Caution in Melt Pressure Sensor Installation
Check hole thread size, Clean carefully, Keep transducers dry ...
Melt Pressure Sensor Check hole thread size
Screwing the converter into a mounting hole with the wrong thread size will damage the threads of the device. This can prevent a tight seal that causes melt leakage and the device will not operate properly or safely. The correct dimensions for the mounting hole must be used to prevent threading. (Threads are generally 1 / 2-20 UNF 2B industry standard.) A mounting well indicator plug should be used to verify that the mounting hole has been correctly machined and cleaned.
Melt Pressure Sensor Clean carefully
Before cleaning an extruder barrel with a wire brush or special cleaning compounds, all transducers must be removed. One of these can break the diaphragm of the transducer. The transducer should be removed while the chamber is hot and the tip wiped with a non-abrasive cloth. The converter hole should also be cleaned with a cleaning drill and guide sleeve.
Keep Melt Pressure Sensor Transducers dry
Although the electronic circuitry of a standard converter is designed to withstand the rigors of the extrusion process, most converters are not waterproof and will not operate when wet. Make sure there are no leaks in the water cooling jackets in the extruder chamber that could damage the converter. If you know that the transducer will inevitably be exposed to water or moisture, specify waterproof transducers.
Melt Pressure Sensor Avoid cold starts
Both the converter and the extruder may be damaged if the extruder is not brought to operating temperature before production begins. Sufficient “dwell time” must be provided for the plastic to transition from solid to molten state. Also, if a transducer is removed from a cold extruder, material may adhere to the converter tip, causing the diaphragm to rupture. Before removing the transducer, make sure the drum is hot enough to make any plastic parts soft.
Melt Pressure Sensor Do not overpressure
While transducers are designed to withstand 50% overpressure (above the rated maximum), avoid risk by making sure you use a model designed for the range of extrusion operating pressures. An important rule of thumb is to use converters designed to withstand twice the rated pressure in your process. If so, the extruder must operate at an extremely high (and unsafe) pressure level in order for the transducer to fail.