You bet it is! Take a look at these 1/2" thick gears made into an interactive exhibit for the Taylor Center Engineering Lab. The largest of these gears would each take hours to make on a 3D printer, but the Engineering Lab's X-Carve computer-controlled router can make them in minutes, and their edges are crisp and perfect, like a gear's should be.
The X-Carve system is like many computer-controlled routers you may have seen, but is unique in that the company, Inventables, has created online design software, called Easel, specifically to bring your design to life in the X-Carve. You can upload your design, made in any 3D or 2D design program, and use Easel to send the design to the X-Carve, or you can start from scratch and create your design in Easel. You can check out Easel for free here: https://easel.inventables.com
HDPE, I recently learned, stands for High Density Polyethylene, and is probably the most commonly used plastic on earth. It's used in things like milk jugs, because of its extraordinary strength to weight ratio. Think about how light an empty milk jug is, and then think about the strength needed to hold a gallon of milk. The craftsmen at the St. Louis Science Center use thick sheets of HDPE for making exhibits, and the folks at the Engineering Lab discovered the trove of scrap HDPE left overs, and started turning them into cool things in their X-Carve.
If you're on an FTC team in the St. Louis area, and you want to try creating a custom part for your robot out of HDPE in the Taylor Center Engineering Lab's X-Carve, please sign up using this form and arrange a visit for your team. The X-Carve can render a variety of designs, including 3D designs that are smaller on the top than the bottom. The precision of the details is limited only by the size of the router bit, i.e. you can't make details smaller than the bit. But if you need hairline precision for a 2D design, you can use the Lab's laser etcher/cutter. The Lab also has a full Skystone practice field your team can practice on while you're there!