Chuck Hull invented stereolithography (also known as 3D printing) in 1983. Since then, manufacturers have industrialized 3D printing, calling it “additive manufacturing” and the technique has been used to create everything from car parts to specialty food.
Creating a physical model of a new product or part can be a significant bottleneck in the development process, consuming time, and valuable resources. Additive manufacturing improves this step significantly by enabling the rapid creation of functional prototypes in a wide range of materials.
What is Additive Manufacturing?
Additive manufacturing (AM), the industrial production name for 3D printing, is a computer-controlled process of creating three-dimensional objects from a digital file. Additive manufacturing builds objects layer by layer, precisely adding material until the desired shape is achieved.
How does additive manufacturing work?
The first step in additive manufacturing involves creating a 3D model of the object you want to print using computer-aided design (CAD) software or a 3D modeling program. This digital file acts as a blueprint. The 3D model is sliced like a loaf of bread, into thin digital layers. Each layer represents a cross-section of the object at a specific height.
Once your 3D model is sliced and ready, it’s time to select the right material to print your object. Choice of material depends on the desired properties and application of the final object. Common materials include plastics, metals, ceramics, and even food.
The printer follows instructions from the sliced model, meticulously laying down each layer of material on top of the previous one, gradually building the complete object. Depending on the chosen printing technology, the printing material might look like filaments (spools of thread-like material), powders, or liquids.
Two common techniques for printing are fused deposition modeling and selective laser sintering.
Fused Deposition Modeling (FDM) is a popular technique, often used in consumer-grade 3D printers. FDM works like a hot glue gun, where a heated nozzle extrudes a thin filament of molten material, building the object layer by layer following the predetermined path from the sliced model.
In Selective Laser Sintering (SLS), a laser selectively sinters (or fuses) layers of powder material together, creating a solid object.
Once printing is complete, any temporary structures used to support overhanging features are removed. The final printed object might require sanding, polishing, or other treatments to achieve the desired surface quality.
What’s the difference between additive manufacturing and 3D printing?
Think of “additive manufacturing” as a category like “vehicles,” and “3D printing” as a specific type of vehicle like a “car.” All cars are vehicles, but not all vehicles are cars. Similarly, all 3D printing is a form of additive manufacturing, but not all additive manufacturing is 3D printing.
While both terms describe the process of building objects layer by layer, “additive manufacturing” is the broader term encompassing various techniques and applications, whereas “3D printing” usually refers specifically to the creation of objects using filament or liquid materials in a smaller-scale setting.
What’s the difference between additive manufacturing and conventional manufacturing?
While both methods serve the purpose of creating objects, additive manufacturing (AM) and conventional manufacturing (CM) approach the process in fundamentally different ways. Here’s a breakdown of their key differences:
Process
Additive manufacturing builds objects layer by layer, adding material until the desired shape is achieved. Conventional manufacturing removes material from a solid workpiece using techniques like machining, cutting, or carving.
Design Complexity
Additive manufacturing often excels at creating complex geometric shapes with intricate details, even internal features, due to the layer-by-layer approach. Conventional manufacturing may face limitations in creating highly complex geometries, especially with intricate internal features, depending on the specific technique employed.
Material Waste
Additive manufacturing generally produces less material waste than conventional manufacturing because unused material is often recyclable or reusable. Conventional manufacturing can generate significant material waste, especially when dealing with intricate shapes or subtractive processes.
Production Volume
Additive manufacturing is traditionally suited to low-volume production or prototyping due to slower printing times and potentially higher costs per unit. Conventional Manufacturing is favored for high-volume production where economies of scale can significantly reduce costs per unit.
Customization
Additive manufacturing enables greater customization of individual objects due to the digital nature of the process. Each layer can be adjusted to create unique features. Conventional manufacturing usually requires significant adjustments or retooling for customization, making it less efficient for personalized items.
Applications
Additive Manufacturing is used in various fields like prototyping, aerospace, medical implants, jewelry, and custom-made products. Conventional manufacturing remains the dominant method for creating a wide range of products, including cars, furniture, appliances, electronics, and construction materials.
Both AM and CM have their strengths and are suitable for different applications. While AM excels in creating complex designs with minimal waste and offers greater customization, CM remains dominant for high-volume production and established functionalities.
Are there different types of AM?
Absolutely! Additive manufacturing encompasses a variety of techniques, each with its own advantages and limitations. Choosing the right technique depends on material requirements, part complexity and desired features, budget and production volume, and desired surface finish and accuracy. Here are some of the most common types:
Fused Deposition Modeling (FDM)
- Process: Uses a heated nozzle to extrude filament (a thin thread of material) layer by layer, building the object.
- Materials: Primarily uses thermoplastics like PLA, ABS, and nylon.
- Pros: Affordable, widely available, good for prototyping and creating simple to moderately complex objects.
- Cons: Limited material selection, can have visible layer lines, may require support structures for complex geometries.
Selective Laser Sintering (SLS)
- Process: Uses a laser to selectively sinter (fuse) powder particles together, creating a solid object layer by layer.
- Materials: Metals (like aluminum, titanium), plastics, and ceramics.
- Pros: High accuracy and detail, excellent for complex geometries, wide range of materials, strong and durable parts.
- Cons: Expensive technology, limited bed size, post-processing required for some materials.
Stereolithography (SLA)
- Process: Uses a laser to cure liquid resin layer by layer, forming the object.
- Materials: Primarily uses photopolymers (light-curable resins).
- Pros: High accuracy and smooth surface finish, good for creating detailed models and prototypes.
- Cons: Expensive materials, limited material selection, post-processing required (washing and curing).
Digital Light Processing (DLP)
- Process: Similar to SLA but uses a projector instead of a laser to cure the resin layer by layer.
- Materials: Primarily uses photopolymers (light-curable resins).
- Pros: Faster than SLA, good for printing larger objects.
- Cons: Similar limitations to SLA, such as material selection and post-processing.
Electron Beam Melting (EBM)
- Process: Uses an electron beam to melt and fuse metal powder layer by layer.
- Materials: Primarily metals (like titanium, Inconel).
- Pros: Excellent for creating strong, complex metal parts, high-quality surface finish.
- Cons: Extremely expensive technology, limited availability, requires careful safety precautions due to the use of electron beams.
Binder Jetting
- Process: Uses a liquid binder to selectively glue powder particles together layer by layer.
- Materials: Wide range of materials, including sand, metal powders, and even food materials.
- Pros: Versatile and can handle a wide range of materials, relatively affordable.
- Cons: Lower strength and resolution compared to other techniques, may require post-processing for some materials.
What kind of materials are used for additive manufacturing?
Additive manufacturing utilizes many different materials to bring digital designs to life. The choice of which material to use depends on several factors, including the desired properties of the final object, compatibility with the chosen printing technology, and the cost and availability of materials.
Here’s an overview of some commonly used materials, categorized by type:
Polymers
- Plastics are the most common materials used in FDM (Fused Deposition Modeling) and are available in various types that offer durability, strength, and heat resistance.
- Resins are used in SLA (Stereolithography) and DLP (Digital Light Processing) for high-resolution and detailed prints.
Metals
Metal powders are employed in SLS (Selective Laser Sintering) and EBM (Electron Beam Melting) to create strong and functional metallic parts. Common choices include titanium, aluminum, and stainless steel.
Ceramics
Ceramic powders can be used in SLS for creating objects with high hardness, heat resistance, and wear resistance. Alumina (aluminum oxide) offers excellent thermal and chemical resistance while zirconia is known for its high strength, biocompatibility, and wear resistance.
Other materials
- Sand is used in binder jetting for creating molds and cores for casting metal parts.
- Emerging technology allows printing with various food materials like chocolate, sugar, and even cheese for creative food applications.
What are the benefits of additive manufacturing?
Some of the potential benefits of additive manufacturing include increased design freedom, reduced waste, on-demand manufacturing, and customization. 3D printing allows for the creation of complex shapes and designs that are not possible with traditional methods and minimizes material waste compared to traditional manufacturing techniques. 3D printing also enables the production of small batches or even single items efficiently and allows products to be tailored to individual needs.
What are some challenges associated with additive manufacturing?
There are also some challenges associated with additive manufacturing including limited material selection, cost, and post-processing needs. While the range of materials used for additive manufacturing is expanding, it is still not as comprehensive as traditional manufacturing. The cost of 3D printers and materials can be higher compared to traditional methods, especially for large-scale production. And some printed objects may require additional finishing steps, such as cleaning or surface treatment, which can add to the turnaround time and cost.
Conclusion
Additive manufacturing revolutionizes the manufacturing landscape by enabling the creation of complex designs, minimizing waste, and allowing for on-demand production. While still evolving, its applications are becoming increasingly widespread across industries, from prototyping and medical applications to customized consumer products.
As additive manufacturing technology advances, we can expect to see even more innovative materials, faster printing speeds, and lower costs, further expanding the potential of AM to shape the future of manufacturing and design.
