When not to use 3D printing in manufacturing?
With 3D printing each layer has to be printed. This means that the motion stage will have to move up and a new layer will have to be applied. So small thin parts with comparatively few layers will take up significantly less machine time. These will be much cheaper and faster to print. Meanwhile parts greater than 40 X 40 X 40 CM can not be made on virtually all 3D printers. Parts that size or greater will also incur significantly long build times. This will partially erase the advantages of the process. Smoothness is still an issue for 3D printing technologies. Typically when Ra is critical using 3D printing may be problematic. Whereas the range of 3D printing materials is ever expanding more materials can be processed using CNC and other technologies. Recently engineering plastics such as PA 12, PC, PET and other materials have been added to 3D printing’s repertoire. In terms of color or overall material grades injection molding and other processes do have a wider selection. Even though it is perfectly possible to make almost any shape on a 3D printer this does not mean that this shape is necessarily functional. Design rules and guidelines must be followed and some parts will not work in 3D printing.
3D Printing intermediates
One major application of 3D printing is in intermediates such as molds. In dental applications such as dental aligners 3D printing is already a mainstay of the industry. All aligners are custom and the parts are relatively small. The time from fitting to user should be timely and the software and 3D printers make the process a highly automated one. Compared to other technologies or making them by hand 3D printing is a low cost alternative.
For investment casting large 3D printed molds are also used. These parts are usually unique and in some cases the 3D printed mold is very cost effective compared to CNC or molds made with another way. This is often dependent on geometry and the part size or complexity.
For lost wax casting millions of 3D printed molds are used each year to make jewelry. The 3D printed molds are less expensive than hand made or conventionally made ones. High fashion and inventory risk also means that start up costs and time to part play a role here.
3D Printing End use parts directly
3D Printed titanium hip cups, dental guides, surgical guides, prosthetics and implants are made in their hundreds of thousands each year. This is because parts are often unique, low volume and timely. Additionally it is possible to using 3D printing create unique surface textures that promote bone adhesion for example. This makes 3D printing a cost effective solution here.
Tens of thousands of 3D printed parts are currently flying on aircraft. For next generation aircraft structural components are being considered. Currently however the parts flying on civilian and military aircraft are mainly non structural components. Weight saving and low volume production is the main reason to use 3D printing in aviation.
One of the largest implementations of 3D printing for manufacturing is in hearing aids. Due to their uniqueness and small size 3D printing supplanted traditional manufacturing in hearing aids. CNC and hand made technologies were undercut and disappeared from In The Ear hearing aids due to 3D printing.
As you can see there are a number of business cases where 3D printing could be a valuable technology for manufacturing organizations. Especially in low volume or unique geometries 3D printing is likely to play a role in many a supply chain. 3D printing is however not a panacea and must be used only if the business case is the right one.