What is the injection molding machine for?

Injection molding machine is also called injection molding machine or injection molding machine. It is the main molding equipment for making thermoplastic or thermosetting plastics into plastic products of various shapes by using plastic molding dies. Divided into vertical, horizontal and all-electric type. The injection molding machine can heat the plastic and apply high pressure to the molten plastic so that it can be ejected to fill the mold cavity. So what is the working principle of injection molding machine? What kinds of injection molding machines are there? Let's take a look at Bian Xiao's related knowledge.

What kind of injection molding machine can the injection molding machine produce? What is the working principle of injection molding machine? How to choose injection molding machine? Operating rules of injection molding machine Common faults maintenance of injection molding machine Brand maintenance 1 What automobile industry can injection molding machine produce: automobile lamp housing, most automobile interior parts, automobile bumper and so on.

Electronic industry: mobile phone shell and some mechanical parts, notebook computer shell, computer display shell, mouse, keyboard, USB, etc.

Household appliances: TV casing, washing machine, refrigerator, hair dryer, telephone, power switch, socket, kettle handle, base, etc.

Daily necessities: microwave lunch boxes, cups, plastic stools, plastic tables, plastic sorting boxes, plastic flowerpots, plastic dustpans, plastic bowls, plastic pots, plastic toys, water dispenser shells, clothes hangers, etc.

Cosmetic industry: some cosmetic packaging (bottles, lids), etc.

Medical industry: disposable syringes, devices for adjusting liquid volume on infusion tubes, etc.

Office supplies industry: whiteboard pens, ink pens, rulers, document racks, printer casings, copier casings, fax machine casings, etc.

Most of the plastic things around us, except films and bottles with small bellies, are injection-molded, blow-molded, blister-molded or hot-pressed.

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2 working principle of injection molding machine The working principle of injection molding machine is similar to a syringe. It is a process of injecting molten plasticized plastic (that is, viscous fluid state) into a closed mold cavity with the help of the thrust of a screw (or plunger), and curing and shaping to obtain a product.

Injection molding is a cyclic process, and each cycle mainly includes: quantitative feeding-melt plasticization-pressure injection molding-mold filling and cooling-mold opening and taking parts. Take out the plastic part, and then close the mold for the next cycle.

Operation items of injection molding machine: Operation items of injection molding machine include control keyboard operation, electric control system operation and hydraulic system operation. Selection of injection process action, feeding action, injection pressure, injection speed and ejection type, monitoring of temperature in each section of the barrel, adjustment of injection pressure and back pressure, etc.

The molding process of screw injection molding machine is generally as follows: firstly, granular or powdery plastic is added into the barrel, and the plastic is melted by the rotation of the screw and the heating of the outer wall of the barrel; then, the machine closes the mold, moves the injection seat forward to make the nozzle close to the gate of the mold, and then introduces pressurized oil into the injection cylinder to push the screw forward, thereby injecting the molten material into the closed mold at low temperature, high pressure and high speed. After a certain period of time and pressure maintaining (also called pressure maintaining) cooling, the product can be taken out after opening the mold (the purpose of pressure maintaining is to prevent the molten material in the mold cavity from flowing back, replenish the material in the mold cavity, and ensure that the product has certain density and dimensional tolerance). The basic requirements of injection molding are plasticization, injection and molding. Plasticization is the premise of realizing and ensuring the quality of molded products, and in order to meet the requirements of molding, injection must ensure sufficient pressure and speed. At the same time, due to the high injection pressure, a relatively high pressure is generated in the mold cavity (the average pressure in the mold cavity is generally between 20 and 45 MPa), so there must be enough clamping force. It can be seen that injection device and clamping device are the key components of injection molding machine.

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3 Types and characteristics of injection molding machines vertical injection molding machine

1. The injection device and the mold locking device are on the same vertical center line, and the mold is opened and closed up and down. Its floor space is only about half that of a horizontal machine, so when converted into floor space, its productivity is about twice that of a horizontal machine.

2, easy to realize insert molding. Because the surface of the mold faces upwards, it is easy to position the insert. If the lower die plate is fixed, the upper die plate is movable, and the belt pulling and conveying device is combined with the manipulator, full-automatic insert molding can be easily realized.

3. The weight of the mold is supported by the horizontal template to open and close up and down, and the phenomenon that the template cannot be opened and closed due to the gravity of the mold caused by the horizontal machine will not occur. Conducive to maintaining the accuracy of machinery and molds for a long time.

4. The cavities of various plastic parts can be taken out by a simple manipulator, which is beneficial to precision molding.

5. Generally, the periphery of the mold locking device is open, and it is easy to configure various automatic devices, which is suitable for the automatic molding of complex and exquisite products.

6. The belt drawing and conveying device is easy to install in the middle of the mold, which is convenient to realize automatic molding production.

7. It is easy to ensure the consistency of resin fluidity and mold temperature distribution in the mold.

8. Equipped with rotary table, movable table and inclined table, it is easy to realize insert molding and in-mold combined molding.

9. In small batch trial production, the mold has simple structure, low cost and easy disassembly.

10, which has withstood the test of many earthquakes, the vertical machine has better earthquake resistance than the horizontal machine because of its low center of gravity.

Horizontal injection molding machine

1. Even the main engine has a low fuselage, so there is no height limit for the factory building.

2. When the product can fall automatically, automatic molding can be realized without using a manipulator.

3. Because the fuselage is low, it is convenient to feed and easy to maintain.

4. The mould shall be installed by crane.

5. When a plurality of units are arranged side by side, the molded products are easily collected and packaged by the conveyor belt.

Angle injection molding machine

The axis of the injection screw of the angle injection molding machine is perpendicular to the movement axis of the mold clamping mechanism template, and its advantages and disadvantages are between vertical and horizontal. Because the injection direction is on the same plane as the parting surface of the mold, the angle injection molding machine is suitable for molds with asymmetric geometry with side gates or products with no gate traces in the molding center.

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How to choose the model of injection molding machine 1, and choose the right model: the product and plastic determine the model and series.

Because there are many kinds of injection molding machines, we must first correctly judge which injection molding machine this product is suitable for, such as vertical and horizontal, or which series of injection molding machines. For example, general thermoplastic or bakelite raw materials or PET raw materials are monochrome, bicolor, multicolor, sandwich or mixed color. In addition, some products need high stability (closed loop), high precision, ultra-high firing rate, high firing pressure or rapid production (multi-loop), and appropriate series must be selected for production.

2. Placement: According to the mold size, judge whether the machine's "big column inner distance", "mold thickness", "minimum mold size" and "template size" are appropriate, so as to confirm whether the mold can be placed.

(1) The width and height of the mould should be less than or at least less than one side of the internal distance of the big column.

(2) The width and height of the mold should be within the size range of the template.

(3) The thickness of the mold should be between that of the injection molding machine.

(4) The width and height of the mold should meet the minimum mold size recommended by the injection molding machine. Too small is not acceptable.

3. Whether the "mold opening stroke" and "mold supporting stroke" are enough for the finished product to be taken out is judged by the mold and the finished product.

(1) The mold opening stroke should be at least twice the height of the finished product in the mold opening and closing direction, and should include the length of the sprue.

(2) The supporting stroke of the mould should be enough to eject the finished product.

4. Lockability: The tonnage of "clamping force" is determined by the product and plastic.

When the raw material is injected into the mold cavity under high pressure, it will produce a force to support the mold, so the locking unit of the injection molding machine must provide enough "locking force" to prevent the mold from being opened. The clamping force requirement is calculated as follows:

(1) Calculate the projection area of the finished product in the mold opening and closing direction according to the appearance size of the finished product.

(2) Mold supporting force = projected area of finished product in mold opening and closing direction (cm2)× number of mold cavities × pressure in mold (kg/cm2).

(3) The pressure in the mold varies with raw materials, and is generally 350 ~ 400 kg/cm2.

(4) The clamping force of the machine needs to be greater than the supporting force of the formwork. To be on the safe side, the clamping force of the machine usually needs to be greater than 1. 17 times of the supporting force of the formwork.

At this point, the specifications of the clamping unit have been preliminarily determined, and the tonnage of the model has also been roughly determined. Then, the following steps must be performed to confirm which injection unit's screw diameter meets the requirements.

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5 Operating Rules of Injection Molding Machine 1. 1 Preparation before Injection Molding Machine Start-up

1. Clean the environment around the equipment, and do not store articles unrelated to production.

2. Clean the sundries inside and outside the workbench and equipment, and clean the injection guide seat and the pull rod of the clamping part with clean cotton yarn.

3, check the equipment control switch, button, wire, operating handle, handwheel for damage or failure. Each switch and handle should be in the "off" position.

4, check the various parts of the equipment safety protection devices are in good condition, sensitive and reliable work. Check whether the "emergency stop" of the test is effective and reliable, whether the safety door slides flexibly and whether the switch limit switch can be touched.

5. Safety protection devices on the equipment (such as mechanical locking lever, baffle, safety protection switch, etc.). ) Don't move, modify or deliberately make it invalid.

6, check whether the screws in each part are tightened, whether there is any looseness, found that parts are abnormal or damaged, should report to the foreman, handled by the foreman or notify the maintenance personnel.

7, check the cooling water pipeline, test the water, check whether the water flow is unobstructed, whether it is blocked or dripping.

8. Check whether there are foreign objects in the hopper. Nothing is allowed to be stored above the hopper. The hopper cover should be covered to prevent dust and sundries from falling into the hopper.

1.2 Start the injection molding machine.

1. Turn on the main power switch of the machine tool, check whether the equipment leaks electricity, preheat the barrel and mold according to the set process temperature requirements, and keep the temperature of the barrel for more than 20 minutes when it reaches the process temperature to ensure the uniform temperature of all parts of the barrel.

2. Open the cooling water valve of the oil cooler, cool the oil return and water delivery throat, and start the oil pump by inching. Only when no abnormal phenomenon is found can the oil pump be officially started, and it can not be operated until "Mount" is displayed on the screen to check whether the safety door works normally.

3, manually start the screw rotation, check the screw rotation for abnormal sound and stuck.

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6 injection molding machine maintenance 1, daily inspection

Check and adjust the safety facilities every day to ensure that the safety facilities are normal before using the operating machine; Check the amount of oil in the lubricating oil tank and add new oil of the same brand; Check the oil level in the hydraulic oil tank. If the oil level drops below the midline of the level gauge, add hydraulic oil above the midline, and new oil of the same brand must be added. After the first operation 1000 hours, it is necessary to replace or clean the oil suction filter, hydraulic oil and oil tank; When running for 5000 hours or at most one year, it is necessary to replace or clean the air filter and hydraulic oil, and pay attention to the fact that old and new hydraulic oil cannot be mixed; When running for 20,000 hours or at most 5 years, check and replace the sealing ring and wear ring of the hydraulic cylinder, and replace the high-pressure hose; Replace the battery of the controller (host) every 3 years; Replace the battery on the operation panel every 5 years.

2. Pay attention to lubrication

During the use of injection molding machine, it is necessary to regularly observe whether the lubrication point of injection molding machine is in normal working condition. Note that the time for each lubrication must be enough to ensure that every lubrication point of the whole lubrication system is well lubricated. The lubrication module (interval time) of the machine and the time of each lubrication are realized by the reasonable setting of computer parameters. Regularly observe the working condition of the lubrication system to keep the lubricating oil in the oil tank at a reasonable oil level. If poor lubrication is found, it should be lubricated in time, and the lubrication of each lubrication point should be checked to ensure good lubrication of the machine.

Step 3 check the air filter

The function of the fuel tank air filter is to breathe in the fuel tank and prevent dirt such as dust from entering the fuel tank, so it is a very important component and needs regular maintenance. The air filter is installed on the top of the fuel tank. When cleaning, loosen the cover, replace the filter element of the air filter, and then tighten the cover again. Be careful that the cover must be tightened, otherwise the oil will overflow.

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7 common faults of injection molding machine maintenance motor does not run, the oil pump is abnormal, does not move, does not fit the mold and does not open the mold.

1, the power fuse is blown; 2. The connector of the start button is poor; 3. The overload relay trips; 4, the main circuit failure, breaker is bad.

job operation

1, change the insurance; 2. Repair or replace related accessories.

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cause

1, the suction side sucks air; 2. The oil filter is blocked; 3, there is wear in the pump; 4. The oil level is too low.

job operation

1. Repair the connector on the suction side; 2. Clean the filter screen; 3. Repair the oil pump; 4, add enough oil.

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cause

1, total pressure valve failure; 2, amplifier board failure; 3, motor, oil pump connecting flange failure; 4. The electromagnetic coil of the servo valve is stuck.

job operation

1, repair the total pressure valve and amplifier board; 2. Repair the connector; 3. Install the electromagnetic coil.

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cause

1, jacking is not in place; 2. The safety door is not relevant; 3. The manipulator did not give the clamping signal; 4, position scale data failure; 5. The directional valve does not work.

job operation

1, check whether the withdrawal is terminated; 2. Check the safety circuit, oil circuit and mechanical insurance; 3. Repair the position of the mechanical arm; 4, check the position ruler; 5. Check whether the valve body has power supply and is stuck.

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cause

1, directional valve failure; 2. Insufficient pressure; 3. Mechanical clamping hole of hand bending machine; 4. The position scale is out of order.

job operation

1, check the valve body; 2. Adjust the mold opening service; 3. Repair the crank arm; 4. Maintenance position ruler.

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8 injection molding machine brand industry recommended brand Haitian International Izumi Lijin L. KKRAUSMAFFEI Klaus Demag Sumitomo Demag Husky Bosch Boch Engel Terry Machine Tederic Donghua Machinery WELLTEC