Hello.
I know it is not quite the answer you expect but I think it´s important that you read this.
It is quite possible to make your own machine but you must consider a series of facts.
First, you must understand that the cost involved in making it will generally exceed that of buying one.
Second. Since you are talking about building a machine from scratch a large number of calculations are involved.
What you are asking for are all the engineering and production information and I sincerely don´t expect that someone will graciously give it away. It´s like asking any machine builder to give that information to you.
Third. It´s irrelevant if you want to build one machine or a million.
Fourth. If you really want to build an industrial grade machine you are required to be willing to pay for all the work from the concept stage, design, prototype, casting, machining, etc. that will be required and that will certainly not be cheap.
Having said all that I think it should now be quite understandable why the DIY wave has gained so much popularity as for small shops and hobbyists alike it offers the possibility to have machines with generally reasonable quality at relatively low cost compared to professional machines.
At this level production capacity is generally not a big issue and thus small production orders can be served with good efficiency.
One last comment in reference to your request,
I suggest that you first decide what type of parts you wish to manufacture. That´s important if you decide to go DIY as that will help determine things like the structure of the machine, that is, steel or aluminum, cast or machined. The type of motors, servos or steppers. The transmissions, ballscrews or leadscrews, gears or time pulleys.
So you see a number of decisions are to be made all to solve some particular manufacturing need.
Professional machnes are designed to solve as many requests as possible. That´s one of the reasons they are expensive.
There are a number of places in the internet that can give you ideas to build DIY machines of all kinds. You can take a look at INSTRUCTABLES, OPENBUILD, etc.
I hope this helps, somehow.
Regards.