Communication Between Machines, Across Company Ensure Maximum Productivity

The combined Dayton Parts punching and forming workcell provides an example of how machine-to-machine communications can improve a process. The supervisory PLC, connected via a standard Ethernet network, interfaces to the two motion controllers and multiple human-machine-interface terminals, and via EtherCat (an Ethernet-based fieldbus) to a series of input/output racks (Fig. 4). Communicating via the networks, the PLC adjusts cycle time of the furnace and sets the speed of subsequent stages in the line. For maximum productivity and also to ensure that heat transfer from the hot parts passing through the system doesn’t affect sensitive system components, it is critical that the process proceeds as smoothly and expediently as possible.

The Dayton Parts system uses recipes, selectable using the touchscreens, to streamline production changeovers and ensure repeatability of the leaf-spring manufacturing process.
Fig. 5—The Dayton Parts system uses recipes, selectable using the touchscreens, to streamline production changeovers and ensure repeatability of the leaf-spring manufacturing process.
The local machine network also connects to the factory LAN so that production information is available to corporate SPC and quality-analysis software. This can help optimize performance and identify maintenance issues before they escalate.

Job Recipes Speed Changeovers

The PLC connects to a Microsoft Access database containing the manufacturing parameters of all leaf springs produced by Dayton Parts. The operator selects the leaf spring to make next via a touchscreen interface and the PLC downloads the appropriate process parameters to the temperature/pressure controllers, and motion sequences to the Delta motion controllers.

“The system automatically processes via recipe (Fig. 5) to speed production changeovers and gain repeatability, which we didn’t have before,” says Shortridge. “We often have relatively small production runs where a spring may contain as many as 12 different leaves. In the old days, we would have to manually dial-in new furnace temperatures, forming pressures and quench-timer settings when we would change parts to be manufactured. This was time-consuming and could introduce errors and downtime that we can’t afford.”

To tune the motion, Shortridge used the set of tools provided by Delta Computer Systems. One of these tools, Plot Manager, enables the designer to visually and numerically compare an axis’ desired motion trajectory with the actual motion profile observed in a test run. With this visibility, control-loop parameter gains can be tweaked and the system re-run until the target and actual positions overlap on the plot, showing that the system is perfectly tuned.

“Without the new motion controllers and the accurate hydraulic proportional control they provide,” says Garcia, “this project would have been a lot more difficult to implement.” MF
Industry-Related Terms: Bending, CAD, Center, Form, Forming, Gauge, Plate, Punch Press, Run, Stripper, Transfer
View Glossary of Metalforming Terms

 

See also: Delta Computer Systems, Inc.

Technologies: Pressroom Automation

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