1 Insufficient filling Inadequate filling is manifested by incomplete injection parts or incomplete details, which is caused by incomplete filling of the mold cavity with plastic. This is a frequently encountered problem, but it is also relatively easy to solve. When it is really impossible to solve the problem by technological means, it can be improved from the perspective of mold design and manufacturing. Generally, it can be solved. There are many reasons for insufficient filling, including injection molding machines, molds, processes, raw materials and products. (1) Injection molding machine ① The plasticizing capacity of the injection molding machine is small, which is not enough to provide enough material, so the machine with large plasticizing capacity needs to be replaced. When the product quality exceeds the actual maximum injection quality of the injection molding machine, it is obvious that the feed quantity is not applied. If the product quality is close to the actual injection quality of the injection molding machine, there is a problem that the plasticization is not sufficient. The material is not heated in the barrel for a long time, and as a result, the appropriate melt cannot be provided to the mold in time. This problem can only be solved by replacing the injection molding machine with large capacity. ② The temperature displayed by the thermometer is not true, which causes the material temperature to be too low. This is due to the failure of temperature control devices such as thermocouples and their circuits or temperature difference millivolt meters, or due to the aging or burning of the heating coil far away from the temperature measuring point, and the heating failure has not been found or timely repaired and replaced. ③ The nozzle is partially blocked. Check whether there is foreign matter or unmelted material in the nozzle hole. The diameter of the nozzle inner hole may be too large or too small. If it is too small, the specific volume of the strip will increase due to the small flow diameter, which is easy to cool, block the feed channel or consume the injection pressure; If it is too large, the flow section area will be large, and the pressure per unit area of plastic entering the mold will be low, resulting in a small injection force. The nozzle and the inlet of the main runner are poorly matched, which often leads to overflow outside the mold and insufficient filling inside the mold. The nozzle itself has great flow resistance or is blocked by foreign matters, plastic carbonization deposits, etc; The spherical surface of nozzle or main runner inlet is damaged and deformed, affecting its good cooperation; The mechanical failure or deviation of the injection seat causes tilting displacement between the nozzle and the main runner axis or separation of the axial compression surface; The nozzle ball diameter is larger than the inlet ball diameter of the main channel. Due to the gap between the edge seams and the gradual increase of the axial pushing force of the nozzle under the pressure of overflow, the products will not be fully filled. ④ Check whether the hopper volume and hopper opening are blocked, and whether the plastic frit blocks the feeding channel. The plastic will melt prematurely when it enters the necking position of the feed opening or the deep groove of the screw starting end due to the partial melting and caking of the plastic in the hopper dryer, or the high temperature of the feed section of the barrel, or the improper selection of the plastic grade, or too much lubricant contained in the plastic, and the particles and molten materials will bond to each other to form a "bridge", block the channel or wrap the screw, and make circumferential sliding with the rotation of the screw, It cannot move forward, resulting in interruption of material supply or irregular fluctuation. This situation can only be fundamentally solved after the passage is chiseled and the block is removed. ⑤ The nozzle cold material enters the mold. Injection molding machines are usually equipped with straight through nozzles due to pressure loss. However, if the temperature of the front end of the barrel and the nozzle is too high, or there is too much material stored in the front end of the barrel under high pressure, "flow casting" will occur, so that the plastic will enter the main channel entrance and harden under the cooling effect of the template when the mold is open without starting injection, which will prevent the molten material from entering the cavity smoothly. At this time, reduce the temperature of the front end of the barrel and nozzle, reduce the amount of material stored in the barrel, reduce the back pressure, and avoid excessive density of molten material at the front end of the barrel. ⑥ The injection cycle is too short. Due to the short cycle, the material temperature is too late to keep up, which will also cause material shortage, especially when the voltage fluctuation is large. The period shall be adjusted according to the supply voltage. Generally, the injection and pressure holding time are not considered in the adjustment, but the time from the completion of pressure holding to the return of the screw is mainly considered, which not only does not affect the filling and molding conditions, but also can extend or shorten the preheating time of particles in the barrel.

(1) Barrel temperature The temperature of molten material is very important, and the temperature of the feeding cylinder used is only a guide. The melt temperature can be measured at the nozzle or by using the air jet method. The temperature setting of the injection cylinder depends on the melt temperature, screw speed, back pressure, injection volume and injection cycle. If there is no experience in processing a particular grade of plastic, start with the lowest setting. In order to facilitate control, the feeding cylinder is divided into zones, but not all are set at the same temperature. If it is operated for a long time or at high temperature, the temperature of the first zone should be set to a lower value, which will prevent premature melting and shunting of plastics. Before injection molding, ensure that the hydraulic oil, hopper blocker, mold and injection cylinder are at the correct temperature. The barrel temperature generally increases gradually from the back to the front for uniform plasticization. (2) Melt temperature The melt temperature plays a major role in the flow performance of the melt. Plastics have no specific melting point. The so-called melting point is a temperature range in the melting state. The structure and composition of plastic molecular chains are different, so their effects on the flow performance are different. Rigid molecular chains are significantly affected by temperature, such as PC, PPS, etc., while flexible molecular chains, such as PA, PP The fluidity of PE is not obvious by changing the temperature, so the reasonable injection temperature should be adjusted according to different materials. (3) Mold temperature Some plastic materials need a higher mold temperature due to high crystallization temperature and slow crystallization speed, and some need a higher or lower temperature due to size control and deformation or demoulding needs. For example, PC generally requires more than 60 ℃, while PPS sometimes needs a mold temperature of more than 160 ℃ in order to achieve better appearance and improve liquidity, so mold temperature can improve the appearance Deformation, size and rubber mold play an important role. On the condition setting of mold design and molding engineering, it is important not only to maintain the appropriate temperature, but also to make it evenly distributed. Uneven mold temperature distribution will lead to uneven shrinkage and internal stress, thus making the molded products prone to deformation and warpage. The mold temperature will affect the hardening speed of the plastic in the mold cavity. If it is too low, it will make it difficult to fill and harden without proper shrinkage (or recrystallization), resulting in more filling and thermal stress residues in the molded products; If it is too high, burrs will appear and a longer cooling time will be required. Mold temperature has a great impact on the internal performance and performance quality of plastic parts. For rubber parts with high surface requirements, mold temperature requirements are high. (4) Injection pressure The melt overcomes the resistance required to move forward, which directly affects the size, weight and deformation of the product. Different plastic products require different injection pressures. For materials such as PA and PP, increasing the pressure will significantly improve their fluidity. The injection pressure determines the density of the product, that is, the appearance gloss. It has no fixed value, and the more difficult it is to fill the mold, the greater the injection pressure. The setting of injection pressure is mainly to control the oil pressure enough to push the screw to reach the set injection speed. Due to the different characteristics of each kind of plastic, the difficulty of flow is also different. The viscosity of the same material will change with different melt temperature. Different products, mold design, and mold temperature will change the resistance formed by material flow. To maintain the same injection speed under various conditions, the injection pressure must be changed to overcome the resistance caused by melt flow. The injection pressure is different from the holding pressure. The injection pressure mainly affects the filling stage, while the holding pressure affects the cooling stage. For plastics with poor fluidity, the injection pressure should be taken as a large value, and for thin-walled rubber with large cavity resistance, the injection hardness force should also be taken as a maximum value. (5) Ejection velocity The setting of injection speed is the most important condition in the flow process, which controls the time and flow mode of the melt filling mold. Whether the injection speed is adjusted correctly or not has absolute control over the product appearance quality. The basic principle of setting the injection speed is to coordinate with the plastic flow in the mold cavity, rise and fall according to the size of the section formed by its flow, and follow the slow → fast → slow procedure to try to be as fast as possible (confirm whether the appearance is defective). The injection speed is achieved by adjusting the amount of oil supplied to the injection cylinder per unit time. Generally speaking (without causing side effects), try to use high injection speed to fill the mold to ensure the welding strength and apparent quality of the plastic parts. The relatively low pressure also reduces the internal stress of the plastic parts and improves the strength. High pressure and low speed feeding can make the flow rate stable, the shear speed small, the size of plastic parts stable, and avoid shrinkage defects. (6) Time parameter (molding cycle) Injection time and cooling time are basic components, and their length has a decisive impact on the quality of injection molded parts. The mold filling time is generally not more than 10s. The pressure holding time is longer, which is related to the wall thickness of the rubber part (the wall thickness takes a longer time) to ensure the minimum shrinkage. The cooling time depends on such factors as plastic crystallinity, product material thickness, mold temperature, etc., and can be adjusted according to the specific situation. The forming cycle is as follows.

(1) Shrinkage rate The form and calculation of molding shrinkage of thermoplastics are as described above. The factors affecting molding shrinkage of thermoplastics are as follows. ① Plastic variety Due to the volume change of crystallization form, strong internal stress, large residual stress frozen in the plastic part, molecular orientation and other factors during the molding process of thermoplastic, compared with thermosetting plastics, the shrinkage rate is larger, the shrinkage rate range is wide, and the directivity is obvious. In addition, the shrinkage after molding The shrinkage rate after annealing or conditioning treatment is generally larger than that of thermosetting plastics. ② Plastic part characteristics During molding, the outer layer of the molten material contacting the cavity surface is cooled immediately to form a low-density solid shell. Due to the poor thermal conductivity of the plastic, the inner layer of the plastic cools slowly to form a high-density solid layer with large shrinkage. Therefore, those with wall thickness, slow cooling and high density layer thickness will shrink greatly. In addition, the presence or absence of inserts and the layout and quantity of inserts directly affect the direction of material flow, density distribution and shrinkage resistance, so the characteristics of plastic parts have a greater impact on the size and direction of shrinkage. ③ Type, size and distribution of feed inlet These factors directly affect the material flow direction, distribution density, pressure maintaining and feeding effect and molding time. The direct feed inlet and the feed inlet with large cross section (especially thicker cross section) will shrink, but with large directionality. The feed inlet with short width and length will have small directionality. Those close to the feed inlet or parallel to the direction of material flow will shrink more. ④ Forming conditions High mold temperature, slow cooling of molten material, high density and large shrinkage, especially for crystalline material, due to high crystallinity and large volume change, the shrinkage is larger. The mold temperature distribution is also related to the internal and external cooling and density uniformity of the plastic parts, which directly affects the size and direction of the shrinkage of each part. In addition, the holding pressure and time also have a greater impact on the shrinkage. Those with large pressure and long time will shrink, but with great directionality. The injection pressure is high, the viscosity difference of molten material is small, the interlaminar shear stress is small, and the elastic rebound after demoulding is large, so the shrinkage can also be reduced moderately, the material temperature is high, the shrinkage is large, but the directivity is small. Therefore, adjusting mold temperature, pressure, injection speed, cooling time and other factors during molding can also appropriately change the plastic shrinkage. During mold design, the shrinkage rate of each part of the plastic part shall be determined based on experience according to the shrinkage range of various plastics, the wall thickness and shape of the plastic part, the form, size and distribution of the feed inlet, and then the cavity size shall be calculated. For high-precision plastic parts and when it is difficult to master the shrinkage rate, the following methods should be generally used to design the mold. ① The outer diameter of the plastic part shall have a smaller shrinkage rate, and the inner diameter shall have a larger shrinkage rate, so as to leave room for correction after mold testing. ② The form, size and forming conditions of the gating system are determined by mold test. ③ The diameter of plastic parts to be post-treated shall be post-treated to determine the size change (the measurement must be conducted 24 hours after demoulding). ④ Correct the mold according to the actual shrinkage. ⑤ Try the mold again and change the process conditions appropriately, slightly modify the shrinkage value to meet the requirements of plastic parts. (2) Liquidity The fluidity of thermoplastics can generally be analyzed from a series of indexes such as molecular weight, melt index, Archimedes spiral flow length, apparent viscosity and flow ratio (flow length/plastic part wall thickness). Small molecular weight, wide molecular weight distribution, poor molecular structure regularity; If the melt index is high, the spiral flow length is long, the apparent viscosity is small, and the flow ratio is large, the fluidity is good. For plastics with the same product name, the instruction manual must be checked to determine whether the fluidity is suitable for injection molding. According to the mold design requirements, the fluidity of commonly used plastics can be roughly divided into three categories. ① Good fluidity PA, PE, PS, PP, CA, and poly (4-methylpentene). ② Medium fluidity polystyrene series values (such as ABS, AS), PMMA, POM, polyphenylene ether. ③ Poor fluidity PC, rigid PVC, polyphenylene ether, polysulfone, polyarylsulfone, fluoroplastics. The fluidity of various plastics also varies with various molding factors, and the main influencing factors are as follows: ① Temperature The fluidity increases when the material temperature is high, but different plastics also have differences. The fluidity of plastics such as PS (especially those with high impact resistance and MFR value), PP, PA, PMMA, modified polystyrene (such as ABS, AS), PC, CA, etc. changes greatly with temperature. For PE and POM, the increase or decrease of temperature has little effect on their fluidity. Therefore, the former should adjust the temperature to control the fluidity during molding. ② Pressure With the increase of injection pressure, the molten material is subject to greater shear and liquidity, especially PE and POM are more sensitive, so it is appropriate to adjust the pressure of the injection molding machine to control the liquidity during molding. ③ Die structure The form, size, layout of the gating system, cooling system design, molten material flow resistance (such as mold surface finish, cross section thickness of the material path, cavity shape, exhaust system) and other factors directly affect the actual fluidity of molten material in the cavity. If the molten material is reduced in low temperature, the fluidity will be reduced if the flow resistance is increased. The mold design should be based on the fluidity of the plastic used, select a reasonable structure. During molding, the material temperature, mold temperature, injection pressure, injection speed and other factors can also be controlled to properly adjust the filling to meet the molding needs. (3) Crystallinity Thermoplastics can be divided into crystalline plastics and amorphous (also called amorphous) plastics according to whether there is crystallization phenomenon when they condense. The so-called crystallization phenomenon refers to the phenomenon that when the plastic changes from melting state to condensation, the molecules change from free movement (completely in a disordered state) to stop free movement, press a slightly fixed position, and have a tendency to make the molecular arrangement become a regular model. As the appearance standard for judging these two types of plastics, it depends on the thick wall of plastics and the transparency of plastic parts. Generally, crystalline plastics are opaque or translucent (such as POM), and amorphous plastics are transparent (such as PMMA). In mold design and selection of injection molding machine, attention should be paid to the following requirements and precautions for crystalline plastics. ① It takes more heat for the material temperature to rise to the molding temperature, so equipment with large plasticizing capacity should be used. ② The heat released during cooling and recycling is large, so it should be fully cooled. ③ The density difference between molten state and solid state is large, forming shrinkage is large, and shrinkage cavity and pore are easy to occur. ④ Fast cooling, low crystallinity, small shrinkage and high transparency. The crystallinity is related to the wall thickness of the plastic part. The wall thickness has slow cooling, high crystallinity, large shrinkage and good physical properties. Therefore, mold temperature of crystalline plastics must be controlled as required. ⑤ The anisotropy is significant and the internal stress is large. Uncrystallized molecules after demoulding tend to continue to crystallize, are in an energy imbalance state, and are prone to deformation and warping. ⑥ The crystallization temperature range is narrow, which is easy to cause unmelted materials not being injected into the mold or blocking the feed inlet. (4) Thermosensitive plastics and easily hydrolyzable plastics Heat sensitivity refers to the tendency of discoloration, degradation and decomposition when the material temperature increases when some plastics are more sensitive to heat and are heated for a long time under high temperature, or the section of the feed inlet is too small and the shear effect is large. Plastics with this characteristic are called thermosensitive plastics. Such as rigid PVC, polyvinylidene chloride, vinyl acetate copolymer, POM, polytrichloroethylene fluoride, etc. The decomposition of thermosensitive plastics produces monomer, gas, solid and other by-products, especially some decomposition gases have irritating, corrosive or toxic effects on human body, equipment and molds. Therefore, attention should be paid to the selection of injection molding machine and molding in mold design. Screw type injection molding machine should be selected. The section of the gating system should be large. The mold and barrel should be chrome plated without material stagnation. The molding temperature must be strictly controlled. Stabilizers can also be added to the plastic to reduce its thermal sensitivity. Some plastics (such as PC) will decompose under high temperature and high pressure even if they contain a small amount of water. This property is called hydrolytic, which must be heated and dried in advance. (5) Stress cracking and melt fracture Some plastics are sensitive to stress, which is easy to produce internal stress and brittle and easy to crack during molding. Plastic parts crack under external force or solvent. Therefore, in addition to adding additives in raw materials to improve crack resistance, attention should be paid to drying of raw materials and reasonable selection of molding conditions to reduce internal stress and increase crack resistance. The reasonable shape of plastic parts shall be selected, and the embedded parts shall not be set to minimize the stress concentration. The mold design shall increase the demoulding slope, select a reasonable feed inlet and ejection mechanism, properly adjust the material temperature, mold temperature, injection pressure and cooling time during molding, and try to avoid demoulding when the plastic parts are too cold and brittle. After molding, the plastic parts should also be subject to post-treatment to improve crack resistance, eliminate internal stress and prohibit contact with solvents. When a certain flow rate of polymer melt passes through the nozzle hole at a constant temperature and its flow rate exceeds a certain value, an obvious transverse crack on the surface of the melt is called melt fracture, which will damage the appearance and physical properties of the plastic part. Therefore, when selecting polymers with high melt flow rate, the cross sections of nozzle, runner and feed inlet should be increased to reduce injection speed and improve material temperature. (6) Thermal performance and cooling rate Various plastics have different thermal properties such as specific heat capacity, thermal conductivity, thermal deformation temperature, etc. The plasticizing machine with high specific heat capacity needs large heat, so the injection molding machine with large plasticizing capacity should be selected. The hot deformation temperature is high, the cooling time of the plastic is short, and the demoulding is early, but the cooling deformation should be prevented after demoulding. The cooling speed of plastics with low thermal conductivity is slow (for example, the cooling speed of ionic polymers is extremely slow), so it must be fully cooled to enhance the cooling effect of the mold. The hot runner mold is suitable for plastics with low specific heat capacity and high thermal conductivity. Plastics with large specific heat capacity, low thermal conductivity, low thermal deformation temperature and slow cooling speed are not conducive to high-speed molding. Appropriate injection molding machines must be selected and mold cooling must be strengthened. Various plastics must maintain proper cooling rate according to their type characteristics and shape requirements of plastic parts. Therefore, the heating and cooling system must be set for the mold according to the molding requirements to maintain a certain mold temperature. When the mold temperature rises, it should be cooled to prevent deformation of the plastic part after demoulding, shorten the molding cycle and reduce the crystallinity. When the waste heat of plastic is not enough to keep the mold at a certain temperature, the mold should be equipped with a heating system to keep the mold at a certain temperature, so as to control the cooling rate, ensure the fluidity, improve the filling conditions, or control the plastic parts to make them cool slowly, prevent the thick wall plastic parts from being internally and externally cooled but uneven, and improve the crystallinity. For those with good fluidity, large forming area and uneven material temperature, it is required to use heating or cooling alternately or use local heating and cooling together according to the molding condition of plastic parts. For this purpose, the mold shall be equipped with corresponding cooling or heating system. (7) Hygroscopicity Due to various additives in plastics, they have different degrees of affinity to water, so plastics can be roughly divided into two types: hygroscopic, adherent and non absorbent. The water content in the materials must be controlled within the allowable range, otherwise, water will be separated into gas or hydrolyzed under high temperature and pressure, which will lead to resin foaming, liquidity reduction Poor appearance and mechanical properties. Therefore, hygroscopic plastics must be preheated with appropriate heating methods and specifications as required to prevent re hygroscopicity during use.

Before starting up: ① Check whether there is water and oil in the electrical control box. If the electrical appliance is damp, do not start the machine. The maintenance personnel shall dry the electrical parts before starting the machine. ② Check whether the power supply voltage conforms to the standard, which should not exceed ± 15% in general. ③ Check whether the emergency stop switch and front and rear safety door switches are normal. Verify whether the rotation direction of motor and oil pump is consistent. ④ Check whether the cooling pipes are unblocked, and fill the oil cooler and the cooling water jacket at the end of the barrel with cooling water. ⑤ Check whether there is lubricating oil (grease) at all moving parts, and add enough lubricating oil. ⑥ Turn on the electric heating control system to heat up each section of the barrel. When the temperature of each section meets the requirements, keep it warm for a period of time to stabilize the machine temperature. The heat preservation time varies according to the requirements of different equipment and plastic raw materials. ⑦ Add enough plastic into the hopper. According to the requirements of different plastics for injection molding, some raw materials should be dried first. ⑧ The heat shield on the cylinder should be covered, which can not only save electric energy, but also extend the life of the electric heating coil and the current contactor. During operation: ① Do not cancel the function of the safety door for convenience. ② Pay attention to the temperature of the pressure oil, and the oil temperature shall not exceed the specified range. The ideal working temperature of the hydraulic oil should be kept between 45~50 ℃, generally within the range of 35~60 ℃. ③ Pay attention to the adjustment of each travel limit switch to avoid the impact of the machine during operation. At the end of the operation: ① Before shutdown, the plastic in the barrel shall be cleaned to prevent the residual material from oxidation or long-term thermal decomposition. ② The mold shall be opened to keep the toggle mechanism locked for a long time. ③ The workshop must be equipped with lifting equipment. Be very careful when assembling and disassembling heavy parts such as molds to ensure production safety.

1、 Working principle of injection molding machine Injection molding machine is called injection molding machine for short Injection molding is to use the thermophysical properties of plastics to add materials from the hopper into the barrel. The outside of the barrel is heated by a heating ring to melt the materials. A screw driven by an external power motor is installed in the barrel. The materials are gradually plasticized, melted and homogenized under the dual role of screw shearing. When the screw rotates, the materials are subject to the effect of chute friction and shear force, Push the molten material to the screw head, at the same time, the screw retreats under the reaction of the material, so that the screw head forms a storage space, and completes the plasticizing process. Then, the screw, under the action of the injection cylinder piston reasoning, injects the molten material in the storage chamber into the mold cavity through the nozzle at high speed and pressure, and the molten material in the cavity is kept under pressure, cooled After curing and shaping, the mold is opened under the action of the mold clamping mechanism, and the shaped products are ejected from the mold through the ejection device. 2、 Analysis of composition and structure of injection molding machine The injection molding machine is a machine with strong electromechanical integration according to the requirements of the injection molding process. It is mainly composed of injection parts, mold closing parts, frame, hydraulic system, heating system, control system, feeding device, etc. At present, the common injection devices are single cylinder type and double cylinder type. There are two types of plasticizing parts: plunger type and screw type. During the continuous pushing process of the rotating screw, the plastic realizes the change of its physical state, and finally is injected into the mold cavity in a molten state. Therefore, the plasticizing part is the core part to complete uniform plasticization and realize quantitative injection.

The daily maintenance of the injection molding machine is mainly divided into three parts to check the machine: 1. Inspection before use. 2. Inspection during use. 3. Inspection after use. As long as the injection molding machine is checked strictly according to the above steps, not only the production efficiency of the injection molding machine can be improved, but also the service life of the injection molding machine can be extended. Method/Step 1、 The pre use inspection is divided into the following steps First, check the oil volume in the oil tank to make sure it is within the oil volume standard. Then check the room heat and oil temperature. Preheat the oil in the room at low temperature. Heat dissipation treatment should be carried out in the room at high temperature. Finally, check the pressure gauge to see whether it swings seriously, whether it can return to zero and mileage status 2、 The inspection in use is divided into the following steps 1. When starting, adjust the overflow valve to the minimum pressure 2. Check and adjust the regulating pressure of the overflow valve for continuous and even rise and fall, and adjust it to the set pressure after everything is normal 3. For the inspection of oil pump/oil shell/electromagnet, the oil temperature is 20 ℃ - 50 ℃, and the pump shell temperature is 10 ℃ - 30 ℃ higher than the room temperature 4. Oil leakage inspection 5. Noise and vibration inspection 6. Check the pressure gauge 7. Check the working condition of electrical components and the reliability of safety devices 8. Check whether the fastening nuts and screws of each column/cylinder element are loose 3、 Inspection after use, that is, after shutdown 1. Oil level inspection of oil tank 2. Check all hydraulic components 3. The handle position of each valve shall be restored to "pressure relief", "stop", "backward" and other positions. 4. Check whether the control switch button and electrical components are loose and sensitive 5. Add lubricating oil to the moving part of the movable connection between the machine column and the oil bearing 6. Turn off the power and do a good job in safety

The so-called two-color injection molding refers to the molding method of injecting two kinds of plastics with different colors into the same mold. It can make plastic parts appear two different colors, and can make plastic parts appear regular patterns or irregular moire patterns, so as to improve the practicality and beauty of plastic parts.

First of all, mold material selection is very important. Materials with high hardness are the first choice. Of course, good materials have high costs; Secondly, the mold processing technology is also important. The slow wire walking should never be used. Although the processing cost will be higher, the quality assurance is irreplaceable. This is why the secret of some molds is that they can not deform without flaring for 300000 times. Of course, this is why there are different quotations for the same mold. Liansheng Precision Company pursues to make precision molds. Quality assurance is the basic premise. We do not participate in the price war. We do brand molds.

The difficulty of the two-color mold is to make two completely identical back molds. To achieve this result, the processing technology and precision of the mold need to be a higher level than that of the monochrome mold, and when one place needs to be modified, both back molds need to be modified at the same time. This problem does not exist in the secondary forming monochrome die, which only needs to be modified separately. To do two things at the same time and two identical things at the same time, everyone can think of the great difference in difficulty and kung fu.

In addition to the process adjustment that can solve some shrinkage problems within a certain range, it is very important that after the customer's product drawings are released, the mold engineer should combine the product structure to improve the structure of structural shrinkage problems and eliminate product shrinkage from the root. This is also the fundamental reason why some molds developed for the same products have good surface quality. Liansheng Precision has rich experience and engineer team in this field.

Inspection and analysis: press the oil pump start button, and the thermal relay trips. This is related to whether the current, load and three-phase resistance are symmetrical. 1) The motor thermal relay is damaged or the setting current is too small. 2) The voltage is too low to cause the current to increase or the three-phase voltage to be unbalanced. 3) The motor three-phase winding resistance is unbalanced. 4) The total pressure or double pump pressure is adjusted too high, which causes the machine to overload and trip. 5) The oil pump is damaged or assembled too tightly, which makes MADA overload operation and trip.

Inspection and analysis: if the mode adjustment mode is selected for operation, the machine cannot realize the mode adjustment movement, the following shall be checked: 1) Whether the conditions for mold adjustment movement are met. 2) Whether the mold adjustment pressure is set too low. 3) Whether the manual operation mode is correct. 4) If there is no problem in the above inspection, check the following: ① Whether the mold adjusting hydraulic motor is stuck or the mold adjusting motor is damaged. ② Check whether the valve core of the mold adjustment hydraulic valve is stuck. ③ Whether the transmission pairs of the mold adjustment mechanism are worn or stuck.

Inspection and analysis: after starting the oil pump, the whole machine has no action both manually and automatically. Press the pressure button manually (pressure and flow have been set parameters) to see if there is pressure. 1. Check if there is no pressure 1) Check whether the rectifier board is damaged or the fuse tube is burned out. 2) Check whether the input and output of P01 board are normal. 3) Check whether the proportional relief valve is properly adjusted, damaged or stuck. 4) Whether the computer works normally. 5) Whether the pressure dial is damaged, whether the circuit is normal, or whether the pressure flow setting is too small. 2. Check if there is pressure 1) Check whether the fourteen way amplifier board is normal. 2) Whether the 0V wiring of all oil valve lines is normal.

Inspection and analysis: close the safety door, press the mold locking button (if a mold is installed, select a slow speed to avoid damaging the mold), and observe whether the mold locking indicator on the panel of the electrical box is on or whether the main computer has a mold locking signal output. 1. Check if there is no signal output 1) If there is signal input, check the external line if there is no signal input. 2) Whether the ejector pin returns to the position. If the ejector pin does not return, the mold cannot be locked. 3) Confirm whether the limit switch (made in Jilin) is damaged after the mold locking is in place. 4) If the mode locking conditions are met without mode locking signal output, the computer is damaged. 2. Check if the computer has signal output but still does not lock the mode 1) Check whether the clamping pressure is normal (press the clamping button to observe the pressure value on the pressure gauge). 2) Whether the fourteen way amplifier is normal (its input and output lights are on at the same time during operation). 3) Whether the constant slow speed valve is properly adjusted or damaged, and whether the mold opening valve is improperly adjusted or damaged. 4) Check whether the circuit connection between the mode locking output of the electrical box and the oil valve is normal, and whether the coil of the mode locking solenoid valve is normal. 5) Check whether the clamping cylinder is damaged.

Inspection and analysis: observe whether the low-voltage mold locking indicator on the panel of the electrical box is on. 1) If the light is not on, check the low-voltage mode locking inductive switch to see if it can be sensed or damaged. 2) If the light is on, check whether the low-voltage dial is properly adjusted or damaged.

Inspection and analysis: if there is no high voltage when the mode locking moves to the high-voltage induction switch, check whether the high-voltage induction switch is damaged or sensed, and the total pressure is set too low and there is no high-voltage mode locking.

Check and analysis: observe whether the computer has constant speed input and output. 1) If the computer has no constant speed input, check whether the line from the external constant speed selection knob to the computer is normal. 2) If the computer has input and no output, it is a computer fault. 3) If the computer has input and output, check whether the fourteen channel amplifier board works normally; Check whether the circuit from the fourteen way amplifier plate to the oil valve is normal; Check whether the oil valve coil is damaged. 4) The valve core of constant speed hydraulic valve is stuck by foreign matters or the constant speed flow is too small.

Inspection and analysis: first, observe whether the mold opening indicator on the panel of the main electrical box is on, and whether the main computer has input and output. 1. No signal output check item 1) Check whether the induction switch for mold opening in place is normal. 2) During manual operation, the mold opening signal light on the computer should be on, otherwise, check whether the wiring between the mold opening button and the computer is normal. If it is normal, the computer is faulty. 3) In automatic mode, if the line of the automatic selection knob is in poor contact (vibration during blanking may cause the automatic signal to break), an action cycle cannot be completed. 2. Check if the computer works normally (with input and output) 1) Check whether the fourteen way amplifier works normally. 2) Check whether the circuit from the fourteen way amplifier plate to the oil valve is normal and whether the oil valve coil is damaged. 3) Check whether the mold opening valve core is stuck by foreign matters. 4) Check whether the mold opening pressure is abnormal (observe the pressure gauge). 5) Check whether the fixing nuts between the piston rod and crosshead are loose. 6) If the power is cut off suddenly after locking the mold, it may not open the mold for a long time. At this time, set the total pressure to the maximum, select quick mold opening, press and hold the pressing button, and then click the mold opening button to open the mold. 7) Check whether the mold locking cylinder leaks.

Inspection and analysis: if the movement of the manually operated punch is normal, but there is no pressing action during the automatic operation, check the following items (the hot chamber die-casting machine should remove the hammer for inspection): 1) Whether the manual and automatic selection knobs are normal. 2) The mode locking termination inductive switch and the mode locking confirmation limit switch are not well matched, and the mode locking termination inductive switch senses, but the mode locking termination confirmation limit switch is not pressed, or the limit switch is damaged. 3) The feed termination induction switch is damaged. (This item is not available for hot chamber die-casting machine) 4) Whether there is an electrical signal in the pressure injection one speed and hammer return oil valve, and whether the valve core acts. 5) The feeding time is too short or the one speed adjustment is too slow. 6) The feed cylinder is damaged. 7) The hydraulic system has no pressure. 8) Whether it is in place before fastening. (This item is not available for cold chamber die-casting machine)

Inspection and analysis: press the oil pump start button and observe whether the motor relay is closed. 1. If the relay does not pull in, check whether 1) the motor thermal relay acts or is damaged. 2) Check whether the power circuit is normal (check with a multimeter). 3) Check whether the start and stop button contacts are normal and whether the control circuit is open circuit. 4) Check whether the relay coil is damaged (check with a multimeter). 2. If the relay is pulled in after the oil pump is started, check whether 1) the oil pump is damaged or stuck. 2) Whether the circuit from the relay to the motor is normal. 3) Check whether the oil pump is damaged or assembled too tightly. It should be easy to move the coupling by hand, and the axial moving coupling should have a clearance of about 3~5mm.