the time and cost of subtractive manufacturing. For smaller one-off designs, VP may be better suited. Otherwise, it may be logical to use ME.

3SP

Scan, Spin & Selectively Cure

3SP manufacturing uses a rotating laser drum to cure the surface of a photopolymer. Due to its unique laser head-drum, a 3SP printer is highly versatile, able to cure many different grades of resin with a smooth surface finish. However, 3SP printers are less common than others of this category due to their comparatively high startup cost.

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Mechanical Systems

...and other structural purposes.

Products requiring superior mechanical properties like strength, rigidity and durability can be manufactured by additive processes on a small scale. While methods like DLD, SLS and PBF are able to produce metal components with ultimately superior properties, 100% infill extrusion can produce components suitable for lower load applications at considerable speed.

Medicinal Purposes

Bioink and bones

As additive manufacturing is able to produce intricate, accurate and irregular shapes in rapid time, additive processes can be used to print compatible bone replacements (or in this image, teeth) or, by using material extrusion, replications of muscle tissues. While bioprinting is in its primitive years, researchers have managed to print a fully functional meniscus using the host's own DNA, meaning the risk of rejection is entirely eliminated.