One of our clients needed a solution for automatically adjusting his horizontal extrusion die. The die controls the thickness of a plastic web about 72 inches wide.
Previously, the 72 bolts across the top of the die were adjusted by hand by an operator. The worker would compare the readings on a nuclear micrometer to what the set point was. This was labor intensive and required a lot of the operator’s attention, time he should have been dedicating to watching the machine and its operation.
Our solution was to incorporate a Yaskawa multi-axis servo controller with four servo amplifiers and motors and Modbus communication to interface with their micrometer.
A brief explanation: Two motors are mounted on two “heads.” Each head consists of:
- A position motor with a gear reducer that travels on a linear gear across the die
- And, an adjusting motor with a socket mounted to the motor shaft that pneumatically lowers down on a bolt to adjust it.
Each head is taught the position of the first bolt by moving it manually to that position. The distance between each bolt is inputted into the system through the Parker HMI. Then each head travels across the die, learning the positions of every bolt and the rotational position of each bolt head. In case of vibrations or other external influences to the bolts, the system has the ability to relearn on the fly the rotational position of any bolt.
The micrometer will message the servo controller via Modbus when a portion of the web is out of tolerance. The servo controller is told which bolt is causing the error and by how much. The “head” closest to the offending bolt will move to a bolt 3 bolts away. Then, alternating between bolts on either side of the offender, the head start adjusting the bolts. The outside bolts receive minor adjustments working up to a full adjustment on the center (and offending) bolt.
Result; the operator can manage the machine and not have to micromanage a bunch of bolts.
Productivity up. We do solutions like this for customers every month. If you tell us y
our problem, we probably can help your efficiency.
Stewart Bissell is a Field Applications Engineer in Innovative-IDM's Dallas office. He can be reached at firstname.lastname@example.org