Does anyone know a free or cheap mechanical CAD program?

[8086]

I want to make some designs for simple cut-outs in some enclosures to get quotes for machining them.

If there's a way to use Altium to generate an appropriate output I would also be interested in that.

Thanks in advance

[128er]

Maybe Designspark Mechanical by RS Components is something for you?Played a few minutes with it. I thought it was good. But i have  no big experiences with mechanical CADs. For my purposes its fine.

[kripton2035]

realcadd is nice and easy to use.

http://www.adx-online.com/realcadd/realcaddus.htm

[ElektroQuark]

Try FreeCAD. It is in his first steps, but pretty useable.

[hagster]

I've been giving Design Spark Mechanical a good run for its money over the past few days and am mightily impressed. Very slightly harder than Sketchup to learn, but a whole lot more powerful. It supports things like draft angles and brilliant edge radiusing tools which are really important if you want to get parts injection moulded. It also supports shed loads of file formats. In fact it's actually a really useful tool just for converting 3D formats.

If it's just for cutouts are you sure you want a 3D program. I know a lot of companies use Adobe illustrator for laser cutting etc. Maybe Inkscape would be a good free alternative.

[8086]

If it's just for cutouts are you sure you want a 3D program. I know a lot of companies use Adobe illustrator for laser cutting etc. Maybe Inkscape would be a good free alternative.

I'm pretty sure I don't want a 3D program... I definitely never said I did. 

Thanks for the suggestions everyone.

[robrenz]

I am pretty sure you DO want a 3D program.  The negative of a slightly steeper learning curve is FAR out weighed by the much greater functionality of 3D. Even if you think you only want to do 2D cutouts, do yourself a favor and learn a decent 3D package. You will be glad you did.  I switched to 3D when Solidworks was a startup company a LONG long time ago.

[8086]

I am pretty sure you DO want a 3D program.  The negative of a slightly steeper learning curve is FAR out weighed by the much greater functionality of 3D. Even if you think you only want to do 2D cutouts, do yourself a favor and learn a decent 3D package. You will be glad you did.  I switched to 3D when Solidworks was a startup company a LONG long time ago.

But why would I want a 3D package when I only want to do 2D cutouts? I want to get things done, not go to college again!

[ecat]

I am pretty sure you DO want a 3D program.  The negative of a slightly steeper learning curve is FAR out weighed by the much greater functionality of 3D. Even if you think you only want to do 2D cutouts, do yourself a favor and learn a decent 3D package. You will be glad you did.  I switched to 3D when Solidworks was a startup company a LONG long time ago.

But why would I want a 3D package when I only want to do 2D cutouts? I want to get things done, not go to college again!

Split the difference maybe?

CamBam is relatively simple but powerful 2.5D drawing/machining software with a quite generous trial period. As a plus it can generate gcode for your machineist
http://www.cambam.info/

I've made good use of Alibre Design in the past, high end functionality and a reasonable trial period at the time. It is now called Geomagic Design, I've not used it since the change.
http://www.alibre.com/

[robrenz]

The learning curve in 3D to do a flat panel with a few cutouts and print out a drawing of it is probably the same as a 2D package.  The ability to model something in 3D including an assembly and how parts interfere or don't is very useful even if you don't have an application right now. Why limit yourself to 2D?  An example is Free Electrons JW pulse generator. He was able to use the existing 3D model of the case to make his PCB outline nest perfectly in the case with no mounting screws.

[hagster]

Some of this depends upon the complexity of the cutouts and how you want to give them the data. For simple stuff an JPEG image or even simple back of envelope sketch with some measurements would probably suffice. For more complex stuff you need to find out what file formats they can accept and base your decision on that.

[mikeselectricstuff]

I want to make some designs for simple cut-outs in some enclosures to get quotes for machining them.

If there's a way to use Altium to generate an appropriate output I would also be interested in that.

Thanks in advance

For simple flat drawings, PCB software can be an option - most will export DXF. Especially useful if the panel has the PCB behind it as you can create a panel layer in the main PCB file to ensure everything lines up.

[MasterBuilder]

I use Draftsight for 2D generation of labels to be printed and a few other tasks.
It is straight forward to use and it seems to have more tools than I will ever need.

I am told by mechanical engineers in work that it is very similar to 2D Autocad.

[Rufus]

But why would I want a 3D package when I only want to do 2D cutouts? I want to get things done, not go to college again!

Because you can export a 3D model of your PCB from Altium, place it in a 3D model of an enclosure and use the components on the PCB as a guide for creating cutouts in the enclosure. You also get to check that things fit together in 3D and a good idea of what it is actually going to look like.

I attach a screen shot of a PCB in a Hammond enclosure during design and a photo of the built item (with annotations removed). 

[rollatorwieltje]

Schaeffer Front Panel Designer is free to use. It can export to DXF, but I've never tried it. I did order panels from them a long time ago, but it's a bit expensive if you order very low quantities.

[GiskardReventlov]

I stumbled over a package yesterday called openscad. I am going to try it out in next few days.
I have no experience with CAD programs but I this one caught my interest due to the interface.


It allows controlling the drawing via a scripting window.

e.g.
http://upload.wikimedia.org/wikipedia/commons/6/67/OpenSCAD_Main_Window.png

[mswhin63]

For 2D - I have used DeltCAD - http://www.deltacad.com/ . I found this to be so easy to use compared to any other CAD software I ever used. For 3D DesignSpark Mechanical excellent but harder to use than Sketchup.

Sketchup can be converted easily to 2D design if necessary.

[markhen]

@GiskardReventlov:

I've used OpenSCAD to design the enclosure for tiq (thanks for your comments over in the Crowd Sourced forum!). Picture attached.

I like it a lot. But, there are a few buts!

- It is programming, not drawing. I'm comfortable with drawing (conventional CAD), but I LOVE programming. For me, I can be more productive and feel more comfortable "programming" 3D in OpenSCAD than I do in a CAD program. BUT, folks with a 3D CAD background will probably hate it, and folks with no programming background will probably find it very difficult.
- It has a few bugs, so far nothing show-stopping for me.
- It doesn't report errors well, so often it just doesn't do what you expect, and it doesn't tell you why?! So quite a lot of "debugging" required (like embedded programming?!?!).
- It's a bit slow, needs a faster machine - common with 3D so perhaps not unexpected. Rendering for output to STL can take a long time - the attached example takes over an hour to render out to STL. While you're working with it it's not that slow (the STL rendering is only when you're ready to print).

I'm going to continue to use it as my "goto" 3D tool. To give you an idea, I learned OpenSCAD by making some very simple cylindrical objects from an example "program". Then I designed the case in the attachment - it has quite a lot of internal details that don't show here. That design took 2 8 hour days, which I consider great, considering I was learning and the complexity of the parts. And the parts came out nicely (Shapeways.com)!

Enjoy!

Mark

[GiskardReventlov]

@markhen, good points about the target user base. It made sense to me to see exactly what generated the output. I'd guess that other cad programs have some similar facility for viewing the underlying data but I hadn't seen one that let you model that way.

I did play a little yesterday and I tried the logo example,  cylinder in a sphere. The cylinder cutouts were there and the sphere was viewable but not the transparent cylinders.