SLA Print Fail......

Hi there readers! So I finished my designs on SolidWorks, got them approved by my advisors and submitted them to be printed. There's just one problem: the format the file was sent in. Sadly, my first SLA print was a failure and that "three piece mold" I am going for was printed as a single block of 3d printing resin filled with wax. Unfortunately this puts me back a couple of days, but I now take my advisors words to heart, "Measure twice, cut once." So now I am stuck with a pretty cool looking paper weight (see figure 1). But I thought that I would take some time to talk about how the SLA (Stereolithography)  or 3D printing process works.



Figure 1

First and foremost, 3D printing or stareolithography is an additive manufacturing process used to construct prototypes, patterns and molds. A photo-reactive resin is repeatedly "printed" and then cured using a ultraviolet laser. It is an emerging technology that was first used in 1986 by a Charles Hull, but it hasn't been widely used until the last decade. One of the advantages of SLA printing is how quickly a part can be processed. Though it depends on the size of the part, a machine ready part can be printed in downwards of half a day. SLA printed parts can be used as prototypes or as machine ready parts in injection molding, thermoforming, blow molding and some types of metal castings. This technology is cutting down processing time for manufacturing companies around the world, if they can afford the startup cost.

Figure 2
SLA printed heart model (Right)/ Actual heart (left)



Figure 3
Machine Ready SLA print

Though there are many benefits and applications of SLA printing, it costs an arm and a leg to buy the printer. Industrial processing quality printers range from $100,000 to $1,000,000 depending on their printing envelope (how big of parts they can print). Additionally, the UV curing resin that the printers use costs about $210 a liter. If a company wants to print anything larger than 1m x 1m they are looking at the price of printers going up astronomically. So the technology is great for specific application and it can cut corners in manufacturing, but one has to weigh in how much it actually costs to use.



Figure 4
SLA Printer

In terms of how it all works, the process is fairly simple. A single platform is suspended in a pool of a liquid polymer (UV Photo-sensitive resin) and then a laser is manipulated via reflecting mirror to create the first "layer" of the shape you wish to construct. The mirror reflects the laser into the liquid resin and it cures as a solid, the platform then lowers itself so now the solid it created is just below the surface of the liquid polymer. The laser again draws the next programmed shape on the liquid and it cures as another layer of solid resign while sticking to the top of the first layer. The platform then lowers itself and the process repeats.
For a better visual and understanding of what I  attempted to explain above, see the video attached bellow. They explain it much more "solidly."



Thank you for taking the time to read through one of my posts. Please comment if you have any questions or just want to be heard. I look forward to responding.