Serious Homemade Manufacturing Equipment on a Shoe String Budget

Step 3: Virtualization & Coolness Enhancement

It's time to get down and dirty with the nitty gritty of your idea in a CAD program.  I use Turbocad for Mac version 3.  Why?  Because I am poor, and I can't afford Autocad or Solid Works yet.  It's a decent CAD program, but a little limited at times.  Use what you have.  Or win an instructables contest that offers Autocad as a prize!

Using my drawings as a general outline, I start to build my first virtual prototype of the machine.  I like this step because you get to see all the details of your general plan come together in the virtual world.

I get out my calipers, and I start measuring all the materials and pre made parts I will be using to the thousandth of an inch.

This can be extremely tedious and time consuming step.  But it prevents countless mistakes and predicts many design flaws.  For example, with the porting machine I was able to determine where I would have space to put the engine of the machine (a power drill).  It allowed me to easily figure out the gearing for the power transmission. It allowed me to make sure I would have enough clearance between the punch and the blank to be able to remove the blank holder from the machine without hitting the stove blank into the punch every time.  They all sound like simple enough problems to avoid as you build.  But when you add all the numerous small issues together, it's so easy to miscalculate or make uninformed design decisions because you don't have the larger picture in mind.  You change one thing, and it can effect every other aspect of your mechanical system. Even with the virtual model there will be plenty of opportunity to deal with unforeseen issues.

The important part is to view this step as a prototyping step.  Don't get so stuck on a particular solution that you aren't willing to overhaul the thing entirely if once it's been built in the CAD program, you come across some obvious design flaws.  This is one of the nice things about virtual models; they are so easy to rebuild from the ground up with little loss in money and materials.  Anyhow, my main point is don't be afraid to start over if needs be.

Coolness enhancement time...

Another enjoyable aspect of the virtualization step is that you also get to finalize some purely aesthetic details of the machine. Things like unimportant fillet radiuses and chamfer dimensions.  Often there are multiple ways to aesthetically execute the same idea. In the example of the porting machine, I got to pick whether I wanted to have the blank holder be parallel with the ground, or to have the punch assembly be parallel with the ground. Either way would have worked the same as far as the mechanical system was concerned, but each provided a different feel and look to the machine.  I have a years worth of industrial design training from my university experience.  To me I get excited about the aesthetics of a machine, and while in a build such as this one I was mostly focused on function and making a working prototype I would take as much time as I could to make it something I was proud of visually as well as functionally.  Is it perfect in it's aesthetic appeal? No, but it was definitely worth it to me to spend time on.

Comments

[jamstir]

Hey.. well done.. I have a few Q.. for yourself, I going to build a CNC milling machine using servo motors/ steppers/ etc, and use Mach3. Now i come from 16 years welding fab and operating or designing using Cad is all new to me, from what i been reading, can Cad design be used to put commands into CNC Mach3?

What i looking is an easy way to tell mach3 what i want it to do.

I have to say again well done on your business, i come from the UK and its manufacturing is near died, so died in fact 5 years ago i had a small workshop were i would build gates/railings/trailers/ and general welding fab work, China at the time were building Shenzhen and bought a lot of steel up, so the price of steel in the UK went up by 3 times the price over night, then the property crash happened and it all went pear shape.

Last year i reg.. a new company within the UK { supply } and i took of into China, everything is near made here, or at least you can get a copy of it. lol
The supply company not doing to good because i am taking a cut and acting as a middle man between people. also China is about to reach its Global export market, which means unless they build a complete new country it cant grow anymore. This will have a knock on with a lot of company,s.

Which takes me back to start manufacturing again, only this time i will be doing it in China, so many company,s have come here from the west due to cheaper labour cost and import tax is lower than manufacturing cost, or it is in the UK anyway. I looked into plastic injection machines and wanted to start making my own plastic moulds for pc tablets and other after market kits like Apple cover,s etc. Which lead me to a big problem... to get a company to make a metal mould for the injection machine is costing anywhere from $5.000 to $50.000 depending on how complex the mould is. So looking at making my own metal moulds brought me to looking at CNC machines here in China, and to be honest at a cost of over one hundred thousand USD thats a no go.. lol I went and looked at one of these machines and the driver,s and motors are not even a brand name from the west. After looking on youtube i found guys that were building these out of wood and some cases aluminium, which is all fine for milling wood/plastic but not when it comes to + / - 00.5 milling metal.

So now you have a clear idea what i up to, can you shed some light on CAD and running Mach3, i am very good at operating programs and working with pc,s linux manly, which i might add is by far better than windows. I am half way though completing my own web site using an old pc with linux, if i had have tried this using windows there would be no end of problems raging from port forwarding to keeping none static ip address up to date.

Anyway, once again, well done and i hope your business all the best.

[pastprimitive]

Any decent CAD program (Autocad, Solidworks, Turbocad, etc...) should be able to save files into the appropriate format for your CAM software. Although those programs are not necessarily my recommendations just ones I know about. I am sure there are plenty of other options, probably even some open source ones as well. I believe Mach 3 is a controller software, but it does not have any CAD or CAM functions.

General Design Workflow for CNC Machines:

1. Design part, product, etc... in CAD (Computer Aided Design) program.
2. Export file into your CAM (Computer Aided Manufacturing) program and create tool paths for CNC.
3. Save tool path file for use with your CNC controller software (Mach 3, etc.)
4. Using CNC controller software execute tool path file and let your CNC machine go to work.

Of course there are some software packages that combine the rolls of the CAD, CAM, and Controller software into one program. Although I have only seen that for consumer use cnc products like vinyl cutters, etc... However there are a few CAD/CAM combination programs out there.

As far as building your own cnc I have seen some people do some nice conversions of mini mills and mini lathes for an extremely affordable price of around $2,000 - $3,000.  I know LittleMachineShop.com sells a prebuilt CNC mill for $6,000 or $7,000.  

There are also online services like emachineshop.com that will take your design and machine it for you.  Although those service are very pricey.  But could provide you a way to get up and running with your production and earn some more cash to buy your own CNC set up if capitol is a challenge for you.
 
Anyhow best of luck with your endeavor and I hope that was helpful.

[svereecke]

Permit me to answer that, you could go indeed the way of Mach3 and fork out cash or you might take a peek at a linux-version centered around CNC called EMC-linux which is an UBUNTU with enhanced features.
You will probably interject and say "But I want support! " but then would give the riposte and tell you that support comes in form of forums peopled with persons who used this distribution before and who give their advice for free.
Several other GPL-cad programs have a G-code generator.
And also have a look for DIYLILCNC , this looks a very promising project , one of its creators has a youtube-tut on how to convert a bitmap-drawing into G-code.

[svereecke]

Your right about Blender not being suited for CAD , it is a visualisation package (CGI), but there is an alternative to AutoCAD called FreeCAD.
On the sourceforge site it is available as Win/Mac/ Linux program.
http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Main_Page
Although it is continuous development ( as most linux based products are),
it has ripened enough to be used for small design projects.
it uses an Inventor approach for designing and has multiple other uses
( even a robotics workbench).
As I am partial to the linux ,my version is continuously updated via the package manager.

[pastprimitive]

Thanks for the heads-up. I may have to download a copy and try it out.

[Fred82664]

I think there is a few scripts that one can run with GIMP that is used to convert the formats. I knew of a friend long a go that done something like this. I do not know if it was his homegrown script or if he got it from a freely available resource. he was a good code hacker he might of chopped it out of other software.

[odalcet]

You can use Blender for your CAD drawings (and animations!) Here is an example:

http://www.nextwavemultimedia.com/html/3dworksamples.html

You can find many more looking for "blender cad" in Google

Blender is open source so you pay nothing. http://www.blender.org/

[pastprimitive]

From what I heard Blender is lacking in the appropriate precision for engineering design.