Application of 6000 Series Frequency Converter in Cold Heading Machine

I. Overview

The cold heading machine is a product that rolls a billet into a certain shape at room temperature. With the continuous development and progress of production technology, fully automatic cold heading machines have been widely used in the manufacture of automobiles and mechanical parts. The equipment fully automates the batch production of standard parts such as nuts, nuts, and other double-click molds. It feeds from the rollers, cuts them in turn, punches and punches, and is completed in one machine, eliminating time-consuming and expensive annealing procedures. The work station is arranged horizontally, the main drive is a secondary drive, the main slide is driven by a pressure-lever-bar structure, and the flywheel and the drive shaft are connected by a pneumatic friction clutch.

One of the company's six plant cooling piers was imported from the former Soviet Union in the 1950s. It is a special production equipment for aircraft rivets. In the early 1970s, the electric control system was transformed into a SCR DC speed control system. It has been in service for more than 30 years. The motor commutator has been seriously worn out, and the control box components have become severely aged. Therefore, the machining accuracy requirements cannot be guaranteed. After analysis, it was decided to use the frequency conversion speed regulation intelligent control system to transform.

Second, the working principle

The method of forging the top of a bar or wire at room temperature. Cold headings are mainly used to make bolts, nuts, nails, rivets, and steel balls. Forging blank material can be copper, aluminum, carbon steel, alloy steel, stainless steel and titanium alloy, material utilization rate of up to 80 ~ 90%. The cold heading is carried out on a dedicated cold heading machine, which facilitates continuous, multi-station, and automated production. In the cold heading machine, the processes of cutting, honing, accumulating, forming, chamfering, twisting, shrinking and trimming can be performed sequentially. High production efficiency, up to 300 pcs/min, and maximum cold-worked workpiece diameter of 48 mm. The bar stock is automatically fed into a certain length by a feeding mechanism, and the cutting mechanism cuts it into billets, which are then sent by the clamp transfer mechanism to the accumulation press forming and punching station for forming.

Third, the system configuration

Frequency conversion speed control system schematic

The speed regulation potentiometer (R) is connected to the external given adjustment input point (10V, AI1, AGND) of the inverter, and the output frequency of the inverter is adjusted to change within the range of 0-50Hz so as to realize the stepless speed regulation of the variable frequency motor. Connect the digital display on the panel of the control cabinet to the output frequency point (DO, COM) of the inverter, and dynamically display the speed of the motor on the digital display; connect the alarm lamp to the relay output point of the inverter (TA, TC). ), Alarm when the inverter works abnormally.

Intelligent Instrument Control System Schematic

Set the total number of machined parts on the counter panel; access the NPN proximity switch (SQ) at the counter's signal input points (9, 12, 14). The cold-piercing machine completes one part per machining and the proximity switch sends a signal to the counter and displays it on the display. When the counter displays the number of parts processing, it decrements the preset total number of operations. When the preset number is reduced to 0, the auxiliary output normally closed contacts (3, 4) are disconnected, causing the intermediate relay KA1 to lose power. The equipment stops running. In order to prevent the data set by the counter from being changed by others during the automatic machining process, a key switch (SA1) is connected to the counter key protection input points (14, 15). After the operator sets the relevant parameters, the SA1 can be turned by turning the counter. All key lock protection on the operation panel.

When the machined workpiece reaches the preset value, the device automatically stops working and waits for a new task. When there is a need to shut down the material or shut down due to a fault in the middle of the machining process, the number of parts processing can be maintained for a maximum of 10 years, and counting can be continued when restarting. The counter can be reset through the operation panel and the back button, which is easy to operate and easy to maintain.

Fourth, system advantages

1. Due to the use of variable frequency speed regulation, the speed can be infinitely adjusted according to the processing requirements of the workpiece.

2. After the frequency conversion control is used, the machine is smooth and shock-free when starting and stopping, prolonging the service life of the machine.

3. In the case of motor overload or other abnormal conditions, the frequency conversion protection function operates to ensure the safety of the equipment.

4 can be used in conjunction with the PLC to achieve a fully automated process.

The frequency converter selects 6000 series, this series frequency changer has the following characteristics:

l Use motor dedicated high-speed 32-bit CPU

l Low frequency characteristics, torque can be automatically increased

l Current adjustment in real time, good dynamic response

l The digital input/output interface is rich in functions and can define interface functions as needed

l With 2 analog inputs, 2 analog outputs, 1 frequency signal output

l Special grounding design, good electromagnetic compatibility

l Abundant real-time monitoring of operating parameters to keep abreast of machine operating conditions

l Complete fault protection and power-down storage

The intelligent reversible preset number counter is used in conjunction with the proximity switch to realize the number of parts processing. The counter has the following characteristics: the use of Switching Power Supply, voltage adaptation range, strong anti-interference ability; direct display of the actual value, and can be set to display the effective number of decimal places; keyboard settings, LCD with backlight display, simple operation; 5 kinds Counting input mode, 4 kinds of output modes, automatic reset time 0.01 ~ 9.99s adjustable; use the keyboard lock function, according to the requirements of locking the keys do not need to prevent misuse.