Joint 3d print


3D Printed Joinery: Simplifying Assembly

Joinery is a term usually found in woodworking, referring to the practice of joining two pieces of wood together by geometrically constraining them. Good joinery provides strong connections with little-to-no help from fasteners like nails or screws. Joinery is useful because it ensures a strong connection with a less complicated assembly process. However, it usually involves complicated shapes that take time to design and create, while bolts and screws just require a hole and a mass-manufactured fastener.


‍‍A classic T-bridle joint, printed in Onyx

3D printing is in an interesting position as a fabrication method because printing complicated geometry is often no more expensive than printing a block. Instead, FDM printing is limited by material properties and the process of building in layers. Thus designing for 3D printing requires a new mindset, and part of that mindset is leveraging the geometric freedom of a 3D printer to reduce the complexity and cost of the final assembly. One way to do that is to look at joinery invented for wood working and injection molding and apply that to the constraints of 3D printing. In this blog, I discuss leveraging simple joints like dovetails and snap fits to improve your 3D printed joint designs, supplemented by some examples.


Dovetails


‍‍A classic dovetail joint

When it comes to constraining two parts, many people think in right angles. And this is efficient, especially when thinking about machining; right angles are generally much easier and faster to make than odd angles, requiring fewer setups and no special bits or indexing tables. To a 3D printer, however, dovetails and straight walls are all the same. With no extra effort, you can constrain another degree of freedom. This comes in handy everywhere, whether you want a sliding assembly or a fastener-less T-joint.


Sliding dovetail box, disassembled
‍The flared walls and tight tolerances allow this box to slide smoothly

When thinking in angles, bear in mind that the established dovetail shape isn’t the only application. The two-part sliding box shown above accomplishes the same restraint as a dovetail, but looks more like a plate with angled sides. This allows it to slide together with the other half of the box easily, and even includes a little detent at the end to snap it shut. This shape would be very hard to manufacture by most other means, but the Mark Two was able to 3D print joints without supporting materials and achieve a great fit.


Check out our Composites Design Guide

Exploring even further, angled geometry in general can help in 3D printing. For instance, printing a sideways V profile, shown below on the left, can create a constraint that would be difficult to machine, but is trivial to print. Meanwhile, a classic tongue and groove joint, as shown on the right, is hard for most printers to make because of the overhang it creates. This overhang results in a poorly supported bottom face with bad dimensional accuracy, and should be avoided if possible.


‍‍Profiles of a sideways V wall (left) and a tongue-and-groove joint (right)

Snap Fits

Snap fits are a commonly used method for cheaply joining injection molded parts. These are good shapes for plastics because they stay within the geometric constraints of mold making and use plastic’s ability to elastically deform and then snap back into shape. Because snap fits are designed for plastic, they are easily adopted for 3D printing…on the XY plane. Most 3D printer users know that objects printed on desktop FDM printers are significantly more susceptible to failure in tension along the Z axis (pointing out of the build plate) than in X and Y, because of the inter-layer boundaries. Since snap fits usually have thin cross-sections (to reduce bending moment of the clip), 3D printed snap fits must be printed “laying down” on the build plate, lest they risk shearing after repeated use.


‍‍‍Diagram of cantilever snap joint, printed in three possible orientations

This diagram shows an exaggerated visualization of the layers of a printed snap fit. When printed upright (pictured at left), the forces that deflect the snap fit also put tension between the layers, making it significantly more likely to break. Printed on its back (pictured at center), a snap fit will definitely be stronger, but still has a shear plane running between the tooth and the arm. Printed laying down on its side (pictured at right), however, the snap fit has no layer boundaries within its cross-section, giving it more predictable strength. And, if the snap fit is big enough, printing it on its side would allow fiber to be routed into the tooth, thereby utilizing the full strength of a Markforged part. This same rule applies for gear teeth, ratchet teeth, and any other protrusion that needs to hold significant load.


Request a free sample part

Bear in mind also that snap fits can take many forms based on application, and that the design and orientation of the snap fit may change based on your project. In particular, snap fits coming out of 3D printer are not constrained by thicknesses or mold shapes, so you can get creative with where you put them (see below). Printers make it quick and easy to prototype, so try a few geometries before settling on the final shape.


A flush snap fit mortise a ndtenon joint
Cross section of flush snap fit mortise and tenon

Putting it Together: Phone Holder

To exhibit sliding fits and snap mechanisms, I designed this cell phone holder that hooks over the hood of the Mark Two and holds any cell phone between 2.5 and 4 inches wide, so that an operator could take a time lapse video or monitor a sensitive print.


‍‍The phone holder with a phone in its grasp

This phone holder has just three parts, two interfaces. One of those interfaces is a twisting joint that acts as a hinge. Though it doesn’t look much like a dovetail, it serves the same purpose: it allows for an easily printable sliding fit, thanks to complementary angles.


‍Disassembled phone holder (left) and hook (right)
‍Rotating joint locking into place

The other interface works like a linear ratchet with angled walls (to keep them from slipping apart) and teeth to set the width of the holder. This would be a very difficult interface to machine make by most other means, but it was quite easy and quick to print!


The teeth of the linear ratchet with the corresponding face (right)
‍‍The linear ratchet for adjusting to phone width, engaged
‍‍The phone case in use, watching a Mark Two print

A Note on Tolerances

As with anything, joinery requires designing in your tolerances. On the Mark Two composite 3D printer, for most general purposes, a .08mm gap between each wall (.16mm diametrically) is enough to allow two pieces to consistently achieve a sliding fit. If one of your surfaces is held up by support material, try bumping up the gap to .15mm or so. Of course, 3D printed parts tend to vary widely, so make sure to unit test and prototype to achieve the fit you want.

This is just one small example of how designing with joinery in mind can lead to designs that are simpler and better-fit for your 3D printer. As you find good joints for printing, tweet at us @MarkForged to share your designs!

3D Printing Joints

  • 3D printing press fit parts
  • 3D printed joinery
  • Snap-fit joints for plastics
  • Snap-fit design manual
  • Buckle example
  • 3D Printed Captured Nuts
  • Fasteners and 3D printed parts

Sliding Fit Assembly – Applying traditional woodworking joinery to 3D printed parts.

  • 3D guide to Joinery (twitter)
  • 50 Digital wood joints

Press-Fit Assembly – Using the friction between two components to hold something in place. A good example for this are lego bricks. They have such a precise tolerance that pieces can snap and come apart with no problems.

Snap-Fit Assembly

Cantilever Snap joints – are the most common – Typically, a semi-flexible cantilevering hook is deflected slightly as it is inserted into a hole or past a latch plate. As the hook passes the edge of the hole, the cantilever beam returns to its original shape.

Annular snap joints – Great for circular applications – Classic examples of ASJs include ballpoint pens with snap-on caps, and the child-resistant cap on Tylenol bottles. One piece is more flexible than the other – in this case when you’re using the same material, that means one piece is thinner and therefore more flexible.

Ball Joints



  • Geodesic Dome Joints

Hinges - Snap fit pivots - A good way to print a hinged pivot point. One component uses a protruding annular ball joint. The protrusion is split in half. When the component is being inserted, this gap allows the two halves to deflect and squeeze together. Once the piece is through the hole, pressure is released and the ball expands again to hold the piece in place.





http://www.thingiverse.com/thing:59332


http://www.caddedge.com/stratasys/3d-printing-blog/3d-printing-living-hinge-protoytpes


Kinematics by n-e-r-v-o-u-s http://www.thingiverse.com/thing:195497

1. Experiment with clearance sizes

Usually when fitting two parts together and printing on a desktop FDM printer, the male and female parts of the joint must have a certain clearance between to account for material tolerance. This clearance can vary anywhere from 0.1mm – 0.3mm depending on the printer resolution, material, speed, and more.

2. Test early and often

It’s good to test your connections to find the right tolerance. To avoid wasting time and material, print only the parts you are trying to test instead of the entire model.

3. Building up snaps in the Z-layer has the least amount of strength

Try to avoid printing your snaps in the Z direction (built up from the print bed vertically), they are much weaker than parts printed in the x/y direction.

4. Be careful with scaling

It is always best to model your parts at the right scale. But when you do need to scale a model with connecting parts, it will require you to readjust your tolerances.

Self Threading Screws

This is a great technique for a quick and dirty prototype. Using self tapping screws is quick, cheap and requires minimal design efforts.



Custom Designed Threads in Your 3D Model

If you are using something with large threads, it is best to design them since trying to self tap would require a huge effort. This is only advised for large components (when printing on desktop FDM printers) – the resolution is not adequate for small machined components.



Captive Nut

A great technique for fastening is designing an inset in your model to hold a hex nut. This is great when you want to use machined bolts. It’s important to use your calipers to get exact dimensions and give enough tolerance for fitting your hex nut.



Using high heat to melt metal threaded hardware into your 3D print. The inside of this is nicely threaded for precise machined screws while the outside is roughed with gripping pattern. When it’s melted into the plastic, it will grip nicely and fit snugly when the plastic cools down around it.



How to:

  • Get a crappy soldering iron (not one of nice working ones from the BTU lab)
  • Heat your iron to low and preheat the threaded insert. This should only take a few seconds.
  • Align and place the insert on your model (use some tweezers)
  • Use the tip of the iron and carefully push the insert into the plastic using little pressure. Once the insert is aligned flat with the top surface of the plastic, remove your iron.

Pro tip: practice on a test print first!!!

All about 3D printing. additive manufacturing. Basic concepts.

  • 1 Technology
  • 2 Terminology
  • 3 Fundamentals
  • 4 Printing Technologies
  • 5 3D printers
  • 6 Application
  • 7 Domestic and hobby use
  • 8 Clothing
  • 9 3D bioprinting
  • 10 3D printing of implants and medical devices
  • 11 3D printing services
  • 12 Research into new applications
  • 13 Intellectual Property
  • 14 Influence of 3D printing
  • 15 Space research
  • 16 Social change
  • 17 Firearms

Technology




Charles Hull - the father of modern 3D printing
3D printing is based on the concept of building an object in successive layers that display the contours of the model. In fact, 3D printing is the complete opposite of traditional mechanical production and processing methods such as milling or cutting, where the appearance of the product is formed by removing excess material (so-called "subtractive manufacturing").
3D printers are computer-controlled machines that build parts in an additive way. Although 3D printing technology appeared in the 80s of the last century, 3D printers were widely used commercially only in the early 2010s. The first viable 3D printer was created by Charles Hull, one of the founders of 3D Systems Corporation. At the beginning of the 21st century, there was a significant increase in sales, which led to a sharp drop in the cost of devices. According to the consulting firm Wohlers Associates, the global market for 3D printers and related services reached $2.2 billion in 2012, growing by 29%.% compared to 2011.
3D printing technologies are used for prototyping and distributed manufacturing in architecture, construction, industrial design, automotive, aerospace, military-industrial, engineering and medical industries, bioengineering (to create artificial fabrics), fashion and footwear, jewelry, in education, geographic information systems, food industry and many other areas. According to research, open source home 3D printers will allow you to win back the capital costs of your own purchase through the economy of household production of items.

Terminology




Additive manufacturing involves the construction of objects by adding the necessary material, and not by removing excess, as is the case with subtractive methods
The term "additive manufacturing" refers to the technology of creating objects by applying successive layers material. Models made using the additive method can be used at any stage of production - both for the production of prototypes (so-called rapid prototyping) and as finished products themselves (so-called rapid production).
In manufacturing, especially machining, the term "subtractive" implies more traditional methods and is a retronym coined in recent years to distinguish between traditional methods and new additive methods. Although traditional manufacturing has used essentially "additive" methods for centuries (such as riveting, welding, and screwing), they lack a 3D information technology component. Machining, on the other hand, (the production of parts of an exact shape), as a rule, is based on subtractive methods - filing, milling, drilling and grinding.
The term "stereolithography" was defined by Charles Hull in a 1984 patent as "a system for generating three-dimensional objects by layering".

Fundamentals


3D printed models

3D models are created by hand-held computer graphic design or 3D scanning. Hand modeling, or the preparation of geometric data for the creation of 3D computer graphics, is somewhat like sculpture. 3D scanning is the automatic collection and analysis of data from a real object, namely shape, color and other characteristics, with subsequent conversion into a digital three-dimensional model.
Both manual and automatic creation of 3D printed models can be difficult for the average user. In this regard, 3D printed marketplaces have become widespread in recent years. Some of the more popular examples include Shapeways, Thingiverse, and Threeding.
3D printing


The following digital models are used as drawings for 3D printed objects , powder, paper or sheet material, building a 3D model from a series of cross sections. These layers, corresponding to virtual cross-sections in the CAD model, are connected or fused together to create an object of a given shape. The main advantage of this method is the ability to create geometric shapes of almost unlimited complexity.
"Resolution" of the printer means the thickness of the applied layers (Z-axis) and the accuracy of positioning the print head in the horizontal plane (along the X and Y axes). Resolution is measured in DPI (dots per inch) or micrometers (the obsolete term is "micron"). Typical layer thicknesses are 100µm (250 DPI), although some devices like the Objet Connex and 3D Systems ProJet are capable of printing layers as thin as 16µm (1600 DPI). The resolution on the X and Y axes is similar to that of conventional 2D laser printers. A typical particle size is about 50-100µm (510 to 250 DPI) in diameter.

One of the methods for obtaining a digital model is 3D scanning. Pictured here is a MakerBot Digitizer
3D Scanner Building a model using modern technology takes hours to days, depending on the method used and the size and complexity of the model. Industrial additive systems can typically reduce the time to a few hours, but it all depends on the type of plant, as well as the size and number of models produced at the same time.
Traditional manufacturing methods such as injection molding can be less expensive when producing large batches of polymer products, but additive manufacturing has advantages in small batch production, allowing for higher production rates and design flexibility, along with increased cost per unit produced. In addition, desktop 3D printers allow designers and developers to create concept models and prototypes without leaving the office.
Machining

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 print head 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, the US-Israeli joint venture Stratasys supplies machines for additive manufacturing ranging from $2,000 to $500,000, 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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The scope of applications of additive technologies is wide: on one extreme - desktop printers "only PLA", for decorative use, on the other - installations for direct printing with metals, between them - equipment and materials in assortment. To understand what materials are needed to obtain a strong and lightweight part, we are moving from personal printing to industrial printing. PLA, ABS, SBS are consumables that are familiar to all printers. PETG, nylon, polycarbonate - rather exotic. But these are far from the most serious materials.

Where are superplastics needed?

Plastics with outstanding properties are very useful in space. No, it’s not yet possible to print a rocket engine out of plastic, the heat resistance is not even close to the same, but it is ideal for various parts around. An example is Stratasys and the "climate control" of Atlas V rockets. 16 printed parts instead of 140 metal parts - faster, lighter, cheaper. And this is not a theoretical project, it has already flown into space.

Another example is aviation. The flight altitude is lower, but the application is more massive. Here, too, there is a reason to reduce the mass of parts, switch to plastic where possible. It is used in the aircraft industry and direct metal printing, when it comes to engine components or fuselage frame parts, but less loaded structural elements, such as cabin ventilation and interior elements, are best made from plastic. This direction is being developed, for example, by Airbus.

We descend from heaven to earth: here the mass is no longer so critical, other properties of engineering plastics are of interest. Resistance to aggressive chemicals and elevated temperatures, the ability to create structures inaccessible to classical methods. At the same time - a lower price, in comparison with metal printing. Printed products are used in medicine, oil and gas industry, chemical industry. As an example, a mixing block with a complex channel structure, made for illustration in a section.

Difference from conventional plastics

Why not launch PLA into space and make ABS air vents in aircraft cabins? A number of requirements are applied to engineering plastics related to resistance to high and low temperatures, fire resistance, mechanical strength. Usually all at once. So, it is undesirable to launch PLA “floating” when interacting with the environment or perfectly burning ABS into the sky.

Now - to what, in fact, plastics are used in industrial printing using FDM / FFF technology.

Polycarbonate filaments

Polycarbonate is a common industrial plastic with high impact resistance and transparency, also produced for the needs of FDM printing. The material holds temperature better than ABS, is resistant to acids, but is sensitive to UV radiation and is destroyed by oil products.

Clear polycarbonate, PC

The maximum operating temperature for polycarbonate products is 130 °C. Polycarbonate is biologically inert, products made from it can withstand sterilization, which makes it possible to print packaging and auxiliary equipment for medicine.

  • Stratasys PC, PC-ISO for Fortus printers. The first is general purpose, the second is certified for biocompatibility, for medical use.
  • Intamsys PC;
  • Esun ePC;
  • SEM PC;
  • PrintProduct PC;

ABS/PC

Polycarbonate/ABS alloy combines the sanding and painting capabilities of ABS with higher impact resistance and operating temperature. Retains strength at low temperatures down to -50 °C. Unlike pure PC, it is better applicable in cases where it is necessary to eliminate the layered structure of the part by grinding or sandblasting. Application: production of housings and elements of controls for piece and small-scale production, replacement of mass-produced plastic parts in equipment, parts for which have ceased to be produced.

  • Stratasys PC/ABS;
  • Roboze PC-ABS;
  • SEM ABS/PC;
  • BestFilament ABS/PC.

Polyamide based filaments

Polyamides are used in the production of synthetic fibers, a popular material for printing by selective laser sintering (SLS). For printing using FDM / FFF technology, polyamide-6 (kapron), polyamide-66 (nylon) and polyamide-12 are mainly used. Common features of polyamide-based filaments include chemical inertness and anti-friction properties. Polyamide-12 is more flexible and resilient than PA6 and PA66. Operating temperature approx. 100 °C, some modifications up to 120.

First of all, gears are printed from polyamide. The best material for this purpose, which can be worked with on a regular 3D printer with a closed chamber. Abrasion resistance allows you to make rods, cams, sliding bushings. In the line of many manufacturers there are composite filaments based on polyamide, with even greater mechanical strength.

  • Stratasys Nylon 6, Nylon 12, Nylon 12CF. The latter is filled with carbon fiber.
  • Intamsys Nylon, PA6.
  • Taulman Nylon 618, Nylon 645 based on PA66 and PA6 respectively. Nylon 680 is approved for use in the food industry. Alloy 910 is a low shrinkage polyamide alloy.
  • PrintProduct Nylon, Nylon Mod, Nylon Strong;
  • REC Friction;
  • BestFilament BFNylon.

Let's move on to the most interesting

You can work with polycarbonate or polyamide on a regular 3D printer. With the filaments described below, it is more difficult, they require other extruders and maintaining the temperature in the working chamber, that is, you need special equipment for printing with high-temperature plastics. There are exceptions - for example, NASA, for the sake of experiment, upgraded the Lulzbot TAZ popular in the USA to work with high-temperature filaments.

Polyetheretherketone, PEEK

The operating temperature of PEEK products reaches 250 ° C, short-term heating up to 300 is possible - indicators for reinforced filaments. PEEK has two disadvantages: high price and moderate impact resistance. The rest is pluses. The plastic is self-extinguishing, heat-resistant, chemically inert. Medical equipment and implants are produced from PEEK, abrasion resistance makes it possible to print parts of mechanisms from it.

  • Intamsys PEEK;
  • Apium PEEK;
  • Roboze PEEK, Carbon PEEK. The second is reinforced with carbon fiber.

Polyetherimide, PEI


He is Ultem. A family of plastics developed by SABIC. The characteristics of PEI are more modest than those of PEEK, but the cost is noticeably lower. Ultem 1010 and 9085 are Stratasys' primary materials for printing functional parts. PEI is in demand in the aerospace industry - the mass is much less compared to aluminum alloys. Operating temperatures of products, depending on the modification of the material, reach 217 ° C according to the manufacturer and 213 - according to the results of tests by Stratasys.

The advantages of PEI are the same as those of PEEK - chemical and temperature resistance, mechanical strength. It is this material that Stratasys is promoting as a partial replacement for metal in the aerospace industry, for drones, the manufacture of tooling for molding, the rapid printing of functional parts in pilot production.

Atlas V rocket cooling system components and Airbus plastic parts shown as an example at the beginning of the review are made of Ultem 9085.

  • Stratasys Ultem 1010 and 9085, for Fortus 450mc and 900mc printers.
  • Intamsys Ultem 1010 and 9085;
  • Roboze Ultem AM9085F;
  • Apium PEI 9085.

Polyphenylsulfone, PPSF/PPSU

Another material that combines in its properties temperature resistance, mechanical strength and resistance to chemical attack. Stratasys PPSF is certified for aerospace and medical applications. Positioned as a raw material for the production of auxiliary medical devices, it can be sterilized in steam autoclaves. It is used in the production of parts for laboratory installations in the chemical industry.

  • Stratasys PPSF;
  • 3DXTech Firewire PPSU.

Polysulfone, PSU

Less common than PPSU, similar physical characteristics, chemically inert, self-extinguishing. 175°C operating temperature, up to 33% cheaper than PPSU.

  • 3DXTech Firewire PSU

Comparison of filament characteristics

* calcination for 2 hours at 140 °C.
** Apium PEEK 450 natural, impact test results not available with similar methods. Temperature resistance is specified for unfilled PEEK.

Data shown for Stratasys filaments, excluding PEEK. If a range of values ​​is indicated, then the tests were carried out along and across the layers of the part.

About composite filaments

Most FDM printing materials have composite versions. If we talk about PLA, then metal or wood powders are added to it to change the aesthetic properties. Engineering filaments are reinforced with carbon fiber to increase the rigidity of the part. The influence of such additives on the properties of plastic depends not only on their quantity, but also on the size of the fibers. If a fine powder can be considered a decorative additive, then the fibers already significantly change the characteristics of the plastic. By itself, the word Carbon in the name of the material does not yet mean outstanding properties, you need to look at the test results. For example: Stratasys Nylon12CF has almost twice the tensile strength, when tested along the layers, than Nylon12.

An exotic variant of Markforged's implementation of continuous reinforcement. The company offers a reinforcing filament for co-FDM printing with other plastics.

Other specific properties

Engineering plastics are not only resistance to high temperatures and mechanical strength. For housings or boxes for storing electronic devices, and in environments where flammable volatile liquids are used, materials with antistatic properties are required. In the Stratasys line, this is, for example, ABS-ESD7.

  • Stratasys ABS-ESD7;
  • Roboze ABS-ESD

Conventional ABS does not have UV resistance, which limits its outdoor use without a protective coating. As an alternative, ASA is offered, which has characteristics similar to ABS, except for the UV resistance.

  • REC Eternal;
  • SEM ASA;
  • BestFilament ASA.

Original alternative

Plastic can replace metal in many areas, as it surpasses it in lightness, thermal and electrical insulation, resistance to reagents. But printouts from the best FDM filaments do not reach the physical indicators of metal products.

Chemical giant BASF offers the Ultrafuse 316LX FDM filament, with a stainless steel content of 80%. The part is printed on an FDM printer and then placed in an oven where the binder plastic is burned off and the metal is sintered. The part obtained in this way is much cheaper than the one made by direct metal printing. With an FDM printer and a suitable oven, no new equipment is needed at all.

Note that a similar solution is offered by the Virtual Foundry company - its Filamet, with bronze or copper powder, is baked in a similar way. The choice of metal hints at decorative rather than engineering applications.

AIM3D has its own implementation of this principle - the ExAM 255 printer does not work with filament, but with granules. This allows the use of raw materials for FDM printing, which are usually used in MIM installations, Metal Injection Molding. For sintering the part, the company offers an ExSO 9 furnace0. It is also possible to print with plastic granules, which is usually cheaper than using traditional filament.

Special machinery for engineering plastics

To recap.


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