Control system design for inducing fully electrical vertical injection molding machine（b）

Date：2014/11/3 16:19:32

3.2 PLC

As the system input, output signal, including the operation instruction signal,safety threshold control panel gives the switching signal, barrel temperature, MC value, MC signal of the action moves to complete thefeedback signal, action, control is complex, coordinated action sequenceand the realization of POD data access, use a Fuji type SPBNW0P60R-31programmable controller, expansion modules for the NW0E32R-3, at the same time in order to increase the sampling data of thermocouple temperature, a temperature control module. Between the main module and the expansion module is connected by bus to transmit data.

The PLC program developed by Fuji motor provides software,communication protocol is EthernetUDP/IP. The procedure of PLC includes:acquiring and processing of I/O signal; fault and abnormal condition judgement; control the timing of judgment; output action instruction;thermocouple data sampling.

3.3 MC

MC uses the TECHE-HOLON four axis special controller, using HITACHISH27045F chip. The component comprises a substrate TH-A0020A, ENCODE processing board TA0021, TH-A0003A digital card (4 pieces), A/D-D/A conversion board. MC built-in Ethernet communication card, with communication function.

The ENCODE board is mainly used to treat the encoder signal, in this system, the injection mold opening motor, motor, top motor adopts the incremental encoder counting. The motor rotates each 1 weeks, the encoder output 2500 pulse, chip PCL6045 through the processing of theencoder signal injection, the mold opening and get out of the top positioninformation.

4 digital card for the amount of I/O reading system. The digital input is mainly the operation instruction signal from the PLC signal, according to thisMC performs the following actions to go. The digital output correspondinginjection, mold opening, ejection frequency converter, the output fourth digital board is given by the MC action completion signals, as the inputcommand signal PLC. Digital board is connected through the ARCNET and MC.

MC uses the current in the field of industrial control application is theL_iTRON real-time operating system widely, which store of the C language program is the core of the whole control system. Development of control program is used HitachiEmbeddedWorkshop development tools and development environment, programming, debugging, compile and link in which completed a compiled program through Ethernet communication is downloaded to the MC chip.

The 3.4 converter selection

This system use 4 converters respectively on the injection mold openingmotor, motor, plasticizing motor and ejector motor control, including control of injection, the mold opening, out of the top 3 inverter motor for Fuji FRENIC5000VG7 vector frequency converter, motor and plasticizing action is simple, no need of vector control function, the choice is the Fuji FRENIC5000G11 frequency converter. The converter has parameters self-tuning function, when using the collocation with general motors, first auto tuning, can achieve better control requirements.

4 operation and main technical performance index

The inducing fully electrical vertical injection molding machine has beensuccessfully developed for nearly a year, is further perfected. The operation process for:

(1) according to the production requirements, set the mold opening speed,pressure on the POD value and the barrel temperature values of partition.

(2) in the control panel select Manual "and" semi-automatic "and" automatic "this 3 operation modes in a, or other functions (such as locking origin selfseeking, manual thimble).

(3) PLC in accordance with the instructions of the received signal and the actual feedback value, determines the next step of MC action.

(4) the MC according to the PLC command signal and the velocity, pressureand other parameters through action, control processing algorithm after certain give control signal to the transducer.

(5) the frequency converter to drive the motor to rotate, the motor is connected with a ball screw through the synchronous belt, the circularmotion into linear motion, so as to realize the control of speed, pressure or position.

Nearly a year of testing show that the inducing fully electrical vertical injection molding machine in the control performance, production efficiency,reliability, energy saving effect and clean environment have a excellent performance. Compared with the oil pressure type vertical injection molding machine of considerable size, no matter what kind of injection moldingproducts production, energy-saving rate in more than 30%; it does not usethe hydraulic oil, so there is no problem of oil pollution, easy to keep the workplace clean and products, and greatly reduce the cost of cooling water;low noise operation process; the operation is convenient and there aremany kinds of protection function; frequency converter speed controlprecision stability, reduce the mold opening shock, avoid equipment impact,which makes a whole life extension; short response time, greatly improve the production efficiency, reduce product cost.

5 Conclusion

The successful development of the induced performance type full electricvertical injection molding machine is not inferior to the domestic manufacturers to develop the AC permanent magnetic synchronous electricvertical injection molding machine, but the cost is reduced by about 50%.

At present, due to special induction motor, vector control inverter and ball screw, the price is more expensive, and the scale of production constraints,3~4 times so that the manufacturing cost of the whole electric vertical injection molding machine for the domestic equivalent size hydraulic vertical injection molding machine, but its performance is much better than thelatter, and with the progress of technology, the related electrical components will cost reduced, after finished industrial production will also cause inducing fully electrical vertical injection molding machine price is higher, the investment of the users can get more effective return.

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