CNC design - Step by step. What and how to do?

[masta_dry]

I am looking for a step by step cnc design manual. Breaking down the design alternatives based on answers given to questions such as:
-What material do you want to work with?
-What tolerances do you need for the machine?
-How much money do you have?

Have anyone seen a guide like that or something similar? Taking vibration, torques, reaction forces into consideration when choosing design alternatives. I’m new in the field, and may not use the correct phrases, but I think you get the idea.

[TOTALLYRC]

Originally Posted by masta_dry I am looking for a step by step cnc design manual. Breaking down the design alternatives based on answers given to questions such as: -What material do you want to work with? -What tolerances do you need for the machine? -How much money do you have? Have anyone seen a guide like that or something similar? Taking vibration, torques, reaction forces into consideration when choosing design alternatives. I’m new in the field, and may not use the correct phrases, but I think you get the idea.

If you search the Zone these types of question come up all the time.

In the proper order they are;

1. How much is the budget? If the money is not there, the rest of the questions are not worth asking.

2. What type of materiel are you going to machine? If you are going to be doing a lot of steel, you will need rigidity right from the start.

3. What kind of tolerances do you need? If you need tight tolerances, you are already building a pretty rigid machine.

Mike

[allesg]

What Mike said. Absolutely.

Design manual? None that I know of, unless you're already a mechanical engineer then you might consider all those books you read in college. If not, try the following path..

#1 -> learn how to use the search function here on the zone.

Most common approach? Most people here seem to have
lurked in the backround for a while reading various threads on machines that others built. Then they build their first one and learn from their mistakes. Next, the second or third one meets their expectations.

Another approach is to buy a turnkey solution - especially for the stuff you know the least about.

There are some good turnkey electronics solutions where you get all your steppers and drivers $500 or less if your machine isn't too fancy. For a little more you get power supply, cables and sometimes even an enclosure.
I like Gecko.

Mach3 seems to be fairly popular software for machine control. Beyond that, you might want CAM and CAD software. TurboCAD and TurboCAM are cheap.
If you want 3D solids modeling, Alibre is perfectly capable but the learning curve can be a problem. I started 3D with Google SketchUp which is free but I then switched to Alibre because it does solids modeling and there is a CAM plugin for it too.

SolidWorks seems to be the Cadillac in 3D solids but a non student license is the price of a pretty nice used car, but then again, you can design a complete car, airplane,
motorcycle and stress test all the parts in advance.

There are some good starting turnkey mechanical solutions for $500 to $800.
Joe's MDF kit is a good start.
I was very very very lucky to find a used WidgitMaster midi, but a WidgitMaster mini is a great piece of hardware to start with.
Another great approach are cnc routers made out of 80/20.
Or a converted Harbor Freight Mill.
Do not be too concerned about how big your first machine is. What you want is to have a platform that lets you go from CAD or 3D CAD to CAM to Mach3 and actually
starts making chips.

Some people spend years and others take months to start making chips. It's a function of what you already know, what you learn here on the zone, what your friends know, where you work and how much money you've got.

I started by reading as many build threads as possible here on the zone. After about 3 manweeks of reading
I felt I knew what I wanted to buy and started teaching myself Alibre. So far, I've managed to design a bunch of different brackets for a project I intend to build with my widgitmaster.

Good Luck!

Gary

Sorry this post is so long, but where else is someone gonna step you through all this?

[masta_dry]

I will first build a low budget unit to get familiar with the scene and possibilities.
I plan to machine plastic and wood.
Tolerances? 0,05 mm would be nice but 0,1 mm will do for the start.
I will surely save time (and money) reading through the zone threads.
A turnkey solution might be a bit costy for me, and I like challenges.
I think about using old A3 sized matrix printer parts.
The controller is going to be an entry level 3 axis custom made unit from the Hungarian hobbycnc community.
I need experience to see the opportunities of the technology so I can decide is it OK to invest more or not.
Thank you both for the posts!

Gabor