That would be casting. The metal is never melted in sintering. It's a combination of heat and pressure that makes the powder fuse.powdered metal, liquefy it, and pore it into a mold (ie sintered)
The manufacturer is just trading the expense of the molding machinery for more labor hours.
Hi,
The next part you might want to look into is the differences in the various alloys used. For example, the 316 vs 303 which are the two I see most used (although there is a new one said to use 304, which is what I would like best). Here is a link to a decent site regarding the 300 series Stainless Steels, if anyone cares. This is getting pretty far beyond what someone shaving would care to know...
Although I find this discussion interesting, I sense a dead horse being beaten.
The two best-made modern razors, in my experience, are the Feather and the ATT. Since I have never had a quality-control or rust issue with either razor, the differences in their manufacturing methods and materials is moot to me.
But as long as we're beating this horse, thread rolling is the best method of forming a handle (stronger than machining), but this would be the ultimate overkill and cost-prohibitive (I think).
A razor is not exactly under great stress when performing it's designed job. I am a vintage Gillette guy, but I would assume that a sintered razor would preform and last as long as a machined one.