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November 1, 1999

4 Min Read
Product News - Transducer News: Something For Injection Molders And ForExtruders

Transducer News: Something For Injection Molders And For Extruders

Dynisco Instruments has introduced two new transducer lines: piezoelectric cavity-pressure transducers for injection molders and a series of melt pressure transducers for harsh extrusion applications. Please contact the company directly for pricing. Use the Key Contact Directory.

In addition, the company has added two new kits to its line of Dynipak 'quick start' kits for extruders (Feb '99 PA, p 10).PN 19a-11/99PN 19b-11/99

Piezoelectric transducers are designed to provide direct or indirect measurement of cavity pressure so injection molders can improve quality and productivity.

By placing a cavity pressure transducer in the last part of the cavity to fill, an output can be generated to indicate the switchover from injection pressure to holding pressure. A transducer located near the gate can be used to monitor the transition from packing to holding, which, in turn, can result in improved visual, dimensional and piece weight consistency.

For indirect measurement of cavity pressure from behind the ejector pin, Dynisco offers Model PCI4012 slide pressure sensor, Model PCI4006 miniature slide pressure sensor and Model PCI4013 button-style miniature load sensor. These units measure loads up to 2250 pounds-force at a resolution of 0.002 pounds-force. Standard or high-temperature sensor cables can be used, either of which can be replaced at the machine for easy maintenance.

For direct measurement of cavity pressures up to 30,000 psi at temperature up to 572 F, Models PCD4025 and PCD4040 are offered. These sensors have diameters of 2.5 mm or 4 mm and an O-ring sealed shaft for easy installation. Like the other models, standard or high-temperature sensor cables can be used.

Also offered is Model CHA40XX, a standard charge amplifier to link the piezoelectric pressure sensors and data analysis equipment. It substitutes for most piezoelectric sensors, including load, pressure and acceleration, and is compatible with most commercially available instruments. 

PN 21-11/99Melt pressure transducers have an Inconel sensing diaphragm for long life in abrasive and corrosive extrusion environments. The DLX Series also has a titanium nitride coating on the transducer threads to protect against damage caused by galling.

All models have a three-year extended warranty and include a certificate for a free transducer calibration.

Units in the series are available with a choice of rigid and flexible stems for easy installation and removal, and an integral thermocouple model that allows simultaneous measurement of pressure and temperature at a single point.

All models have a standard 3.33 mv/v low-level output at ranges from 0 to 500 psi to 0 to 30,000 psi. An internal 80% shunt calibration is said to simplify set-up. Measurement accuracy is rated at 0.25% and units are claimed to have superior thermal stability and repeatability.

They can be used for pressure control along the extruder barrel, adapter or die, as well as anywhere else process measurement at a range of temperature is needed. Units are also said to meet CE requirements. PN 20-11/99

Two new 'quick start' kits, called Dynipaks, are available. The Differential Dynipak is for processors who want to measure and control differential pressure and the Amplified Differential Dynipak is for processors who want to use a high-level signal to control differential pressure.

The first kit consists of two of Dynisco's Model PT452E transducers ordered for any standard pressure range and the DPC535-1-1-1-2K controller. The second has two of the 4-20 mA output model PT4624 transducers order-ed for any standard pressure range and the DPC535-1-1-5 controller.

In addition, the kits include a connector cable, 'quick start' instructions, anti-seize compound, 'Tips On Melt Pressure Transducers For Extrusion' (reprint- ed from Jan/Feb '98 PA, p 28) and a baseball cap. This gives the user the ability to order an entire package with a single part number.

A laminated 'Quick-Start' card provides, on one side, three simple steps for transducers (preparing the mounting hole, installation and wiring) and on the other side, four steps for instrumentation (mounting, wiring, scaling and calibration/operation).

Dynisco Instruments
Sharon, MA

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