3D printed transmission

FDM Type 3D Printers
Although the resolution of the printers is adequate for most projects, printing slightly oversized objects and then subtractively machining them with high-precision tools allows you to create models of increased accuracy.
The LUMEX Avance-25 is an example of devices with a similar combined manufacturing and processing method. Some additive manufacturing methods allow for the use of multiple materials, as well as different colors, within a single production run. Many of the 3D printers use "supports" or "supports" during printing. Supports are needed to build model fragments that are not in contact with the underlying layers or the working platform. The supports themselves are not part of the given model, and upon completion of printing, they either break off (in the case of using the same material as for printing the model itself), or dissolve (usually in water or acetone - depending on the material used to create the supports). ).

Printing technologies

Since the late 1970s, several 3D printing methods have come into being. The first printers were large, expensive and very limited.

Complete skull with supports not yet removed

A wide variety of additive manufacturing methods are now available. The main differences are in the layering method and consumables used. Some methods rely on melting or softening materials to create layers: these include selective laser sintering (SLS), selective laser melting (SLM), direct metal laser sintering (DMLS), fusing deposition printing (FDM or FFF). Another trend has been the production of solid models by polymerization of liquid materials, known as stereolithography (SLA).
In the case of lamination of sheet materials (LOM), thin layers of material are cut to the required contour, and then joined into a single whole. Paper, polymers and metals can be used as LOM materials. Each of these methods has its own advantages and disadvantages, which is why some companies offer a choice of consumables for building a model - polymer or powder. LOM printers often use regular office paper to build durable prototypes. The key points when choosing the right device are the speed of printing, the price of a 3D printer, the cost of printed prototypes, as well as the cost and range of compatible consumables.

Printers that produce full-fledged metal models are quite expensive, but it is possible to use less expensive devices for the production of molds and subsequent casting of metal parts.
The main methods of additive manufacturing are presented in the table:

Method	Technology	Materials used
Extrusion	Fused deposition modeling (FDM or FFF)	Thermoplastics (such as polylactide (PLA), acrylonitrile butadiene styrene (ABS), etc. )
Wire	Manufacture of arbitrary shapes by electron beam fusing (EBFȝ)	Virtually all metal alloys
Powder	Direct Metal Laser Sintering (DMLS)	Virtually all metal alloys
	Electron Beam Melting (EBM)	Titanium alloys
	Selective laser melting (SLM)	Titanium alloys, cobalt-chromium alloys, stainless steel, aluminum
	Selective heat sintering (SHS)	Powder thermoplastics
	Selective laser sintering (SLS)	Thermoplastics, metal powders, ceramic powders
Inkjet	3D Inkjet Printing (3DP)	Gypsum, plastics, metal powders, sand mixtures
Lamination	Lamination Object Manufacturing (LOM)	Paper, metal foil, plastic film
Polymerization	Stereolithography (SLA)	Photopolymers
	Digital LED Projection (DLP)	Photopolymers

Extrusion Printing

Fused Deposition Modeling (FDM/FFF) was developed by S. Scott Trump in the late 1980s and commercialized in the 1990s by Stratasys, a company of which Trump is credited as one of the founders. Due to the expiration of the patent, there is a large community of open source 3D printer developers as well as commercial organizations using the technology. As a consequence, the cost of devices has decreased by two orders of magnitude since the invention of the technology.
3D printers range from simple do-it-yourself printers to plastic...
Fusion printing process involves the creation of layers by extrusion of a fast-curing material in the form of microdrops or thin jets. Typically, consumable material (such as thermoplastic) comes in the form of spools from which the material is fed into a printhead called an "extruder". The extruder heats the material to its melting temperature, followed by extrusion of the molten mass through a nozzle. The extruder itself is driven by stepper motors or servomotors to position the printhead in three planes. The movement of the extruder is controlled by a manufacturing software (CAM) linked to a microcontroller.
A variety of polymers are used as consumables, including acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactide (PLA), high pressure polyethylene (HDPE), polycarbonate-ABS blends, polyphenylene sulfone (PPSU), etc. Typically, polymer supplied in the form of a filler made of pure plastic. There are several projects in the 3D printing enthusiast community that aim to recycle used plastic into materials for 3D printing. The projects are based on the production of consumables using shredders and melters.

FDM/FFF technology has certain limitations on the complexity of the generated geometric shapes. For example, the creation of suspended structures (such as stalactites) is impossible by itself, due to the lack of necessary support. This limitation is compensated by the creation of temporary support structures that are removed after printing is completed.
Powder print

Selective sintering of powder materials is one of the additive manufacturing methods. Model layers are drawn (sintered) in a thin layer of powdered material, after which the work platform is lowered and a new layer of powder is applied. The process is repeated until a complete model is obtained. The unused material remains in the working chamber and serves to support the overhanging layers without requiring the creation of special supports.

The most common methods are based on laser sintering: selective laser sintering (SLS) for working with metals and polymers (e.g. polyamide (PA), glass fiber reinforced polyamide (PA-GF), glass fiber (GF), polyetheretherketone) (PEEK), polystyrene (PS), alumide, carbon fiber reinforced polyamide (Carbonmide), elastomers) and direct metal laser sintering (DMLS).
... to expensive industrial plants working with metals
Selective Laser Sintering (SLS) was developed and patented by Carl Deckard and Joseph Beeman of the University of Texas at Austin in the mid-1080s under the auspices of the Defense Advanced Research Projects Agency (DARPA). A similar method was patented by R. F. Householder in 1979, but has not been commercialized.

Selective laser melting (SLM) is characterized by the fact that it does not sinter, but actually melts the powder at the points of contact with a powerful laser beam, allowing you to create high-density materials that are similar in terms of mechanical characteristics to products made by traditional methods.

Electron Beam Melting (EBM) is a similar method for the additive manufacturing of metal parts (eg titanium alloys) but using electron beams instead of lasers. EBM is based on melting metal powders layer by layer in a vacuum chamber. In contrast to sintering at temperatures below melting thresholds, models made by electron beam melting are characterized by solidity with a corresponding high strength.

Finally, there is the 3D inkjet printing method. In this case, a binder is applied to thin layers of powder (gypsum or plastic) in accordance with the contours of successive layers of the digital model. The process is repeated until the finished model is obtained. The technology provides a wide range of applications, including the creation of color models, suspended structures, the use of elastomers. The design of models can be strengthened by subsequent impregnation with wax or polymers.

Lamination

FDM 3D printers are the most popular among hobbyists and enthusiasts
Some printers use paper as a material for building models, thereby reducing the cost of printing. Such devices experienced the peak of popularity in the 1990s. The technology consists in cutting out the layers of the model from paper using a carbon dioxide laser with simultaneous lamination of the contours to form the finished product.

In 2005, Mcor Technologies Ltd developed a variant of the technology that uses plain office paper, a tungsten carbide blade instead of a laser, and selective adhesive application.

There are also device variants that laminate thin metal and plastic sheets.

Photopolymerization

3D printing allows you to create functional monolithic parts of complex geometric shapes, like this jet nozzle
Stereolithography technology was patented by Charles Hull in 1986. Photopolymerization is primarily used in stereolithography (SLA) to create solid objects from liquid materials. This method differs significantly from previous attempts, from the sculptural portraits of François Willem (1830-1905) to photopolymerization by the Matsubara method (1974).

The Digital Projection Method (DLP) uses liquid photopolymer resins that are cured by exposure to ultraviolet light emitted from digital projectors in a coated working chamber. After the material has hardened, the working platform is immersed to a depth equal to the thickness of one layer, and the liquid polymer is irradiated again. The procedure is repeated until the completion of the model building. An example of a rapid prototyping system using digital LED projectors is the EnvisionTEC Perfactory.

Inkjet printers (eg Objet PolyJet) spray thin layers (16-30µm) of photopolymer onto the build platform until a complete model is obtained. Each layer is irradiated with an ultraviolet beam until hardened. The result is a model ready for immediate use. The gel-like support material used to support the components of geometrically complex models is removed after the model has been handcrafted and washed. The technology allows the use of elastomers.

Ultra-precise detailing of models can be achieved using multiphoton polymerization. This method is reduced to drawing the contours of a three-dimensional object with a focused laser beam. Due to non-linear photoexcitation, the material solidifies only at the focusing points of the laser beam. This method makes it easy to achieve resolutions above 100 µm, as well as build complex structures with moving and interacting parts.

Another popular method is curing with LED projectors or "projection stereolithography".

Projection stereolithography

This method involves dividing a 3D digital model into horizontal layers, converting each layer into a 2D projection similar to photomasks. The 2D images are projected onto successive layers of photopolymer resin that harden according to the projected contours.

In some systems, the projectors are located at the bottom, helping to level the surface of the photopolymer material when the model moves vertically (in this case, the build platform with the applied layers moves up, rather than sinking into the material) and reduces the production cycle to minutes instead of hours.

The technology allows you to create models with layers of several materials with different curing rates.

Some commercial models, such as the Objet Connex, apply resin using small nozzles.

3D printers

Industrial plants

Industrial adoption of additive manufacturing is proceeding at a rapid pace. For example, US-Israeli joint venture Stratasys supplies $2,000 to $500,000 additive manufacturing machines, while General Electric uses high-end machines to produce gas turbine parts.
Home appliances

LOM takes papier-mâché to the next level The development of 3D printers for home use is being pursued by a growing number of companies and enthusiasts. Most of the work is done by amateurs for their own and public needs, with help from the academic community and hackers.

The oldest and longest running project in the desktop 3D printer category is RepRap. The RepRap project aims to create free and open source (FOSH) 3D printers provided under the GNU General Public License. RepRap devices are capable of printing custom-designed plastic components that can be used to build clones of the original device. Individual RepRap devices have been successfully applied to the production of printed circuit boards and metal parts.

Due to the open access to drawings of RepRap printers, many of the projects adopt the technical solutions of analogues, thus creating a semblance of an ecosystem consisting mostly of freely modifiable devices. The wide availability of open source designs only encourages variations. On the other hand, there is a significant variation in the level of quality and complexity of both the designs themselves and the devices manufactured on their basis. The rapid development of open source 3D printers is leading to a rise in popularity and the emergence of public and commercial portals (such as Thingiverse or Cubify) offering a variety of printable 3D designs. In addition, the development of technology contributes to the sustainable development of local economies through the possibility of using locally available materials for the production of printers.
Stereolithographic 3D printers are often used in dental prosthetics

The cost of 3D printers has been declining at a significant rate since about 2010: devices that cost $20,000 at the time are now $1,000 or less. Many companies and individual developers are already offering budget RepRap kits under $500. The Fab@Home open source project has led to the development of general purpose printers capable of printing anything that can be squeezed through a nozzle, from chocolate to silicone putty and chemicals.
Printers based on this design have been available as kits since 2012 for around $2,000. Some 3D printers, including the mUVe 3D and Lumifold, are designed to be as affordable as possible from the start, with the Peachy Printer being priced around $100. .
Professional Kickstarter funded printers often perform well: Rapide 3D printers are quiet and fumes free at $1499. 3D Doodler's '3D Printing Pen' Raised $2.3M in Kickstarter donations, with a selling price of $99 for the device itself. True, it is difficult to call the 3D Doodler a full-fledged 3D printer.

3D Systems Cube is a popular consumer 3D printer

As prices drop, 3D printers are becoming more attractive for home production. In addition, home use of 3D printing technologies can reduce the environmental footprint of industry by reducing the volume of consumables and the energy and fuel costs of transporting materials and goods.

Parallel to the creation of home 3D-printing devices, the development of devices for processing household waste into printed materials, the so-called. Recyclebot. For example, the commercial model Filastrucer was designed to recycle plastic waste (shampoo bottles, milk containers) into inexpensive consumables for RepRap printers. Such methods of household disposal are not only practical, but also have a positive impact on the ecological situation.

The development and customization of RepRap 3D printers has created a new category of semi-professional printers for small businesses. Manufacturers such as Solidoodle, RoBo and RepRapPro offer kits for under $1,000. The accuracy of these devices is between industrial and consumer printers. Recently, high-performance printers using a delta-shaped coordinate system, or the so-called "delta robots", are gaining popularity. Some companies offer software to support printers made by other companies.

Application

The use of LED projectors helps reduce the cost of stereolithography printers. In the illustration DLP printer Nova

3D printing allows you to equalize the cost of producing one part and mass production, which poses a threat to large-scale economies. The impact of 3D printing may be similar to the introduction of manufacture. In the 1450s, no one could predict the consequences of the printing press, in the 1750s, no one took the steam engine seriously, and transistors 19The 50s seemed like a curious innovation. But the technology continues to evolve and is likely to have an impact on every scientific and industrial branch with which it comes into contact.

The earliest application of additive manufacturing can be considered rapid prototyping, aimed at reducing the development time of new parts and devices compared to earlier subtractive methods (too slow and expensive). The improvement of additive manufacturing technologies leads to their spread in various fields of science and industry. The production of parts previously only available through machining is now possible through additive methods, and at a better price.
Applications include breadboarding, prototyping, molding, architecture, education, mapping, healthcare, retail, etc.
Industrial applications:
Rapid prototyping: Industrial 3D printers have been used for rapid prototyping and research since the early 1980s . As a rule, these are quite large installations using powder metals, sand mixtures, plastics and paper. Such devices are often used by universities and commercial companies.

Advances in rapid prototyping have led to the creation of materials suitable for the production of final products, which in turn has contributed to the development of 3D production of finished products as an alternative to traditional methods. One of the advantages of fast production is the relatively low cost of manufacturing small batches.

Rapid production: Rapid production remains a fairly new method whose possibilities have not yet been fully explored. Nevertheless, many experts tend to consider rapid production a new level of technology. Some of the most promising areas for rapid prototyping to adapt to rapid manufacturing are selective laser sintering (SLS) and direct metal sintering (DMLS).
Bulk customization: Some companies offer services for customizing objects using simplified software and then creating unique custom 3D models. One of the most popular areas was the manufacture of cell phone cases. In particular, Nokia has made publicly available the designs of its phone cases for user customization and 3D printing.
Mass production: The current low print speed of 3D printers limits their use in mass production. To combat this shortcoming, some FDM devices are equipped with multiple extruders, allowing you to print different colors, different polymers, and even create several models at the same time. In general, this approach increases productivity without requiring the use of multiple printers - a single microcontroller is enough to operate multiple printheads.

Devices with multiple extruders allow the creation of several identical objects from only one digital model, but at the same time allow the use of different materials and colors. The print speed increases in proportion to the number of print heads. In addition, certain energy savings are achieved through the use of a common working chamber, which often requires heating. Together, these two points reduce the cost of the process.

Many printers are equipped with dual printheads, however this configuration is only used for printing single models in different colors and materials.

Consumer and hobby use

Today, consumer 3D printing mainly attracts the attention of enthusiasts and hobbyists, while practical use is rather limited. However, 3D printers have already been used to print working mechanical clocks, woodworking gears, jewelry, and more. Home 3D printing websites often offer designs for hooks, doorknobs, massage tools, and more.

3D printing is also being used in hobby veterinary medicine and zoology – in 2013, a 3D printed prosthesis allowed a duckling to stand up, and hermit crabs love stylish 3D printed shells. 3D printers are widely used for the domestic production of jewelry - necklaces, rings, handbags, etc.

The Fab@Home open project aims to develop general purpose home printers. The devices have been tested in research environments using the latest 3D printing technologies for the production of chemical compounds. The printer can print any material suitable for extrusion from a syringe in the form of a liquid or paste. The development is aimed at the possibility of home production of medicines and household chemicals in remote areas of residence.

Student project OpenReflex resulted in a design for an analog SLR camera suitable for 3D printing.

Clothing

3D printing is gaining ground in the fashion world as couturiers use printers to experiment with swimwear, shoes and dresses. Commercial applications include rapid prototyping and 3D printing of professional athletic shoes - the Vapor Laser Talon for soccer players and New Balance for track and field athletes.

3D bioprinting

EBM titanium medical implants

3D printing is currently being researched by biotech companies and academic institutions. The research is aimed at exploring the possibility of using inkjet/drip 3D printing in tissue engineering to create artificial organs. The technology is based on the application of layers of living cells on a gel substrate or sugar matrix, with a gradual layer-by-layer build-up to create three-dimensional structures, including vascular systems. The first 3D tissue printing production system based on NovoGen bioprinting technology was introduced in 2009year. A number of terms are used to describe this research area: organ printing, bioprinting, computer tissue engineering, etc.

One of the pioneers of 3D printing, research company Organovo, conducts laboratory research and develops the production of functional 3D human tissue samples for use in medical and therapeutic research. For bioprinting, the company uses a NovoGen MMX 3D printer. Organovo believes that bioprinting will speed up the testing of new medicines before clinical trials, saving time and money invested in drug development. In the long term, Organovo hopes to adapt bioprinting technology for graft and surgical applications.

3D printing of implants and medical devices

3D printing is used to create implants and devices used in medicine. Successful surgeries include examples such as titanium pelvic and jaw implants and plastic tracheal splints. The most widespread use of 3D printing is expected in the production of hearing aids and dentistry. In March 2014, Swansea surgeons used 3D printing to reconstruct the face of a motorcyclist who was seriously injured in a road accident.

3D printing services

Some companies offer online 3D printing services available to individuals and industrial companies. The customer is required to upload a 3D design to the site, after which the model is printed using industrial installations. The finished product is either delivered to the customer or subject to pickup.

Exploring new applications

3D printing makes it possible to create fully functional metal products, including weapons.
Future applications of 3D printing may include the creation of open source scientific equipment for use in open laboratories and other scientific applications - fossil reconstruction in paleontology, the creation of duplicates of priceless archaeological artifacts, the reconstruction of bones and body parts for forensic analysis, the reconstruction of heavily damaged evidence collected from crime scenes. The technology is also being considered for application in construction.

In 2005, academic journals began to publish materials on the possibility of using 3D printing technologies in art. In 2007, the Wall Street Journal and Time magazine included 3D design in their list of the 100 most significant achievements of the year. The Victoria and Albert Museum at the London Design Festival in 2011 presented an exhibition by Murray Moss entitled "Industrial Revolution 2.0: how the material world materializes again", dedicated to 3D printing technologies.

In 2012, a University of Glasgow pilot project showed that 3D printing could be used to produce chemical compounds, including hitherto unknown ones. The project printed chemical storage vessels into which “chemical ink” was injected using additive machines and then reacted. The viability of the technology was proven by the production of new compounds, but a specific practical application was not pursued during the experiment. Cornell Creative Machines has confirmed the feasibility of creating food products using hydrocolloid 3D printing. Professor Leroy Cronin of the University of Glasgow has suggested using "chemical ink" to print medicines.

The use of 3D scanning technology makes it possible to create replicas of real objects without the use of casting methods, which are costly, difficult to perform and can have a destructive effect in cases of precious and fragile objects of cultural heritage.

An additional example of 3D printing technologies being developed is the use of additive manufacturing in construction. This could make it possible to accelerate the pace of construction while reducing costs. In particular, the possibility of using technology to build space colonies is being considered. For example, the Sinterhab project aims to explore the possibility of additive manufacturing of lunar bases using lunar regolith as the main building material. Instead of using binding materials, the possibility of microwave sintering of regolith into solid building blocks is being considered.

Additive manufacturing allows you to create waveguides, sleeves and bends in terahertz devices. The high geometric complexity of such products could not be achieved by traditional production methods. A commercially available professional EDEN 260V setup was used to create structures with a resolution of 100 microns. The printed structures were galvanized with gold to create a terahertz plasmonic apparatus.

China has allocated nearly $500 million. for the development of 10 national institutes for the development of 3D printing technologies. In 2013, Chinese scientists began printing living cartilage, liver and kidney tissue using specialized 3D bioprinters. Researchers at Hangzhou Dianqi University have even developed their own 3D bioprinter for this challenging task, dubbed Regenovo. One of Regenovo's developers, Xu Mingeng, said it takes less than an hour for the printer to produce a small sample of liver tissue or a four to five inch sample of ear cartilage. Xu predicts the emergence of the first full-fledged printed artificial organs within the next 10-20 years. That same year, researchers at the Belgian Hasselt University successfully printed a new jaw for an 83-year-old woman. After the implant is implanted, the patient can chew, talk and breathe normally.

In Bahrain, sandstone-like 3D printing has created unique structures to support coral growth and restore damaged reefs. These structures have a more natural shape than previously used structures and do not have the acidity of concrete.

Intellectual property

Section of liver tissue printed by Organovo, which is working to improve 3D printing technology for the production of artificial organs
3D printing has been around for decades, and many aspects of the technology are subject to patents, copyrights, and trademark protection. However, from a legal point of view, it is not entirely clear how intellectual property protection laws will be applied in practice if 3D printers become widely used.
distribution and will be used in household production of goods for personal use, non-commercial use or for sale.

Any of the protective measures may negatively affect the distribution of designs used in 3D printing or the sale of printed products. The use of protected technologies may require the permission of the owner, which in turn will require the payment of royalties.

Patents cover certain processes, devices, and materials. The duration of patents varies from country to country.

Often, copyright extends to the expression of ideas in the form of material objects and lasts for the life of the author, plus 70 years. Thus, if someone creates a statue and obtains copyright, it will be illegal to distribute designs for printing of an identical or similar statue.

Influence of 3D printing

Additive manufacturing requires manufacturing companies to be flexible and constantly improve available technologies to stay competitive. Advocates of additive manufacturing predict that the opposition between 3D printing and globalization will escalate as home production displaces trade in goods between consumers and large manufacturers. In reality, the integration of additive technologies into commercial production serves as a complement to traditional subtractive methods, rather than a complete replacement for the latter.

Space exploration

In 2010, work began on the application of 3D printing in zero gravity and low gravity. The main goal is to create hand tools and more complex devices "as needed" instead of using valuable cargo volume and fuel to deliver finished products to orbit.
Even NASA is interested in 3D printing
At the same time, NASA is conducting joint tests with Made in Space to assess the potential of 3D printing to reduce the cost and increase the efficiency of space exploration. Nasa's additive-manufactured rocket parts were successfully tested in July 2013, with two fuel injectors performing on par with conventionally produced parts during operational tests subjecting the parts to temperatures of around 3,300°C and high pressure levels. It is noteworthy that NASA is preparing to launch a 3D printer into space: the agency is going to demonstrate the possibility of creating spare parts directly in orbit, instead of expensive transportation from the ground.

Social change

The topic of social and cultural change as a result of the introduction of commercially available additive technologies has been discussed by writers and sociologists since the 1950s. One of the most interesting assumptions was the possible blurring of boundaries between everyday life and workplaces as a result of the massive introduction of 3D printers into the home. It also points to the ease of transferring digital designs, which, in combination with local production, will help reduce the need for global transportation. Finally, copyright protection may change to reflect the ease of additive manufacturing of many products.

Firearms

In 2012, US company Defense Distributed released plans to create a "design of a functional plastic weapon that could be downloaded and played by anyone with access to a 3D printer." Defense Distributed has developed a 3D printed version of the receiver for the AR-15 rifle, capable of withstanding more than 650 shots, and a 30-round magazine for the M-16 rifle. The AR-15 has two receivers (lower and upper), but legal registration is tied to the lower receiver, which is stamped with a serial number. Shortly after Defense Distributed created the first working drawings for the production of plastic weapons in May 2013, the US State Department requested that the instructions be removed from the company's website.

The distribution of blueprints by Defense Distributed has fueled discussion about the possible impact of 3D printing and digital processing devices on the effectiveness of gun control. However, the fight against the proliferation of digital weapon models will inevitably face the same problems as attempts to prevent the trade in pirated content.

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Architectural 3D Printing Modeling Strategy Guide and Software Usage

At a Glance

3D printing brings enormous benefits to the conventional architectural workflow. You can print complex designs without the need for skilled craftsmen, and quickly modify these designs without too much difficulty. Stereolithographic (SLA) 3D printing delivers incredibly high surface quality and detail, making it suitable for architectural applications. This paper explores modeling strategies and software workflows that enable architects and designers to easily integrate 3D printing into existing design methodology, create best practices based on internal testing by Formlabs and architecture firms, successfully using Form 2 to create 9 models0054

WHAT YOU WILL LEARN:

Design strategies for 3D printed architectural models

Tips for improving your workflow Pre-print processing software

• Building information model (Revit, ArchiCAD)
• Surface modeling (Rhino, SketchUp)

Good post-processing techniques

• Compound
• Finishing

Introduction

The 3D printing market today offers affordable options in both price and scale. While professional-grade technology used to be costly, desktop stereolithography 3D printers allow architects, designers, and model makers to offer high-quality, in-house fabricated parts.

Most models cost less than $10 per part.

3D printing opens the door to creating complex designs with less effort and fewer materials, but the successful transition from a CAD model to a printable file is based on a basic understanding of design for 3D printing. This document will help you understand how standard modeling constraints relate to preparing a file for 3D printing, as well as approaches and decision making for intelligent modeling - from scale selection to design and assembly for post-processing.

To integrate these strategies into existing workflows, this booklet explores ways to approach modeling strategies tactically by examining three of the most common software ecosystems: allows you to include small details even on the smallest models. This example of a small city model has a scale of 1/32″ = 1’ and is completely printed on a Form 2 3D printer. Many small details and parts of this design will take significantly longer if cut and assembled by hand. Model from LaneyLA Inc.

This auditorium section was 3D printed as one piece on a black resin Form 2. Model from DLR Group.

Modeling strategy

Architectural models are usually assembled using various materials and components. 3D printers help combine these components into as few separate parts as possible, but assembly manipulation is still necessary for two reasons:

1. Build Volume Limitations: Printers with large build volumes are either expensive or compromise on surface quality. Form 2 build volume is 57 x 57 x 69 inches (145 x 145 x 175 mm)
2. Need to show interior details or materiality : Some models require components to be separated to show more design information.

DESIGN FOR ASSEMBLY

All 3D models require preparation before they can be sent to the 3D printer. In the case of architectural models for the Form 2, this often involves splitting the model into smaller parts to fit the scope of the Form 2 build. The parts can then be easily joined together by chemical adhesive or mechanical assembly; high precision printing ensures that the parts fit together.

Dimensioning for parts to be separated must take into account the final orientation of the model. Most architectural prints need to be oriented at a 45 degree angle due to floor slabs being considered large horizontal projections. Dividing the model into long, thin parts helps maximize the diagonal length of the build volume while achieving perfect orientation

Strategy overview

There are several strategies for assembling 3D printed models. Your strategy will depend on what you hope to represent with the design, as well as the scale and geometry of the model. Consider the following parameters:

• Need to show internal or external parts
• Easy Split (You want to split the model by the least complex part of the model)

It is necessary to show a certain part of the program: typology, structure, floor layout

Splitting at a seam

STRAIGHT CUT

The easiest way to split a model is with a straight cut. This is a simple command to execute in most CAD software. The bridge model is divided lengthwise using straight cuts into four parts, one of which is shown above. Each support post is inserted into

mating hole that does not require glue. Regardless of which method you choose, if you have a large number of parts (more than 10), it can be helpful to add a unique identifier for each part to help solve the puzzle during assembly.

Pros:

• Least heavy use of CAD
• Greater tolerance for prints that warp or have a higher degree of dimensional change

Cons:

• Assembly requires manually leveling each piece and fixing it in place until the adhesive is fully bonded

Try to print all components in the same orientation so that the layer lines and subsequent dimensional inaccuracies follow the same pattern.

MATCHING TOOLS

Another approach is to add features to the design that will allow the prints to align. When adding mate fixtures, try to subdivide the model in areas with the least complex geometry. Use the CAD tool of your choice to split your model and add basic alignment fixtures such as slots, pins, grooves, recesses and flanges, or more complex fixtures such as dovetails and cuts that follow existing model curves. In addition, it is important to create a design with ~0.25 mm tolerance between mating parts to prevent additional sanding at the post-printing stage.

Pros:

• Easy alignment Parts that are not accurate
• Easy to assemble (mating parts help create more surface area for adhesion)
• High precision SLA allows tight fit with high tolerance and can be used without adhesive

Cons:

• Parts that are not true to size will not fit well. High fine details are often less accurate.

SECTION MODEL

The separation of the model with a seam has the additional task of showing the section model for structures with irresistible interior details. Initially, the model can be presented as a whole to the client, and then disassembled to reveal interior details as desired. These LaneyLA examples show how the same model conveys different types of information based on open and closed configurations

This model from LaneyLA was printed on a White Resin Form 2.

Model by Stanley Sitetowitz | Natoma Architects Inc.

Since each body block followed the same pattern, it makes sense to simply print one removable block that will allow the customer to understand the typology of the typical device to print as a single block or separate along the seam.

905 PreForm

While BIM (Building Information Model) software is popular with architecture firms, it is not always used for direct 3D printing models. There are some high level steps that you can take

take to create a 3D printed model from these programs. This workflow is widely applied to Autodesk Revit or Graphisoft ArchiCAD software, both of which are IMZ parametric modeling programs.

PREPARE THE FILE

STEP 1: Prepare a separate stand-alone file

STEP 2: Component Management: remove ducts, double glazing, HVAC units and internal parts that will not be visible in model

STEP 3: Select all components to be sealed (eg doors, windows, walls, slabs). The parametric nature of the model allows you to simultaneously compact the dimensions of several objects.

EXPORT FILE

Select the scale at which you want to export the file. Select export options depending on the needs of your model:

EXPORT AS STL

Exporting the file as a mesh is very difficult to manipulate, so this is only useful if you don't want to edit any geometry after this step. You can then use your software to correct the mesh of your choice, as well as subdivide the mesh along the main Cartesian planes.

EXPORT AS 3D DWG

Export as surfaces allows you to easily manage and edit geometry in Rhino or SketchUp. This step is recommended for those who want to split the model programmatically or by component, or split by a seam that is not on the normal Cartesian plane. You can then export the STL file from Rhino or SketchUp using the plug-in

EXPORT USING ARCHICAD

Perform a geometry transformation to Morphs and a "consistency check" before exporting the model as STL. When printing in parts, use tool

"Divide" to cut the model for multiple print platforms, if needed. This operation basically creates printable files, but a quick check in mesh repair/analysis software never hurts.

USING STL REVIT EXPORTER

This method automatically removes smaller details such as doorknobs and railings. However, it is not reliable and still often requires some post-processing in other CAD environments before being sent to print.

Surface modeling workflow

AutoCAD → Rhino/SketchUp → Model Diagnostics → PreForm

This workflow is often an easier approach and starts with 2D drawings solely for the purpose of 3D printing