Guía de solución de problemas de matrices de extrusión: Zonas eléctricas y calentadores
A veces, incluso las operaciones más organizadas pueden enfrentar problemas inesperados al iniciar la producción que requieren una resolución de problemas exhaustiva. Es posible poner en funcionamiento con éxito un sistema mediante un enfoque sistemático para definir el problema, clasificar las posibles causas y luego desarrollar una solución.
Nuestras experiencias en servicio y soporte técnico en el campo nos han permitido identificar algunas causas comunes de problemas de configuración, lo que ayuda a agilizar el proceso de resolución de problemas.
Comprobación de los calentadores
Es importante verificar los calentadores cada vez que se vaya a reinstalar el troquel y/o el bloque de alimentación en una línea de producción. Esto es cierto si el equipo fue retirado recientemente del almacenamiento, fue remodelado recientemente o simplemente se apagó para un evento de mantenimiento preventivo.
Al revisar sus calentadores antes de completar el proceso de instalación, se asegurará de que estén calentando correctamente y no causarán más problemas cuando comience la producción.
Al verificar sus calentadores, consultará la información incluida en el dibujo eléctrico provisto con su matriz o bloque de alimentación. El dibujo eléctrico mostrará la cantidad de zonas, cuántos calentadores hay en cada zona y la potencia de los calentadores en cada zona.
Example Electrical Drawing
- In this example drawing, we see the zones for the flex and non-flex bodies of an extrusion die (highlighted in orange). Each zone is labeled, for a total of 10.
- This diagram also shows that the end zones (1, 5, 6, and 10) have fewer heaters than the center zones (highlighted in green). This also means that these zones have a reduced number of total watts.
- Finally, at the center of the drawing (highlighted in blue), we see the pin designations, beginning on the left.
This information will be important to note as you begin checking heaters.
Once you’ve reviewed the information in your electrical drawing, you may begin testing the heater by checking the ohms in each zone using a multimeter, reading across the corresponding pins. We will use the information from the drawing above as an example, so Zone 1 is across from Pins 1 and 2.
First, we need to calculate the total number of ohms (Ω), using Ohm’s Law, in Zone 1:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
3 Heaters x 500 W Each = 1,500 Total Watts
57,600 ÷ 1,500 W = 38.4 Ω (± 10%)
The number of heaters differs for each zone in this die, so we will need to complete a similar exercise to find the total number of ohms for Zone 2, as well as any other zones with a different number of heaters:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
4 Heaters x 500 W Each = 2,000 Total Watts
57,600 ÷ 2,000 W = 28.8 Ω (± 10%)
Using an ohmmeter, check the value of the corresponding pins for each zone. If the measurements differ from the calculated value, then you’ll need to check each individual heater within the zone as there may be an issue. To do this, you will need to calculate the heater ohms (Ω) of the individual heater:
Ohm’s Law: Ohms = Voltage (V) x Voltage (V) ÷ Watts (W)
240 V x 240 V = 57,600 Total Voltage
Divide the Total Voltage by the Heater’s Wattage (500 W)
57,600 ÷ 500 W = 115.2 Ω (± 10%)
If your heater ohm reading differs from this value, verify that the installed heater has the correct voltage and wattage required (this information is engraved on the heater). If this information is correct, then the heater may be bad and should be replaced.
Checking Electrical Connections to the Die System Zones
Whether you are installing a brand-new die or feedblock, or one that’s been recently refurbished or pulled from storage, it’s important to ensure that all electrical components are in the proper position to function correctly. This process can be completed in a relatively short time and saves a lot of frustration later during start-up.
This procedure should be completed when your die or feedblock is at an ambient temperature. Starting from one end of the die, begin turning power on to one zone at a time. Once the temperature begins to climb for the activated zone (approximately 10°F), turn the power back off and move to the next zone to repeat the process.
While simple, this process ensures two things. First, you are confirming that the correct zone is heating once power is applied. Second, you are confirming that each thermocouple is installed in the correct location.
If you notice that a different zone is heating when power is applied, then there could be an issue related to wiring or thermocouple placement. If a zone does not turn on, check if there is a solid-state relay that needs to be replaced, if there is a fuse blown in the control panel, or if there is a loose or broken wire.
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