Presses offer advantages for molding large parts
Molders of large parts have more options when it comes to choosing hybrid injection molding machines, with several suppliers introducing new or upgraded models at NPE2018.
CHEN HSONG UPDATES ITS TWO-PLATEN LINE
Chen Hsong Group, Hong Kong, has introduced the latest generation of its Supermaster two-platen injection molding machines with an advanced servo drive, and announced new representation.
Newly formed CH America is responsible for sales, service and support of Chen Hsong products in the U.S. and Canada. Based at a 40,000-square-foot office and warehouse facility in Torrington, Conn., it also operates offices in Detroit and Dallas. Several machines are already in stock.
Chen Hsong, marking its 60-year anniversary this year, said the latest generation of its Supermaster two-platen (SMTP) servo-hydraulic series for large-part molding delivers better performance and greater energy-efficiency than competing machines.
The Supermaster line includes 14 different models with clamping forces ranging from 772 tons to 7,165 tons. The company offers 14 injection units with different shot capacities that can be mixed and matched with the clamping units. The injection units provide shot weights from 4.3 pounds to 233.9 pounds.
The updated machine line incorporates a package of related technologies designed to make machine operations very stable, precise and repeatable. The technology approach, dubbed Non-Stop, is the result of an ongoing eight-year strategic cooperation between Chen Hsong and a team of technical experts from Japan (primarily Mitsubishi) and Europe, that has been working to achieve zero-defect molding.
The Non-Stop approach, first incorporated into the second generation of Supermaster machines, guarantees annual unscheduled downtime of less than 0.5 percent of the machine's scheduled runtime. The technology combines precision hydraulics that minimize pressure drops or spikes, the use of reliable components with patented mechanical designs, and dynamic control to achieve high repeatability and performance.
The machine uses the latest machine controller from Beckhoff of Germany, which Chen Hsong said provides more control than previous types. Also included is a second-generation servo- drive system that comprises a new power-pack design, fast-response gear pump and high-precision servo motor integrated with a proprietary servodrive.
The SMTP line has a patented interlock mechanism that provides precise and quiet clamping. It can achieve clamp movements as fast as 29.5 inches per second, as well as overall dry cycle times of 8 seconds.
Response times are less than half that of an injection molding machine with a variable-displacement pump.
The new configuration reduces energy consumption by as much as 80 percent compared to a machine using a displacement pump, while raising repeatability to within 0.5 percent.
The SMTP line includes a patented circular platen that delivers more uniform distribution of pressures vs. competing platen designs. It exhibits enhanced stiffness and structural integrity o make it suitable for a wide range of molding applications.
WELLTEC EXTENDS SERVO-HYDRAULIC SERIES
Welltec Machinery Ltd., Hong Kong, has extended its JSeII line of two-platen servo- hydraulic machines with the 650 JSeII model with 650 tons of clamping force. The line previously included models with clamping forces ranging from 1,000 tons to 4,400 tons.
Machines in the line have four clamping cylinders installed on the fixed platen to ensure that the platen experiences uniform stress during lockup. Short-stroke, high-pressure cylinders generate clamping pressure. Each pressure-generating cylinder is used with a pressure sensor and real-time monitoring device to ensure clamping force repeatability. The patented, direct-clamping system, in conjunction with the pressure transducer, minimizes platen deflection.
JSeII presses have a platen carriage that accommodates oversized platens to handle large molds, yet can operate at a high speed, allowing the machine to produce large parts in less time than competing designs.
Featuring a 10.4-inch color display, the B&R Automation controller operates the high-performance servodrive system. The controller provides 10 stages of closed-loop injection speed control, 10 stages of closed-loop holding-pressure control, and five stages of closed-loop metering control. A noncontact absolute-position transducer controls the injection stroke.
Closed-loop control ensures optimal operation of the servo driven hydraulic system. The design also allows for the recovery of energy from the servodrive system. This allows the machine to use 40 percent less energy than an injection molding machine with a traditional variable-volume system. The press also provides four stages of clamping speed and pressure adjustment.
At the show, the 650 JSeII press produced and labeled an 880-gram storage box made from PP in a single-cavity mold every 30 seconds.
L.K. SYSTEMS BOOSTS FORZA'S VERSATILITY
L.K. Machinery Group, Hong Kong, now offers its Forza III series of two-platen servo-hydraulic machines with an option for an electrically driven injection screw drive.
The second-generation design of the Forza III line, which was introduced during K2016, has a new electric injection unit option. It allows a molder to perform injection and clamping in a parallel, simultaneous fashion rather than in sequence. This can shorten production cycle times and improve part quality. L.K. has increased to four the number of injection units available for each size in the Forza III line.
To take advantage of the parallel operating option, molders must upgrade the machine controller from the Keba i2000, which is standard on the Forza III, to the Keba i5000 controller. L.K. said other options allow molders to add a platen that is 10 percent larger than the standard platen size; with a change in components, operators also can increase injection and clamping speed.
The Forza III is designed for packaging and automotive molding applications. Features that ensure responsive, precise and repeatable operation include the use of linear rails to support the movement of the injection cylinder, injection carriage and moving platen. A rapid pressure-buildup system incorporates short-stroke, high-pressure clamping cylinders to achieve clamping.
LS MTRON LAUNCHES MACHINE SERIES
LS Mtron Ltd., Anyang, South Korea, introduced the One series, its new hybrid injection molding machine line that improves upon the company's hydraulic machines in regards to versatility and performance. The company offers 10 models in the One series, with clamping forces ranging from 551 tons to 3,640 tons.
The hydraulic system has features that enhance its performance compared to competing systems. It can perform under conditions of rapid pressurization, from 2,683 pounds per square inch (psi) to 3,045 psi, resulting in mold opening and closing speeds as fast as 39.37 inches per second and a 30 percent improvement in dry-cycle speed, compared to competing machines.
A special ceramic and glass coating on the internal wall of the hydraulic fluid tank keeps the fluid clean while reducing the possibility of oil leaks. To further minimize leaks, the series uses galvanized expansion pipes instead of welded pipes, better O-ring-type hose fittings and improved pipe sealing.
The design of the half-nut devices in each corner of the moving platen that clamps onto each tie bar has been improved so that locking or unlocking occurs 30 percent faster than competing designs. The new tooth pattern used to lock the half nuts to the tie bar enhances locking strength while minimizing locking errors.
To ensure accurate mold and clamp positioning, the One series incorporates SSI-type digital position sensors rather than analog sensors, and high-capacity electronic proportional valves tailor hydraulic oil flow rates precisely and repeatably. Mold position is repeatable to within 0.2mm.
The One series features an improved support device for the fixed and moving platens that handles molds as much as 250 percent heavier than competing injection molding machine models can employ. The smallest model in the line, the One 500, handles a maximum mold weight of 17,637 pounds.
The machine line also has a one-touch, automatic tie-bar-pulling system that allows for large molds to be installed when the ceiling height in the molding facility is limited. The function separates the tie bar from the platen, taking about 1 minute to pull the tie bars from the molding machine.
Clamping pressure is generated using a direct clamping mechanism driven by a servo-hydraulic pump. The double-sealed hydraulic system is 99 percent leak-free. Clamp pressure build-up time is short, taking no more than 0.7 second. The clamping mechanism and related components such as the platen are designed to work together to reduce deflection up to 30 percent compared with competing designs.
Additional features include a Pulsar screw and bimetallic barrel for material plasticization and injection, both manufactured by Nordson Xaloy, New Castle, Del. LS Mtron developed a new quick barrel-change system in which the injection unit is lifted, rather than rotated, from the base of the injection unit when the barrel assembly is replaced.
A controller from Keba, Linz, Austria, controls all machine operations.
In addition to the One series, LS Mtron produces the Wiz-E line of all-electric presses and its Wiz-T line of servo-hydraulic machines.
In the U.S., Daiichi Jitsugyo America (DJA) distributes the machines.
Mikell Knights, senior staff reporter
Contact:
CH America, Torrington, Conn., 860-840-7070, www.ch-america.com
Daiichi Jitsugyo (America) Inc.,
Wood Dale, Ill., 630-875-0101,www.dja-global.com
L.K. Systems Inc.,
Ladera Ranch, Calif., 949-373-0585,www.lksystems.us
Welltec North America, Pacific, Mo., 913-486-9211, www.welltecna.com
