Condition Monitoring in Injection Molding

Monday, February 22, 2016 by Fluid Gas Handling Team

Condition Monitoring in Injection Molding - injection molding machine - SensoNODE - Quick Coupling Division Parker Hannifin Reactive and preventive maintenance practices just don’t cut it in modern manufacturing. Predictive maintenance – changing parts and fluids only when their conditions deem necessary – is truly the best practice for saving costs and preserving your assets.

That being said, an advanced condition monitoring solution can also be necessary to keep product quality high and scrap low in the injection molding process.

There are several points throughout the injection molding process where changes in an asset’s temperature, pressure, or humidity can compromise product quality. If left unchecked, such changes can lead to:

Part deformity.
Stress cracks.
Extra flashing.
Excess scrap.
Increased recall costs.
Trapped air or moisture.
Shrinkage.
Voids in molded parts.
Overall poor end result quality.
Unmet specifications, like especially tight tolerances.

Conditional Monitoring in Injection Molding - schematic of injection molding machine - SensoNODE application - Parker Hannifin

Consistent and accurate condition monitoring is critical to ensure the molding process isn’t costing your company thousands annually in additional operational costs.

Temperature monitoring

If the equipment is running too hot or too cold, the two seconds it takes for the initial mold process can be enough to jeopardize product quality. From the resin storage area to the mold itself, there are varying temperatures that must be kept consistent.

For instance, clogged water channels in the injection mold won’t show an increase in water temperature, but cavity temps will rise, hindering the cooling process and leading to product deformations. Being cognizant of changes throughout the system helps operators quickly diagnose and address issues.

Pressure monitoring

From the injection screw that pushes material into the mold to the clamp that holds the mold shut, insufficient pressure can let air and moisture seep into the material, leading to batch defects:

Short shot: A void of material in a portion of the part due to insufficient pressure

Flash: Excess pressure forces mold open just enough to allow material seepage, resulting in defective parts and potentially damaging the mold
Dimensional variation: Packed mold is fully compressed, but cavity pressure changes at a critical point
Warp: Variations in packing pressure (as well as cooling rate/time) that leads to random distortions in part

Maintaining proper working pressure is a vital part of the injection process.

Humidity monitoring

Plastic resin is subject to changes in ambient humidity conditions in storage containers, as well as the process lines. Too much humidity can add moisture to the resin, changing its properties and preventing it from molding like it’s supposed to.

However, measuring ambient humidity isn’t enough. You need to monitor humidity in the plastic itself, as well as the moisture content of the air being blown from your resin dryers.

A solution that makes sense

conditional Monitoring in Injection Molding - SensoNODE sensor image - Parker Hannifin

Parker’s condition monitoring solution of SensoNODE™ Sensors and Voice of the Machine™ Software platforms scan multiple points of interest throughout the injection molding process simultaneously, quickly giving operators a picture of their assets that is accurate and complete.

SensoNODE Sensors monitor your assets for changes in temperature, pressure, humidity, and vibration then wirelessly transmit that data to Voice of the Machine Software’s easy-to-use and understand interface, saving time and reducing labor cost.

View our Injection Molding Success Story and visit our condition monitoring website to learn more.

Condition Monitoring in Injection Molding - Parker Hannifin - Marc Williams, SensoNODE Sensors and Voice of the Machine Software Article contributed by Marc Williams, IoT project lead, Parker Hannifin Corporation

Comments for Condition Monitoring in Injection Molding

John Carston

I'm still learning about plasticity in injection molding and I found a lot of great info here. It's interesting to know that the molding process must be very precise and all conditions known to avoid the many problems that can occur in this process. I can see that there are several forms of monitoring to help prevent any unwanted variation. Thanks for the educational info.

Avishek Prasad

Hi there i need to understand the solution you are providing for the conditioning monitoring of Molds.
What parameter you measure, what are the sensor you install etc

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