Why Robot Made (CNC Tools) is Green.
Because of the precision of the CNC routing table, we can nest parts very close together, maximizing how many parts can come from a single sheet of material. Typically hand-cut parts create more waste, for nesting parts so close is difficult and sometimes not even possible. Labor is also the highest cost for traditional shops, so spending extra time to save material loses out to generating more waste but doing the job faster. Also certain parts can't be cut out by hand safely without having a bit of waste to hold the part while cutting.
CNC cuts are also much more clean and less error prone, making for much less waste due to mistakes made while hand cutting, and much less waste in the sanding and finishing of a part. Finally, when cutting with the CNC, it's effortless to throw into a cutting run extra parts for some other job to use up the rest of a sheet of material. With hand-cutting, this again is extra work, and extra time, so that leftover scrap material is much less likely to be used, and is much more likely to be simply tossed at the end of the job.
Less Tools and People.
Because the CNC routing table can do the work of many traditional shop tools, it makes for less machines to maintain and less steps involved in a part's creation. Instead of needing four big industrial tools, like a tablesaw, shaper, plainer, and drill press, which all consume power, oil, space, and maintenance time, we can do the same job with one tool that can be much more efficient. And again, due to it's clean and precise cuts, less finish work and special steps mean less hand tools.
Also, because there is so much less labor in producing parts via CNC, and those parts can be made to fit together perfectly, less people are needed. The designer is enabled to produce product themselves directly, and to even mass produce and mass customize those products. All without exploiting others via cheap manual (and dangerous) labor, going overseas for production, or other activities that tend to produce more problems and environmental impact when a lot of people are needed to do something messy and dangerous.
Our CNC table itself has two main power-consuming parts; it's brain that powers and controls the drive motors, and the cutting tool that those motors move around. In our case that's a 3 ½ HP shop router. The brain uses about the same amount of power when it's on and running that your PC is using right now to read this essay on-line. We actually have it hooked to a old junk UPS to 'clean' the voltage it's getting (helps with the accuracy) and it can almost run just off of that alone if you unplug it (and it's an old worn-out UPS we got for free!). The router, while heavy duty, only uses as much power as a router does, which isn't trivial but is still much less than a industrial shop tool. The thing that probably uses the most power in the whole setup is the dust collection system, not really part of the table itself (it doesn't play a role in cutting, just in capturing the constant and ever-present dust). Something we'd like to make more efficient in the future. But still, for a setup that uses less power than a shop tablesaw, and a touch more than your PC, we're able to generate a huge amount of work that requires little cleanup and sanding.
Also the amount of steel and the motors that make up our CNC table is vastly less material then what's even in a traditional industrial tablesaw, let alone something as heavy-duty as a plainer. It takes a lot less energy to make a CNC table than it takes to make just one of the four shop tools it easily replaces, so there's a lot less 'embedded energy' (that's the total amount of energy it takes to make, ship, maintain, and dispose of an item) in the picture too than in a traditional shop.
Finally, the CNC table is fully modular, hackable if you will, so it can be repaired easily, modified for more tasks, enhanced for better capability, or simply upgraded with better software to run faster or smoother. Fixing a tablesaw isn't too hard, really, but it's only ever going to be a tablesaw, and it's hard to make it a better tablesaw for there isn't a whole lot there to work with in the first place. And I doubt you'll ever be able to simply install a software patch to your tablesaw and suddenly have it be able to do something new. So again, less energy is needed to maintain it, and less to expand it's abilities in the future.
To produce something via CNC, it must be drawn or modeled on the computer first. Just by going through that process a lot of errors are caught, and new, better ideas introduced. Special software can predict where things will fail, not be strong enough, or root out design problems prior to production. Less prototypes are needed overall, for most of them are made and studied virtually. Puzzle-like joints normally too laborious to make by hand make for quick, clean assembly without the need of additional brackets or parts. Material can be practically optimized within a design to be used to it's fullest, making for more efficient designs. Larger parts can be easily broken down into a modular kit of parts to maximize material use. 'Boring' materials, such as less exotic sustainable woods, pressboard, MDF, and plywoods can be made very interesting due to complex carving and shaping, instead of a design relaying upon the finish of an exotic wood or toxic finish to make it look great.
And finally, the price of custom work is so greatly reduced that we can provide totally custom products for slightly more than the price of a mass produced product. That custom product can fit the client's needs perfectly, and can have a much more attractive and unique design, so it's much more likely to be fully used, and used for a long time. Instead of a 'just ok throw away' we can produce 'one of a kind treasures' yet remain affordable. And we can make replacement parts to fix things, or new parts to change it, it's just a matter of pulling up the old job file. So the things we make are much less likely to wind up in the landfill.