The field of additive manufacturing, which is the industry term for what most people call 3D printing, has experienced explosive growth in recent years. Creating items layer by layer out of metal powder or a thermoplastic filament instead of using a grinding or milling machine to manufacture parts out of a solid block of raw material reduces waste and saves money, and being able to control the entire manufacturing process with a single machine shortens lead times and greatly improves design flexibility. Additive manufacturing techniques were once used primarily for rapid prototyping and very small production runs, but there are few complex machines today that do not contain at least one 3D-printed part.

Additive manufacturing is now used by multinational corporations and small enthusiast companies alike to accomplish things that were once thought impossible. The Ferrari Formula 1 team uses 3D printers to develop new engine pistons and make racing car sensor mounts, and a British restoration company used the technology to reverse engineer a classic 1952 Ferrari coupe (source). Car makers like Ferrari use 3D printing to make key components from steel alloys when the finished part needs to be stronger and have superior heat resistance, but there are many other good reasons to take an additive rather than a subtractive approach to manufacturing.

The Benefits of 3D Printing

Manufacturers are expected to keep costs low and meet strict schedules, so they rarely introduce new technology unless they are confident that it will save them time, money or both. Additive manufacturing was once fringe technology that few outside the R&D community were even aware of, but it is now revolutionizing entire industries. Here are some of the reasons why manufacturers have started to take a lot more interest in 3D printing:

• A single machine: Turning a block of raw material into a finished product sometimes takes several machines. One or two machines could be needed to remove large sections of the material, and then several more machines may be required to perform more delicate operations. When a part is 3D printed, just one machine is needed to turn a computer aided design and some PLA filament into a finished item.

• Increased speed: When the manufacturing process is controlled by CAD files and parts are made by 3D printers, making changes is very easy. Recalibrating an entire production line of machines can take hours or even days, but computer code can sometimes be modified in minutes. This responsiveness and adaptability is what made 3D printing such a popular technology for research and development projects.

• Rapid prototyping: Creating casts and molds to make parts takes a long time and only makes financial sense if a lot of units will be produced. When prototypes are built, only a handful of examples are needed and speed is of the essence. This is why virtually all of the world's leading companies use 3D printers for rapid manufacturing and to build and develop their prototypes.

• Reduced waste: Subtractive manufacturing is inherently wasteful because the process starts with far more material than is needed. When 3D printers are used, only the amount of material necessary to make the finished part is used.

• Exotic materials: The vast majority of 3D-printed items are made out of PLA filament purchased from vendors like Printed Solid, but switching from subtractive to additive manufacturing techniques also opens up a world of exotic materials that include sophisticated metal alloys and advanced thermoplastics like PLA and PTEG. Additives can be used to make these materials glow in the dark or give them other special properties, and adding UV or heat-sensitive substances to ABS or PLA creates items that can change color (source). Traditional manufacturing techniques are best suited to making mass-produced items out of basic materials like wood, steel or plastic.

• Digital precision: Recreating a part from a long out-of-production machine using traditional tools and technology requires extraordinary levels of craftsmanship and skill, and even then there would be no guarantee that the new component would be an exact duplicate of the original. CAD scanners measure the tiniest gaps and the remotest nooks and crannies with digital precision, and the files they generate recreate even extremely sophisticated parts with scarcely believable accuracy. The parts 3D printers make are so good that even experts using the latest equipment cannot tell them from original components, which has caused havoc in enthusiast circles like the classic car community where originality is everything (source).

• Complex designs possible: Advanced rocket and jet engine components must be able to cope with heat that even the most advanced alloys can't handle. To solve this problem, a British team of researchers used 3D printers to make parts with cooling ducts thinner than a human hair (source) This would not have been possible if only traditional manufacturing techniques had been available.

• Ideal for small production runs: Traditional manufacturing processes only save companies money when production runs are large and economies of scale kick in. When production runs are smaller, additive techniques usually make more sense.

• Virtual warehouses: Creating rarely-ordered parts on demand using 3D printers makes a lot more sense than producing them in advance and then storing them in warehouses. Computer aided design files can be stored on a flash drive or uploaded to the cloud, and only parts that have been purchased and paid for are shipped out of a virtual warehouse.

• Free resources: There are dozens of open source and free resources to help individuals and companies to get started with additive manufacturing. The resources these websites offer include free 3D printer files, free 3D printer slicers and free 3D software.

3D Printing vs. CNC Machining

When companies need quality parts and they have little time to waste, they often end up choosing between 3D printing or CNC machining the required components. CNC stands for computer numerical control, and CNC machining is a process that uses high-speed cutting implements set at various angles to form relatively complex designs out of materials like plastic or milling steel. While this is an example of subtractive manufacturing, it is often confused with 3D printing because both 3D printers and CNC machines get their instructions from CAD files.

CNC machines take information from computer aided design files and use it to determine how much milling steel or other material to remove in order to only be left with what is needed. When 3D printers are sent a CAD file, they use the information to create parts one layer at a time using just the amount of material needed to complete the job. CNC machining is more cost effective than many other traditional manufacturing techniques, but a CNC milling machine will never be able to match a 3D printer for efficiency. What CNC equipment can do is handle a wide variety of materials ranging from milling steel and aluminum to engineered plastics like Teflon and PEEK.

The Various 3D Printing Processes

All additive manufacturing printers gather information from three dimensional software and use it to create 3D models out of metal, plastic or even glass, but they do not all bond material in the same way to form layers. Some of these additive processes are used to manufacture parts out of plastic, while others are reserved for creating components out of metals and metal alloys.

The first additive process was called stereolithography, which was invented in 1984, hit the market in 1986 and is still used today to create items that have smooth surfaces and lots of detail. Stereolithography uses light rather than heat to bond oligomers and monomers together to form polymers, and it can be used to create extremely complex components. Medical models and computer hardware are still made using stereolithography, but less expensive techniques are usually used to 3D print plastic and metal parts today. These cheaper alternatives include:

• Selective laser sintering: SLS uses heat generated by lasers to melt nylon powders and turn them into solid plastic. SLS is one of the 3D printing processes popular in rapid prototyping situations because items made out of thermoplastic material are suitable for testing. SLS produces stronger parts than stereolithography, but it can not replicate the older technique's smooth finishes.

• Digital light processing: Like stereolithography, digital light processing uses light to cure liquid resin. What makes DLP different is that it uses a digital light projector instead of an ultraviolet laser to create light. This change in technologies allows digital light processing 3D printers to image entire layers at once and complete projects far more quickly. DLP machines are some of the best 3D printers currently available, and they are not cheap.

• Polyjet: This is one of the additive processes that can produce 3D models and parts that are more than one color or made out of more than one material. This increases the costs of 3D software like STL files slightly, but it is an expense worth bearing if the alternative is investing in complex tooling at the very beginning of a project.

• Multi jet fusion: Instead of using a laser or light to fuse plastic powder together, the multi jet fusion process uses inkjets to apply fusing agents. Multi jet fusion machines are some of the best 3D printers on the market because they create useful 3D prints with exceptionally consistent mechanical properties and a surface finish that surpasses even stereolithography.

• Fused deposition modeling: If you go into a big-box store to buy a printer to make 3D models, you will almost certainly leave with a machine that uses the fused deposition modeling 3D printing process. It may not be the most sophisticated additive process, but fused deposition modeling is a quick and cost-effective way to make parts out of plastic. Fused deposition modeling is sometimes called fused filament fabrication because it makes parts by extruding thermoplastic filaments made out of materials like PLA and ABS through a heated nozzle that melts them to form layers. The PLA filaments sold by companies like Printed Solid for use in home 3D printers can be used to make durable and attractive items, but it is not strong enough for rapid manufacturing or prototyping applications.

• Electron beam melting: Electron beam melting machines are some of the most expensive and best 3D printers available. They keep the printing bed heated and in a vacuum throughout the process, and they use electron beams controlled by powerful electromagnetic coils to heat metal powder to its melting point.

• Direct metal laser sintering: Most 3D-printed metal parts are made using the direct metal laser sintering process. The finished result is an item that is as strong as a machined or cast part but can be made in short runs far more quickly and inexpensively using 3D software and a 3D printer.

3D Printing Resources

The world of additive manufacturing can seem a little bewildering if you are not familiar with terms like STL file, milling steel or PLA filament. Fortunately, there is a treasure trove of resources like free 3D printer slicers to help you get acquainted with the technology and create useful 3D prints. Here are some of the free tools that can make even an inexpensive machine feel like one of the best 3D printers available:

• Thingiverses: Founded in November 2008, Thingiverses is a website that allows its visitors to upload and share digital designs and download free 3D printer files. Designs on Thingiverses usually have a Creative Commons or GNU General Public License, which means they can be used to create three dimensional objects using 3D printers, milling machines or laser cutters with few restrictions.

• Octoprint: Users with several 3D printers to keep track of have been able to turn to Octoprint since March 2020. The web-based interface monitors the status of the print job, and Octoprint also keeps an eye on performance metrics like the temperatures of the print nozzle and printing tray. Octoprint has not been on the market for very long, but there are already more than 300 user-created plugins available to extend its functionality.

• Ultimaker Cura: Downloadable 3D printer slicers like Ultimaker Cura take 3D images like STL files and convert them into instructions that additive manufacturing devices can understand. The Cura slicer is an open source solution that is now maintained by the 3D printer company Ultimaker, but it can also be used to create instructions for printers made by other manufacturers. Ultimaker Cura is extremely popular and is used to handle more than a million 3D printing jobs every week. When the 3D Printing Industry held its annual awards ceremony in London in 2019, the Cura slicer was named the year's best software tool. Businesses and consumers trust Ultimaker Cura because it is free, very easy to use and plugins are available to integrate the Cura slicer with AutoDesk, MakePrintable and Siemens NX.

• FreeCAD: Like the Cura slicer, FreeCAD is an open source solution that is free to use. FreeCAD, as its name suggests, allows users to create designs for three dimensional objects on their computers without paying for software or signing up for a subscription. FreeCAD is available to make 3D model designs using the Windows, iOS and Linux operating systems.

• Free 3D models: Those who do not know how to use platforms like FreeCAD to make three-dimensional images from scratch can still enjoy the benefits of 3D printing because there are a number of online sources that offer free 3D models. The formats that these free 3D models can be downloaded in include OBJ, FBX, 3DS, MAX and C4D, and the most popular places to find them are free3d.com, cgtrader.com and sketchfab.com.

• Free 3D printer files: Free 3D models are not the only open source resources individuals or organizations can use to get started with 3D printing and additive manufacturing. There are also platforms that can convert images into STL files for 3D printing or turn analog sketches into computer aided designs. Several web portals offer free 3D printer files, but some of them ask users to sign up before downloading them.

• You can find more resources on our dedicated page.

Choosing a 3D Printing Service

If you think additive manufacturing techniques could save your company time and money but you don't know where to start, an experienced and dedicated 3D printing service could point you in the right direction. Look for providers that have facilities filled with the latest and most sophisticated 3D printers and milling machines, and make sure that you deal with professionals who will dedicate themselves to making sure that your project is successful.

Another thing to look for when choosing a 3D printing service is engineers who are capable of taking an incomplete design and finishing them. They should also feel just as comfortable working with exotic materials like advanced alloys as they are making items out of Printed Solid plastic filament. A good 3D printing service should make entering the world of rapid manufacturing an exciting rather than intimidating experience, and they should be able to turn out useful 3D prints every time.

At Performant, we will be happy to help you with your 3D printing needs, whether your design is finished or not. If we can’t print it ourselves, we will point you in the right direction.