I'm not an engineer. As a matter of fact, I'm a graphic designer at an injection molding and plastic parts manufacturer in Toledo, Ohio. However, I do work with a couple of engineers here that receive requests for quotes. The funny thing is that we get requests for quotes from people all the time who send us sketches on paper, cocktail napkins, or whatever, for injection molding quotes. They go to our website, see what we do (and CAD design is not what we do), and they will contact us anyway asking us to design their parts for them based on drawings, sketches or even proper schematics. We need a 3D model in order to produce a mold and part.
That's the situation, here's the solution to anyone trying to get what they really need: if you have a 3D CAD model that's already been designed for your plastic parts, any mold manufacturer can produce it. However, if you only have a sketch, schematic, or drawing and you are looking to get quotes, typically that can be done without having a 3D CAD model, but usually it would have to be designed using a 3D CAD program (like Solidworks, for example) then it could get produced. There are very few plastic injection mold manufacturers that do design work and design work as well.
What about timing? So, you have your 3D CAD model, and now you need to get that part made— so you need to get a quote. Typically, a quote for a molded plastic part (this means the tool to make the part and the parts themselves) can take anywhere from several days to over a week. This means for days, you would have no idea what the cost is going to be for that part— or if it's even moldable because you may have to adjust the design in order to make the part or parts moldable. Now, here at our company we developed an online instant quoting and project management system that can get you an unconfirmed quote estimate on your molds and parts immediately after you upload your 3D model. "Unconfirmed" you ask? One you upload the 3D model, choose your number of cavities, material, color finish, and quantity or parts you'd like, the numbers update as you make your changes. Once you have submitted your quote to us, we will then confirm the quote, sometimes it can be a little lower or higher than the unconfirmed quote that was submitted because the logic in our proprietary quoting program just can't "see" what humans can see when producing a mold tool. This means perhaps your tool needs a slide action, or maybe if we reposition the part in the mold, your particular part may not need a slide action at all. A human with hands-on your quote will always determine more accurately what your confirmed quote will actually be because humans can make the determinations that the computer can't.