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Quick Understanding of Mould Maintenance Common Sense

Click:96 Time:2019-07-07 10:00:00

For newcomers in material purchasing, mould maintenance and maintenance are more professional, so they need to know some basic knowledge. Understanding the maintenance time of the mould, the key point is to control the time variable factors in the delivery date of the finished package products, to ensure the controllability of the product delivery date, so as to effectively guarantee the immediate delivery of orders. Therefore, this paper outlines the basic knowledge of mould maintenance, for your reference:

1. Why do we need to maintain the mould?

Due to the variety of products and frequent replacement of moulds, injection moulds are usually stored in storage until the next production cycle comes. If insufficient attention is paid to the preservation of moulds, rust and surface finish will occur during the preservation period of moulds, resulting in a decline in product quality and high rejection rate. Some moulds are even difficult to reuse. A large amount of funds need to be invested to replace new moulds, resulting in great waste. _

Mould use and maintenance account for 15%-20% of the influencing factors of mould life. The service life of injection moulds can generally reach 800,000 times. Some foreign well-maintained moulds can even be extended by 2-3 times. However, due to neglect of maintenance in domestic enterprises, the service life of injection moulds is relatively short, which is equivalent to only 1/5-1/3 of that in foreign countries. Therefore, the maintenance of injection moulds is very important.

A pair of mould after good maintenance and maintenance can shorten the assembly and debugging time of the mould, reduce the production failure, make the production run smoothly, ensure product quality, reduce waste loss, and reduce the operation cost and fixed assets investment of the enterprise. When the next production cycle begins, the enterprise can produce quality smoothly. Qualified products. Therefore, for the processing of injection moulded products, in the current fierce market competition, the maintenance of good moulds can help enterprises.

2. Basic Cognition of Mold Maintenance

Because of the short service life of the die, steel processing time and energy are wasted, as well as the huge economic losses caused by the impact on product quality. Therefore, the maintenance of injection moulds is very important, as follows:

1. Finding problems through plastic parts

Under the normal operation of injection moulding machine and mould, all kinds of properties of the mould are tested, and the size of the final moulded part is measured. Through these information, the existing state of the mould can be determined, and the damages of the cavity, core, cooling system and parting surface can be found out. According to the information provided by the plastic part, the damage of the mould can be judged. Bad condition and maintenance measures.

2. Maintenance of Mould Parts

Injection mould technology content is very high, there are many parts. If we do not pay attention to the maintenance of various parts in the use process, it is very easy to damage and rust, resulting in tens of thousands or even millions of yuan of economic losses. Therefore, special attention should be paid to the maintenance and maintenance of the mould in the use process to ensure the quality of the long-term use of the mould. For this reason, first of all, every die should be equipped 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, so as to provide information for finding and solving problems, as well as the forming process parameters and products of the die. The material used can shorten the test time of the die and improve the production efficiency.

3. Attention should be paid to surface maintenance of dies

It has a direct impact on the surface quality of products, and the key point is to prevent rust. Therefore, it is particularly important to select a suitable, high-quality and professional rust-proof oil. When the mold is finished, the residual injection moulding should be carefully removed by different methods according to different injection moulding. Copper rod, wire and professional mould cleaner can be used to remove the residual injection moulding and other deposits in the mold, and then air-dried. It is forbidden to clean hard objects such as iron wire and steel bar so as to avoid scratching the surface. If there are rust spots caused by corrosive injection moulding, polishing treatment should be carried out, professional rust-proof oil sprayed, and then the mould should be stored in a dry, cool, dust-free place.

4. 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 the ejection of the plastic parts. If any part of the die is stuck due to damage, it will lead to stop production. 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. It is found that it is necessary to replace it in time; after a production cycle, professional anti-rust oil should be applied to the working surface, moving and guiding parts of the die. In addition, the cleaning of the cooling duct is of great importance to the production efficiency and product quality. With the continuous production time, the cooling passage is easy to deposit scale, rust, sludge and algae, which makes the section of cooling passage smaller and the cooling passage narrower, greatly reduces the heat exchange rate between cooling fluid and mould, and increases the production cost of workshop. Therefore, the cleaning of cooling passage for water transportation should be paid attention to.

 

For the hot runner die, the maintenance of heating and control system is helpful to prevent production failure, so it is particularly important. Therefore, at the end of each production cycle, the heater, heating probe and thermocouple on the die should be measured with ohmmeter. If there is damage, it should be replaced in time, and compared with the die resume to make a good record, so that problems can be found in time and countermeasures can be taken.

When the mold is finished, attention should be paid to the surface maintenance of the mold, which directly affects the surface quality of the product. The key point is to prevent corrosion and scale removal. Different methods should be taken to carefully remove residual injection moulding according to different injection moulding. Copper rods, wires and cleaners can be used to remove residual injection moulding and other deposits in the mold, and then air-dry. It is forbidden to clean hard objects such as iron wire and steel bar so as to avoid scratching the surface. If there are rust spots caused by corrosive injection moulding, grinding and polishing with a grinding machine or special purpose, and coated with anti-rust oil, then the mould is stored in a dry, cool, dust-free place.

III. First and Second Level Maintenance of Dies and Moulds

1. Primary Maintenance of Mould

The first-level maintenance of the die refers to the daily maintenance of the die carried out by the operator in production. The main contents are cleaning, lubrication and inspection.

A. Maintenance during moulding:

The upper and lower surfaces of the dies should be cleaned before loading, so as to ensure that the mounting surface of the dies and the working table of the press are not damaged and the parallelism of the upper and lower mounting surfaces of the dies in production. After the dies are installed, the dies will be opened and all parts of the dies will be cleaned, especially the guiding mechanism. For the surface parts of the dies, the surface of the dies should be cleaned. To ensure the quality of the parts; lubricate and grease the sliding parts of the die; inspect the parts of the die, especially the safety parts. For example: safety side pin, safety screw, side guard plate, punching waste channel, etc.

B. Maintenance in production:

Oil the corresponding parts of the mould regularly in production. For example, the pressing ring and fillet of the drawing die, the knife edge of the trimming die, the flanging knife block and so on, and the small hole waste track of the trimming and piercing die is regularly cleaned up.

C. Post-production maintenance:

After production, the mould should be inspected comprehensively; the mould should be cleaned comprehensively to ensure the cleanliness of the mould; the waste in the mould should be cleaned up to ensure that there is no waste in the waste box; and the use status of the mould and the situation after use should be faithfully fed back to the "Work Summary for the Use of the Mould".

2. Secondary Maintenance of Mould

Secondary maintenance of dies refers to the periodic and systematic maintenance of dies according to the technical status and complexity of dies. The maintenance work is completed by the die repairman, and records are made according to the maintenance situation. The following describes the requirements and methods of the second warranty for different parts:

A. Drawing die punch and die:

The main problems of punch and concave dies of drawing dies are drawing and pressing pits on the surface of the die, and polishing the rounded corner of the die during maintenance is the main problem. If there are pressure pits, the die should be repaired and welded, and then repaired.

B. Guiding parts (guide pillar, guide sleeve and guide plate, etc.)

Drawing marks and other phenomena will appear in the work of the die. The main causes are dirty lubricating oil and bias of guide clearance. When the drawing marks of the guide parts occur, the polishing method is adopted to eliminate them.

C. Edge trimming edge:

In the process of using the die, the blade is easy to collapse and collapse. At this time, the damaged parts of the die should be repaired and welded.

D, spring and other elastic parts:

Spring is one of the most easily damaged parts of die in the process of use, which often occurs fracture and deformation. The method adopted is to replace, but in the process of replacement, we must pay attention to the specifications and models of springs. The specifications and models of springs are determined by three items: color, outer diameter and length. Only when these three items are the same, can they be replaced.

E. Punch and punch sleeve:

Most of the punches and blanking sleeves used in the die are standard parts. The punches are easy to break, bend and gnaw during the use of the die. The blanking sleeves are generally gnawed. The damage of punch and punch sleeve is usually replaced by parts of the same specification. The main parameters of the punch are working part size, installation part size, length size, etc.

F. Fastening parts:

Check whether the fastening parts are loose or damaged. The method adopted is to find parts of the same specifications for replacement;

G. Pressing and unloading parts:

Pressing parts such as pressure plate, high strength glue, unloading parts such as unloading plate, pneumatic ejector, etc. Inspect the assembly relationship of each part during maintenance and repair the damaged part. Check whether there is air leakage in pneumatic jacking material, and take measures to the specific situation. For example, the damaged trachea should be replaced.

IV. Maintenance Instructions for Key Components of Dies and Moulds

Taking injection mould as an example, the maintenance of key components of mould

1. Models

Mould surface (including male BLOCK, guide pillar, slide seat, slide rail, etc.) should be clean and rustless, and the appearance should be checked for obvious damage.

2. Mother model

Mould surface (including mother BLOCK, inclined guide pillar, baroclinic block, guide sleeve, etc.) should be clean and rust-free, and the appearance should be checked for obvious damage.

3. Placement of slider in mould

The slider should be kept in the initial position when opening the mould on the mould, and check whether the slider slides smoothly on the slide seat manually.

4. Placement of slider in mother mould

The slider can't be placed on the edge of the mother die casually. It should be set on the inclined guide pillar to prevent the slider from falling, falling, falling or bruising.

5. BLOCK

The slider can't be placed on the edge of the mother die casually. It should be set on the inclined guide pillar to prevent the slider from falling, falling, falling or bruising.

6. Maintenance of Pillar and Pillar

The guide pillar plays a guiding role on the die, and the male and female die cooperate with the positioning function. The guide pillar must thoroughly remove the residual oil (residual oil in the oil ring) before maintenance, and then apply butter evenly around the guide pillar with fingers.

7. Oblique guide pin and baroclinic block

The inclined guide pin and the baroclinic block must be kept clean and clean. The angle of the inclined guide pin mainly determines the stroke of the slider. The baroclinic block plays the role of locating the slider when closing the mould.

8. Maintenance of slider

After cleaning the slider's surface, apply butter evenly on the bottom and side of the slider with your finger. Note that butter should not be applied too much.

9. Maintenance of sliding seat

Wipe the surface of the sliding seat with a cloth, then apply butter evenly on the sliding seat surface with your fingers, pay attention to cleaning the oil groove of the sliding seat.

10. Slide track

The sliding track is the entry and exit track that the sliding module cooperates with the die. The size and height of the track not only determine the tightness of slider sliding, but also determine whether the combination of slider and BLOCK is in place.

11. Limited Steel Balls

Limited steel ball prevents slider from sliding out of sliding track when opening die. Limited steel ball installed on sliding seat plays a limiting role. Limited steel ball is generally a standard part.

12. Adjustment of Limited Steel Balls

The adjustment of limit steel balls is achieved by screwing in or out from the bottom of slide seat. The adjustment of limit steel balls should be tight and moderate, not too tight or too loose.

13. Limiting Hole

Limit holes are used in conjunction with limit beads. The position of the limit hole determines the position of the slider on the slide rail after the die is opened.

14. Thimble

There are standard and non-standard parts for the thimble; the thimble should not be folded or burred; the thimble should not be damaged to prevent bristles; the method of maintaining the thimble is to wipe the thimble clean with a cloth and then spray the thimble oil.

15. Spring

Spring is part of the ejection system of the die. The different color of the spring represents different elastic coefficients. The size of the spring includes the warp, pitch, length and so on. The two ends of the spring must be ground into a plane.

16. Mold closure

Attention should be paid to guide pillar, guide sleeve, oblique guide pillar and oblique guide pillar hole aligning at the same time when closing the mould. The closing of the mould should be smooth and not forced closing.


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