Flat needles are needles soldered in a straight line on a needle bar. These needles are usually for lining because their shape lets them deliver more ink to the skin.
Cork cutter is also called balsa cutter. It is widely used for cutting structural sandwich materials, vacuum materials, glass fiber fabrics, resin-based materials, etc.
A fully-opening safety valve is a safety valve with a opening height greater than or equal to 1/4 of the flow path. The operating characteristics of this safety valve are two-stage safety valves.