Since getting my first 3D printer and realizing its actually a really fun, useful piece of equipment, I've been thinking of moving into a bigger printer. Comparing different leading printers however, it seems they all have pretty similar build volumes, maybe maxing out around 10 x 10 x 10 with a single extruder (less with a dual extruder setup) and they are all about the same price, about 2000 dollars give or take. Well, I figure I could do a lot with 2000 dollars, and I have a suspicion that the typical pulley systems in use become much less effective as belt size and mass of components increase. Additionally I can see lack of structural rigidity being a factor that will reduce print quality in larger printers since there is a lot of mass moving around at high speed.
So what is my ideal 3D printer? Well, having a build volume in the range of 12 x 12 x 12 would give all the volume you could ever reasonably want. Its rare to print a single object that big, but its pretty common to have print jobs that include multiple small parts which on a large printer can all be done at once. Additionally a large build volume reduces the penalty one pays for having a dual extruder setup which I would like to have. In my design all the drive components are either rack and gear or ACME rod so the stepper motors are always directly driving each axis. I have also looked at reducing friction to the absolute minimum and eliminate any flex or vibration through the use of track and ball bearing carriers for linear motion.
I want the structure of the printer to be as rigid as possible and it seems most things can be pretty easily made out of plate aluminum. The greatest advantage of using plate aluminum is its ease of manufacture. Rather than having complex bent sheet metal or machined components, each plate can be laser cut, then holes can be drilled to size and tapped by hand. Another advantage of laser cutting parts is cost. At Palatov it has been found that getting parts laser cut often ends up cheaper or about the same cost as just buying the plate itself.
Finally, I intend to use as many off the shelf components as possible such as extruders and electronics. Other companies have worked out all the problems in that regard so there is no sense in reinventing the wheel and it will allow for fairly seamless integration with software. It might take some calibration to dial in the distance traveled per step and to tell the software how much build volume is but that's not a big deal.
At this point my design is still at the 'wish list' stage where I find what is easily available from McMaster Carr and other sources and drop it in. Once everything is roughed out i'll go back and refine components and try to reduce the cost. As it stands there is about 1000 dollars worth of precision track and ball bearing carriers in the design alone, ouch! Still if the precision parts cost that much and everything else is 1000 dollars, I'd call it a success seeing as for the same cost I could have bought a different printer with less capability. If it works there is always the potential to offer it as an upgrade kit that people can buy to upgrade the capability of printers they already have.
