Additive versus Subtractive technologies

I design products and we use all kinds of rapid prototyping. Ive had parts made by almost everything available. Some of the best lately have been what we call fast casting where a wax is made by either fdm or a type of 3d printing, then investment cast. We can get really nice parts done like this in about a week. I mostly design climbing and ski gear these days and was testing some climbing gear with parts cast this way yesterday on the rocks, not usually possible with most rp stuff.(I do back things up in case of a failure, as a fall from a hundred feet or so usually hurts) I was using grips I designed that were 3d printed and some machined aluminum parts too. Pretty amazing how quickly we can get to a useable prototype these days.

Where most RP stuff is great for part fitting and modeling it's rarely very strong, but its getting better pretty quickly. We have lots of plastic parts CNC'd from the real materials so we can test prototypes in the real world. We're kind unusual that way but for our needs there has to be a balance between testable parts and models.

There are some bicycle dropouts on the market now that are laser sintered, and I think that's where the real breakthroughs will happen. The cutting egde of that is making parts that have better porosity than castings.

I started designing cars in about 1990 and back then, we had the most sophisticated stuff there was. Intrestingly, I'm from the last generation that ever learned to design car bodies by hand using body drafting.
Everything is done on a computer now and it can be faster, but not always.
Now my laptop is more powerful than the $250K Silicon Graphics computer I had then. The speed that the technology is accelerating right now is pretty amazing.
 
You live the sort of interesting life that I had in my last job several years ago, but in my case it was electronics. I now work in Utilities and everything is old...

If you were starting machining as a hobby today with this knowledge, is there a price point where you could say your investing too much in a field that is becoming somewhat obsolete?

bugeyepaul said:
...The speed that the technology is accelerating right now is pretty amazing.
Click to expand...
 
There is lots of interest in Additive Manufacturing, but there is still a huge gap between what people think it can do, what the equipment can currently do, and what it actually takes to make a good part. Most of the additive processes still waste quite a bit of very expensive input material, still require heat treatment and/or hot isostatic pressing (HIP), and machining to get a good surface finish.

There are also economies of scale to think about. For a few parts, additive might be the way to go. For thousands of parts, it can't compete.

It is cool what can be produced this way. Extreme geometries that can't be produced with traditional machining and mechanical structures based on organic originals.
 
Well, to throw a curve ball, my daughter, whenever I talk to her about Additive Manufacturing, simply replies..."Dad, the uterus has been doing it for years".

Pretty hard to top that comment!
 
Well, its kind of funny how fast things move, and from what I have seen once they get the tech tweaked it will take over big time. Remember in HS electronics we were taught vacuum tubes, and my first major home project was a heath-kit oscilloscope made from tubes (using only the book and all parts made with what was at hand). My first cell was a Motorola "brick" and I used to make computers (IBM XT's) which was high tech over the apple lumps and commodore 64's lol

I no longer mess much with computers as the tech moved ahead just too fast, and lost pace last working with the high tech 8086 processors lol. I think manual machines will still have a place, but probably small, as now manual mills are old school, being replaced with CNC all over. The other thing to consider is the materials themselves, as in the old days everything was basically made of wood. Steel took over but with carbon fiber I can see steel going towards the seconds bin once the manufacturing cost comes down. Once they can rack up a sky scraper with carbon fiber, steel will start its fall :(

Anyway, just hope I have 50 or so more years in me so I can see what happens in the decades to come :)
 
blacksmithing has become popular now and in 1960s it was all but extinct

I think of subtractive as lathe/mill where you remove stuff to make something

I think of additive as metal casting where you add stuff to make something

a neutral where you don't add or subtract would be bending or fastening metal together like origami
 
I recall a time many years ago where the English thought they had mastered mass production of Titanium through a chemical process that was cost effective. It was never heard of ever again; I wonder what became of that promising break through...

From memory, Titanium is a significantly more abundant material than just about any other if it can be manufactured cheaply. What's it like to machine?

I was chatting to a vendor in Oz recently who was at an exhibition earlier this year where 3D Printing was demonstrated, and he had this to say:

"There was lots of interest in “Additive Machining” which is effectively 3D Printing. Currently, it is used for modelling new products and prototyping. My belief is that it will never replace normal metal removal techniques, for standard commercial products.

... it all depends upon what you want to make. If you are interested in designing prototype products to present to companies which will then manufacture en-mass, then maybe 3D printing is the better choice. But if you already have manual machining skills and want to go to CNC, then the Tormach ( or equivalent) is the way to go. If you want to make things out of different materials such as St/St or any Ferrous or Non Ferrous Metal, then CNC machining is the only way to go. 3D printing is way too slow at present.

But who knows, technology changes so fast... I do not believe in my lifetime that 3D printing will replace metal removal techniques The materials can not be generated with the same grain structure and the strength etc., cannot be reproduced by additive machining. But I must admit, it is a fantastic way of prototyping."

Most people I know already have hands on experience with machining. I have little, apart from woodworking, so from my perspective it becomes about the level of investment to make in machinery and tooling. I am only interested in this as a hobby. We tend to spend a lot on our interests, whether motorbikes, cars or this. However, I wonder what the limit is for machines that will progressively lose value and have a lower number of future buyers due to shrinking skill sets...
 
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