3D Printing Explained

3D Printing is going to be bigger than what 3D printing companies are saying. Today we are going to take a look at 3 different types of 3D Printing

sla printing

Stereolithography (SLA) Technology

SLA is a fast prototyping process. Those who use this technology are serious about accuracy and precision. It can produce objects from 3D CAD data (computer-generated) files in just a few hours. This is a 3D printing process that’s popular for its fine details and exactness. Machines that use this technology produce unique models, patterns, prototypes, and various production parts. They do this by converting liquid photopolymers (a special type of plastic) into solid 3D objects, one layer at a time. 

The plastic is first heated to turn it into a semi-liquid form, and then it hardens on contact. The printer constructs each of these layers using an ultra violet laser, directed by X and Y scanning mirrors. Just before each print cycle, a recoated blade moves across the surface to ensure each thin layer of resin spreads evenly across the object. The print cycle continues in this way, building 3D objects from the bottom up.

Digital Light Processing (DLP) Technology

DLP is the oldest of the 3D printing technologies, created by a man called Larry Hornbeck back in 1987. It’s similar to SLA (see above), given that it also works with photopolymers. The liquid plastic resin used by the printer goes into a translucent resin container. There is, however, one major difference between the two, which is the source of light. While SLA uses ultra violet light, DLP uses a more traditional light source, usually arc lamps. 

This process results in pretty impressive printing speeds. When there’s plenty of light, the resin is quick to harden (we’re talking seconds). Compared to SLA 3D printing, DLP achieves quicker print times for most parts. The reason it’s faster is because it exposes entire layers at once. With SLA printing, a laser has to draw out each of these layers, and this takes time.

Another plus point for DLP printing technology is that it is robust and produces high resolution models every time. It’s also economical with the ability to use cheaper materials for even complex and detailed objects. This is something that not only reduces waste, but also keeps printing costs low.

dlp printing
sls printing

Selective Laser Sintering (SLS) Technology

An American businessman, inventor, and teacher named Dr. Carl Deckard developed and patented SLS technology in the mid-1980s. It’s a 3D printing technique that uses high power CO2 lasers to fuse particles together. The laser sinters powdered metal materials (though it can utilize other materials too, like white nylon powder, ceramics and even glass). Here’s how it works:

The build platform, or bed, lowers incrementally with each successive laser scan. It’s a process that repeats one layer at a time until it reaches the object’s height. There is un-sintered support from other powders during the build process that surround and protect the model. 

This means the 3D objects don’t need other support structures during the build. Someone will remove the un-sintered powders manually after printing. SLS produces durable, high precision parts, and it can use a wide range of materials. It’s a perfect technology for fully-functional, end-use parts and prototypes.