Types of materials that can be used with 3D printers
For 3D printing that does not fail, it is necessary to consider not only the shape of the modeled object but also the appropriate material according to the application. 3D printers for metals Nowadays, it has become possible to model various materials such as metals, carbon materials, and super engineering plastics with 3D printers. Before talking about -, let's first look at the major categories of the main materials.
Material 1. plastic
One of the most frequently used materials is plastic material. Materials that can be handled by personal and home 3D printers are basically classified as plastics, so you'll likely see them a lot. The biggest reason for its frequent use is that the processing equipment is simple. There are many types of plastic materials such as PLA, nylon, and ABS, but most of them have thermoplasticity that softens when heated, or are light-curing resins that harden when exposed to light. Also, it is much cheaper than other materials.
On the other hand, the property of softening when heated is also a weakness from the viewpoint of heat resistance, so care must be taken when using it in a high temperature environment. It is also difficult to use as an industrial part. There are plastic materials with excellent durability, heat resistance, and chemical resistance called super engineering plastics, but 3D printers that can handle them are correspondingly expensive.
Material 2. Composite
A composite material that combines two or more types of materials is called a composite, and in the 3D printer industry, it mainly refers to FRP materials (fiber reinforced plastic materials) that combine plastic and fiber materials. By mixing carbon fiber, glass fiber, Kevlar fiber, etc., the fiber strengthens the material and achieves a high strength that cannot be achieved with plastic alone. Composite 3D printed objects maintain the ease of processing and lightness of plastic, while exhibiting strength comparable to that of metal.
However, since the main material is plastic, it is also vulnerable to high heat and surface friction. If you take this point into consideration and use it properly, it will be possible to manufacture highly competitive parts that are stronger than plastic, lighter and cheaper than metal, and it is already being used in many industrial fields.
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Material 3. metal
As the third major category, we will introduce metal materials, which is the main topic of this article. In general, metals are materials with higher heat resistance than plastics, higher strength and rigidity, chemical resistance, and electrical conductivity. Because of this feature, metal 3D printers can be used in more demanding conditions.
On the other hand, metals are more stable than plastics and take time to deform, so large-scale equipment is required for processing. In addition to the weight of materials and objects, electrical and ventilation equipment is required at industrial standards, so not only the 3D printer itself but also the equipment must be of a certain scale. In some cases, chemicals that require management are used, and it is not possible to introduce them as easily as 3D printers for plastic materials.
However, since there are many effects of using 3D printers, it is desirable to identify effective situations and operate them in appropriate situations, rather than blindly introducing them. Details will be introduced below.
Elastomer material is introduced as an extra edition. Since it is classified as a polymer resin, it is a material similar to plastic, but it is characterized by being soft like rubber and having a certain degree of deformation, elasticity, and resilience even after molding. Most of them are 3D printed by light curing, and are mainly used in fields such as shoe cushions and parts such as springs, which are complex and require different shapes each time.
At the research level, 3D printing of cells, semiconductors, magnets, etc. is being attempted.
Features and processing methods of metal 3D printers
There are various methods for metal 3D printers. It is important to select the appropriate method because the types of materials that can be used, the shapes that can be molded, the sizes that can be molded, and the method of post-processing change greatly depending on the molding method. Here, we will introduce three main molding methods.
PBF (Powder Bed Fusion) method
PBF is a method translated as "powder bed fusion bonding". Fine metal powder is spread thinly over the entire area inside the device, heated with a laser beam or electron beam, etc., partially melted and bonded, and repeatedly layered to create a modeled object. Masu. While it is possible to create complex shapes similar to 3D printing, it is not good at materials such as aluminum and copper, which have high light reflectance, and some of the metal powders used are at risk of burning if exposed to air, making them expensive. Large-scale facilities and equipment are required, such as protective equipment, equipment to prevent dust explosions, and priority and management of inert gas to prevent oxidation. In addition, used metal powders may be required to be discarded except for a portion that can be reused, and even replacing materials requires extensive maintenance by experts.
Directed Energy Deposition (DED) method
DED is a method called "directed energy deposition method" and is sometimes called PD (Powder Deposition) method. The basic method and energy used are common to the PBF method, and both use lasers, electron beams, etc. to melt and layer metal materials.
However, while PBF spreads the powder layer by layer over the entire surface, DED places the material only in the area to be irradiated, which is a major difference. Therefore, while there is the advantage of using less material, more accurate material supply to the laminated part is required.
Due to the above characteristics, the larger the layered part, the more stable the molding, so the DED method is good at manufacturing relatively large and simple shapes. In addition, since it is possible to add materials locally, it is also possible to repair existing products.
Related: W-LMD (Wire Laser Metal Deposition) method
As a derivative of the DED method, a method called W-LMD is also attracting attention. It is a method that should be called "laser metal deposition", and a melt pool (welding point) is generated by irradiating a metal wire with a laser. Metal wires are continuously fed and shaped by precisely stacking layers of weld beads.
The main feature is that it uses metal wire instead of metal powder, and it is cheaper and faster to form metal parts than other metal materials. It does not require large-scale equipment to avoid dust explosions or material oxidation, and is easier to handle.
In addition, compared to WAAM, which uses arc discharge (the WAM section below), because the metal is locally melted, the molding accuracy is higher, and the amount of energy is suppressed, so warping is suppressed and post-processing is reduced. You can also save time.
This method is used in the products of overseas manufacturer Meltio.
Meltio details: here
WAM (Wire Additive Manufacturing) method
In Japanese, it is a 3D printing method that applies welding build-up, called "wire additive manufacturing method". Because it uses arc discharge, it is sometimes called the WAAM (Wire and Arc Additive Manufacturing) method. Metal wires are melted by arc discharge and layered manufacturing is performed. Although it becomes a large-sized model, it enables faster modeling than the PBF method, and is compatible with a wide variety of metal materials. However, since cutting and polishing are essential for parts that require precision, they are subject to almost the same shape restrictions as existing cutting methods. It can be said that it is a method that prioritizes speed and the size of the modeled object over the complexity of the shape.
ADAM (Atomic Diffusion Additive Manufacturing, MIM×FFF) method
The ADAM method, which is also translated as "atom diffusion additive manufacturing method", is a method that combines FFF* (Fused Filament Fabrication), which is used in 3D printers for plastic materials, and MIM (Metal Injection Molding), which molds metal. metal powder injection molding method).
First, using a special material that mixes heat-melting wax and metal powder, 3D printing is performed by FFF to obtain a molded product called a green part. This green part is a mixture of wax and metal powder, so after washing and removing the wax, the molded product is sintered in a high-heat furnace to obtain a finished product called a silver part. Since the molded product shrinks during this sintering process, green parts that are molded with a 3D printer have the characteristic of using 3D data that has been converted to a slightly larger shape than the final shape.
Compared to the above PBF and WAM, there are fewer equipment requirements, and the advantage is that the shape can be expected to be as complicated as a 3D printer for plastics.
* Also called FDM.
Differences between 3D printers for metal and conventional metal processing
Most of the conventional metal processing is categorized into what is called "FM: Formal Manufacturing" typified by injection molding and "SM: Subtractive Manufacturing" typified by cutting. On the other hand, the modeling method using a metal 3D printer is called "AM: Additive Manufacturing", and it is a new manufacturing method with different characteristics from FM and SM. I will briefly introduce each of them.
It is a method of forming a dense structure with a tight interior, like casting or press molding. Molten metal is poured into the formwork and later removed from the mold. In some cases, there are shape restrictions such as overhang angles, and designers consider them when designing processes. This method is suitable for mass production because the same shape can be mass-produced by using the mold repeatedly.
It is a method represented by cutting, and is also called a subtractive method because it is processed while removing the material of the object like sculpture in the art field. If it is possible to access the processing surface (the tip of the processing equipment touches the surface), you can create a model with a high degree of freedom. At actual manufacturing sites, it is sometimes used for post-processing and finishing in combination with other methods.
Additive Manufacturing (3D printer)
Contrary to SM, it is a method called additive method. It is a method of modeling by piling up while adding materials, and most 3D printers belong to the classification of boxes.
Compared to the above two conventional processing methods, one of the major strengths is the high degree of freedom in modeling. This is because there is no need to be conscious of the overhang angle, which is essential for FM, and there is no need to be conscious of the accessibility of the machined surface, which is essential for SM. It also has the advantage of not requiring molds, jigs, or fixtures, and it differs greatly from conventional processing methods in that there is almost no need to consider expenses other than the 3D printer equipment and the materials consumed. Another important feature is that the shape of the product can be changed quickly by changing the input data.
What a 3D printer for metal can do
Based on the content so far, we will introduce what is possible with a metal 3D printer and the benefits that are easy to understand.
High performance metal products
AM with a metal 3D printer can form high-performance complex shapes represented by topology optimization and metamaterials, which were impossible with conventional FM and SM. For example, it is possible to reduce the weight by making the inside into a honeycomb-like honeycomb structure, or to increase the heat exchange efficiency by increasing the surface area three-dimensionally.
reduction in joints
It is also related to the complication of the internal structure mentioned above, but with a metal 3D printer, it is now possible to form a structure that could only be achieved by joining objects together.
For example, in the past, complicatedly intertwined pipes had to be assembled by joining pipes with relatively simple shapes such as straight lines and curves. As a result, a lot of time and resources were spent on the overall process design itself, which even considered joining. However, if you use a metal 3D printer to form a whole tangled pipe, the joining and assembly work itself becomes unnecessary, so it is possible to reduce the time required for process design. Reducing the number of joining points also leads to the omission of the joining process and the reduction of the quality control process.
Repair of metal parts
Once damaged, metal parts were basically replaced, but by using a metal 3D printer and adding new materials to the damaged parts, it is possible to regenerate the lost parts. Even if there are no design documents left, it is possible to carry out reverse engineering on site by optically scanning inventory items.
Possibilities of 3D printers for metal
How was it? Starting with a summary of materials that can be used for 3D printing, we introduced the classification of metal 3D printers, their actual uses and their characteristics. Finally, I will talk about the actual implementation.
If used effectively, 3D printers for metal can lead to solutions to conventional problems, but like other manufacturing methods, they are not a panacea. Depending on the method, there are restrictions on the shapes that can be stacked, and the types of materials that can be used. Also note that 3D CAD data is required.
In terms of cost, an initial investment of 10 million to several hundred million yen is required to utilize a metal 3D printer, and the intended use and operation system must be fully developed.
However, the AM manufacturing method has different characteristics from the conventional manufacturing methods such as FM and SM. The use of metal 3D printers is still creating unprecedented problem-solving methods in research fields and manufacturing sites. There is no doubt that it is a technology that can realize a new future for industry. 3D Printing Corporation will carefully support you from consulting on actual use to test manufacturing of benchmarks and guidance on equipment installation. If you are interested, please feel free to contact us. (via email: firstname.lastname@example.org)
Metal 3D modeling for industrial use with Meltio's 3D printer
3D Printing Corporation serves as the sole agent in Japan for Meltio (CEO: Ángel Llavero), a Spanish 3D printer manufacturer. Meltio offers metal 3D molding systems that are safest for workers and can be used in a clean environment by using the cheapest welding wire among metal materials. .
It is sold at the online store operated by 3D Printing Corporation.
Click here for the online store (Meltio)
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