What is the best mechanical CAD program for designing robots?

[Osman Eralp]

For designing the mechanical portion of my robots, I've dabbled with several programs, including SketchUp, Solidworks, and Autodesk Inventor. I'm going to do a lot more mechanical design in the future, so I need to pick one program and become an expert with it. My criteria are

• The program must allow me to export data for CNC milling and 3D printing.
• The program should be one that is used in the robotics industry.
• It would be nice if models are available from the designer community.

Ease of learning the program is not important. Cost of the program is also not important.

Does anyone have any suggestions on which program I should choose? What program do you use? 

Thanks!

Osman

[Tyson Messori]

I've used both Pro-E and Solidworks extensively to design robots.  I would say Pro-E is better if your assemblies are going to be very large and complicated. Solidworks is a little faster when creating sketches and features up front, but tends to get bogged down and buggy when your assemblies become larger than a couple hundred parts.  I currently use Solidworks at work for small to medium size products - (100-200 parts).  My system is pretty beefy but I still have stability issues with my largest assemblies.  On the flip side I think Solidworks has been consistently getting more stable since the 2008 release.  Now I only experience 1-2 crashes per day instead of 3-4 :)

Tyson Messori
Senior Mechanical Engineer

Santa Barbara Infrared (SBIR)

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[Wayne C. Gramlich]

Osman:

That is a huge topic you have opened up. It shows up time and
time again on many of the groups out there. I have heard it
referred to as "CAD/CAM Hell" and I think that is an appropriate
description.

The usual work flow for CNC is:

CAD => CAM => CNC

All three of these steps can be quite expensive and complicated.

I strongly encourage that you sign up for some classes at the
local community college before laying out some serious money.
The community colleges that still do CNC in the South Bay area
are De Anza (quarter system) and San Jose City College (semester
system.) In East Bay, there is Chabot community college.
One of our members went to Modesto community college to learn CNC.

Another advantage to the community colleges is that sometimes you
can get student versions of the otherwise extremely expensive
packages. While cracked versions of many of these programs are
out there, this mail list is absolutely not the place to talk
about them.

My recommendation is that you figure out how you intend to do
your manufacturing first and the work backwards from there.

For me, the cost of commercial products exceeded my available
budget by several orders of magnitude. As usual for me,
I wrote some C and Python code to get the job done for me.
I used OpenSCAD as my model:

http://www.openscad.org/

OpenSCAD is primarily for 3D printing.

Regards,

-Wayne

On 09/17/2012 10:05 AM, Osman Eralp wrote:
> For designing the mechanical portion of my robots, I've dabbled with
> several programs, including SketchUp, Solidworks, and Autodesk Inventor.
> I'm going to do a lot more mechanical design in the future, so I need to
> pick one program and become an expert with it. My criteria are
>

> * The program must allow me to export data for CNC milling and 3D
> printing.
> * The program should be one that is used in the robotics industry.
> * It would be nice if models are available from the designer community.

>
> Ease of learning the program is not important. Cost of the program is
> also not important.
>
> Does anyone have any suggestions on which program I should choose? What
> program do you use?
>
> Thanks!
> Osman
>

[Bob Allen]

Osman,

I use Solidworks and it will do all that you are asking. I like the fact that I can sent a Solidworks file to Shapeways to be printed.

 

Bob

 

OLogic Inc

831-336-8401

www.OLogicinc.com

b...@ologicinc.com

--

[Tim Craig]

I use Inventor mainly because it's what I have available at TechShop.  I'm hardly an expert but getting better.  I've gotten fairly quickly to where simple parts are easy to design.   It does output STL files for 3D printing directly.  I mainly use ShopBots for my CNC so I use Inventor to produce an AutoCAD 2D drawing and go through V-Carve Pro to produce the machine cut files.  Again, this is what TechShop has available.  V-Carve has some quirks but is fairly usable.   I believe there are add-ons which allow you to go directly from the 3D Inventor files to CNC cutting.

Tim

[Dave Curtis]

We use SolidWorks. Shiloh has a student license :) I've never tried Inventor, although I've heard from multiple past Inventor users that SolidWorks is better. We've exported stl files for 3D printing, but I've never tried a CAM path to get to CNC milling. All my CNC work has been via .dxf to gcode. SolidWorks can be coaxed into exporting .dxf files, with effort.

SolidWorks takes quite a while to get comfortable with. They all do. I've grown to like SolidWorks for what we do.

None of these are cheap. When you say "cost is not important".... are you aware of what these cost? Since your wife is a teacher, you might check out if you can get the educational discount on a license for it. (Try Academic Superstore.) That will save you the cost of a couple years of TechShop membership right there. For SolidWorks, the difference between "full" and "student" version is: a) the Student version is about 1 yearly release cycle behind, and b) every file is written with a watermark that says "Student version". You can ship the file to anybody and they can read it. You won't necessarily be able to read files generated by the "full" version.

Ask Bob what he paid for the SolidWorks->gcode exporter.... I've seen where those CAM packages run about $1000 an axis.

-dave

[Brandon Fosdick]

I started off using a mix of SketchUp and Inventor (via the TechShop), but quickly grew frustrated with them. SketchUp just isn't built for mechanical design; it seems to be targeted at the artistic and architectural crowds. But, it does have a builtin Ruby interpreter that adds a lot of flexibility.

I found Inventor to be very capable and not too hard to learn. The intro classes at the shop definitely helped. My biggest gripe is that the file format is proprietary and not easily diff'd. I want all of my files to be managed in a git repository and Inventor makes that more trouble than it should be.

OpenSCAD looks like it has promise, but like Wayne said, it seems to be mostly for 3D printing.

At one point I started writing some SketchUp plugins to try to make it more useful, but quickly decided that it's beyond help. So, instead of doing the sensible thing and making do with the available options, I decided to write my own. I now have a rough collection of Ruby gems that do what I've needed so far, and I add to them as needed. It's nothing fancy, and it doesn't have a GUI (I export to either STL or SketchUp for visualization), but I've managed to use it to model, and print, some simple brackets. I'm also working on a custom 3D printer design and all of that work is being done in Ruby. Obviously I'm crazy, so maybe you shouldn't listen to anything I say.

[Bob Smith]

Dave Curtis wrote:
> ......

> All my CNC work has been via .dxf to gcode.

> ......

Do you know of a Linux way to convert .dxf to gcode?

thanks
Bob

[e...@okerson.com]

Bob,

You can use dxf2gcode:

http://code.google.com/p/dxf2gcode/

Install instructions here:

http://code.google.com/p/dxf2gcode/wiki/Installation

Ed Okerson

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[Dave Curtis]

Ed,
What is the state of dxf2gcode? The last I looked at it, it wasn't very far along, but that has been a while.
-dave

[e...@okerson.com]

Bob,

I haven't used it a lot. It seems to be OK with basic 2D drawings.
Doesn't handle 3D at all.

I gave up on dxf some time ago, and have been playing with Sketchup a bit
with the Phlat3d plugin that generates gcode directly. It doesn't run
natively on Linux, but it seems to work OK under Wine. I haven't done
anything fancy, but it will drive my little mill.

Ed

[George Taylor]

Et al,

I've recently acquired the right to use a V.23 version of BobCAD www.bobcad.com to design parts to be cut with my homebrew CNC machine. BobCAD provides a complete design system for 2D and 3D parts including gear design as well as v-carving. Output is gcode. Various post processors are available to adapt the gcode to a specific CNC machine. I've been using the free version of MACH3 that is crippled to 500 lines of gcode. Before I acquired the right to use BobCAD, I use g-simple http://www.gsimple.eu/ . that can be downloaded for free.

If you are just getting started in the CNC world, I suggest using the free g-simple and MACH3 combination. MACH3 provides a means to simulate the cuts without having a CNC connected to your computer although it appears one needs to configure MACH3 as if a CNC were attached. Hard to beat the price if you want to start learning how to work with a CNC machine.

George Taylor

AA6QZ

[William Garrido]

I just started learning SketchUp. I get started I like it. There are a few web based CAD sites, I can't remember the names right now, but there was two that I saw. I only tired one of them. They are limited unless you pay up, but it isn't much. 

I find that Shapeway's is pricey so I am going to look into ponoko. 

One of the CAD programs should do the eagle cad model, where you can build small designs with their free version. 

--
-William

http://mobilewill.us

[e...@okerson.com]

Forgot to mention that I have started using grbl
https://github.com/grbl/grbl to drive the mill. It is a g-code
interpreter that runs on an Arduino. It isn't an Arduino sketch, it is
native c code that you install on the AVR, but it connects to the stepper
drivers directly and handles all the timing, etc. You just plug the PC
into the USB port and spew the g-code to it and it runs the mill, so no
more software on the PC, and no more need for parallel ports.

Ed

[Brandon Fosdick]

On Sep 18, 2012, at 08:15 , William Garrido <blacksp...@gmail.com> wrote:

One of the CAD programs should do the eagle cad model, where you can build small designs with their free version. 

Autodesk seems to be heading in that direction. They have a free trial download page (http://usa.autodesk.com/products/free-product-trials) and the new 123D family of apps (http://www.123dapp.com/) is free. Although, I haven't tried any of them, so I can't vouch for them.

[Dave Hylands]

Hi Bob,

I use SheetCam (http://www.sheetcam.com/). They have a windows version
and a linux version. The windows version works under Wine, and the
linux version works natively.

--
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com

[Tim Craig]

A low cost alternative to get started in 3D CAD is available through the
Local Motors group. You can get a license for Solid Edge's Design1
package on a subscription basis for $19.95 a month. I don't know what
what's included or what's crippled, if anything. However, $240 a year
is less than the usual annual upgrade fee for most high end CAD packages.

http://www.localmotors.com/

Tim

[Osman Eralp]

Many thanks to everyone for your feedback on what mechanical CAD program you use for designing robots. I obtained 20 data points. Here are the results.

First, I surveyed 8 robotics companies about what software they use. I double checked that all of this data is publicly available. In some cases I inferred what software is used by looking at the company's job postings. Here is the data:

Company     CAD Software

NeatO Robotics     Pro/Engineer

iRobot     Pro/Engineer

oLogic     SolidWorks

Alderberan     SolidWorks

Intuitive Surgical     SolidWorks

Boston Dynamics     SolidWorks

Willow Garage     SolidWorks

Heartland Robotics     SolidWorks

The results are clear: if you want to learn a tool that is used by robotics businesses, learn SolidWorks. I find it interesting that AutoDesk products are nowhere to be found; I did not expect that.

Second, I tallied 12 responses from individuals. Here are the results:

# Responses     CAD Software

3     SketchUp

3     custom scripts and software

2     SolidWorks

2     AutoDesk Inventor

1     Pro/Engineer

1     BobCAD

The results make sense: half of the respondents use free tools, and it's expected that home-brew robot builders would use home-brew CAD software.

So what did I decide for myself? Thinking long term, I need to become an expert with SolidWorks: most people use it, and it can output files for 3D printers easily. Unfortunately, 3D printing is still expensive, so for now I will have to cut my own parts. A couple people said to me, "Use the software supported by your machine shop." I had hoped to use the milling machines at TechShop, and TechShop uses AutoDesk Inventor. Thus, I will learn Inventor for now, and when 3D printing comes into my price range, I will switch to SolidWorks.

--Osman

[Wayne C. Gramlich]

Osman:

Thank you for the summary.

Regards,

-Wayne

On 09/21/2012 05:27 PM, Osman Eralp wrote:
> Many thanks to everyone for your feedback on what mechanical CAD program
> you use for designing robots. I obtained 20 data points. Here are the
> results.
>
> First, I surveyed 8 robotics companies about what software they use. I
> double checked that all of this data is publicly available. In some
> cases I inferred what software is used by looking at the company's job
> postings. Here is the data:
>

> *Company CAD Software*

> NeatO Robotics Pro/Engineer
> iRobot Pro/Engineer
> oLogic SolidWorks
> Alderberan SolidWorks
> Intuitive Surgical SolidWorks
> Boston Dynamics SolidWorks
> Willow Garage SolidWorks
> Heartland Robotics SolidWorks
>
> The results are clear: if you want to learn a tool that is used by
> robotics businesses, learn SolidWorks. I find it interesting that
> AutoDesk products are nowhere to be found; I did not expect that.
>
> Second, I tallied 12 responses from individuals. Here are the results:
>

> *# Responses CAD Software*

[George Campbell]

The Techshop in San Jose has two computers that run SolidWorks.

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