Why do you have minimum amounts for some services, like prototyping?

For very simple products, “making a prototype” might simply mean pressing a button and sending a CAD file to a 3D printer. For the products we tend to work on, it means some initial analysis, the testing of a few hypotheses, some engineering design work, discussions with a few specialized suppliers about the feasibility of a certain approach (for production), purchasing parts and assembling them, having them tested based on a customized plan, and sending the prototype. Oh, and most products require several rounds of prototyping, especially if they include electronic parts.

All this takes a certain number of hours. It is better if we are straightforward and mention a minimum amount (which might end up being much higher for a given project), to avoid breeding unrealistic expectations.

We can find people with lower rates. What justifies your rates?

If you look online, you will find many people with low rates, and many (probably most) of them work remotely.
Our product engineers work on-site in our facility and within the frameworks of our company. Their managers look after the quality of the work. They have access to rapid prototyping equipment and testing equipment.

They also work within a larger team. They can tap our purchasers when they need to find sources for certain parts – not just to make a prototype, but also with the capability to make production batches. They can ask our process and manufacturing engineers to confirm the feasibility of certain designs.

All this translates into better work, fewer obstacles that slow a project down, and much lower risks of losing intellectual property.