These are sometimes called tooling costs. There is no charge for these if the same PCB design is made again in the future.
For a manufacturer, these costs include:
- Loading the design files into their system
- Checking the PCB for any manufacturing problems and adjusting as neccessary (e.g. removing soldermask slivers)
For an assembler, these costs include:
- Loading the design files into their system. This is normally substantially higher than the similar manufacturing costs, as they have to load all of the components into their system
- Sourcing all of the required components (this may also fall under re-occurring costs)
- Manufacturing a soldermask stencil (typically laser cut from stainless steel)