Niigata launches machines, technologies, joint venture
At the International Plastic Fair (IPF) in October, Niigata Machine Techno Co. Ltd. made some big announcements for the upcoming year. Niigata is introducing three new machine series, a new process for making carbon-fiber-reinforced parts, and a joint venture with Haitian Injection Molding Machine Co. Ltd., Ningbo, China, said Peter Gardner, VP and GM at Niigata’s U.S. unit, Daiichi Jitsugyo (America) Inc., Wood Dale, Ill.
MD-S8000 HORIZONTAL MACHINE SERIES
Niigata, based in Niigata City, Japan, rolled out the latest generation of the MD-S series of all-electric injection molding machines. Features of the MD-S8000 line include a newly developed toggle-clamp system that delivers high-speed mold opening and closing actions, and increases the stroke of the clamp by 10 percent compared with the prior version. The series also has larger platens to accommodate bigger molds.
The new machine now incorporates linear guides throughout for smoother operation, as well as more repeatable movement and positioning of the clamp or injection unit. “The new line also introduces Niigata’s new S8000 controller, which upscales the interface to a 15-inch touch screen, about 3 inches larger than the previous generation, for ease of viewing and navigation,” Gardner said.
At the show, an MD-S8000 model with 393 tons of clamping force produced a sample product from PP in a single-cavity mold, using a 68mm-diameter screw.
MDVR-S8000 VERTICAL PRESSES
Niigata also introduced its new MDVR-S8000 series of all-electric vertical injection molding presses. Two models in the line were at the show.
The company’s MDVR75S8000 machine, with about 85 tons of clamping force, also features the S8000 controller. Mold opening and closing speed has increased 20 percent for faster cycle times than older versions. Other features include a low table for easier access to the mold or part; quieter rotation of the servo-driven rotary table; and faster mold-height adjustment, which saves setup time, Gardner said.
A CC-Link provides a simple way to connect a robot to the injection machine. Niigata said its Hiper Navi controller eases setup programming for integration, and users can achieve improved efficiency and yield rates through the use of a new system that detects defective insert parts.
At the show, the MDVR75S8000 produced a battery adapter made from PP that incorporated an aluminum insert.
An MDVR100S8000 with 110 tons of clamping force demonstrated an enhanced version of Niigata’s mold-protection program. The updated software monitors the torque of the servo motors during the entire operation of the screw — not just during mold opening and closing, Gardner said.
The mold-protection system, in conjunction with the updated machine controller, creates a benchmark based on data from 20 to 30 molding cycles. Users can then adjust the sensitivity of the system, allowing the user to operate the machine faster as more of the molding cycle is evaluated. At the show, the machine produced a lens from polymethyl methacrylate (PMMA) in a two-cavity mold.
Niigata also unveiled an electric vertical injection molding machine and a new process to produce carbon-fiber-reinforced parts. Niigata collaborated with mold maker Go-factory Ltd., Yokohama, Japan, to create the MDV200TY-GM system for molding a carbon-fiber-reinforced thermoplastic using rapid heating and cooling in the mold.
What is unique is that the system thermoforms a sheet of carbon-fiber prepreg in the injection mold and then injects the substrate material in a single process. This approach, shown for the first time at an event by Niigata, can improve adhesion of the material while minimizing process time. The mold heating/cooling system shortens cycle times compared to those that heat and form the sheet in one mold, then transfer it into an injection press with a cooling mold where the thermoplastic material is injected, Gardner said.
At IPF, Niigata demonstrated the process by making an oil pan from carbon-fiber sheet and a polyamide (PA) resin. Six sheets of the carbon-fiber prepreg were heated and pressure-formed into a shape in the mold. The mold indexed on the rotary table so that the PA could be back-molded onto the fiber-reinforced sheet.
Go-factory produces the Go Molding System for heating and cooling. The mold, the center component in the system, can be heated to 482 degrees Fahrenheit then cooled to 248 degrees Fahrenheit. The clamp actuates a mechanism within the mold that forms the carbon sheet once it is heated.
Niigata also unveiled its new CNS series of low-cost, general-purpose, all-electric machines. The CNS series, which is available for purchase, comprises six models with clamping forces ranging from 55 tons to 220 tons, said Chris Unseth, a U.S. regional sales manager for Niigata.
Features of the CNS line include the incorporation of four servo motors, each of which performs a single task: injection, recovery, clamping or ejection. An induction motor handles the carriage movement.
The machines have a five-point, double-toggle clamp and an advanced platen design to ensure even distribution of clamping forces. The machines feature a platen that is larger than competing presses of comparable size, Niigata said. This allows the injection molding machine to accommodate larger molds. An anti-wear screw for plasticating and injection is standard.
The CNS line incorporates Niigata’s S7000 controller and is designed to provide injection speeds of 200mm per second as standard, with an upgraded version that reaches 300mm per second available as an option.
Niigata featured two CNS models at the show. A CNS 50 with 55 tons of clamping force molded a 25mm optical lens from a 7.8-gram shot of PMMA in a two-cavity tool with a 60-second molding cycle.
A CNS 100 model with 110 tons of clamping force molded a complex component for a printer from ABS in a two-cavity mold. The part was hollowed out during molding using a gas-injection method in which the gas is generated inside the mold then released by ejector motion. The new gas-release method was developed by Doushi Kagaku Kougyo-sho of Japan. No gas-suction device is required, and clogging is eliminated, according to Niigata.
A NEW COMPANY IS BORN
The new joint venture company, Niigata Haitian Injection Molding Machine Co. Ltd., is owned by both companies and will focus on the development of electric molding machine technology.
“The joint venture enables Niigata to leverage Haitian’s substantial manufacturing capacity, high production capability and buying power in the production of high-precision, all-electric molding machines,” Gardner said.
The CNS machine introduced at IPF is the first collaborative effort by the joint venture company. While the machines are built at the company’s Niigata City factory, castings and other mechanical components are supplied by Haitian. The CNS series machines cost about 20 percent less than Niigata’s standard MD series, Gardner said.
Niigata said that because Haitian already produces a large quantity of heavy metal parts for its own lines of injection presses, having Haitian make those parts results in lower costs and time savings.
Masaki Kakimoto, Niigata’s managing director, is president and CEO of Niigata Haitian Injection Molding Machine Co. Ltd. “Niigata Machine Techno sources components and material through Haitian at a cheaper cost to lower the machine production cost,” he said.
Niigata will continue to make all of its machines in Japan. Final assembly, test runs and quality control will still be done at its Niigata City factory.
Mikell Knights, senior staff reporter
Daiichi Jitsugyo (America) Inc.
Wood Dale, Ill., 630-875-0202, www.niigata-us.com