Additive manufacturing builds things by adding layers of material, while subtractive manufacturing makes parts by taking away material. Even though these methods are fundamentally different, subtractive and additive manufacturing are often used together because their application can sometimes overlap.
At first, it can take a lot of work to determine how best to use each type of technology to improve product development and manufacturing. Sometimes, it makes more sense to use one method over the other. For example, one method might be better for a certain amount of production or at a particular stage in developing a product.
In this guide, we'll take a closer look at the different techniques and uses of additive and subtractive manufacturing, as well as their advantages and disadvantages, to help you figure out how to use them in your processes.
Additive manufacturing can also be called "3D printing,". It is a computer-controlled industrial process that builds 3D objects by layering materials on a base material. The most essential part of this method is putting things together to make something new. However, additive manufacturing uses different materials depending on the printing process. Some materials include metal alloys, thermoset polymers, composites, thermoplastics, etc.
Additive manufacturing technology was first used in the aerospace and medical fields, but it is now used in other areas. You can also see its ever-growing reach in end industries like cars, oil, gas, and heavy machinery.
The standards for classifying Additive Manufacturing put its processes into seven different groups. Some of which include:
This is a type of additive manufacturing in which solid layers are made by dropping a binder on a powder bed in a controlled way. The materials used for binder jetting must be in small pieces. These pieces can be made of metal, sand, or ceramics.
Binder jetting uses a roller to evenly spread powdered material on the build platform. The next step is to put glue on the powdered material in a controlled way. The roller then spreads another layer of powder with glue over the first layer. The process continues until the whole part is ready.
The only difference is that this method uses wax instead of the binder. Instead of using glue on the powder bed, the operation also builds up layers of material to make an object. MJ puts wax on the platform of a building. Most producers like MJ because it is less expensive and gives better accuracy and high-quality surface finishes.
This method is a difficult way to build 3D objects. Most of the time, they use powder or metal wire. The material melts with the help of a beam or laser, and then it is carefully poured into the building platform. The liquid gets hard and forms a layer. This process continues until the final phase.
Other additive manufacturing processes are:
● VAT Photopolymerization
● Sheet Lamination
● Material Jetting
● Stereolithography (SLA)
● Selective laser sintering (SLS)
● Fused deposition modeling (FDM)
Below are some of the advantages and disadvantages of additive manufacturing:
Advantages
● It is very effective and doesn't waste anything.
● It is faster
● It is easy to make complicated designs
Disadvantages
● Compared to other processes, it can only use a few materials.
● When metals are involved, they can be expensive.
● It is not suitable for mass production.
As the name suggests, subtractive manufacturing involves removing parts of an object to make a new one. It also includes removing pieces from a solid metal, plastic, or wood block. A milling machine that creates holes in metal or plastic is a good example. Subtractive manufacturing lets you design, make prototypes and make things out of materials used in the final product.
It is also the best way to get specific mechanical properties or finishes for small and large-scale productions. It can be used to cut aluminum, brass, ABS, Delrin, Nylon, PEEK, PVC, plexiglass, PCA, Polypropylene, wood, and so on.
Cutting, milling, and sanding are all common types of subtractive manufacturing. Here is some detail about them:
CNC machining is a way of making things where industrial tools and machinery are guided by computer software that has already been set up. This type of subtractive manufacturing cuts things into three dimensions with just one set of instructions.
But before you can turn on a CNC system, you must program the necessary software cuts. This tells the right tools and machines how to do their jobs according to the dimensions you set.
In this process, different materials are cut into shapes with a laser. The products that come from this process are often used in industry and the arts. Computer Numerical Control (CNC) and optics help direct the powerful laser beam onto the material during the laser cutting process. A motion control system helps ensure that the CNC cuts the material in the way that was planned. After that, vaporization or high-pressure gas jets give the surface a good finish.
EDM is a type of subtractive manufacturing that uses electrical discharges to make the needed shape. Spark machining is called spark eroding, die sinking, burning the wire, or wire erosion.
It uses a series of quickly repeating current discharges between two electrodes (the tool electrode and the workpiece electrode), separated by a dielectric liquid and given an electric voltage. At the end of the EDM process, materials are taken away from the workpiece. Note that the tool and the workpiece do not touch each other during this process.
Below are some of the advantages and disadvantages of the subtractive process:
Advantages
● It works with many things, like metal, plastic, wood, and composites.
● It is used for all shapes, like holes, cylinders, screw threads, or flat surfaces.
● It is great for getting a smooth finish.
● It has a high accuracy with a close tolerance of 0.0025 mm.
Disadvantages
● It is wasteful
● It takes time
Both subtractive and additive manufacturing can be used to make prototypes and finished products, but they do so in different ways. These are some of the most important differences between subtractive and additive manufacturing.
The machines used for subtractive manufacturing are more accurate than the ones used for additive manufacturing. Also, if you want high accuracy with additive manufacturing, you must machine the part after printing it.
When you compare additive manufacturing to subtractive manufacturing, one big difference is the types of materials that can be used. In the additive manufacturing process, you can only use a few materials. Also, most materials used in this process are made from plastic. Some other materials used in additive manufacturing are ceramics, biochemicals, thermoplastics, metals, and resins.
In contrast, subtractive manufacturing starts with a single solid piece of material. This material could also be made of glass, metal, plastic, wood, composite material, or something made from plastic.
The speed of an additive manufacturing process depends on the batch size and how it will be used. Also, one of the benefits of additive manufacturing over subtractive manufacturing is that 3D printing makes prototyping and the total time needed for small-volume production faster. But 3D printing takes more time to print a single part than subtractive manufacturing. Also, 3D printing isn't as fast for manufacturing many plastic parts simultaneously.
This compares the different costs of subtractive and additive manufacturing to know which is more expensive.
The cost of the materials used in additive manufacturing is often higher than those used in subtractive manufacturing. According to the international cost estimating and analysis association, the materials used for additive manufacturing are eight times more expensive on a per-weight basis than those used for subtractive manufacturing.
However, the exact cost of additive manufacturing is based on the material and additive process.
Precision additive manufacturing equipment is very expensive to buy and set up. This means that buying machines adds the most to additive manufacturing costs.
The cost of tools is 5% of the total cost of production for additive manufacturing.
Also, layer-by-layer printing makes additive manufacturing very flexible and saves money because it can be used for many different products. On the other hand, it is crucial to consider how the tool will be made for each subtractive manufacturing process.
Both methods involve a lot of automation, so labor costs are a small part of the total cost. In additive and subtractive manufacturing, making parts simpler helps cut down on labor.
This means changing how a product is made to need fewer parts. This redesign would also reduce the costs of producing, putting together, and finishing the product. In additive manufacturing, labor costs usually make up less than 10% of the cost of making something.
Ares Prototyping is a certified company that uses additive and subtractive processes to manufacture prototypes and product parts. We also make the best parts to meet the needs of our customers and keep up with the standards.
We also offer instant quotes and guarantee that our automated DfM analysis is the best. We also ensure that the best quality parts are delivered on time by combining our strong manufacturing skills with the hard work of our employees.
