3D printing is a very versatile method of production and rapid prototyping. Above last decadesit has made waves in many industries around the world.
3D printing is part of a family of manufacturing technologies called additive manufacturing. This describes creating an object by adding material to the object layer by layer. Throughout its history, additive manufacturing has gone by different names, including stereolithography, 3D layering, and 3D printing, but 3D printing is the best known.
So how do 3D printers work?
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How does a 3D printer work?
The process of 3D printing begins by making a graphic model of the object to be printed. These are usually designed using computer-aided design (CAD) software packages, and this can be the most laborious part of the process. Programs used for this include TinkerCAD, Fusion360and sketchup.
For complex products, these models are often extensively tested in simulation for any potential flaws in the final product. Of course, if the object to be printed is purely decorative, it matters less.
One of the main advantages of 3D printing is that it allows rapid prototyping of almost anything. The only real limit is your imagination.
In fact, some objects are simply too complex to be created in more traditional manufacturing or prototyping processes like CNC milling or molding. It is also much cheaper than many other traditional manufacturing methods.
After design, the next phase is to digitally cut the model to get it for printing. This is an essential step because a 3D printer cannot conceptualize a 3D model the way you or I can. The slicing process breaks up the model into multiple layers. Each layer’s design is then sent to the printhead to be printed or deposited in order.
The slicing process is usually completed using a special slicing program like Arts and crafts Where Astroprint. This slicing software will also handle “infilling” the model by creating a lattice structure inside a solid model for extra stability if needed.
This is also an area where 3D printers excel. They are able to print very resistant materials with very low densities thanks to the strategic addition of air pockets inside the final product.
The slicer software will also add support columns, if needed. These are necessary because the plastic cannot be dropped in the air and the columns help the printer fill in the gaps. These columns are then removed later if necessary.
Once the slicer program has taken effect, the data is then sent to the printer for the final step.
From there, the 3D printer itself takes over. It will start printing the model according to the specific instructions of the slicer program using different methods, depending on the type of printer used. For example, direct 3D printing uses technology similar to inkjet technology, in which the nozzles move back and forth, up and down, dispensing thick wax or plastic polymers, which solidify to form each new cross-section of the 3D object. Multi-jet modeling uses dozens of jets operating simultaneously, for faster modeling.
In binder 3D printing, inkjet nozzles apply a fine dry powder and a liquid glue, or binder, which come together to form each printed layer. Binder printers make two passes to form each layer. The first pass deposits a thin layer of powder and the second pass uses the nozzles to apply the binder.
In light-curing, drops of a liquid plastic are exposed to a laser beam of ultraviolet light, which converts the liquid into a solid.
Sintering is another 3D printing technology that involves melting and fusing particles to print each successive layer. Related sElective laser sintering relies on a laser to melt a flame retardant plastic powder, which then solidifies to form the printed layer. Sintering can also be used to make metal objects.
The 3D process can take hours or even days, depending on the size and complexity of the project.
“There are faster technologies splashing the industry, like the Carbon M1, which uses lasers shot into a bed of liquid and extracts the print from it, dramatically speeding up the process. But these types of printers are much more complicated, much more expensive, and only works with plastic so far.” – howtogeek.com.
Regardless of the type of 3D printer used, the overall printing process is generally the same.
- Step 1: Produce a 3D model using CAD software.
- 2nd step: The CAD drawing is converted to Standard Tessellation Language (STL) format. Most 3D printers use STL files in addition to other file types such as ZPR and ObjDF.
- Step 3: The STL file is transferred to the computer that controls the 3D printer. There the user designates the size and orientation for printing.
- Step 4: The 3D printer itself is configured. Each machine has its own set-up requirements, such as filling polymers, binders, and other consumables that the printer will use.
- Step 5: Start the machine and wait for the build to complete. The machine should be checked regularly during this period to ensure that there are no errors.
- Step 6: The printed object is removed from the machine.
- Step 7: The last step is post-processing. Many 3D printers require some type of post-processing, such as brushing off any remaining powder or washing the printed object to remove water-soluble carriers. The new object may also need hardening.
What can a 3D printer do?
As we have already seen, 3D printers are incredibly versatile. They can, in theory, create almost anything you can think of.
But they are limited by the types of materials they can use for “ink” and by their size. For very large objects, say a house, you will need to print individual parts – or use a very large 3D printer.
3D printers are able to print in plastic, concrete, metal and even animal cells. But most printers are designed to use only one type of material.
Some interesting examples 3D printed objects include, but are not limited to:-
- Prosthetic limbs and other body parts
- Houses and other buildings
- Fire arms
- Liquid structures
- Glass products
- Acrylic objects
- Movie props
- Musical instruments
- Medical models and devices
3D printing has clearly applications in many industries.
What are some types of 3D printing software?
Different CAD software will use a variety of file formats, but some of the most common are:
- STL – Standard Tessellation Language, or STL, is a 3D rendering format that can usually only handle a single color. This is typically the file format used by most desktop 3D printers.
- VRML – Virtual reality modeling language, the VRML file is a newer file format. These are typically used for printers with more than one extruder and can handle creating multicolor models.
- MFA – Additive manufacturing file format, it is an open standard based on .xml for 3D printing. It can also support multiple colors.
- GCode – GCode is another file format that can contain detailed instructions for the 3D printer to follow to lay down each slice.
- Other formats – Other 3D printer manufacturers also have their own proprietary file formats.
What are the advantages of 3D printing?
As already discussed above, 3D printing can have various advantages over more traditional manufacturing processes such as injection molding or CNC milling.
3D printing is an additive process, rather than a subtractive one like CNC milling. 3D printing builds things up layer by layer as the latter gradually removes material from a solid block to create a product. This means that in some cases 3D printing can be more resource efficient than CNC.
Another example of traditional manufacturing processes, injection molding, is ideal for making many high-volume items. Although it can be used to create prototypes, injection molding is best suited for large-scale mass production of an approved product design. However, 3D printing is better suited for small limited runs or prototyping.
Depending on the use, 3D printing has other advantages over other production processes. These include, but are not limited to:
- Faster production – Although sometimes slow, 3D printing can be faster than some conventional processes like injection molding and subtractive production.
- Easy access – 3D printing has been around for a few decades now and has exploded since around 2010. There are now a wide variety of printers and software packages available (many of which are open source), making it easy for almost anyone to learn to do it.
- Better quality products – 3D printing produces consistent product quality. As long as the model is accurate and fit for purpose and the same type of printer is used, the end product will generally always be of the same quality.
- Ideal for product design and testing – 3D printing is one of the best tools for product design and testing. It provides opportunities to design and test models to enable refinement with ease.
- Profitable – 3D printing, as we have seen, can be a profitable means of production. Once the model is created, the process is usually automated and raw material waste tends to be limited.
- Product designs are nearly endless – The possibilities of 3D printing are almost limitless. As long as it can be designed in CAD and the printer is big enough to print it, the sky is the limit.
- 3D printers can print using various materials – Some 3D printers can actually mix or switch between materials. In traditional printing, this can be difficult and expensive.