In article , LdB wrote:
I've made raised panel doors out of wood. Standard rail and style
frame routed with a profile to hold the raised panel in place. The
raised panels are made slightly smaller that the rail and style frame
opening. Small rubber barrels are put in the slots of the frame to
cushion the panel and keep it in place. I assume this is done to
compensate for any movement in the wood over time.

I'm now helping friends build their cupboards. These doors will be the
same raised panel type but are being made out of MDF. Not my choice,
I'm just the helper with the tools.

Hopefully, you're making only the raised panels from MDF. The rails and stiles
should still be solid wood: MDF doesn't hold screws very well.

Is there any reason to make the MDF doors any different than wood
doors? Should we make the MDF raised panels smaller than the frame
openings, then use the same rubber barrels in the MDF rail and style
frame slots?

Not necessary, since MDF isn't going to change size with the seasons.

Can the MDF raised panels be made the same size as the opening in the
rail and style frame? If so should the raised panel be glued into place?

I wouldn't glue it. You'll still want it a trifle smaller than the opening,
since solid-wood rails and stiles are going to expand a little bit. This time
of year, in the northern hemisphere, you could make it the same size as the
opening; as the humidity decreases in the winter months, the rails and stiles
will shrink a little bit and make the fit a trifle loose.