SLA printing is a type of 3D printing often called resin printing. Instead of using a spool of solid plastic that is melted an SLA printer starts with a liquid material (resin) that is cured with a laser. This gives the appearance of your solid 3D object being pulled out of a pool of liquid. This method can produce a higher quality than more common 3D printing methods. This makes it ideal for mold making for casting and injection molding.