Additive manufacturing is a very important term that explains new technologies in manufacturing. The name gives a direct idea about the general methods in additive manufacturing. This term is related to the manufacturing techniques which obtain the part with the addition of material in each pass. Here, you will have a great idea about this topic. You can find this information about additive manufacturing here;
- What is additive manufacturing?
- General steps of additive manufacturing techniques.
- Applications of additive manufacturing.
- Advantages and disadvantages of them.
- Types of these systems.
- FAQs about this manufacturing technique.
What is Additive Manufacturing?
Additive manufacturing term refers to the general methods that are creates or produce the products by material adding in each step. For example in machining processes, they remove material to obtain the shape that they need. But here, we are adding materials to obtain shapes.
In general, the applications of these techniques start with creating the part in the CAD program. After creating the data, we can start to produce the part from this CAD data without any deep manufacturing analyses.
For example, if we want to obtain a part in a metal casting operation, we need lots of considerations such as placements of cores, creating the mold, etc. But in additive manufacturing techniques, we can directly start the production of the part.
This is another term that they call instead of additive manufacturing. Rapid prototyping is directly related to the phenomenon above. We can directly produce the part that we design in CAD environments. Because of it, they call these processes rapid prototyping.
Layers are very important in these techniques. Because the production takes place layer-by-layer method. So, we need to convert the CAD data .STL format before starting. In each pass, a layer is deposited on the previous layer to obtain the part.
Another important aspect of additive manufacturing technologies, we do not only obtain the required shape. Also, we create the shape in the tolerances for the fit applications. For example, surface tolerances are very important in part design. We can obtain these tolerance values in rapid prototyping applications.
This means in lower cost and labor, we can obtain the most complex parts easily.
Automated Free-form Fabrication of Materials
For instance, in machining operations, we can not say all the machining operations are automated. Only we can state that CNC machines are automated. But, rapid prototyping techniques are completely automated production processes.
Also, we apply these automated processes in the manufacturing of nearly all shapes. We can create free-forms in any shape to produce different kinds of parts.
Layer based approach is a very useful approach in the production of parts. This approach provides freedom of part shape without consideration of the shaping capabilities of additive manufacturing techniques.
We can produce any kind of shape with a layer-by-layer approach. So, the general rapid prototyping machines use layer-based manufacturing.
Also, this is a very common term that describes additive manufacturing techniques. People generally call all these techniques as 3D printing. In general, we are doing the printing on paper in 2D. But these machines are making printing operations in 3D. Because the working principles of these machines are familiar to the printers.
General Steps in Additive Manufacturing Techniques
Unlike other conventional manufacturing techniques, additive manufacturing has very distinct steps to obtain the products and parts. If we take a look at the other methods, there is a production of rough parts and shaping of this rough part into the desired part. But in rapid prototyping methods, we directly create the shape. These steps like below;
1 – Preparing CAD Data
Firstly, we need to obtain the part design that we need. CAD data is very important in the production of the part. We can design whatever we want without considering the manufacturing techniques. Additive manufacturing techniques can create this data without facing any problems.
2 – CAD to STL Conversion
Slicing is very important to obtain the layers of the CAD data. STL format includes the information in these layers. Rapid prototyping machines require this data to produce the part. In general CAD tools available in the market, there are tools to convert CAD data to STL data.
So, as you understand that after the design of the part, we directly continue with the setting up the production of the part with additive manufacturing techniques. We do not deal with the review of the part according to the manufacturing technique that we use.
3 – STL Transfer to Additive Manufacturing Machine
After creating the STL file, we need to transfer this file to the rapid prototyping machine. This is a very important step because we will define the general positioning of the part in the machine. Orientation of parts is very important in the additive manufacturing machine to obtain successful designs.
4 – Setup of Rapid Prototyping Machine
Before starting the production and laying the layers to produce the part, the operator must make adjustments to the additive manufacturing machine. In this setup, we consider the material situation, energy source, and other stuff.
5 – Production Step
In this step of rapid prototyping, we start the machine to build the part. In general, this is an automated step in which the machine produces the part. But we need to supervise the possible material or software errors to prevent them. The general errors can be the misuse of material and software errors can cause the production of wrong shapes.
6 – Material Removal
After a while, the production of the part will complete in the additive manufacturing machine. We need to remove the part from the machine. We need to give special care to the removal. Because there can be supportive sections of the machine and the part. If you do not consider these sections, the part gets deteriorated.
7 – Additional Processes
After taking the part from the rapid prototyping machine, we need to apply some additional basic processes such as removing the supportive sections in the production phase. Also the surface treatment for the rough sections.
Types of Additive Manufacturing Methods
There are different types of methods in additive manufacturing. These methods are;
- Photopolymerization processes
- Powder bed fusion processes
- Extrusion-based systems
- Printing processes
- Sheet lamination techniques
- Beam deposition techniques
- Direct writing technologies
This is a type of rapid prototyping process where the curing of the thermoset resins is used. Thermosetting polymers are a type of polymers that get solid and hard to UV light exposure. This technique is the basic technique that we use in the photopolymerization processes.
In these types of additive manufacturing devices, we obtain the layers of the object and we use UV light to make it solid. In each layer, machines apply the same principle. And the part takes place after a while from thermoset resin material.
The material limitation is a very important consideration here. We can use the thermoset resins in these rapid prototyping machines. So, you need to consider the capabilities of these materials before designing and producing your material.
Also, they call this process VAT polymerization. Because the applications take place in a container that we call vat. There is a liquid in this vat that cured layers stay in.
Powder-bed Fusion Processes
This an also one of the most common additive manufacturing techniques. So in this rapid prototyping technique, they use material powders in each layer and fuse these powders with a heat source. This resembles the sintering techniques.
In these techniques, a layer of powder is spread out on the previous layer. After that, the fusion of the powder between each other and the previous layer takes place with the application of a laser heat source. After a while, the product is obtained.
The most important advantage of the powder-bed fusion processes, we can apply this additive manufacturing technique to different kinds of materials. We can produce metal parts, ceramic parts, and composite parts from their powders of them. The heat source is very important here. If we can apply the fusion heat of these materials to the powders, we can obtain the powder-bed fusion technique for that material.
Extrusion-Based Additive Manufacturing Systems
This refers to a technique of the material depositing as layers. In most additive manufacturing systems, we use extrusion-based machines to deposit materials. So, in these systems, the positioning of the extrusion edge is very important.
In these rapid prototyping systems, the material is heated and fed through the nozzle of the end effector. The material comes from the nozzle in a liquid state. And then, the nozzle travels the route to deposit the liquid material layer by layer to obtain the complete shape. This is an automated system.
So, the feeding rate of the material is very important. The machine adjusts the required amount of material for the thickness of the layers. Constant extrusion of the material is very important to obtain the required characteristics of the material.
The other important factor is the liquification of the material. There is an energy requirement for it. the capabilities of these additive manufacturing machines according to the materials change.
Solidification and bonding of the material are also very important factors in extrusion-based additive manufacturing systems. Solidification of the material must take place in the intended time. Also, the bonding of the solidified material with the previous layer is very important to obtain a complete part.
Above all, we need to have advanced positional control of the nozzle. There is software that we use in machines that follows the STL traces to obtain the part. With the changing layer thickness and material, the rate of extrusion and nozzle speed changes.
Supports are also very important in extrusion-based systems. Because some sections can require support structures up to solidification. So, we need to remove these support sections after the rapid prototyping process comes to an end.
Sheet Lamination Processes
This is also a very different technique in additive manufacturing. The general working principle of these techniques, is there are special sheets that are wrapped over the surface layer by layer. On each sheet, the machine applies heat to melt the material on the sheet. Also, the machine cut the sheet according to the cross-sectional shape of the part in each layer.
So, melting and bonding of the thermoplastic material is a very important parameter for this type of rapid prototyping. There are different types of sheet lamination processes according to the applications. Some machines firstly give the cross-sectional shape to the lamination sheet, then bond that layer with the previous layers. Also, some machines firstly bond the layers and give the final shape.
In the cutting of lamination sheets in these additive manufacturing machines, we use a laser. Laser cuts the slices in each layer. And stacking of the layers takes place. This stacking and cutting of the sheet layers create the lamination of the part. After that, binder removal and sintering are applied.
Beam Deposition Rapid Prototyping Machines
In this technique of additive manufacturing, a beam of molten material is deposited by an end effector to obtain the layers. In general, they use this rapid prototyping technique in the production of metal parts.
The difference between the beam deposition technique from the extrusion, not all the material is melted during the process. Only the material that is being deposited is melted. So, a focus on energy deposition on the material is used in these techniques.
This type of melting is very useful in the melting of materials that have very high melting temperatures such as common metal alloys. Furthermore, this process makes it possible to produce very complex shapes from very hard materials.
Advantages and Disadvantages of Additive Manufacturing
If we compare it with other kinds of conventional production techniques, there are various kinds of advantages and disadvantages of additive manufacturing and rapid prototyping techniques.
Rapid prototyping and additive manufacturing techniques are brand-new and developing techniques. So, there are some disadvantages of these systems like the other systems. But with the improving technology, these disadvantages will be eliminated.
- As we stated above, the most important advantage of the additive manufacturing techniques, we can produce much more complex parts more easily if we compare with other conventional techniques.
- In prototyping the parts, we do not need to review and change the shape of the part according to the capabilities of the production techniques. Because we can produce all types of complex shapes on layer by layer basis.
- In general, no need for a skilled workforce to operate rapid prototyping machines. Because additive manufacturing is a highly automated system.
- Also, additive manufacturing operations are generally single-step operations after setting up the machine. So, we do not need to interfere to make intermediate changes during the processes.
- The main disadvantage of the additive manufacturing systems is the limited material diversity. Yes, we can use the different kinds of materials from different classes. But in general, there are specific alloys and specific plastics that can not be used in rapid prototyping machines.
- Additive manufacturing techniques can be slow if compare with other conventional techniques. Because machines are building the parts layer by layer. This takes time. With the increasing surface and structural quality of the part, the printing will take much more time. This is a problematic issue in serial production.
- The general devices and machines used in additive manufacturing are high-tech systems. So, maintenance of these devices is generally a high-cost kind of stuff. Spare parts can be high cost.
- Layer by-layer technique is the general technique that the rapid prototyping machines are using. The structural integrity and mechanical properties may affect by layered structures. Because layered structure gives less homogenous structures in additive manufacturing systems.
Application Examples of Additive Manufacturing Techniques from Industry
Additive manufacturing is a brand-new and developing technology that different companies are using professionally. They produce different kinds of products with additive manufacturing techniques.
Maybe the most important example company that uses additive manufacturing techniques. General Electric designs and produces different kinds of energy systems such as wind turbines, hydroelectric power plants, generators, etc. Also, the jet engine systems of General Electric are renowned.
These complex systems include very complex parts from advanced materials. In the production of these systems, General Electric is heavily using rapid prototyping systems.
Boeing is also a very important example that using additive manufacturing techniques. They are producing parts for aerospace products in general. They made it possible to produce these products for aerospace applications.
Ford Motor Company is one of the most important examples of the automotive industry. They are using rapid prototyping systems in the production of different parts of automobiles. They are a leader in the use of additive manufacturing techniques in the automotive industry.
You know that Nike is one of the biggest companies that produce textile products. In textile products, Nike uses additive manufacturing techniques commonly. Especially in the production of shoe soles, they use these systems. So, additively manufactured products becoming very common day by day.
Additive manufacturing techniques are a very promising area in the manufacturing industry. There are different kinds of rapid prototyping and 3D printing techniques that use in this area. And also, there are main application steps of rapid prototyping and additive manufacturing.
According to the application types and materials, these techniques have different methods. You can select one of these methods to apply to the production of different things.
And also, you need to consider the advantages and disadvantages of these techniques. Like other manufacturing processes, these systems have advantages and disadvantages.
There are lots of big technology companies using additive manufacturing techniques. So, these systems are becoming more common day by day.
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FAQs About Additive Manufacturing Techniques
Additive manufacturing is the technique to produce parts by depositing the material on a layer-by-layer basis. So, it is a brand-new approach to manufacturing techniques.
Probably will not completely replace the conventional manufacturing techniques. Because these techniques are different approaches to manufacturing. It has advantages and disadvantages. So, because of them, they will replace the conventional ones in specific areas. But not in all areas.
Yes, they have the same meanings. But additive manufacturing is more professional than the 3D printing notion. People generally use 3D printing terms but professionally, you can say additive manufacturing.
If we compare it with conventional production techniques such as metal casting, the answer is yes. Because nearly no material is wasted in these technologies. And also, energy requirements to produce parts with these technologies are simpler than others.
Different companies are using these techniques in serial production. Among these companies; are General Electric, Ford Motor Company, and Nike.
The most common technique is the powder bed fusion technique. Because we can use a wide variety of materials in these machines.
These systems are important because they provide the ease of production of very complex shapes from different materials. Also, they are highly automated systems in human operations that do not require.
According the methods, there are different types; photopolymerization processes, power-bed fusion processes, extrusion-based systems, sheet lamination, and beam deposition techniques.