Ningbo Economic-Technical Development Zone Yunhai Machinery Co., LTD was established over 20 years, we are producing a variety of screws for sewing machine; mobile phone; wristwatchs; computer/laptop and all of minitype and nonstandard hardware components for electronic industry. We are keep to purchasing all of advanced equipments. also to increasing our  technics and quality of our productions. Maintaining good reputation and rapid lead-time. We get support and trust from all the customers.  The double-knife slot machine without burr was developed by our own R&D department based on customer's inquiry with good performance according to market feedback since 2005. It has loved by people and find a rapid way for bolt and nut with bur after been notch while this kind of machine to the market in 2005. This is unique high technologic invention in China. So We had two patents based on this invent in 2007: one is invent patent (ZL 2006 1 0092061.0) and another one is new practicability patent (ZL 2006 2 0117491.9). in order to meet the market demand, through continuous efforts to explore and research, we develop the slotting machine in the original data base, which has high speed and precision.We can process 500pcs items each minute, and the working efficiency is equal to the production of European factory  Our company had following advanced equipments: cooling-stamping molding machine; thread rolling machine(made in Taiwan); Automatic measuring appliance engine bed(Ningjiang brand CG1107 and G1104). automatic instrument lathe in blade; slot machine(without burr); CNC lathe; Milling machine; Grinding machine; linear cutting machine; Thread roller^etc. equipmentsWe are producing all kind of nonstandard; a variety of hardware and special inquiry from customer. Our Process range: 0.4mm-18mm for both screw, bolt and nut; Our Testing and inspecting equipment: Projector; V model hardness inspecting tool; Microscope and High Precision Micrometer etc.