In the 1940's sci-fi short novel called "Things Pass By", Murray Leinster talked about an arm which draws things in mid-air, flowing molten plastic and hardening it where it stays. This was the stuff of fantasy back then, ok they also thought we'd have flying cars and live on the moon , but 3D printing has been one of the sci-fi subjects which has revolutionised the way we manufacture and engineer things nowadays.
Today, you can sit in your own home designing your own parts, hit print, and out will come a 3 dimensional representation of your design, and it's fully functional, ready to use. We are living in an amazing time!
3D printing has endless uses. You can make trinkets, keyrings, models, tools, or other fairly complex parts. From your individual at home, or a commercial business manufacturing prototype components for motorsport or the manufacturing industry. My first play with additive manufacturing came out of necessity. I had built a track-ready motorcycle, just for using on a race circuit. One of the first times using it at Donington park in the UK, I was flying along a set of curves down a steep hill, called Craner Curves, and anyone who's ridden there will tell you, it's not for the feint hearted. Anyway, when flipping the bike side to side, I accidentally flipped the ignition switch and cut the engine... NOT what you want to happen! Luckily I stayed on and was ok, so I set to work to stop this happening again. I produced a cover to sit over the switch, to prevent my hand from knocking it off. Job done.
This is an ideal use for simple 3D printing. A simple sturdy component that fits a purpose.
However, there are companies out there producing, much, much more complex designs than this, in metal. So what does this mean for the future of manufacturing? Well, lets look at the current situation. You have either Additive Manufacturing, or Subtractive Manufacturing. The majority still default to Subtractive, in the form of machining. It's cost effective, widely accurate and if really pushed with 5+ axis machine tools, can make pretty much anything. You can use plastics, metals, wood, high density foams, the list goes on. You can either buy a small DIY CNC router for home use, or a fully fledged Haas VMC with some serious material removal capabilities, so there's something to fit all budgets. Now here lies the issue; Time.
In an age where we want everything yesterday and time is considered a limited resource, machining can come with certain restraints. Often machine shops are stacked out with high work loads (which for now is great!) which means your part may not make it onto the machine for a few days. then once it's ready to machine, the part has be programmed and set up - depending on the part, this could take another day or maybe more. If you want a sample for fit and function, it has to be set up and machined before production can begin, which can prove challenging. 3D printing is a different story - once your part is ready (with a little tweaking to make it printable) it can be printed pretty much straight away with minimal fuss. Your fit and function sample can be tested before a CNC machine has even been powered up. Now, this can be done relatively cheaply, however that comes with a problem. Cheap machines are unreliable and inaccurate, and often tie themselves in knots, for example if it's a filament fed machine. You can leave a part running all night only to find a puddle of mushy plastic everywhere the following morning. Really the most accurate and usable method is laser sintering, then this comes with a much, much larger cost. Also the cost for the materials can be massive. Then again, the cost of waste from machining a part from billet can be pretty high too if you're only making small batches.
3D printing really does have it's place, however I believe that it will never replace machining. There may be a time fairly soon when the two machines are combined, for example we do see printed parts with post-op machining done... I think the future won't necessarily lie with the method itself now - there is plenty of development work making 3D printing better and better all the time, this is inevitable. If anything, it will get that good that it may eliminate the requirement for casting processes. 3D printers are already in use printing moulds in sand rather than traditionally hand packing them.
What really is the future is how these processes are going to be managed. Industry 4.0 is pushing more and more automation, and along with it more companies are popping up where you upload a 3D model to a website, then a few days later your machined part arrives via courier. I think further development of this is where it's at. It's already happening. I've seen a factory in the UK with about 20 vmc's with one operator just loading billets, all making injection moulding tooling to go all over the world in all industries. None of it is programmed by a human being, not even the quoting - it's all taken care of via software and is turned around ultra fast.
Imagine a super fast and accurate VMC that can 3D print metal components through the spindle then do a tool change and create machined faces with cutting tools... have I just invented AddiSub Manufacturing? I'd better get to the drawing board....