INJECTION MOULDING MACHINE AND PREVENTIVE MAINTENANCE
Injection molding machine is commonly used in plastic processing industry one of the devices, usually it has to work long hours, so how to ensure continuous production of injection molding machine in the normal and stable work, both for the manufacturer of injection molding machine or the user is a worthy and efforts to resolve the problem, the user point of view, the correct selection of models under the premise of injection, regular preventive maintenance is to protect the injection machine to work as an effective way.Hence- called preventive maintenance is a series of prevention and inspection, in case the failure to extend the working life of parts, such as suddenstop caused by the fault into a predictable and can be planned downtime to repair or overhaul; timely find and replace damaged parts to prevent damage to other chain are the purpose of preventive maintenance work.
First, the preventive maintenance,
The hydraulic part of the
Easy oil shortage will cause the oil temperature increases, the air is easy integration into the oil and hydraulic oil to affect the normal operation of the system, fuel oil, or less than is usually due to loss of repair, this routine should be aware that there is no leak check site, early replacement of worn seals, tighten loose joints, repaired fuelto check in time supplies.
- Hydraulic oil temperature:Working hydraulic system temperature should be between 45 -50 deg c, due to a hydraulic system is based on oil viscosity and the pressure of the selected design, but the viscosity will change with the level of oil, thereby affecting the system work components, such as cylinders, hydraulic valves, so that the control accurac-y and response sensitivity decreased, the situation is even worse precision injection machine. Temperature will also accelerate the aging of the seal so that it hardened, break; temperature is too low then the processing energy consumption, the operating speed decreases. Therefore, pay close attention to the work of the hydraulic oil temperature is very necessary. Causes of high oil temperature varied, but many attributed to oil cooling system failure or failure and so on.
3. Hydraulic oil quality:
One of the important properties of hydraulic oil is its chemical stability, that is, oxidation stability. Oxidation is to determine the service life of hydraulic oil the most important factor, oxidation of wood tar, sludge and insoluble materials such as carbon residue can contaminate the hydraulic system, and increase the wear of hydraulic components, reduce a variety of gaps, plugging holes, the final result hydraulic system failure. The oxidation rate depends on the hydraulic oil itself and the working conditions and other factors, among which temperature is the main factor, so use the appropriate hydraulic oil, hydraulic oil and regularly check the degree ofoxidation (the color of the oil transfer from deep to determine ), more than a certain number of working hours after the oil change isabsolutely necessary to take the initiative.
4. Filter cleaning:
Oil filter plays the role of clean hydraulic oil, the oil filter should be cleaned once every three months to maintain the smooth flow of the oil suction tube Ga, also check the oil filter network for damage.
5. Cooler cleaning
Cooler should be cleaned once a year, or according to their ability to work has reduced the cleaning, cooler internal blockage or fouling will affect both the cooling efficiency, cooling water should choose soft (no minerals) is better.
(B), Electrical parts
Wire Connector check
Joints will not tighten the joint position of the wires have heat or sparks to damage, poor joint will also affect the signal transmission; Contactorjoint movement due to vibration and electromagnetic release more easily, so need to regularly check cable connector position and tightened.
General Motors are air cooled, and dust accumulation can cause heat problems, so regular cleaning each year, usually in the circuit is equipped with a motor overload cut off the device, the protective device current limit is adjustable, electrical power should be based on appropriate choices, once the overload protection starts, should be sure to check whether the less phase, bad contacts, or by high oil temperature recovery after the position switch.
3. Heating tube and the thermocouple:
Heating tube should be fastened on the check in order to ensure effective heat transfer, heat production in the normal burning barrel isimperceptible, this should pay attention to the temperature controller’s work, judging from heat tube is normal. Another common damage to the heating tube is that cable connection, due to bad joints, contact resistance increases, so the connection to local overheating caused interface oxidation damage.
4. Electromagnetic cont-actor:
Contactor for the electric part of the action more frequently because of its loss rate is also faster, if the melting of the main contacts overheating may result in bonding the heating temperature control, so if found contact with overheating or breaking rattle when the fire is large, then the damage will be replaced as soon as possible.
5. Computer-controlled part of the
With computer control technology applications in injection molding machines, parts and related auxiliary microcomputer electronic board to work on the supply voltage fluctuation, the working environment of temperature and humidity, the installation of seismic disturbance as well as the outside world have made high-frequency signal the higher demands, for maintaining control box ventilation fan used to work, using high precision voltage regulator equipment supply, to reduce the control box to external vibration, should
effectively address these issues and regular inspection.
(C), The mechanical parts
1, the template parallel:
Template that best reflects the parallel modelocked part of the state, the template does not cause product failure and the parallel increase in equipment and tooling wear. Parallelism of the template by the end of clamping plate when the movement and appearance of the product reflected the initial analysis, but the exact circumstances, such as equipment testing needs to dial indicator derived. Shall be parallel to adjust the template of the steps by a familiar person, or improper adjustment of the machine more damage.
2, the mold thickness adjustment Mold thickness should be adjusted regularly use the system, the module thickness from the thickest to the thinnest to the callback action to ensure a smooth, longterm production of machines with the same mold, this check must be carried out in order to avoid failure.
3, the central lubrication system All mechanical moving parts need to have proper lubrication, the central lubrication system is one of the necessary injection molding Central oil lubrication system should pay attention to always check whether the fill, the use of lubricating oil to be clean and free of impurities to ensure that all locations of lubrication oil supply. Found to be blocked or leaking pipes should be immediately replaced or repaired. Most of the mechanical wear is occurring due to lack of lubrication, and therefore the importance of adequate lubrication.
4, maintaining the smooth operation Smooth movement or vibration may be inappropriate because of the speed adjustment, speed changes and time inconsistent or mechanical, hydraulic adjustment caused. Mechanical part of such shock will accelerate the wear and loosening the screws have been tightened, it should reduce and prevent vibration.
5, bearing checking Bearing a different sound at work issue, or the internal temperature means that the bearing is worn, it is timely inspection or replacement, and re-injection of grease.
6, injection system Injection screw, check ring and barrel form the heart of injection molding machine to determine the processing quality and efficiency, we must keep them in good working condition. First to take the necessary measures to prevent nonplastic debris mixed with plastic material flow, the addition should pay attention to check the screw and barrel, the check ring and barrel of the correct gap, the normal clearance should be able to return and produce plastic sealed required plasticizing shearing, when found slow melt, melt spotted and black spots, forming unstable or product should check the screw, check ring and barrel wear.
Second, some of the causes of common faults and solutions
, the oil temperature is too high
Abnormal rise in oil temperature may be normal or hydraulic cooling system components are not at work caused by generating heat.
1, the cooling system is not normal
1) inadequate supply of cooling systems, water valves not fully open, water pressure or pump flow does not meet the needs.
2) pipe plug, such as filters, cooling towers or water blockage.
3) cooling water temperature is too high, such as insufficient cooling capacity cooling towers, or damage or the temperature too high.
2, the hydraulic system to produce heat
1) The pump is damaged, the internal parts wear at high speed rotation produces heat.
2) improper pressure regulator, high pressure hydraulic system and a long period of overheating.
3) hydraulic components within the leak, such as the direction of valve damage or ring damage that high pressure oil flows through the small space heat.
(B), the noise generated
Abnormal noise generation, there are parts that damaged or improperly adjusted, the noise issue should identify the reasons for the location of real-time maintenance.
1, less than the hydraulic oil, oil pump or oil filter dirt blocking the air inhaled can cause pump starvation, resulting in air in the discharge of oil leaves the noise impact, the solution is to check the oil, to prevent the inhalation of air and cleaning oil filter.
2, hydraulic oil viscosity is high, increase the flow resistance, the right to replace the hydraulic oil.
3, the pump or the motor bearings or blade damage caused by the coupling concentricity deviation of the noise, should adjust the concentricity or replacement parts.
4, the direction of valve failure but the function is still reactive, such as heart valve wear, internal leakage, burr block does not move freely, the electromagnetic valve failure due to insufficient current will produce noise. The solution is to clean the spool, spool to be replaced with new parts wear, the current to be stable and adequate.
5, hydraulic components damaged or blocked oil pipeline that high-speed flow of hydraulic fluid when the noise.
6, mechanical failure, lack of lubrication or mechanical bearing wear or component loosening, should find out the cause of the fastening parts or replacement – Ensure there is sufficient oil.
(C), unstable or substandard products
In a stable production cycle, the emergence of unstable product quality, may be the mechanical parts caused by wear or improper adjustment.
1, screw, check ring and barrel wear.
2, injection of the fuel caused damage to the seals leak.
3, the heating tube temperature control instability.
4, pressure, speed control part of the disorder.