With the rapid development of the stone industry, the requirements for deep processing of stone continue to increase, and stone machinery has also followed the steps of the times and gradually became intelligent. It has made significant contributions to the development of the stone industry.
At present, most of the domestic stone cutting machines use the traditional relay-contactor control method. The control method is relatively backward, the cutting accuracy is poor, and on-site control is required during cutting. A large amount of dust on the cutting site is harmful to the operator's physical health. Poses great harm. This article designs a set of online automatic stone cutting and cutting system. This system can automatically cut and count large stones . The system has the characteristics of simple operation, convenient maintenance, low cost and friendly man-machine interface. Very suitable for the needs of most small and medium township enterprises .
1 system working principle
This design is to initialize the PLC by inputting the required cutting parameters of the stone into the human interface (HMI), and use a rotary encoder to replace the traditional travel switch or limit switch to locate the cutting length. The rotation frequency of the motor in each direction is measured by the rotary encoder and converted into high-speed counting pulses and sent to the PLC for counting operations to obtain the precise displacement of the saw or trolley. Compare it with the set initial value. When the value is set, the PLC resets the corresponding direction motor coil to stop it. The system control principle is shown in Figure 1. This control system adopts Delta DVPES2 series as the controller, and is equipped with Delta encoder and Delta DOP-B series touch-screen human-machine interface. The system control part has a simple and flexible structure and low system cost.
Fig.1 Control principle of stone cutting machine PLC control system
Figure 2 is a schematic diagram of the PLC control system of the modified gantry bridge cutting machine
Gantry bridge type stone cutting machine is mainly composed of main body guide rail, support system, spindle system, rotary table system, vertical lifting system, lateral movement system, motor position detection system, cutter head motor current alarm protection system, cooling system, brake and electric Control system and other components.
1.Body guide and support system
The main rail and support system are composed of columns, beams and slides. The pillar is a reinforced cement concrete pillar as the supporting structure, which ensures the smooth operation in the whole machine. A slide rail is installed on the column. The slide moves up and down along the rail through a gear drive. The stroke can reach 1600mm. It can cut large stone blanks. It can cut continuously with one feeding, which greatly saves loading and unloading time, improves production efficiency, Significantly reduced labor intensity.
2. Spindle system
The spindle system device is composed of a cutter head motor box, a cutter head flange, etc., and is fixed on the inner frame with bolts. The structure is compact, the transmission is stable, the noise is low, and the cutting speed and efficiency are high.
3. Rotary table system
The trolley working table is used to send the stone blank to be cut to the appropriate initial cutting position. The rotary table is used for the working table. When the vertical reference plane of the stone is inconsistent with the walking direction of the cutter blade, the rotary table can be adjusted to reach the optimal cutting position. The trolley has two functions of moving automatic and manual jogging, and the segmentation is accurate and uniform.
4.Vertical lifting system
The vertical lifting system is mainly composed of a Z-axis lifting motor, a slide guide and a transmission gear, etc., which is used to realize the vertical lifting movement of the cutting saw blade.
5. Lateral movement system
The lateral movement system is mainly composed of the X-axis cutting motor, transmission gear, beam guide and inner frame. The inner frame is moved by the cutter motor on the beam guide through the gear to move left and right to realize the feed motion of the cutting blade.
6. Motor position detection system
The motor position detection system is to detect the drive displacement of the motor in all directions. Accurate motor drive displacement detection is an important prerequisite to ensure the cutting accuracy of stone fragments.
7. Knife disc motor current alarm protection system
The system uses a current meter with a switching value to monitor the current of the cutter head motor. Once the load current exceeds the alarm current setting value, the current meter will output a switching signal to the PLC controller, and the PLC will send a control signal Stop the cutter head motor to protect the motor.
8. Cooling system
The cooling system of the stone cutting machine is mainly composed of a cooling water pump, a solenoid valve and a pressure switch. The knife saw of the stone cutting machine will increase the temperature of the saw blade due to long-term friction with the stone. In order to prevent the saw blade from being damaged by high temperature, the cooling water pump provides stone cutting. Machine-specific coolant for cooling protection.
9. Electric control system
The control cabinet is used for centralized operation control, which can realize manual and automatic control. The initial cutting position of the stone blank can be adjusted by jogging through the feed adjustment handpiece. The stone piece control can be accurately positioned by the encoder and controlled by the PLC to automatically cut and cut. The cutting parameters can be set through the system's human interface input.
3 system software design
The stone cutting machine PLC controls the stone automatic segmentation cutting program, which includes initialization, measurement, evaluation, advance, retract and other parts. The initialization part is mainly to set the length, width, and thickness of the stone cutting and the number of pieces according to the actual situation. The measurement part is mainly input through the encoder high-speed counting pulses and converted by PLC into the forward displacement of the saw and the trolley. The main part is to compare whether the command reaches the set cutting size through the PLC comparison instruction and the parameters set in the initialization. The feeding part is the sequential control of the motors in all directions through the PLC program. The retracting part is the reverse process of the feeding control. Figure 3 shows Flow chart of stone cutting process control program.
Figure 3 Flow chart of control program of stone cutting process
4 human-machine interface screen design
The human interface of this system is designed with a total of four interfaces, which are the system main menu screen, parameter setting screen, operation monitoring screen, and manual operation screen.
The system main menu operation interface is shown in Figure 4. You can enter different system interfaces through the main menu options.
The system parameter setting interface is shown in Figure 5. Through this screen, you can set the cutting size and the number of pieces for automatic stone slicing.
The system monitoring screen is shown in Figure 6. The main function of this screen is to monitor whether the load current of the cutter head is overloaded, whether the cooling water pump is supplying water normally, and whether the power supply of the system is normal. The normality of these states is to ensure the normal operation of the entire cutting process; When something is abnormal, an audible and visual alarm device will be triggered to prompt the staff to diagnose the fault.
The system manual operation mode is shown in Figure 7. The function of this screen is to manually control the cutting operation of the stone cutter by the function keys in the screen.
In this design, the inputs of the PLC are all digital inputs. The analog input is converted into digital input by the ammeter and water pressure switch of the digital output, which avoids the A / D conversion and saves the system cost. The control system of the stone cutting machine designed in this paper is low in cost and suitable for the actual production of small and medium-sized enterprises.