About kitchen sliding doors

The "sliding door" you mentioned is the "sliding door" often referred to in engineering.

As you said, if there is no track installed below, it should be a "suspended sliding door". The slide rail is installed above the door. And you are talking about a two-piece "opposed sliding door" with double slide rails on the door!

What do you mean by "the two doors can't be opened all the way, and there is always a gap"? I don't know what you want to say specifically? Does it mean that the door piece cannot be close to the door frame, resulting in a gap? Or does it refer to the gap between the two doors when they are completely closed?

If it refers to the gap between the door piece and the door cover, that should be eliminated! Make a small groove in the door frame, and when the door is closed, the door will just slide into the groove.

If it refers to the gap between the door pieces, there must be a seam. It’s just that this seam should be called a craft seam, which is the gap between the overlapping parts of the two doors (because each door can slide independently). Usually when the two doors are completely closed, the middle part of the door overlaps (the overlapping part Roughly 60~100mm). The distance (gap) between the door pieces is 10~15mm.

This is just for reference.