currently employed want to sell spare parts

What is the name of your state (only U.S. law)? Wisconsin

I am curently employed by a US distributor of a machine maufacturer based in Germany. We sell and service the machines and spare parts all built in Germany we do not do any manufacturing.

I would like to leave my current job and start my own buisness manufacturing spare parts for the machines that I currently service.

Basically I would like to "copy" some of the parts and sell them legally myself.

I have never signed any non disclosure or non compete forms from my employer.

What are the do's and don'ts when trying to start this business.

Thanks in advance

Manufacturing generally has a high barrier to entry. How do you intend on financing the capital investment required to product these parts?

And there very well may be patent issues with the design of these parts.

And the companies that buy these replacement parts may have exclusive contracts with their suppliers.

So that's just naming a few off the top of my head.

I have enough money saved to finance the initial investment of manufacturing the parts. This is something I have been planning for awhile now. I am just making sure that I don't do anything illegal before I make the final move and leave my job.

I will check with a patent laywer to make sure that I am Ok there, that is a good point.

I know the business really well inside and out and I don't know of any contract that customers have with us. While I am employed at my current postion would it be Ok to contact customers and ask them if they would buy parts from my new company when I leave?