Hello,
My name is Sean and I have been designing a product that I eventually hope to get manufactured via injection molding and I have some questions on working with manufacturers. I have tried to design my parts so that they can all be made with a 2 part mold, but as a layman I can not be sure that I was successful. In addition to this my parts currently have varied wall thicknesses, no draft angles, and large sections of material that need to be hollowed out. In addition to this in order to reduce the number of molds needed (and hopefully the price as well) I wanted to lay out many parts on the same sprue like you would see with hobby model kits. The questions I have include:

When approaching a manufacturer do the parts need to be ready for injection molding, or will they work with me to get them to spec? Will this change the price of the service?

If I want to lay out multiple parts on the same sprue to I need to design the layout or does the mold maker take care of this?

Do manufacturers take a job if they are not confident that the parts will not come out correctly? If parts don't come out correctly do they ship them anyway or do they remake them? If they get remade is it at their expense or mine?

What is the typical size of a smaller run? I was hoping to start with 500-1000 units. Will this be a tiny order or fairly typical?

Any guidance on any of these questions would be hugely appreciated.

-Sean