for this branding I'd probably look at something like an electrolytic marker or etcher.
basicially it's a power source and a block of metal wrapped in a wad of soaked fabric, along with a resist of some sort.
you place the resist on the work, hold the block of metal on with a the power running though, remove the block, remove the resist and move on to the next one. normally takes about a minute to do a good deepish etch.
you can get reusable resists made.
this is a posh one. but you get the idea.
The ME3000S is suitable for applications where the information to be marked does not change often as marking settings cannot be stored. It does have a timer to enable consistent marks to be produced on each component. See the ME3000T for additional features and versatility.
www.ums.co.uk
you can make your own easy enough and there are plenty of videos to that end out there.