tips & techniques

Moldflow Manufacturing Solutions Hints and Tips
Using the Moldflow Plastics Xpert Setup Xpert to Reduce Mold Setup Times and Increase Productivity

By Dean Piepiora, Moldflow Corporation

How long does the average mold change and setup take at your company - 30 minutes, 60 minutes, 90 minutes? How do you compare versus the industry average? In a recent Injection Molding Magazine Benchmarking Report (August 2002), it was reported that the average mold change time in 2002 is 122.5 minutes, and over 56 percent of mold changes take between just over 1.5 hours and 8.5 hours.

This may or may not sound like a long time for one mold. But considering that the study also reported that the average number of mold changes per machine per week is 6.6, that equates to a minimum of 10 hours of machine downtime per week just because you completed one run and have to change the mold to start a new one.

There are many reasons why mold changes can take a significant amount of time, some of which are purely physical in nature. For example, it takes a certain amount of time to disconnect and remove the current mold from the machine and to mount and connect the new mold. Larger molds normally require longer mold change times due to their physical size. However, there are other reasons that can affect the overall time it takes to change a mold, including:

• There are not enough experienced mold setup technicians or process engineers to set up every mold as soon as it is ready, resulting in unproductive machine downtime.
• A time-consuming, trial-and-error approach is used to set up a new or complex mold being run for the first time.
• A change to the supplier, batch or lot of material means the mold must be set up anew based on the new material flow characteristics.

Until recently, software tools to automate the setup and optimization of the injection molding process and decrease overall mold change times were virtually non-existent. However, the Moldflow Plastics Xpert^® (MPX^®) Setup Xpert module has changed that. Setup Xpert allows machine operators to set up molds in less time versus the typical trial and error approach. How does it work? Setup Xpert allows users to methodically determine a combination of processing parameters to mold good parts using a series of velocity-phase and pressure-phase setup routines. The setup routines each address specific parts of the velocity and pressure phases and allow users to eliminate various molded part defects.

Before entering Setup Xpert, a Profile Initialization Wizard is used to determine the initial velocity and pressure profiles. The wizard can calculate profiles based on mold/machine information or results data from Moldflow Plastics Insight^TM and Moldflow Plastics Advisers^TM analyses, or profiles can be uploaded from the injection molding machine controller if the mold in question has been run before. Once the starting velocity and pressure profiles have been determined, Setup Xpert automatically selects the best series of routines based on the way the initial profiles were obtained. The user then starts the process of running Setup Xpert to eliminate various defects. The basic sequence of Setup Xpert is as follows:

• The machine operator molds a part.
• Setup Xpert asks the operator if the part has any defects.
• If the part has a defect, the operator provides feedback on the type of defect and rates the severity of the defect.
• Because MPX takes data from the machine and therefore, knows what the machine is doing, and the user provides feedback on molded part quality, Setup Xpert processes this information to determine a parameter change to make in order to improve the part quality.
• The new parameters are then uploaded to the machine controller, the machine is cycled again, the user provides feedback on the new part, and so on.

Here are some hints and tips for running Setup Xpert to decrease process setup times and therefore, overall mold change times as well.

To run Setup Xpert:

1. Touch the Setup button at the top of the MPX window.

2. You may accept the default velocity and pressure phase routines, or customize the selections as appropriate for your application. In most cases, we recommend using the default selections for best results.

3. Touch the Start button to run Setup Xpert.
   

4. Manually cycle the injection molding machine and make a part.

5. In the Select defect dialogue box that appears after the machine has cycled, select the most prominent defect for the part, rate the defect as appropriate, and cycle the machine again. If the part has no defect, select the no related defects checkbox to move on to the next selected setup routine.

6. Continue molding parts, selecting and rating defects as they occur, and continue through all of the Setup Xpert routines until you have an acceptable quality part.

7. An information dialogue box appears when Setup Xpert is complete. Setup Xpert then returns the machine to manual mode.

The MPX Setup Xpert allows machine operators to set up the injection molding process quickly, consistently, and systematically. Setup Xpert has demonstrated time and time again that users can decrease mold setup times an average of 20 percent.

On average, MPX has been proven to reduce scrap rates by 50 percent, cycle times by 20 percent and material usage by 10 percent. Based on the numbers cited in the Benchmarking Report, it is easy to see how using the MPX Setup Xpert can achieve productivity gains by significantly decreasing mold change times and therefore, increasing overall machine efficiency.

Want to learn more about Moldflow Manufacturing Solutions products?
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