Why Put Sensors in a Mold?

Simply put, what happens in the mold stays in the part. Cavity pressure and temperature sensors are the proven way to know without a doubt what is happening to the plastic as it forms the part.

Why Measure Cavity Pressure?

Pressure data can help identify:

  • Sinks
  • Shorts
  • Flash
  • Voids
  • Dimensional Variation
  • Weight
  • Chemical Resistance
  • Warp or In-Molded Stress
Why Measure Temperature?

Temperature data can help identify:

  • Cooling circuit variation
  • Imbalance or blockage—warp due to semi-crystalline shrinkage behavior
  • Improper melt temperatures

Technology Types

We offer two different technology styles of cavity pressure sensors, meaning they have different technology within the sensor head that create a pressure reading differently.

Piezoelectric

There is a crystal inside the sensor head. Pressure on the crystal creates a small charge which converts into a reading via
an amplifier.

Pros: Detachable cable
Cons: More expensive

Strain Gauge

Has a wheat stone bridge gauge and pressure on this gauge creates a reading.

Pros: Less expensive. Includes an option for large ejector pin sizes.

Sensor Head Styles

Indirect (Piezo or SG technology)

This round sensor is placed behind either an ejector, transfer, or static pin. When plastic pushes on the pin, that pressure is then transferred onto the sensor head. Sometimes referred to as a button sensor.

Loadwasher sensors (Piezo) are indirect sensors that go behind an ejector sleeve.

Pros: Less expensive than direct. Depends on the space in the tool.

Direct (PZ technology only)

This sensor is installed with the tip of the sensor flush with the cavity wall. This puts the sensor in direct contact with plastic.
Sometimes referred to as a flush sensor.

An option if you can’t get behind an ejector pin. Just depends on the space/needs of the customer.

Note: Transfer pin installation can be used with any of our indirect sensors. May become the preferred installation method. Can get to it easier, and it’s exposed to less heat.

Electronics Types

Single Channel

Each sensor is purchased and installed with an individual connection to the outside of the mold. They will each have a teal Lynx box. Can handle up to 140 degrees. In piezo or strain gauge.

Pros: Most sense with single sensors.
Cons: Takes up more real estate on the mold.

Lynx Embedded (Strain Gauge only)

The lynx technology is taken outside of the Lynx box and installed directly into the steel. Each sensor cable then comes together into one connection point on the mold. Everything is contained in the plate. Up to 16 sensors per connection. Can handle standard temps.

Pros: All technology is safely contained into the mold and less susceptible to damage. There is only one connection point.
Cons: Installation?

Multi-Channel Sensor Systems

Up to 8 sensor cables plug into one connection on the side of the mold. Can handle up to 80 degrees (SG) and 200 degrees (PZ)

Pros: Robust, takes up less space on the side of the mold. Cost effective. Can use the adapters on different molds.
Cons: Needs more amplifiers than the LES.