[rally]

Rom,

How about some rubber or polyurethane blocks in the right spots.

If it weighs a few hundred kgs then it will have a lot of energy if you slam it too fast
So rather than break something it will compress the rubber gently and then return in the other direction.

If you put a rack and pinion on it now - it might be a bit slower to close but it would be hard to get up too much speed
Then when you get your automation sorted out - its ready to go