If you are confused with the terms “alpha and beta prototypes”, do not feel bad. Many of you are on that boat. Also, these terms have different meanings for different industries (e.g. software vs hardware). Since my field is medical device design, I am talking about hardware prototypes here.
The product development process takes place in stages. First, you have an idea. You then develop that idea into a concept (or many different concepts) of how it might be as a product.
Once you get the feeling that you think it will work, you set about turning it into a working model. Your work model may be an intermediate stage to prove the feasibility of your concept (you have to build many to make Kinks work), or it could be your actual feasibility model. A possible prototype is intended to prove that you can turn your concept into something that works normally as you intended. It gives you confidence that your idea is sound and should be able to be made using technology and readily available components (another question is whether your idea is commercially viable).
Achieving a feasible design is your first major milestone. The next milestone is the alpha prototype. Product development between feasibility and the alpha prototype involves much of the effort. You look for standard parts that you can use in your design and design custom parts if you can not store them. Most problem solving, testing and repetition takes place here. The goal is to build a design / prototype of your product that will use the components of the product that you will eventually sell to consumers. This is an alpha prototype.
The important thing to understand is that Alpha is still an estimate of how your product will look. Now you can improve the design with the aim of reaching the final look that you make and sell. The alpha prototype is close to you, but changes and improvements still need to be made. You will probably find suppliers who can provide an equivalent of what you used for your alpha prototype but with better volume reduction for commercial sizes. You want to include those parts in the design and make sure that the new parts do not introduce unexpected consequences. You will need to make touches to specific areas of the design. You can find parts that have better performance features than you can find for Alpha Build.
A beta prototype will be built incorporating final changes and improvements. Beta is as close as possible to commercial production. Why is it not a commercial product? This is because it is not built using actual manufacturing methods and tools required for commercial volume production. In most cases, beta prototypes are built by hand one by one. They are close to the commercial product that can be put through the final test. If the beta prototypes work reliably beyond the rest of the test requirements, you are ready to transfer your design to manufacturing. Five paragraphs ago the dream you started came true.