Injection molding machine frequency conversion transformation plan

I. Introduction

As we all know, energy-saving emission reduction and low-carbon life are an inevitable trend of modern society. The energy crisis will continue for a long time in the future, so this inevitable trend will gradually become a living habit and even become a national policy.

In the 13th Five-Year Meeting, the goals and requirements have been clarified for energy conservation and emission reduction. In key areas, especially in industry, energy conservation must be strengthened. Enterprises above designated size are required to reduce energy consumption by more than 10% annually. The government will also support it. Key industries will be upgraded and upgraded to build a green manufacturing system.

In 2017, especially in the past summer, there were power shortages in various places in the country during the peak period of power consumption. The government districts cut power limits, and called for corporate business desks and office buildings, as well as citizens to save electricity and use household high-power appliances. Try to avoid the peak of electricity consumption, use high-energy-consuming appliances as much as possible, open one less light, and use less electrical appliances. The air conditioning temperature of institutions, institutions, commercial, entertainment, and public places is not less than 26 degrees Celsius.

According to statistics, in the first eight months of this year, China's industrial electricity consumption increased by 6.1% compared with the same period of last year. If you do not pay attention to energy conservation and emission reduction, the electricity consumption situation will only become more and more severe.

In response to these circumstances, local governments are also actively working hard, especially in cities with relatively fast economic development. The government encourages energy conservation and emission reduction from policy and taxation, and promotes green, low-carbon and circular development of the manufacturing industry.

The trend of the big environment is obvious, and as the business owner, with the rising cost of raw materials in the past few years, the business is getting harder and harder, the profit margin of the enterprise is compressed, and the energy consumption, which accounts for an increasing proportion of corporate expenditure, also begins. The boss is valued, especially the bosses of many small and medium-sized manufacturing companies, and the electricity bills can't be exchanged quickly. Many of China's early mechanical and electrical equipment did not consider energy conservation and emission reduction, or for the sake of short-term benefits, did not choose expensive energy-saving equipment, so that there are many no-load operations in the production process, and a lot of energy is wasted, and this part Waste As industry profits fall, business owners have to find ways to reduce costs by considering long-term energy savings. The following is an example of an injection molding machine, which mainly introduces the working principle of an injection molding machine and an energy-saving retrofit solution.

Second, injection molding machine, hydraulic machine power saving work introduction

The hydraulic system of the injection molding machine is a system with large fluctuations in pressure and flow. The pressure and flow rate must change regularly during different working stages such as mold opening, mold clamping, injection molding, material returning and ejection. Most of the time, the actual fuel consumption of the load is less than the oil supply of the oil pump, causing the hydraulic oil in the high pressure state to overflow through the hydraulic components such as the relief valve and the proportional valve. The overflow portion not only does not have any useful work, but also generates heat, which causes the hydraulic oil to generate heat, which is both energy consuming and harmful. According to the current working state of the injection molding machine, such as mold opening, mold clamping, injection molding, material returning, ejection, etc., as well as high pressure and speed requirements, the speed of the oil pump is automatically adjusted to adjust the oil supply of the oil pump so that the oil pump is actually supplied. The oil quantity and the actual load flow rate of the injection molding machine are consistent at any working stage, so that the overflow part of the hydraulic oil is lost, the overflow phenomenon is completely eliminated, the oil pump output is reduced, and the power consumption of the oil pump motor is saved. The frequency conversion energy-saving controller uses the principle of controlling the oil supply motor at different stages to provide the corresponding rotation speed, so that the quantitative pump becomes an energy-saving variable, so as to achieve the purpose of energy saving of the injection molding machine.

Third, the energy consumption analysis of injection molding machine

a. Where is there a serious waste in the injection molding machine?

99% of injection molding machines use hydraulic transmission and electro-hydraulic proportional control technology. The hydraulic system process of installing quantitative pumps is generally divided into clamping, injection, melting, holding, cooling, mold opening, thimble, standby (semi-automatic), etc. In each stage, the pressure and flow required for each stage are different. For the oil pump motor, the injection process is in a changing load state. In the hydraulic system of the dosing pump, the rotational speed provides a constant flow rate, and excess hydraulic oil is returned through the overflow valve. This process is called high pressure throttling. According to statistics, the electrical energy loss is as high as 35%-70%.

b. What is the proportion of the power consumption of the injection pump oil pump motor in the whole process of production?

According to the requirements of the injection molding machine equipment process, the power consumption of the injection pump oil pump motor accounts for more than two-thirds of the total power consumption of the equipment. Great energy saving potential.

c. What is the status of the international injection molding machine?

With the increasingly stringent requirements of environmental protection, such as energy consumption, noise, and leakage, the energy-saving systems for injection molding machines have become the focus of research. In view of the large energy loss of the valve-controlled electro-hydraulic control system, Germany, Japan and other countries have begun to study the load-sensing injection molding electro-hydraulic control system combined with the electro-hydraulic proportional valve. To further reduce energy consumption and reduce costs. The motor is driven by a hydraulic pump with an adjustable speed motor. Energy saving and noise reduction are achieved under the conditions of constant pressure, cooling and idle running conditions.

Fourth, injection molding machine, hydraulic machine power saving transformation principle

1. Power saving transformation scheme using proportional valve control:

The flow rate Q of the injection pump is proportional to the pump speed n. As long as the speed of the pump motor is changed, the pump speed can be changed, thus changing the pump's oil absorption. An economizer is added in front of the oil pump motor, and the speed signal of the economizer is taken from the driving signal of the proportional flow valve (0-1A), so that the output speed of the economizer is synchronized with the flow rate of the injection valve proportional flow valve. For example, the actuator requires 50% flow, and the economizer drives the motor (Ne=1500) to provide 750 rpm synchronous speed. Then the motor drives the oil pump to extract 50% of the flow from the cylinder. The part of the flow that does not extract the overflow will not cause unnecessary waste. During the special cooling and discharging process, the oil pump does not draw the flow from the cylinder at all, and the motor can be completely stopped without consuming electricity. It is in complete agreement with the whole process of the injection molding machine, and achieves high efficiency and energy saving without affecting production efficiency.

2. Injection molding machine energy-saving inverter features

The special energy-saving frequency converter suitable for energy-saving and automatic transformation of injection molding machine adopts excellent control strategy to make it have fast dynamic response. Advanced current limiting technology and hardware optimization design make the product have super overload capability and can guarantee When the load fluctuates frequently, the energy-saving inverter does not trip. And has the following characteristics:

a. High reliability

Perfect reliability design: such as redundant design, derating design, etc. All components are in industrial or military grade, all key components are imported components, and all key circuits are highly integrated thick film IC, thus ensuring the whole machine. Reliability

b. High power saving rate

The original control mode of the injection molding machine is kept unchanged, and the advanced microcomputer control technology is adopted to make the quantitative pump become an energy-saving variable pump. The hydraulic system of the injection molding machine is matched with the power required for the operation of the whole machine, and there is no high-pressure throttling overflow energy. Loss, improve the power factor of the pump motor to 0.96 or above, the power saving rate is generally 25% to 65%, and all investment can be recovered within 6~8 months.

c. Soft start energy saving

Since the motor is directly started or Y/Δ started, the starting current is equal to (3-7) times the rated current, which will cause serious damage to the electromechanical equipment and the power supply grid, and the grid capacity requirements are too high, and the startup is large. Current and vibration are extremely detrimental to the service life of the equipment. After using the variable frequency energy-saving retrofit, the soft start function of the inverter will start the starting current from zero, and the maximum value will not exceed the rated current, which will reduce the impact on the power grid and the requirement of power supply to prolong the service life of the equipment and the mold.

5. Application range of special power saver for injection molding machine and hydraulic press

There are quantitative pumps with proportional valve control oil system... one horizontal injection molding machine, vertical injection molding machine, die casting machine, blow molding machine, including single pump, multi pump system, single motor and double motor injection molding machine, power saving effect Up to 20%-65%;

All variable pumps that use proportional valves to control the oil circuit system... as for injection molding machines, die casting machines, and hydraulic presses, the power saving effect can reach 15-40%;

All the quantitative pumps that use the directional valve to control the oil circuit system, such as horizontal injection molding machine, vertical injection molding machine, hydraulic press, large hydraulic press, can save 20-65%.

Sixth, injection molding machine special power saver selection and transformation plan

At present, our company has the following three ideas for the energy-saving transformation of injection molding machines:

First, the motor part of the injection molding machine is changed to servo, and this is divided into several small categories, which is also the focus of this article;

The second is to adopt a new heating method for the heating barrel of the injection molding machine;

The third is to recycle excess heat from the heating part of the injection molding machine to the baking material.

Injection molding machine. Analysis of investment benefits before and after installation of hydraulic press:

Investment benefit analysis of a vertical injection molding machine with a 25-ton 5.5KW oil pump motor:

1, 25 tons of vertical injection molding machine: power is 5.5Kw: a = 5.5Kw

2, daily power consumption (b): calculated according to the load rate of 60%

b=a*b*24

=5.5KW*0.6*24

= 79 degrees

3. The electricity fee is 0.7 yuan/kWh, and the daily electricity saving fee (c) is:

C=b*0.7=79*0.7=55 yuan

4. Power saving analysis after transformation

Calculated at the lowest power saving rate of 35%

Monthly electricity savings (D) is: D = C * 0.35 * 30 = 55 * 0.35 * 30 = 578 yuan

Annual electricity saving (G) is: G=D*12=578*12=6930

Return on Investment Analysis (E):

1 A 5 5KW oil pump motor vertical injection molding machine, equipped with a set of Ken WK9600-3T-00550Z power saver, after the transformation, the company can save 578 yuan per month, saving $ 6930 per year

Power Saver used for more than 8 years, will bring to the enterprise (6930 * 8 = 55440 yuan return on investment

2 investment 20 vertical injection molding machines

It will be recycled every year: 6930*20=138600 yuan:

8 years will be produced: 8*138010=1,108,800 yuan

in conclusion

1. Conclusion of intuitive power saving effect

After the energy-saving transformation of the injection molding machine, the investment cost can be recovered in just 6 months according to the lowest power saving effect, and the equipment can be used for at least ten years. “Power saving is the fastest investment in the recovery period. The longest investment." Users can reduce actual electricity bills, save money, reduce operating costs, and promote business development.

2. Implied economic benefits

According to the power-saving principle of the power saver, in addition to the intuitive power-saving effect, the protection of the equipment and the line will result in prolonging the operating life of the system, the heat generation of the device is small, the operating efficiency is improved, and the maintenance cost is reduced. Investors are also an economic benefit that cannot be ignored. Especially after the power saving reform, the electricity consumption is reduced by 20-40%, which reduces the power loss in the distribution network and improves the power efficiency of the transformer. The hidden economic benefits are also for the investors. A substantial gain.