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Monday, April 2, 2012

'Validator' Ensures Quality Control for Plastic Injection Machines

Schlemmer Associates develops a monitoring application to alert plastic injection machine operators to potential quality issues immediately.

 

Figure 1: Chris Bayless, Process Engineer, TGKY

  • Schlemmer Associates worked with Kemper Controls to develop an InduSoft Web Studio HMI for the Validator system for plastic injection machines.

 

  • The Validator system alerts machine operators to problems with the injection process immediately by monitoring the machine.

 

  • This application has provided a dramatic improvement in the production of quality product for major japanese automotive buyers.


 

Figure 1: Chris Bayless, Process Engineer, TGKY

 

Background
No machine operator wants to see the result of a machine error after the fact. The ability to monitor a process as it happens and guard against problems is a cornerstone of an efficient production line. That’s why the well known Japanese manufacturer of the machine developed for Toyoda Gosei (TGKY), contacted  Schlemmer associates to develop an application that would assist operators of a plastic injection molding facility in  Lebanon, Kentucky, monitor their injection molding process in real-time.

The TGKY plant in Kentucky is a producer of molded plastic parts for prominent Japanese automotive companies. Producing a high quality product is critical to maintaining business contracts, and the ability to better monitor the process promised to be vital in improving the overall efficiency of the plant and the quality of the parts produced there.

The manufacturer of the machine then contacted Schelmmer Associates to develop a ‘Validator’ solution. the Validator designed by Schlemmer Associates incorporates PLCs and an HMI running Windows CE.

The Challenge
Developing the Validator system involved ingenuity from Schlemmer Associates. According to Dennis Redwine, “The initial goal of the solution we provided was to monitor water flow through the mold. Water is circulated through the mold(s) to ensure that the correct amount of heat is dissipated while the plastic is curing in the mold. Too much or too little water flow can produce a defective part. For various reasons, water flow can be interrupted causing major quality issues with the parts that are manufactured.” This crucial balancing act was the key focus of the project. Just as important was monitoring capabilities for the mold heater temperatures and the monitoring of the machine status.

Another requirement of the project included the incorporation of alarm monitoring capabilities that would allow machine operators to see problems immediately, and shut down the machine, rather than allow the production of a non-conforming product.

The main challenge Schlemmer Associates faced was finding the best HMI for the job. They contacted Kemper Controls, a local InduSoft Web Studio distributor, to develop the HMI application for their Validator solution. Because InduSoft Web Studio offers one of the best HMI solutions for Windows CE and embedded Windows PLC solutions The dependability of InduSoft Web Studio was also a factor, as was the ease of using its graphical interface.

Figure 2: The alarm pop-ups clearly display alarm status, and allow for quick identification of problem areas. In these screens, temperature values are monitored. 

 

 

 

 

Figure 2: The alarm pop-ups clearly display alarm status, and allow for quick identification of problem areas. In these screens, temperature values are monitored.

 

 

 

 

 

The Solution
The Validator system developed by Schlemmer monitors the inputs from the PLC in order to make decisions about alarming and recipe download verification. It provides the operator interface on the HMI and allows the operator to see process data, alarms and input data. According to Dennis Redwine, “It was very easy to develop the application and was economical for what we needed.”

 

QuoteIn addition to water flow, the system includes alarm monitoring capabilities from the Hot Runner system, and the injection machine control. The machine’s limits are loaded into a recipe file for each mold the customer may run on that machine. The Validator then checks the machine status to ensure that criteria for production are met. This includes verifying that each of the three hoses is connected properly, and  the thermalator that regulates the mold’s temperature is turned on. To verify that the Validator is monitoring the correct parameters, the machine control sends a binary code which designates the correct product. As the machine runs, the Validator constantly monitors flow rate and alarm inputs from the machine alarms and sends an output which turns an Andon light board. When plant personnel see that the light is on, they are immediately alerted to a problem.

The Result
The results of this monitoring capability have been impressive for TGKY. The Validator system based on InduSoft Web Studio saves the operators of the injection molding machines many hours that otherwise would have been spent replicating good parts, as well as the material waste of making defective parts. Figure 3: The Validator solution monitors the energy use of the machine for greater efficiency in production.

 

 

Figure 3: The Validator solution monitors the energy use of the machine for greater efficiency in production.

 

 

 

 

Dennis Redwine, of Schlemmer Associates, provided two examples of how the Validator system has directly affected production at TGKY:

•  Result: The Validator received an input from the machine monitor management that the screw was bottoming out (or lost cushion position). The Validator turned on the Andon light which alerted plant personnel of a problem. Upon further investigation, a faulty valve on the machine was discovered. During this time, non-conforming parts were being produced so it was imperative to stop the machine and troubleshoot the problem. The Validator saved them the material and run-time by alerting them to the problem right away.

 

 

Figure 4: Energy values can be displayed for current or historical levels.Figure 4: Energy values can be displayed for current or historical levels.

 

•  Result: The Validator received an input alarm from the Hot Runner system and again turned on the Andon light to alert that there was a problem. It was discovered that non-conforming parts were being produced due to one of the heaters on the Hot Runner system was turning off and on intermittently. A defective connector was discovered to be the problem. Again, without the Validator alarming plant personnel of a problem, it may have taken hours to discover the issue by inspecting the parts after the fact.

Schlemmer offers their Validator system in markets beyond injection molding, and hopes to expand their solution to a wide range of machines. They intend to continue using InduSoft Web Studio in their product, in order to provide reliable and economical interfaces to their clients. 




 









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info@indusoft.com or 877-INDUSOFT (877-463-8763) or 512-349-0334.


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