Encoder/Glass Scale
A linear encoder is the typical way that CNC machines measure motion. It’s electro-mechanical device that creates digital signals that correlate to a position, a velocity, and a direction along a path. A linear encoder acts as a sensor and when linked to a scale it encodes a position. The sensor reads the scale and converts the encoded position into a meaningful value in the form of a digital or an analog readout. Optical linear encoders utilize a combination of light, lenses, photosensors, and a glass scale. The light source in conjunction with a lens creates a beam of light, which passes through a scanning reticle and then through the glass scale. That light is then picked up by photosensors, which creates a type of sine wave output, which the linear encoder interprets (Figure 5, Anaheim Automation, 2016). The level of accuracy created in this system is very high but the glass scale and …show more content…
The two main types of 3D printing are FDM and SLA. FDM stands for Fused Deposition Modeling, in FDM a thermoplastic resin, usually in the form of a wire (Figure 7), is fed through a hot extruder in turn heating the plastic allowing it to become formable. As the plastic is heated it is precisely placed by the printer head. The melted plastic is placed layer by layer to create a detailed model. There are also SLA printers. SLA stands for stereo lithography. Similar to FDM, SLA uses an additive method as well; models are built layer-by-layer (FDM vs SLA: 3D Printing Explained and Compared,