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Hi! Where to start? [message #42971] Sat, 28 January 2012 15:04 UTC Go to next message
avatar Scrim  is currently offline Scrim
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Hi! Razz I'm new to to all this, but want to design mechanical structures using things like Gear Wheels and Struts. What sort of software do I need to look at?
Re: Hi! Where to start? [message #42981 is a reply to message #42971 ] Sat, 28 January 2012 17:25 UTC Go to previous messageGo to next message
avatar aeron203  is currently offline aeron203
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Hello, and welcome. You can build those things in just about any software if you really know what you're doing, but you'll have a much easier time in a parametric CAD modeler like Solidworks or Catia. A less expensive, but moderately full-featured one is Alibre Design. There are some free ones, but they are so manual you are going to have to do all of the math yourself and make everything completely from scratch. So, basically you need either very expensive software or a degree in engineering, probably both to do anything reasonably complicated, like a functional vehicle model. You could try to find working assemblies on other sites, maybe free ones on Thingiverse.com, and piece them together, but making that work is going to be more challenging in the computer than say, buying RC car parts and attaching them to a frame you printed.

The short answer is that there is no easy solution to doing something as complicated as you describe, even if the technology is capable of producing it, which is also not certain. Hopefully you don't find that off-putting, and I encourage you to seek out others to collaborate with to divide the work if you have a cool idea for a project.



Aaron - 40westdesigns.com/blog
Re: Hi! Where to start? [message #42992 is a reply to message #42981 ] Sat, 28 January 2012 20:15 UTC Go to previous messageGo to next message
avatar Scrim  is currently offline Scrim
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Thanks for your help, but I'm not planning anything so complicated as a car!

In fact I want a pair of 'Crown' gears, but with an awful lot of teeth, so something to automate the generation of hundreds of teeth would be needed to make it practical.

The other thing I'd like to make is a 'Recursive Truss', which is a normal engineering truss but built from smaller trusses, and so on to the smallest scale possible. Something to automate the recursion would be great, but I'm not expecting that much help as it's a bit of a specialist requirement!

What would best suit that type of thing?



Re: Hi! Where to start? [message #42996 is a reply to message #42992 ] Sat, 28 January 2012 21:02 UTC Go to previous messageGo to next message
avatar JACANT  is currently offline JACANT
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I've just come across this software myself, it looks awesome. I hope the learning curve isn't to steep.
http://sourceforge.net/apps/mediawiki/free-cad/index.php?tit le=Main_Page
http://freecad-tutorial.blogspot.com/2011/10/engine-5-camsha ft-gear.html
Have fun


jacantdesign@gmail.com
Re: Hi! Where to start? [message #43055 is a reply to message #42971 ] Sun, 29 January 2012 20:17 UTC Go to previous messageGo to next message
avatar aeron203  is currently offline aeron203
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Like Jacant, I recently discovered FreeCAD and I see it has some real power under the hood in the form of the OpenCASCADE kernel. I remember trying it a while ago, and it kept crashing before I could make anything, but it has just edged over the line into usefulness. The available operations are very limited and the interface is crude... but it's a free solid modeler (that means it always makes printable models). The only other free app in it's class is 123D from Autodesk.

Both of your projects can also be done without scripting in any polygon modeler that has an Array command. Blender has a tough learning curve but is among the most capable out there. I have a tutorial where I show how to build arrays in blender here: Model Grouping for 3D Printing Part 3 - Blender Arrays. Of course there are dozens more on Youtube.

Finally, while it doesn't make crown gears, eMachineShop.com has free software with a really nice gear generator built in. That will make perfect involute curves that will mesh together nicely. Export those profiles and modify/assemble them in Blender, Sketchup, etc. You might try chopping one tooth off and rotating it upward, making an array of them on a disk to make your crown gear.


Aaron - 40westdesigns.com/blog
Re: Hi! Where to start? [message #43161 is a reply to message #43055 ] Mon, 30 January 2012 23:16 UTC Go to previous messageGo to next message
avatar Scrim  is currently offline Scrim
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That's great - thanks - much appreciated! Smile

How much use is AutoCAD for this type of work?

[Updated on: Mon, 30 January 2012 23:23 UTC]

Re: Hi! Where to start? [message #43168 is a reply to message #43161 ] Tue, 31 January 2012 00:48 UTC Go to previous messageGo to next message
avatar pfeiffer stylez  is currently offline pfeiffer stylez
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Scrim wrote on Mon, 30 January 2012 23:16


How much use is AutoCAD for this type of work?


If you want it accurate, much more than 3D modelling software. ^^

I think Inventor/Solidworks/Catia/(something like that) would be better, but as long as you don't need to hollow out your final design(s), AutoCAD should do the job.
Re: Hi! Where to start? [message #43178 is a reply to message #43168 ] Tue, 31 January 2012 02:19 UTC Go to previous messageGo to next message
avatar Scrim  is currently offline Scrim
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It's just that learning a new software packages can be really hard work Confused and I've already got other reasons to learn AutoCAD. What do you mean about 'hollowing out'?

Re: Hi! Where to start? [message #43223 is a reply to message #43178 ] Tue, 31 January 2012 19:28 UTC Go to previous messageGo to next message
avatar JACANT  is currently offline JACANT
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AutoCad is just fine if you have spatial awareness in 3D. You can get a bit lost with the WCS and UCS (World and User Coordinate System) until you understand it.
Some of my models including my Chess Set were all created in Autocad.
As for hollowing your model, Autocad has a 'shell' command were you can input your exact wall thickness.
The only problem with it is everything you design has to be a solid object using boolean commands, because that is the only way to export to STL.


jacantdesign@gmail.com
icon5.gif  Re: Hi! Where to start? [message #43361 is a reply to message #43223 ] Thu, 02 February 2012 23:28 UTC Go to previous messageGo to next message
avatar Scrim  is currently offline Scrim
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Thanks, but what does this mean:
Quote:

The only problem with it is everything you design has to be a solid object using boolean commands, because that is the only way to export to STL.



Re: Hi! Where to start? [message #43367 is a reply to message #43361 ] Fri, 03 February 2012 00:22 UTC Go to previous messageGo to next message
avatar JACANT  is currently offline JACANT
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When creating solid objects in AutoCad and other software a 'Boolean' command can join objects together, or subtract objects from each other, or intersect the objects to create a new shape.
I was wrong about exporting just solids. You can export a watertight mesh. I just find it easier to create in solids. I should mention after I export, I open the .stl file in http://www.netfabb.com/basic.php to check repair or scale.


jacantdesign@gmail.com
Re: Hi! Where to start? [message #43410 is a reply to message #43367 ] Fri, 03 February 2012 21:01 UTC Go to previous message
avatar Scrim  is currently offline Scrim
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OK, thanks. Time to start experimenting!

 
   
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