Ⅰ. Introduction to CNC machine tools

Computer numerical control machine tools is an automated machine tool equipped with a program control system. The control system can logically process a program with a control code or other symbolic instructions, decode it, express it with coded numbers, and input it into the numerical control device through an information carrier. After arithmetic processing, the numerical control device sends out various control signals to control the action of the machine tool, and automatically process the parts according to the shape and size required by the drawing. CNC machine tools have solved the problems of complex, precise, small batch, and multi-variety parts processing. It is a flexible, high-performance automatic machine tool, which represents the development direction of modern machine tool control technology.It is a typical mechatronics product.

1. Features of CNC machine tools

(1) High processing accuracy. CNC machine tools are processed according to instructions given in digital form. At present, the pulse equivalent of CNC machine tools generally reaches 0.001, and the backlash of the feed transmission chain and the lead screw pitch error can be compensated by the CNC device. Therefore, the CNC machine tool can achieve high machining accuracy. For medium and small CNC machine tools, the positioning accuracy is generally up to 0.03, and the repeat positioning accuracy is 0.01.

(2) Strong adaptability to processing objects. When changing the machining parts on the CNC machine tool, you only need to reprogram the program and input the new program to realize the processing of the new parts. This provides great advantages for single-piece, small-batch production and trial-manufacture of new products with complex structures. convenient. For those precision and complex parts that are difficult or impossible to be processed by ordinary manual machine tools, CNC machine tools can also realize automatic processing.

(3) High degree of automation and low labor intensity. The machining of parts by the CNC machine tool is automatically completed according to the pre-programmed program. The operator does not need to perform complex repetitions except for placing punched tape or operating keyboard, loading and unloading workpieces, intermediate inspection of key processes and observing the operation of the machine tool. Manual operation can greatly reduce labor intensity and tension. In addition, CNC machine tools generally have better safety protection, automatic chip removal, automatic cooling and automatic lubrication devices, and the operator's working conditions are also greatly improved.

(4) High production efficiency. The time required for parts processing mainly includes two parts: maneuvering time and auxiliary time. The spindle speed and feed of CNC machine tools have a larger variation range than ordinary machine tools. Therefore, each process of CNC machine tools can choose a favorable cutting amount. Due to the good structural rigidity of the CNC machine tool, it allows powerful cutting with a large amount of cutting, which improves the cutting efficiency and saves maneuvering time. Because the moving parts of the CNC machine tool have a fast idle stroke movement speed, the clamping time and auxiliary time of the workpiece are less than that of the general machine tool.

When the CNC machine tool replaces the processed parts, it is almost unnecessary to re-adjust the machine tool. Therefore, the installation and adjustment time of parts is saved. The processing quality of CNC machine tools is stable, and generally only the first part inspection and sampling inspection of key dimensions between procedures are performed, so the downtime inspection time is saved. When processing in the machining center, a machine tool realizes the continuous processing of multiple procedures, and the improvement of production efficiency is more obvious.

(5) Good economic benefits. Although CNC machine tools are expensive and the depreciation of equipment allocated to each part during processing is high, but in the case of single-piece and small batch production: ① Using CNC machine tools for processing can save time for marking and reduce adjustment, processing and inspection time , Saving direct production costs; ②Using CNC machine tools to process parts generally does not require special fixtures, which saves process equipment costs; ③The CNC machining accuracy is stable, reducing the scrap rate, and further reducing the production cost; ④CNC machine tools can realize one machine Multi-purpose, saving plant area and saving investment in plant construction. Therefore, the use of CNC machine tools can still obtain good economic benefits.

2. Application of CNC machine tools CNC machine tools have many advantages that ordinary machine tools do not have. Its application range is expanding, but it cannot completely replace ordinary machine tools, nor can it solve all the problems in machining in an economical way. CNC machine tools are suitable for processing parts with the following characteristics:

(1) Multi-variety, small-batch production parts.

(2) Parts with more complicated shapes and structures.

(3) Parts that need frequent modification.

(4) Key parts that are expensive and are not allowed to be scrapped.

(5) Design and manufacture urgently needed parts with short manufacturing cycle.

(6) Parts with larger batches and higher precision requirements.

Ⅱ. CNC machine tool transformation plan

1. Equipment overview

The main parameters of the energy-saving transformation machine tools of Zhongshan Liqiong CNC Processing Plant are as follows:

(1) Machine tool brand: Yirun. Keitel Model: YRX-46A Machine tool spindle power: 7.5KW

(2) Running cycle 5 seconds, braking time 1 second, braking current 12A

(3) Power supply: 380V 50HZ

2. Treatment of regenerative electric energy

When the CNC machine tool completes an action or a work cycle ends, the motor of the machine tool will be in the state of regenerative power generation. The six diodes in the inverter convert the mechanical energy of the transmission mechanism into electrical energy and feed it back to the intermediate DC loop, and cause the voltage across the energy storage capacitor to rise. If necessary measures are not taken, the inverter will trip over voltage when the DC link capacitor voltage rises to the protection limit value. In high-performance engineering inverters, there are two solutions for processing continuous regenerative electric energy: ① Set a resistor in the intermediate DC circuit, and let the continuous regenerative electric energy be consumed in the form of heat through the resistor. This method is called Energy consumption braking; ② The regenerative rectifier method is adopted to send continuous regenerative electric energy back to the grid. This method is called regenerative braking.

(1) Energy-consumption braking Energy-consumption braking is composed of a braking unit and a braking resistor.

(2) Regenerative braking In order to realize the feedback of the regenerative power of the motor in the braking state to the grid, the grid-side converter should adopt an invertible converter. The IPC-PGC sine wave energy-saving feedback device launched by CANON has the same grid-side converter and inverter structure and adopts a grid voltage identification board with PWM control mode. Due to the use of PWM control technology, the magnitude and phase of the AC voltage on the grid side can be controlled, and the AC input current can be in phase with the grid voltage and close to a sine wave. The power factor of the transmission system is greater than 0.96, and the feedback braking is 100%. Power grid feedback capability without autotransformer.

The IPC-PGC sine wave energy-saving feedback device can feed the regenerative electric energy generated in the process of motor speed adjustment to the grid, avoiding the energy loss caused by the resistance heating of the conventional energy-consuming braking unit, so as to achieve the ideal energy-saving effect , To achieve efficient operation.

3. Selection and configuration

1. According to the working conditions and parameters of the site, combined with the experience of our company's engineering transformation, the recommended selection is as follows:

4. Control principle

5. Use case Economic benefit calculation of CNC machine tools for a hardware processing factory in Zhongshan City:

The power consumption of a CNC machine tool is directly determined by the motor power of the machine tool and the continuous running time of the machine tool, and the continuous running time of the CNC machine tool is determined by the operating conditions of the machine tool, namely the start and stop frequency, acceleration time, processing time, and stop time. Therefore, we calculate the power consumption according to the power, running time and operating condition coefficient of the CNC machine tool.

Power consumption calculation

Benefit calculation

The site of the energy-saving renovation of CNC machine tools, the installation of electric meters to actually measure the energy-saving

Ⅲ. Product introduction of IPC-PGC sine wave energy-saving feedback device

The IPC-PGC sine wave energy-saving feedback device is a low-noise energy-saving product manufactured using Canadian technology. It uses advanced algorithms to achieve complete sine wave energy feedback. It can feed back the regenerative electric energy generated in the process of motor speed regulation to the grid, avoiding the energy loss caused by the use of conventional energy-consuming braking units, thereby achieving energy-saving effects. PGC sine wave energy-saving feedback device products have installed reactors and noise filters inside, which can be directly connected to the power grid without causing interference to the power grid and surrounding electrical equipment.

It has been widely used in CNC machine tools, servo control systems and other occasions.

The principle diagram of the main circuit is shown in Figure 4-1:

Figure 3-1

When the spindle of the CNC machine tool or servo control system brakes rapidly, the motor will be in a state of regenerative power generation. The six diodes in the inverter convert the mechanical energy of the transmission mechanism into electrical energy and feed it back to the intermediate DC loop, and cause the voltage across the energy storage capacitor to rise. In order to realize the feedback of the regenerative electric energy of the motor in the braking state to the grid, the grid-side converter should adopt a reversible converter. The IPC-PGC electric energy feedback device launched by CANON uses a grid voltage identification board with PWM control mode. Due to the use of PWM control technology, the magnitude and phase of the AC voltage on the grid side can be controlled, and the AC input current can be in phase with the grid voltage and close to a sine wave. The power factor of the transmission system is greater than 0.96, and the feedback braking is 100%. Power grid feedback capability without autotransformer.

The IPC-PGC electric energy feedback device can feed back the regenerative electric energy generated in the process of motor speed adjustment to the grid, avoiding the energy loss caused by the resistance heating of the conventional energy-consuming braking unit, so as to achieve the ideal energy-saving effect. Run efficiently.

When the motor is working in the power generation state, the electric energy generated by the motor flows back to the DC bus through the diode on the inverter side. When the DC bus voltage exceeds a certain value, the IPC-PGC electric energy feedback device will start to invert the DC into AC. The voltage phase and amplitude of the electric energy feedback device feeds the electric energy back to the grid to achieve the purpose of energy saving.

At this time, the energy flows to the grid through the inverter part and the feedback part. The inverter works in the second and fourth quadrants. The main function of the output reactor is current filtering. The waveforms of feedback current and grid voltage are shown in Figure 4-2.

Figure 3-2

The main technical characteristics of IPC-PGC sine wave energy-saving feedback device:

Technical index:

Maximum mechanical energy recovery power: 12KW

Conversion efficiency of mechanical energy to electrical energy: 70%-95%

Power quality: pure sine wave, THD <5% @ 100% load

Response time: 10ms (0.01 seconds)

Adapted motor: spindle motor system, servo motor system

Maximum downtime: 0.3 seconds

Normal downtime: 1-4 seconds

Adaptation voltage: 360V-460V, 50/60HZ, three-phase

Safety and electromagnetic compatibility standards: EN50178-1997 EN12015-2004 EN12016-2004 EN61000

Ⅳ. Advantages of using IPC-PGC sine wave energy-saving feedback device

4. Built-in reactor and filter, plug and play

PGC adopts integrated structure design, built-in reactor and filter, users do not need to purchase separately

5. Completely replace resistance braking

PGC can completely replace resistance braking, turn energy-consuming parts into seizure parts, and can save more than 60% of the installation space.

6. Simple operation, reducing installation and training costs

Before each PGC product leaves the factory, the technical parameter settings that meet more than 90% of the needs have been set up, and can be plug and play. At the same time, in order to meet the needs of complex working conditions, users only need to simply adjust the action threshold, namely Can ensure 100% use. Therefore, even if you are not a technical expert, you can quickly get started with PGC.

7. Use the frequency of the global power grid, and the application has no geographical restrictions

PGC product THD meets the world's filtering standards; EMC/EMI meets the harsh EN55022 Class A standard; it can work stably under the grid frequency of 45Hz-65Hz. Therefore, the application of PGC products is completely free from geographical restrictions

Ⅴ. Quality Assurance and Service Commitment

1. Quality Assurance

The company's products have an 18-month free warranty period (except for products exported to foreign countries/non-standard machines) starting from the date the user purchases them from the manufacturer, and enjoy paid lifetime services. However, if the failure is caused by the following reasons, it will be repaired for a fee even within the warranty period:

1. Due to incorrect use, self-modification and improper maintenance, etc.:

2. Use beyond the technical standards and specifications:

3. Earthquakes, fires, lightning strikes, abnormal voltages, other natural disasters and other reasons (for details not covered, please refer to the warranty clauses of "IPC-PGC Energy-saving Feedback Device")

2. Service commitment

1. During the warranty period, if the failure is not due to improper operation and force majeure, we will be responsible for free maintenance;

2. Commitment of after-sales service: respond within 2 hours of service, and arrive on-site service within 24 hours;

3. For repairs beyond the warranty period, the user will be charged for the device after the repair.