Injection Molding Control Solutions, Upgrades and Retrofits Utilizing Allen-Bradley / Bosch Rexroth Solutions
Since 2002 JVH has been combining the machine automation expertise of Allen-Bradley with the hydraulic control expertise of Bosch Rexroth to provide a world class control solution. JVH has designed a new platform of injection molding controls utilizing the Bosch Rexroth DPQ-2X and DPC closed loop controllers in conjunction with the Allen-Bradley PLC platform of your choice (CompactLogix, ControlLogix, SLC 500 or PLC 5) and the operator interface to meet your size and price (PanelView Plus, VersaView CE or VersaView 6181 with RSView32). This injection molding system is designed with “off the shelf” Allen-Bradley processors, I/O and operator interfaces. The DPQ-2X (closed loop injection and ejector control) and the DPC (closed loop clamp control) have DeviceNet communications built into the hardware. This allowed JVH Engineering to design PLC communications to download the setpoints, trigger the profile and read back actual values from the injection molding machine cycle. (click graphic to enlarge)
With this topology, the Bosch Rexroth controllers become co-processors. They provide closed loop algorithms optimized for hydraulics to create the best possible closed loop injection molding controller in the plastics industry. As displayed in the comparison below, it is possible to utilize existing machinery to meet or exceed the standards of a world class molding machine.
Barrel and mold temperature is handled differently based on the AB controller selected. Temperatures are controlled with the 1746-BTM (Barrel Temperature Module) in the SLC platform, 1771-TCM in the PLC platform and the Enhanced PID (PIDE) auto-tune instruction in the Logix platform. These proven temperature control schemes provide the fastest startup with minimal overshoot. And, since they are integrated into the Allen-Bradley machine controller, interlocks are provided to allow maximum protection of the barrel and screw.
JVH has configured injection molding control solutions for most molding machine manufacturers including: Van Dorn, Cincinatti, HPM,
Husky, Farrel, New Britain, UBE, Boy, Gluco, Bucher, JSW, and Engel. This experience gives JVH the hydraulic and controls expertise to design the best solution to meet your company’s needs.
DPC & DPQ
Seconds required for pressure to
settle after 1000 PSI pressure change
Failed - Pressure
% difference from velocity set point
8.41 (note A)
Injection Load Compensation
% change in velocity per 1000 PSI change in load
Millimeters variation at open stop position
1.676 (note B)
3-Stage Injection Capability
Ability to control a velocity profile, pack pressure profile, and transfer between the profiles based on mold cavity pressure
Millimeters variation at extended position
Injection Decompression Repeatability
Cubic centimeters of injection volume variation
Cubic centimeters per second
Note A: Measured linearity is affected by the slow (greater than .200 seconds) response of the original fixed pump pressure relief valve.
Use of variable displacement pumps or accumulator technology would improve the measured results.
Note B: Clamp stopping repeatability is limited by the 1.300 millimeter minimum resolution of the original analog position feedback that
was used. Use of SSI digital position feedback would improve the measured results.
DPC & DPQ
COMPLETE CONTROL SOLUTIONS
Allen Bradley ControlLogix, CompactLogix, PLC5 or SLC platform
16 bit analog inputs/ouputs for fine resolution
2ms closed loop control
All "Off the shelf" components allowing maximum system flexibilty
VersaView, Panelview Plus, Panelview Plus CE or Standard Panelview;
Sizes range from 4" to 17" displays based on requirements