Maintenance and Maintenance of Injection Mold

Injection mold is the most important forming equipment for injection products processing, and its quality is directly related to the quality of products. Moreover, because the mold occupies a large proportion in the production cost of injection processing enterprises, its service life directly affects the cost of injection products. Therefore, improving the quality of injection moulds, maintaining and maintaining them well and prolonging their service life are important issues for injection moulding enterprises to reduce costs and increase efficiency.

Due to the variety of products and frequent replacement of moulds, injection moulds are usually stored in storage until the next production cycle comes. However, some processing enterprises do not pay enough attention to the preservation of moulds, which results in the corrosion of moulds and the decrease of surface finish during the preservation period, resulting in the decline of product quality and high rejection rate. Some moulds are even difficult to reuse, and a large amount of funds need to be re-invested to replace new moulds, resulting in great waste. The data show that the service life of injection moulds accounts for 15%-20% of the influencing factors. The service life of injection moulds can generally reach 800,000 times. Some well-maintained moulds abroad can even be extended by 2-3 times. However, due to neglect of maintenance, the service life of injection moulds in domestic enterprises is relatively short, which is equivalent to only 1/5-1/3 of that in foreign countries. Due to the short service life of the die, steel processing time and energy waste, as well as the impact on product quality caused by the loss of billions of yuan annually. Therefore, the maintenance of injection moulds is very important, as follows:

1. Processing enterprises should first equip each die with a resume card to record and count its use, nursing (lubrication, cleaning, rust prevention) and damage. According to this, we can find out which parts and components have been damaged and the extent of wear and tear, in order to provide information for finding and solving problems, as well as the forming process parameters and materials used in the product of the die, so as to shorten the test run time of the die. Meanwhile, improve production efficiency.

2. Processing enterprises should test all kinds of properties of moulds under normal operation of injection moulding machines and moulds, and measure the size of final moulded parts. Through these information, the existing state of moulds can be determined, and the damages of cavity, core, cooling system and parting surface can be found out. According to the information provided by moulds, the damaged state of moulds and maintenance measures can be judged.

3. Important parts of the die should be tracked and inspected. The function of ejection and guide parts is to ensure the opening and closing movement of the die and ejection of the plastic parts. If any part of the die is blocked due to damage, it will lead to shutdown. Therefore, the lubrication of the ejector pin and guide pillar of the die (the most suitable lubricant should be selected) should be maintained regularly, and the deformation and surface damage of the ejector pin and guide pillar should be checked regularly. Once the injury is found, it should be replaced in time; after a production cycle, professional anti-rust oil should be applied to the working surface, movement and guide parts of the die, especially the elastic strength protection of the bearing parts of the gear and rack dies and the spring dies to ensure that they are always in the best working state; with the continuous production time, the cooling passage is liable to deposit scale and rust. Mud and algae make the section of cooling runner smaller and the cooling passage narrower, which greatly reduces the heat exchange rate between coolant and die, and increases the production cost of enterprises. Therefore, attention should be paid to the cleaning of runner. For the hot runner die, the maintenance of heating and control system is helpful to prevent the occurrence of production failure, so it is particularly important. Therefore, at the end of each production cycle, the ohmmeter should be used to measure the belt heater, rod heater, heating probe and thermocouple on the die. If there is damage, it should be replaced in time, and compared with the die resume to make a good record so as to find the problem in time and take corresponding measures.

4. Attention should be paid to the surface maintenance of the mould, which directly affects the surface quality of the product. There is a new way to remove residual injection moulding and dry ice cleaning. No residue, the effect is better, now more popular in foreign countries, but not enough in domestic promotion, the company now used KOK, and other foreign enterprises, after testing, can really improve the output, improve the utilization of the mold! The principle is that dry ice ejection medium dry ice particles accelerate in high pressure airflow, impacting the surface to be cleaned. The unique feature of dry ice cleaning is that dry ice particles gasify at the moment of impact. The momentum of dry ice disappears at the moment of impact. The heat exchange between the dry ice particles and the cleaning surface occurs rapidly. As a result, solid CO2 is rapidly sublimated into gas. Dry ice particles expand nearly 800 times in a few thousandths of a second, thus creating a "micro" at the impact point. Due to the volatilization of CO2, no secondary waste is produced during the dry ice cleaning process, leaving only the dirt to be cleaned up. A pair of molds after good maintenance and maintenance can shorten the assembly time, test run time, reduce production failure, make production run smoothly, ensure product quality, reduce waste losses, and reduce the operation cost and fixed assets investment of enterprises. When the next production cycle begins, enterprises can produce products with qualified quality smoothly. Therefore, for injection molding products processing enterprises, under the current fierce market competition, good mold maintenance can help enterprises.

Material Mixing Guidance for Injection Molding Production

Objective: To standardize the mixing operation and stabilize the production situation.

Scope of application: It is suitable for the operation of mixers in injection moulding department.

3. Duties:

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Material Mixing Guidance for Injection Molding Production

Objective: To standardize the mixing operation and stabilize the production situation.

Scope of application: It is suitable for the operation of mixers in injection moulding department.

3. Duties:

According to the production order, batching list and mixing process requirements, to ensure that the mixing material is uniform, no impurities and other impurities, and timely supply of production materials.

4. Process:

Fifth, job control:

A. pay attention to safety production, check the condition of the equipment before starting the machine, whether the timer is normal or not. When the equipment fails, it should stop immediately.

Turn off the power supply when not in use or off duty; white mineral oil and other easy-to-use products must be sealed and placed separately;

B. Every change of material and color must be clean inside and outside the mixer. When cleaning, the surface dust and toner should be cleaned with cotton cloth.

Then wipe it with white cotton cloth and white electric oil, and then wipe it with clean white cotton cloth.

C. When mixing, you must check the ingredient list, label and substance. If they are consistent, you can mix them. You can't change the ingredient list at will.

D. It is necessary to measure accurately the materials that need pounds or quantitatively added diffusive oil, white mineral oil, diffusive powder, etc.

E. Pay attention to the order and time when raw materials, colour powder, nozzle and diffuser are added into the mixture. Ordinary mixing sequence

And the time is:

Add sequential time (stirring) total time

1. Raw material + water agent (diffused oil, etc.) for 2 minutes

(2) Powder (colour powder, diffusion powder) 4 minutes 6-8 minutes

(3) 1.5 minutes with granular material (nozzle material, etc.)

Guidance of Modifier in Injection Molding Production

Objective: To meet the product quality requirements with the fastest speed, the lowest cost and the best forming cycle.

Scope of application: It is suitable for adjusting the machine and production process of the adjuster in injection moulding department.

3. Work flow:

IV. Operational Control:

1. Homework preparation:

A. Whether new products or products already produced, they must have the necessary production process information, product model, material performance capital.

Material and product weight, die structure information. Products that have been produced, find out production process information, input computers and die.

The equipment and equipment are adjusted to the prescribed state.

B. Check whether the equipment, dies and materials can be adjusted, whether the materials are dried, whether the dies are cleaned and can work normally.

For example, whether the barrel is cleaned, whether the temperature of the barrel reaches the forming temperature, whether the water is opened, etc.

2. Shunting:

If the product has been manufactured, the process parameters are input and the operation is normal, the product can be mass produced after QC inspection of OK. For new products:

A. Set the barrel temperature to the normal forming temperature. According to the weight of the product, set the melt and spray travel.

B. Determine the pressure velocity of the injection according to the injection process of the die, generally taking medium pressure (50-80), speed (30-60);

C. Pressure holding time of injection is set according to gate type and size (point gate 6-8S, side gate and direct gate 8-10S);

D. Determine the cooling time according to the distribution of cooling water channel and product wall thickness, initially set to 15-20 seconds;

E. Manual beer is then processed to increase or decrease the relevant data according to beer defects until the product quality requirements are met and the normal production can be continued.

F. Change from manual to semi-automatic, adjust data while producing to find the best injection cycle. Molding cycle = unlocking time + injection time + melt time + cooling time, shorten the above four times as much as possible. Generally, a 4-oz injection molding machine, such as a two-plate mould, can control the opening or locking time in about 2 seconds, and the line position can be slowed down appropriately. The injection time was adjusted by 0.5 seconds to decrease the test beer until the defect occurred. Stop the adjustment and return to the previous data. The determination of melt time should minimize back pressure and speed up the melt speed, so as to avoid mixing and sparkling. The cooling time is the same as the injection time. The beer is tested with 1 second as the decreasing time. If the quality of the adjusted product is the same as that of the standard sample, the optimal adjustment time is obtained.

Attentions in Installing Hydraulic Components in Hydraulic System

1. Before installation of hydraulic components, kerosene should be used to clean them. Sealing and pressure test should be carried out for self-made important components. The test pressure can be 2 times of the working pressure or 1.5 times of the maximum service pressure. The test should be carried out in different grades, not to rise to the test pressure at once, and be checked once every step.

2. The directional control valve shall be installed horizontally on the axis.

3. When installing plate elements, check whether the sealing rings at the oil inlet and outlet meet the requirements. Before installing, the sealing rings should highlight the installation plane to ensure a certain amount of compression after installation, so as to prevent leakage.

4. When installing plate elements, the tightening force of the fixing screw should be uniform, so that the installation plane of the elements can be in good contact with the floor plane of the elements.

How to deal with excessive temperature rise of hydraulic system of injection moulding machine

1, according to different load requirements, check and adjust the pressure of the relief valve regularly to make it right.

2. Reasonable selection of hydraulic oil, especially the viscosity of oil. When conditions permit, try to use a lower viscosity to reduce the friction loss of viscosity.

3. Improve the lubrication condition of the moving parts to reduce friction loss, which is conducive to reducing workload and fever.

4. Improving assembly quality and Self-precision of hydraulic components and systems, strictly controlling mating clearance of fittings and improving lubrication strips