Machine tools

Application of Sunfar inverter on infrared testing of plastic machine

Abstract: Chemical fiber plates, especially the plates for architectural decoration, are basically molded by the plastic machinery. In pursuit of the high efficiency and production yield, previous controlling system is obviously unable to meet the requirement in the current environment. In order to meet the market needs, Sunfar has developed a special infrared-controlled variable driver on the basis of E280 series.

 

Keywords: infrared testing of plastic machine, Sunfar

    Chemical fiber plates, especially the plates for architectural decoration, are basically molded by the plastic machinery. In pursuit of the high efficiency and production yield, previous controlling system is obviously unable to meet the requirement in the current environment. In order to meet the market needs, Sunfar has developed a special infrared-controlled variable driver on the basis of E280 series.

 

Production and technique requirements:

    Heat raw material powder from the earliest stage to a certain temperature; squeeze the heated powder into molding tool through main driver (power 22-75KW) and mold it into required plates; tract the plates to a later stage by a tractor (two 1.1-1.5kw) and cut it according to the required size with a fixed ruler. End products may be uneven in actual production due to mechanical error or speed difference of the motor during the production. If the tractor keeps a constant speed, the instability of the material squeezed out will influence the width of end products.Therefore, the speed of the tractor shall be adjusted immediately according to the amount of the material squeezed out by main driver in actual production.
      

Control principle:

      According to the mechanical features of extruding machine, an optical fibre sensor, which is used to test the relative width of plates, has been fixed at the end of the extruder. The frequency of the tractor will be changed in accordance with the signal sent out by the sensor. When the plate squeezed out becomes wide the tractor will speed up and on the contrary when the plate becomes narrow the tractor will slow down. In this way, the speed of the tractor will change automatically with the amount of the material squeezed out so as to keep the width of the plates consistent.

Control principle as shown in the following figure:

Figure 1

 

The inverter is started.

Figure 2

 

Control process:

    As shown in Figure One and Figure Two, the three conversion buttons SB1-SB3 on the faceplate of the control cabinet are separately in charge of the starting of the inverter, the increasing or reducing of the speed and the starting of the sensor. KT1-KT3 are responsible for the time when to turn on terminal UP/DW and when to start alarm; in normal operation, the second speed is higher than the first speed. The set value of the two speeds are  separately displayed on the two 10V on the faceplate of the control cabinet. 

    When started for the first time, the system will run at the first speed. If the sensor tests a signal, which indicates over width of the plate and the tractor needs to speed up, the inverter will change its main frequency to the second speed instantly by KA electric relay. And at the same time if the sensor keeps testing a signal beyond the time set by relay to speed up, inverter terminal X1 will send out a signal to add a frequency based on main frequency to accelerate motor.

    Conversely, if the sensor fails to test a signal, which indicates that the plate becomes narrow and the tractor needs to slow down, the inverter will change its main frequency from the second stage to the first stage (if the system run at the first stage speed, the main frequency will keep the same). Accordingly, if the sensor fails to test a signal within the time set by relay to slow down, inverter terminal X1 will send out a signal to make the inverter slow down until the sensor tests a signal.

    The consistency of the width of plates will be achieved through the change of the speed of tractor under the real-time monitoring of plates by sensor. Major parameters of special type Sufar inverters are as follows: 

 

F0.1=8        set of selection of the combination of input modes of frequency      

F0.4=0001    selection of outer control terminal through operation channel    

F0.10=6       time to speed up

F0.11=6      time to slow down

F2.12=31     VC2+UP/DW   select VC2+UP/DW to give set frequency

F2.18=0001    UP/DW    no memory while power down UP/DW

F3.0=13       increase progressively

F3.1=14       reduce progressively

F4.23=0.3      UP/DW modify frequency through terminal UP/DW

 

Debugging instruction:

    Though with the optimum parameters set in factory, the inverters need debugging due to different working conditions. At the early stage of debugging, infared switch and switch UP/DW shall be off for the first operation. According to empirical value the first stage speed shall be set as 24HZ and the second stage speed as 26HZ. Time relay to control terminal UP/DW is 2 seconds. Whether to turn on alarming relay depends on real conditions.  

    If there is no feedback from the system and there is no big deviation from the speed of tractor line based on the speed of the main motor, the main frequencies for the first stage and the second stage shall be determined. Then the infrared control shall be turned on to adjust speed. At the same time, the speed of UP/DW shall be set. The speed of these terminals shall be from 0.3 to 0.5 for the quality of the plates will be impacted if the value is too high, which will cause severe shake, or too low, which will lead to delayed response.

 

Conclusion:

    After debugging, the system will meet the client’s requirements perfectly and increase production efficiency and quality greatly as well. The successful application of Sufar products on infrared testing of plastic machine gives another proof that Sufar has a quick response to market and a powerful group to research and develop.