Three dimensional printing has many uses in the medical field and is quickly emerging as an essential tool for operative planning and training in such diverse fields as neurosurgery, orthopedics, otolaryngology, urology, craniofacial maxillary and cardiac surgery.
There are various processes for making a three-dimensional object of almost any shape. The most well-known method is subtractive manufacturing, which is like creating a sculpture by chipping away at an ice block. Most references to manufacturing are actually referring to subtractive manufacturing.
Another novel method of manufacturing is Additive Manufacturing (AM) or what is commonly referred to as 3D Printing (3DP). This is the process of making a three-dimensional object through additive processes using electronic data in which successive layers of material are laid down under computer control. Building a Lincoln log cabin where one takes individual components, like logs, and layer them to build a structure, like a cabin, demonstrates the idea of additive manufacturing.
There are many methods for 3D printing but here are few of the more common techniques.
1. Fused Deposition Modeling (FDM) is one of the more common techniques and is great for creating concept models. FDM is similar to a hot glue gun that extrudes plastic and builds a model - layer by layer. This particular method is used in the aerospace, automotive, industrial, commercial and medical industries.
2. Stereolithography (SLA) creates 3D objects by curing photo-active liquid plastics into a solid object using a light source. The print begins with a pool of liquid plastic on a platform. A light source then hits the platform and hardens the liquid in the shape of the 3D object, one layer at a time. The platform drops and the light continues to harden additional layers until the object is formed. This process is known for producing extreme detail. Jewelers and engineers have been known to use this printing method because it is a tough resin.
3. Polyjet layer additive is another type of 3D print that is used to create plastic prototypes. This process is one of the fastest and is ideal for smaller parts. It is very similar to how an inkjet printer lays down pigment; like a printer you would have at home. It deposits small amounts of ultraviolet, curable material onto the platform eventually forming a single cross section of the part. The platform continues to be lowered to make room for the next layer. It is well suited for quick, economical prototypes with high detail.
4. Selective Laser Sintering (SLS) uses powered nylon material and metals, like titanium. It is light weight and durable, as well as heat and chemical resistant. A tool spreads powered material onto the platform and a laser traces the cross section. The material is heated and fused together. The powder bed is lowered to make room for more layers. This process is mainly used for tools, fixtures, fuel tanks, automotive designs, architectural models and artistic sculptures.
Since the advent of 3D printing in the 1980’s, it has been used in a variety of industries including aerospace, automobile and defense. 3D printing can also be used in medicine for patient education, medical training and surgical planning.