Injection blow molding machines from Jomar Corp are used by manufacturers to produce thin-walled items like bottles and containers used in pharmaceutical, health care, personal care, beauty, food, beverage, and household-goods markets. Jomar Corp.’s newest 85S Model of IntelliDrive injection blow molding (IBM) machines is equipped with a Syntronix servo-driven hydraulic system from Bosch Rexroth, boosting efficiency by 40%-50% compared to conventional drives. The new system is the first of its kind to incorporate several new-to-market components in a unique, space-saving design.
The design takes high pressures into consideration as the plastifier's screw drives inject melted plastic into the molds, and compressed air is introduced in the mold to create a vacancy. The molds are held tightly shut by a clamp, which is opened and closed over millions of cycles to form and release the products. To supply these pressures with higher efficiency, Jomar and Bosch Rexroth investigated a closed-loop, servo-driven hydraulic system that would replace the all-electric platform used in previous models. The new system combines intelligent digital controls with a 4-quadrant pump-servo motor system that regulates the speed and flow of hydraulic oil.
Since the plastifier is the largest energy consumer on the machine, the team first looked to equip it with Rexroth's Syntronix variable speed drive. The system consists of a Rexroth A10 axial piston pump, and a Rexroth MSK servo motor with an IndraDrive C that are sized to provide the right torque, speed, and horsepower to a motor driving the plastifier. The variable speed drive operates in four quadrants; it changes direction of rotation and has two pressure sides that respond to operational changes in the motor, eliminating the need for proportional directional control valves and saving on cost and energy.
The A10 Rexroth axial piston pump is a relatively new design that operates at higher speeds, performs proportional operations, and operates in all four quadrants of the Syntronix hydraulic system. It supplies hydraulic oil to turn a Hagglunds CAb radial piston motor connected to the plastifier screw. The result is a closed-loop pump driving a hydraulic motor on an extruder in bidirectional operation. Specifically designed for plastics' industry plastifier drives, CAb is known as the “hidden beast” because it packs a lot of power into a compact, low-noise design. To reduce the overall footprint, the CAb was vertically mounted to drive a vertical plastifier. The Hagglunds Cab radial piston motor is the first to be sold in North America.
The machine also combines a Bosch DRn frequency drive with the Sytronix hydraulic system to save energy as a variable speed drive. It calculates the most efficient motor speed based on the current pump operating conditions. This allows the system to run at optimal motor speed without programming by the customer. The Jomar-Bosch Rexroth team also considered the Bosch Rexroth VT-HACD controller device for a design that allows fully closed-loop control of velocity and positioning for the injection and blow clamps. This allows for a faster overall machine cycle, better closing cushion-control for the molds, and less wear on the hydraulic cylinders.
The 85S Model of IntelliDrive injection blow molding (IBM) machine will be showcased at the K Show for plastics and rubbers in Dusseldorf, Germany this year.
