Rapid prototyping is the process of quickly creating physical parts to use for testing the look, fit, and/or functionality of a design. Traditional manufacturing processes can take weeks or months to set up, not to mention thousands of dollars. That is why rapid prototyping is so important. It not only saves time, but money as well, in most cases.
There are many companies that offer rapid prototyping services, and there are many services offered by them. Some of the popular services are examined below.
Types of Manufacturing
There are two basic types of prototype manufacturing: additive and subtractive. Subtractive processes involve older techniques such as milling (including CNC milling). Machines start with an oversized block of material and gradually take away material until the part is finished. Additive processes, such as 3D printing, are relatively newer and they work by creating layer upon layer of material until the part is finished. Both types of manufacturing can take hours or days to complete but each process has unique advantages.
One rapidly-growing process is called 3D printing. It is one of the newest and most affordable processes available. It is an additive process where layers of material, usually a plastic or a photopolymer, are built up one at a time over several hours to create parts. Some printers can even use real metal. There are several ways to create the layers. One involves an inkjet type system, where a liquid photopolymer is sprayed across a table in the shape of the layer and dried by ultraviolet lamps. Another system extrudes very small strips of plastic, much like a tiny hot glue gun, and a mechanical positioning system places the plastic in the right areas to create a layer with the correct outline. Still another system uses a laser to aim at a layer of powder to fuse tiny areas together to create a layer with the proper outline. There are other systems out there, but this is a good overview of this process.
Stereolithography, or SLA, is one of the oldest and most popular rapid prototyping techniques out there. It offers a good level of strength, surface detail, and cost. SLA is an additive process that involves a vat of liquid photopolymer. A laser system cures the appropriate sections of each layer.
Selective Laser Sintering (SLS)
Selective Laser Sintering, or SLS, is another popular service offering. It is usually more expensive and parts often have a rougher finish than SLA but there are a wider range of materials available, including metal, plastic, ceramic and glass.
When multiple prototypes are needed, it is sometimes more economical to have the parts molded using a urethane casting method. The typical quantities involved are about ten to one hundred. A master part is usually made using SLA and then a silicone RTV mold is created around it. Then the castings are made from a urethane or polyurethane. These urethanes come in a wide variety of material properties and colors, which can be a big benefit to the customer.
CNC Machined Plastic
Another service that some companies offer is machined plastic parts. Usually CNC mills make parts using metal such as steel or aluminum, but they can also be used to make prototype parts or low-volume parts out of many different kinds of plastic.
This article has covered some of the popular services offered, but there are many more that can be researched online, including 3D scanning, metal castings, and rapid injection molding.
Post time: 03-22-2017