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| Re: Making a casing for an electronic print [message #1213 is a reply to message #1197 ] Fri, 05 September 2008 07:35 UTC |
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If this is not a mass product I would suggest using hex screws to close the container. If it is a mass product (and having no experience with gripping edges), I would suggest several snap connections. My gut feeling says they can be made bigger for equal closing force than a gripping edge and hence tolerances are less strict.
Can you explain more about the deformation. I can not get a feeling from it from the pictures.
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| Re: Making a casing for an electronic print [message #1214 is a reply to message #1213 ] Fri, 05 September 2008 07:47 UTC |
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| svenpb wrote on Fri, 05 September 2008 03:35 | If this is not a mass product I would suggest using hex screws to close the container. If it is a mass product (and having no experience with gripping edges), I would suggest several snap connections. My gut feeling says they can be made bigger for equal closing force than a gripping edge and hence tolerances are less strict.
Can you explain more about the deformation. I can not get a feeling from it from the pictures.
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Hi Sven, thanks for replying
Using snap connections is a good idea! I will talk to my collegue about this. Could you direct me to some kind of blueprint for this?
I will google for this too.
The deformation takes place when my model is imported. If you follow the link i gave earlier to the shapeways model and view it in 3d, you will see what i mean.
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| Re: Making a casing for an electronic print [message #1217 is a reply to message #1214 ] Fri, 05 September 2008 17:38 UTC |
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Don't worry about the deformation. It is actually an annoying rendering artefact. There is more on this topic in the forum.
I can assure that we print it exactly as you uploaded it.
And yes, we are working on fixing the 3D viewer and thumbnail generator to better portray the actual 3D meshes we import.
Cheers!
Robert
Robert Schouwenburg
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| Re: Making a casing for an electronic print [message #1223 is a reply to message #1197 ] Fri, 05 September 2008 20:38 UTC |
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Ok first off, the locking edges might not work to well without adhesive used on them, which would make it so you could not open again.
I would suggest using at least 2 locking tabs on each of the long sides.
Heres a basic pic and file

This would allow you to open the case/box by applying pressure at just the right areas to lift the tabs off the pegs.
[Updated on: Fri, 05 September 2008 20:39 UTC]
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| Re: Making a casing for an electronic print [message #1228 is a reply to message #1223 ] Sat, 06 September 2008 12:11 UTC |
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Something like Dalhimar.
I've drawn what I had in mind, but this is just a first idea of a process. For example, the walls will bend because of the force and so additional support ribs will be necessary I guess. Also you want the thickening for the snap to be local and not to be part of an increased wall thickness. Same is true for the guidance that is now part of the wall. Don't think you want it the way it is drawn.
Guidelines exist, e.g. you should calculate the allowable deformation of the material while the snap occurs. And calculate the angles of the snap.
Maybe you better buy some stuff in your local shop, take it apart and learn from it. I actually think you'll end up with Dalhimar's design or something similar.
[Updated on: Sat, 06 September 2008 15:52 UTC]
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| Re: Making a casing for an electronic print [message #1240 is a reply to message #1197 ] Mon, 08 September 2008 00:16 UTC |
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I only see one real problem with your idea Svenpb.
The Lighter blue could easily slide down into the space between the tab and wall.
But that is a good idea, Go get some cheap cases or whatnot and look at how they are held together, this will give you an idea on how to design you locking structure. The one i did a rough design of is just that of a really common design. Look at as many sources as you can, then decide on what would fit your project the best.
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| Re: Making a casing for an electronic print [message #1250 is a reply to message #1240 ] Mon, 08 September 2008 14:51 UTC |
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Sven en Dalhimar, thanks to you both for the input! You have helped me a great deal. Even though I'm still not sure it is going to work on the first try when i read this page:
http://www.efunda.com/designstandards/plastic_design/snaps.c fm
The math is way too complicated for me, but there are some good tips on that page. I'm going to try and do it with real models. If anyone got some tips.... that is always welcome and appreciated!
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| Re: Making a casing for an electronic print [message #1253 is a reply to message #1250 ] Mon, 08 September 2008 17:59 UTC |
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That's a very concise website. Good find.
What they are trying to calculate (from scanning the page) is to be sure the bend is within the range of elastic deformation. If the bend is too large, the deformation is plastic, which means that the latch will not return completly to its initial position. [edit: they are trying to calculate the force, sorry]
I'm not sure if this calculation is very important for prototyping.
The locking -angle from what I understand starts at about 60 degrees. If the angle is bigger, you can not disassemble te part.
[Updated on: Mon, 08 September 2008 18:36 UTC]
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