CNC = Computer Numerical Control

Milling is the process of machining using rotary cutters to remove material by advancing a cutter into a workpiece. This may be done varying direction on one or several axes, cutter head speed, and pressure.

CNC machining is best known for producing precision metal parts for use in automotive, engineering and aerospace applications

CNC Mill Tolerance = ±0.0002 inches

An injection molding machine, also known as an injection press, is a machine for manufacturing plastic products by the injection molding process. It consists of two main parts, an injection unit and a clamping unit.

Injection Moulding Tolerance = ±.002 inches

Injection moulding is used to create many things such as wire spools, packaging, bottle caps, automotive parts and components, toys, pocket combs, some musical instruments (and parts of them), one-piece chairs and small tables, storage containers, mechanical parts (including gears), and most other plastic products.

Metal forming is a fabrication process that creates structural parts and components out of metal sheets or tubing. A basic metal forming process will bend or deform a metal workpiece to a desired geometric shape.

Tolerance = ±.003 inches

Powder bed fusion (PBF) methods use either a laser or electron beam to melt and fuse material powder together. ... The process sinters the powder, layer by layer. Selective Heat Sintering differs from other processes by way of using a heated thermal print head to fuse powder material together.

Photopolymerization 3D printing technology encompasses several different process that rely on the same basic strategy: a liquid photopolymer contained in a vat (or tank) is selectively cured by a heat source. Layer by layer, a 3D physical object is built until completion.

Fused deposition modeling, or FDM 3D Printing, is a method of additive manufacturing where layers of materials are fused together in a pattern to create an object. ... These layers are fused together, building up throughout the print, and eventually they will form the finished part.

Layer Height is the thickness of each layer used to 3D print a part using FDM. The same object can be printed with different layer thicknesses.

Shells are the number of perimeters used when 3D printing an object. Increasing the number of shells will make the print stronger but will increase print time.

Infill or infill density is the amount of material printed on the inside of objects. Low infill (10% - 20% is typically used for decorative prints. High infill (50% - 80%) is typically used for functional parts that incur stress.

The first layers of plastic that stick to the print bed are the most important! Without the first layer sticking nothing can be printed on top without errors. There are three print settings to help avoid print errors from bad adhesion; Rafts, Brims, and Skirts

A raft is a solid plate printed under the object. This setting uses a lot of material and reduces the quality of the bottom surface of the print but ensures a successful print.

A brim is a thin layer of material that is printed around the object. The object is touch the print bed and the brim is ATTACHED to the print object.

A skirt is a line of material around the object. The print object is touching the print bed and skirt does NOT touch the object. This setting helps only clear the nozzle before the object is printed.

Bridging is when a 90 degree overhang is connected between two supported areas. In the example the short bridge at the bottom has little deformation but the larger bridge at the top show drooping.

Supports are printed scaffolding to support overhanging areas of a 3D printed part. Supports are designed to be removed but can leave a rough surface where in contact with the part.

The rotation of a part before starting a print will affect how many supports will be printed. In the example on the left. The left side would require support material for nearly the entire bottom surface. The right side will require no supports because of its rotation.

Unlike injection molded objects, 3D printed objects are built using layers. These layers can DELAMINATE if stress is applied in parallel to the layers. Parts should be printed perpendicular to the stress that will be applied to them.