[Matterhackers] has a nice video tutorial on using vacuum forming to create plastic items. Sure, you have a 3D printer, but vacuum forming has some advantages if you are making thin and flexible items quickly. But don’t feel bad. The master item in the process is from a 3D printer. Like a mold, the forming won’t produce a duplicate of the master, called a buck. Rather, the buck provides something like a die that the plastic wraps around.
While obvious vacuum-formed items include such things as take-out food containers and plastic blister packaging for retail items, you can also make more substantial items. Apparently, all theStar Wars movies in the original trilogy used vacuum forming to create stormtrooper armor.
Like many fabrication technologies, there are special design rules. For example, you can’t have any overhangs or else the plastic will not release from the buck. In fact, ideally, the buck will have a slight slope on all sides so that the bottom is wider than the top to simplify separating the buck from the finished product.
Another concern with a 3D printed buck is that the plastic will completely conform to the surface. So if you have layer lines or other irregularities, they will show up in the finished product also. You may not care or you may want to sand and possibly seal the print. Of course, you can make the buck out of anything that can withstand the heat including, according to the post, including a raw potato. While PLA is iffy because of the heat, the post indicates that they have used normal PLA successfully by increasing the number of top layers when printing. However, using an advanced PLA with a higher temperature, ABS, or PETG is recommended.
The Makyu Formbox hooks up to a shop vac or household vacuum cleaner to provide the negative pressure. The device — which unsurprisingly [Matterhackers] sells isn’t dirt cheap, but we can remember paying more for a 3D printer (the cheapest option is about $700).