the implications of smooth, high tolerance, strong parts of good geimetries range

Ok, I have started to come to the opinion that one of the major things we could do in society to make some progress is to think collaborative on the core things.

I don't know how core this is more generally, but I have been thinking a lot recently about the implications of a 3d printer ,alas, probably work a whole set of post processing and maybe mould making to transfer the shapes to better materials, that can deliver high tolerance, like a thousandth of an inch over ten inches, like milling, almost any shape you can draw on the computer (probably excluding fabrics and a few others), including smooth surfaces, and, perhaps through moulding as post processing, strong materials, ideally full strength steel, but at least fiber reinforced polyurethanes, for instance.

Also including larger ones like a car body, although that is again secondary.

And when I put forth this notion, of course it is a sorry of bargain between what seems possible and what is desirable, as all useful thinking tends to be, but a sorry of sweet spot. What do you think of the implications of such a system? When I look around, I see really a lot of important and valuable stuff you could make with this.

Not much.

Well as a statement of desirability then yes I agree. I would like to be able to buy for modest cost a machine that can produce parts in a wide range of useful materials including metals, that are smooth, made to high precision and fast to produce.

Now the important bit is how do we make one?

Whilst a brainstorming session is very useful from time to time, I think that almost everything you and I desire from a 3D printer is being developed and tested right now. Today's 3D printers are desktop machines, costing hundreds of dollars, which can produce small objects fairly quickly to reasonably high precision, whereas 20 years ago to do this required a machine costing $xxx,xxx and a small room to put it in. That's progress isnt it? I've only been playing with these things for 2 years and the machines I have now are nothing like the machine I had 2 years ago so things are moving forwards.

Have you any ideas how we might move things forward? Any ideas that are not currently patents held by the big boys like Stratasys?

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Although it is obviously good to have printed parts that are accurate, strong and aesthetically appealing, to think that 3D printing should replace all other manufacturing processes is not practical and will lead to disappointment. Incremental improvements in 3D printing are worth pursuing, but not at the expense of spending effort that would be better dedicated to engineering the product or part so that it can satisfactorily be made with 3D printing methods.

I think that my point is best shown by pointing to the construction of the bridge at Ironbridge in Shropshire (U.K.). This was the first ever cast iron bridge and was made in 1779. The construction, including all of the parts, are made with the same joints as would be used in a wooden bridge and the iron beams even have the same dimensions as would have been used in a wooden bridge.

As fascinating as it is to look at the iron bridge now, at that time many would have seen it as a complete folly: Nearly as much wood would have been used to make the patterns for the parts as would have been used had it been an all timber construction. This is not to mention the wood used to make the charcoal for smelting the iron and the labour of mining the ore, casting everything and assembling the heavy cast iron.

Before trying to make unbreakable and very accurate parts which are as smooth as lacquer it would be better to engineer them to take advantage of their strengths and use other processes such as machining or fitting inserts to make up for the deficiencies. It is a mindset thing, don't look at the broken impeller of you vacuum cleaner and think you can replace it with a 3D printed part, look rather to the thing that nobody makes at all because of shape complexity or for some other reason.

Mike

Yes, I very much agree with the great promise, power, also the centrality of human ingenuity of that sort. Indeed, looking at the basic things like safety, being warm, having nutritious food, which many of us even in developed countries are missing, improved capacities of printers seems kind of low on the list of ways forwards... and indeed, the flexibility that arises with the range of manufacturing options etc. really does let you get a long way.


But it is just this: I have seen many times how much we do actually really bang into a wall when it comes time to try to make even rudimentary objects of the kinds we see around us and tend to value. And ultimately, human ingenuity directed at doing somthing like trying to make a better cpap machine may be seen as simply extending backwards up the production chain sometimes. For example, I have read that the printing process called ultrasonic consolidation was actually developed by a company that made sensors, but wanted a higher degree of flexibility in making the housings for the sensors they were making. In other words, developing a better printer is merely an extension of the enterprise of designing things.

There is a time to turn to inserts, but there is also a time to do a sort of foundation building, to get the apparently minor improvement of no longer needing the insert, but it then applies to all kinds of things in the future. This benefit can really add up after all. I mean we gotta progress somehow, and we certainly need both the last minute grab what you got and forge ahead, but there is also a place for building that foundation up so we can stand a little higher, you know?

Quote
leadinglights
Although it is obviously good to have printed parts that are accurate, strong and aesthetically appealing, to think that 3D printing should replace all other manufacturing processes is not practical and will lead to disappointment. Incremental improvements in 3D printing are worth pursuing, but not at the expense of spending effort that would be better dedicated to engineering the product or part so that it can satisfactorily be made with 3D printing methods.

I think that my point is best shown by pointing to the construction of the bridge at Ironbridge in Shropshire (U.K.). This was the first ever cast iron bridge and was made in 1779. The construction, including all of the parts, are made with the same joints as would be used in a wooden bridge and the iron beams even have the same dimensions as would have been used in a wooden bridge.

As fascinating as it is to look at the iron bridge now, at that time many would have seen it as a complete folly: Nearly as much wood would have been used to make the patterns for the parts as would have been used had it been an all timber construction. This is not to mention the wood used to make the charcoal for smelting the iron and the labour of mining the ore, casting everything and assembling the heavy cast iron.

Before trying to make unbreakable and very accurate parts which are as smooth as lacquer it would be better to engineer them to take advantage of their strengths and use other processes such as machining or fitting inserts to make up for the deficiencies. It is a mindset thing, don't look at the broken impeller of you vacuum cleaner and think you can replace it with a 3D printed part, look rather to the thing that nobody makes at all because of shape complexity or for some other reason.

Mike

Quote
DjDemonD
Well as a statement of desirability then yes I agree. I would like to be able to buy for modest cost a machine that can produce parts in a wide range of useful materials including metals, that are smooth, made to high precision and fast to produce.

Now the important bit is how do we make one?

Have you any ideas how we might move things forward? Any ideas that are not currently patents held by the big boys like Stratasys?

I have really been keeping my eyes out, and googling a lot, including on google scholar (which is a lot better in getting results generally).

There is subtractive out of a glass block, like the lightscribe. It is very slow, but perhaps the concept could be extended, using melting rather than ablation, so you don't need a high power laser. The possiblity of using so called optical limiting dyes, which absorb light to a much higher degree when exposed to higher power density light, may allow the heat to be absorbed at the focal point of the laser (or indeed, a cheaper light source) to a degree which is useful in carving the material by melting, or vaporization (for example, sublimation of water). To prevent refreezing, there are agents which cause a so called thermal hysterisis, such as the antifreeze proteins. The ice melts at zero degrees, but does not actually refreeze till minus ten degrees. That means what gets melted stays melted.

From the way melting works, energy input equals melting. When the input stops, melting stops. I don't want to go on about the details too much, but I think that is one possiblity. I worry a bit about the tolerances, but I think it would be quite good. Laser cutters have similar issues; how fast the laser is moving affects the cut width etc., but you can still compensate and get to within a thousandth of a inch. I worry about build speed, though.

Another is the use of laser melting with very fine particles and a material that does not contract or expand, leaving no residual stress (and therefore not curling). There are some articles about using super fine, micron sized powders and layer heights to make very high definition objects.

Lastly, I am a sunbstantial fan of the so called shape deposition modelling. With the use of the right materials - which do not shrink upon deposition, that is the hardest property to achieve - I think it has a lot of potential. There is quite a bit of work done on it already, and I know milling, having worked in the field of multi axis milling for about a year and a half.

I drop those because I agree to some degree that there is not that much point in thinking about this if it appeared impossible anyway, but I think things have to be moved forwards on both counts at once; the implications of getting certian output characteristics are a valuable thing to explore, as it tells us how much effort is worth even putting into this.

I am particularly baffled at how there seems to be little discussion on the subject.

p.s. Sigh, I know these kinds of discussions have a poor history of not going very far, but ultimately, I have come to a point where I believe "we have to talk". We really do. And often in the world we are too geographically separated to do this in person...

I can think of more discussions purely on practical matters which became discussions about the wider implications than the other way around.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

alas, we hardly did the subject justice, did we. how will we ever advance if we can't even talk? As humankind, even. I mean seriously, in person works a bit but odds that everyone feels like talking about high level stuff at any given time are slim. We need to be able to talk over windows of time and space that are larger..... arg

Ah but you need to be in the mood and inspired at the moment to really get stuck into one of these, and invariably we all have a ton of more mundane things to get done. This is not a good reason not to talk ideas, I love to generally. But I think some of the ideas you mentioned are interesting for sure. I think most people are into incrementing rather than revolutionising things, which takes high-mindedness, determination, drive and money.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I think most changes are actually done for money, rather then the love of reprap... If you're a guy with big ideas, chances are you don't want to give them away for free.

Other then that, the big ideas are usually the result of one person's innovation, and people flocking to that idea. Come up with an idea, develop it, make it open source and you will find people who want to collaborate with you.

I can second that my twist on the piezo sensor has resulted in a very engaging collaboration with a whole bunch of people, and that's merely an increment of something many have developed over the last few years. If you have a really groundbreaking idea and can convince people that its a real breakthrough then a lot of people are going to want to get involved.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions