3D PRINTING

3D printing is when 3D solid objects are made from a model on a computer. 3D printing is done by building up the object layer by layer. 3D printing is usually done with a materials printer. Since 2003, many more materials printers have been sold than before. Also, the cost of 3D printers has gone down. 

The term "3D printing" originally referred to a process that deposits a binder material onto a powder bed with inkjet printer heads layer by layer. More recently, the term is being used in popular vernacular to encompass a wider variety of additive manufacturing techniques. United States and global technical standards use the official term additive manufacturing for this broader sense. 

General Principles

• Modelling

3D printable models may be created with a computer-aided design (CAD) package, via a 3D scanner, or by a plain digital camera and photogrammetry software. 3D printed models created with CAD result in reduced errors and can be corrected before printing, allowing verification in the design of the object before it is printed. The manual modelling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting.

• Printing

Before printing a 3D model from an STL file, it must first be examined for errors. Most CAD applications produce errors in output STL files, of the following types:

1. holes;

2. faces normal;

3. self-intersections;

4. noise shells;

5. Manifold errors.

• Finishing

Though the printer-produced resolution is sufficient for many applications, greater accuracy can be achieved by printing a slightly oversized version of the desired object in standard resolution and then removing material using a higher-resolution subtractive process. All of the commercialized metal 3D printers involve cutting the metal component off the metal substrate after deposition. A new process for the GMAW 3D printing allows for substrate surface modifications to remove aluminium or steel.

• Multi-material printing

Multi-material printing allows objects to be composed of complex and heterogeneous arrangements of materials. It requires a material being directly specified for each voxel inside the object volume. Metallographic materials of 3D printing is also being researched. By classifying each material, CIMP-3D can systematically perform 3D printing with multi materials.