In fact, the scientific name of 3D printing is "additive manufacturing", which is a kind of rapid prototyping technology. Based on a three-dimensional digital model file, it uses bondable materials such as plastic or powdered metal to create objects by building up layer by layer.
Principles and Uses of 3D Printing
The following is a relatively authoritative categorization of 3D printing processes by the American Standards Committee.
Light Curing
Liquid photosensitive resins undergo a curing reaction after exposure to light and solidify into the shape of the product.
Laser Sintering
Powdered raw materials (metal, plastic, gypsum, etc.) are irradiated by energy beams (lasers or electron beams, etc.), and the layers are melted and molded; or the powder is bonded and molded by some adhesives.
Lamination
An older 3D printing process, first used in archaeology, when dinosaur fossils or human skulls were recovered, using the way of cutting cardboard to make a model of the fossil.
Fused Deposition
A more common process, the desktop machine is a machine based on the extrusion process. A wide variety of materials are used, including not only plastics, but also some foods, such as chocolate, bean paste, and even construction-type materials, such as cement, mud, and other pastes.
Directed Energy Deposition
The metal powder or wire directly on the surface of the product melting and curing, suitable for repair parts, but also in the unity of the parts using a variety of materials. This technology is still the leading technology in our country, won the first prize of the National Scientific Progress from Beihang Wang Huaming team, is the use of this technology to produce about four meters of aircraft parts, and used in aerospace related industries.
Hybrid Additive
This is a relatively new technology, is a CNC machine tools supporting additive manufacturing package, the typical materials are metal powder, wire and ceramics. Because almost all 3D prints don't end when they are printed, they require post-processing. So this technique of using both additive and subtractive materials can solve the problem of post-processing at the same time.
The uses of 3D printing can be broadly categorized into three types: concept modeling, prototype testing, and direct digital fabrication.
Concept modeling and prototype testing are the two more traditional uses, which simply means making models, and the main function is to do verification, such as structural verification, appearance verification, functional verification and assembly verification. Direct digital manufacturing is now a popular trend, that is, the finished product can be printed directly as a final product or parts directly to the end use.
I can give you a few examples. For example, concept modeling, our company and Chevrolet cooperation to do a public service activities, content is to collect children's imagination of the future of the car. Through their paintbrushes to draw a car pattern, and we turn the pattern into a digital model, and then through the printing and post-coloring to form a physical object. It's a dream-turned-reality process that can turn an original idea into a beautiful prototype.
There is also a robotics company doing prototype testing at our company. Initially we would print the drawings of their design, but as soon as there was a non-compliant part in the middle, we replaced it immediately. Through constant iteration and repeated validation, we finally printed a grid of shells. As you can see in the picture below, the gap between the initial design and the final product is still quite large.
An example of direct digital fabrication is fashion-related, the work of a Wuhan University student. Both the bracelet and the garment were printed in nylon. After the designer finished the design, we printed the entire concept and then tested it for wearability and toughness before the model wore it on the runway.
Direct manufacturing tools in this area are generally related to the metal class, the current price is still relatively high, mostly used in the defense, aviation and other industries with weight reduction and confidentiality requirements. The country is building the world's largest astronomical observatory telescope in the eye of the sky some of the key components by us to design and complete the manufacture of metal printing.
The routine process of 3D printing
The first thing is to have the data, if there is a physical object can be built through 3D scanning 3D printing model, if there is a 2D drawing can be converted into a 3D model through software. If there is nothing, then the only way to start from scratch is to use software to model. Then the model with slicing software, after completing the slicing can start 3D printing. After the printing is completed, most of them still need to do post-processing (sanding, plating, spraying, stretching, etc., coloring is optional), otherwise it is a semi-finished product.
The main advantages of 3D printing
First of all, it saves time, in contrast to traditional processes, which themselves are still a bit slow to be honest. Secondly, it saves material, as it produces almost no waste. Furthermore, it is accurate, especially for curved surfaces and the reduction of complex processes. Finally, it is individuality, which can meet the design of more and more personalized and complex prototypes. So on the whole, 3D printing is very suitable for personalized, complex, small batch, non-standard parts of the prototype production.
But its biggest advantage is that, as the complexity of the part increases, the difficulty and cost of its manufacturing process does not increase. That is, designers only need to consider the realization of the function of the part, and do not need to be too entangled in what manufacturing process to be used to produce.
3D printing for the manufacture of complex parts have very big advantages, so it is still mainly used in industrial manufacturing. This brings us to the question of the level of application of 3D printing, that is, why we do not feel that 3D printing has made any direct changes to our lives.
Levels of 3D Printing
"Prototyping" is the lowest level of 3D printing, such as making models, prototypes, and other individual things, but it is also the most traditional application of 3D printing.
The second level is "substitution". Making a part that replaces an existing part. But the application is not widespread, because the traditional manufacturing process is very suitable for large-scale batch production, 3D printing is not superior.
The third is "part integration". Single-part production 3D printing may not be advantageous, but if you can integrate multiple parts into a single part printed out, the overall value will go up.
The most advanced applications not only integrate multiple parts, but also optimize them. Because 3D printing can do very complex processes that can't be done with other processes. General Aviation previously used 3D printing to make an aero-engine nozzle, which is a landmark case. This injector nozzle integrated more than 20 parts, there are very complex cooling pipes, lubrication pipes. Not only does it improve fuel efficiency highly, but it also extends the service life by five times without the need to produce more than 20 parts to assemble them.
So how 3D printing affects everyone may require some adjustments in thinking. At some point in the future, when we design, we don't need to think about what tools to use for production, and even the process of thinking about how to design will change. We only need to think about the design goals, give boundary values, and get the optimal result through math and computer simulation. For example, last year, one of the highest design awards in the UK was given to such a case. A small aerospace part, through topology optimization, the weight is less than half of the original, but the strength is more than double the original, and finally the manufacturing method of 3D printing. In this way, the advantages are obvious.
Economization analysis of 3D printing
The number of products is still relatively obvious within a thousand, but as the cost of 3D printing decreases, the range of quantities is increasing. In the case of casting, for example, there is also a balance between the factors of quantity, production time and complexity. In the future we will see more and more odd shaped objects that are shaped directly by math and computers. This increase in process complexity will not make 3D printing difficult, but for traditional processes this increase is a nightmare.
The number of companies using the 3D printing process to do production is increasing now, and a while back General Motors bought two 3D printing companies that do 3D printing of metals. Many believe that this may be a sign that 3D printing is entering mainstream manufacturing. In addition, 3D printing has some applications in medicine, and some people use it to print some optical devices. In the future, construction, aircraft and other kinds of applications, will be involved. 3D printing is actually a kind of basic instrumental things, just like the Internet or highway, is everyone will be used.