What is the maximum bend "tension/compression" load limit before a frame can buckle under load?

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I like to know and see how if even possible, future frames could be built vi 3d printing. The other idea, print each piece and then bolt/weld together.
 
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You would have to identify the alloy of the steel used, measure the wall thickness of the frame, and then model the overall cross section of the frame to determine that analytically.

3D printing frame components is not ideal use of 3D printing. The frame components can be bent up from sheet stock much faster on a brake or press.
 
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3D printing metal does not have any structural integrity because there’s no molecular bond between the layers. Unless you put the printed parts into an oven and heat it properly it will never be strong enough to use as frame material for a car. At least that’s where I understand the technology to be at this point. I’ve seen some companies try to make 3D printed gun barrels and they will fire one or two rounds but there is just no strength to withstand intense pressure. That technology just isn’t there yet unless I’ve missed some breakthrough they’ve made.
 
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3D printing metal does not have any structural integrity because there’s no molecular bond between the layers. Unless you put the printed parts into an oven and heat it properly it will never be strong enough to use as frame material for a car. At least that’s where I understand the technology to be at this point. I’ve seen some companies try to make 3D printed gun barrels and they will fire one or two rounds but there is just no strength to withstand intense pressure. That technology just isn’t there yet unless I’ve missed some breakthrough they’ve made.
 
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If we forget the 3D printing for a minute and focus on your first question this is a pretty easy question. You will just need a diagram of the frame and some information about the material used as well as its cross section dimensions. You can look at the moment arms in the frame and the loads and put together a freebody diagram and just work your way through to figure out what sort of loads you will see.

The 3D printing question is not so easy to answer and is really a theoretical at this point simply because I don't think there is a metal printing machine big enough yet to print a whole car frame. 3D printed parts are better than castings but not as good as forging. You could however build a scale model of your idea but just be aware that not everything scales linearly.

From a practicality point of view 3D printing automotive frames is not cost effective at this point in time. The industry I work in we do use 3D printing for actual hardware but only pieces that are too complex internally for casting and where machining internally afterward is difficult or impossible.
 

stevebradford

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If we forget the 3D printing for a minute and focus on your first question this is a pretty easy question. You will just need a diagram of the frame and some information about the material used as well as its cross section dimensions. You can look at the moment arms in the frame and the loads and put together a freebody diagram and just work your way through to figure out what sort of loads you will see.

The 3D printing question is not so easy to answer and is really a theoretical at this point simply because I don't think there is a metal printing machine big enough yet to print a whole car frame. 3D printed parts are better than castings but not as good as forging. You could however build a scale model of your idea but just be aware that not everything scales linearly.

From a practicality point of view 3D printing automotive frames is not cost effective at this point in time. The industry I work in we do use 3D printing for actual hardware but only pieces that are too complex internally for casting and where machining internally afterward is difficult or impossible.
I think 3D printing would be an excellent route for prototyping replacement parts to be stamped or forging. Making scale models is also a very viable use of the technology at its current state. There are 3D printers that are large enough to make a car frame but it’s the metallurgy that’s lacking. Have you seen the 3D printed houses?? Very cool! Mobile printers that use a cement/aircrete type substance and can build a house to exact dimensions rather quickly. Cost effective? I doubt it at this point, but nifty none the less.
 
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I think 3D printing would be an excellent route for prototyping replacement parts to be stamped or forging. Making scale models is also a very viable use of the technology at its current state. There are 3D printers that are large enough to make a car frame but it’s the metallurgy that’s lacking. Have you seen the 3D printed houses?? Very cool! Mobile printers that use a cement/aircrete type substance and can build a house to exact dimensions rather quickly. Cost effective? I doubt it at this point, but nifty none the less.
I meant there are not metal 3D printers large enough to do a car yet. I have seen the concrete printers and large format resin printers. Metal printing is another level of complexity. It’s good for complex parts with complex internal passages . It’s not a fast process so it’s not good for high volume yet.
 
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It also doesn’t make sense to go backwards. Printing an auto chassis should be one part of a whole new design where you can optimize every piece of the design for your end goal.
 
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I meant there are not metal 3D printers large enough to do a car yet. I have seen the concrete printers and large format resin printers. Metal printing is another level of complexity. It’s good for complex parts with complex internal passages . It’s not a fast process so it’s not good for high volume yet.
Exactly. I guess what I was getting at is: they have large printers and are capable of making them, but for metals, they have not bridged the technology gap yet. There are so many things to consider when printing with metals. Some resins are proving to be stronger than some metals, especially printed metals. But I’m no expert in any of this and only know what I’ve seen in articles and videos.

And to your other comment… that’s a very good point. A very good one.
It also doesn’t make sense to go backwards. Printing an auto chassis should be one part of a whole new design where you can optimize every piece of the design for your end goal.
 
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The printers we have for metal are all heated to a very high temperature in the print area. Would be a real challenge to maintain that level of heat for something so large. I think there are cooler print area printers for metal but probably require heat treatment after.
 
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The printers we have for metal are all heated to a very high temperature in the print area. Would be a real challenge to maintain that level of heat for something so large. I think there are cooler print area printers for metal but probably require heat treatment after.
That’s what I understand too. I looked into 3D printed firearms parts and there are lots of pieces that work well, but as far as anything that needs structural integrity goes, it’s just easier to mill out a billet. For things like a chamber and barrel there’s only one way to get the metal strong enough to withstand the intense pressure and heat cycles… and that’s coal fired heat and forging. I’ve seen carbon fiber barrels before, but they’re lined with heat treated chrome. Still requires old fashioned metal work.
 
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