In order to achieve machine performance and prolong service life, machine should be checked regularly and repaired accordingly. Oil sealing ring, rubber ring, etc. of machine will naturally wear and tear over time. If they lose their function and cause oil leakage, they only need to be replaced according to specifications. If machine has been stopped for a long time, or when different plastics need to be injected, remaining rubber in melt cylinder must be removed first.

 

Hydraulic device is composed of precise hydraulic components. After a long period of operation, pressure oil will inevitably be polluted, resulting in oil may contain pollution and solid substances such as metal powder, oil seals, debris, and silt. In fact, more than 70% of failures of hydraulic devices are related to pressure oil.
Valve core is blocked by dirt in hydraulic components. Reasons are as follows:
1) In process of adding new pressure oil, because pressure oil enters oil tank of injection molding machine through delivery pipe, it is easy to bring in a lot of metal and rubber particles.
2) Due to wear and tear of hydraulic components such as oil pumps, hydraulic motors, directional valves and pump cores, particles easily enter hydraulic system with pressure oil, thus causing pollution.
In order to ensure normal operation of hydraulic system and reduce failures, pressure oil air filter, oil filter and cooler must be maintained and inspected.

Within six months of using the pressure oil, 100C.C. pressure oil should be taken from oil tank and sent to laboratory for testing. If pressure oil is found to have deteriorated, it should be replaced immediately. Please replace pressure oil within 3 months of new machine running. Then replace pressure oil once a year.
If for some reason, it cannot be sent to laboratory, you can refer to following methods for inspection:
Take a sample of pressure oil from oil tank, and observe color of pressure oil after extraction. If it turns milky white, it may be that air or water is mixed in pressure oil.
At this time, pressure oil should be placed in room and observed every other day. If pressure oil has become clear, it means that air is mixed into oil, and air leakage of hydraulic system should be found out; System has been mixed with water; if it is milky white, it means that water has been mixed into pressure oil for a long time, and new pressure oil must be replaced. Check condition of each hydraulic component and find out way of water mixing.
Usually caused by a broken cooler. Using filter paper or toilet paper, you can also check whether there is water or impurities in pressure oil. Drop sample of pressure oil on filter paper or toilet paper. If pressure oil contains water, water content in pressure oil can be identified due to fast diffusion speed (compared with new pressure oil). Pour pressure oil through filter paper and let filter paper stand for several hours. If pressure oil has deteriorated or contains impurities, black marks or impurities will appear in the center of filter paper. (Above method of checking pressure oil is for reference only, and it is recommended to send it for testing).
When changing pressure oil or replenishing pressure oil, following items should be paid attention to:
1) Supplementary pressure oil must be exactly same as pressure oil in the system. After different pressure oils are mixed, chemical reactions will occur, which will affect quality of pressure oil.
2) If pressure oil decreases without reason, reason should be found out first, then supplemented.
3) When replacing pressure oil, all oil in oil tank should be pumped out. Also clean inside of fuel tank.
4) When changing oil, oil filter should be cleaned first.
5) Throat used for adding pressure oil must be kept clean.
6) When adding pressure oil, do not directly add it to oil tank, but use a filter to filter it before adding it.
Do not use rags for cleaning, as lint left behind will clog filter screen of oil filter.

On top cover of fuel tank, an air filter that doubles as an oil inlet for pressure oil is installed. According to change of oil level in fuel tank, air in fuel tank is easy to enter and exit. After adding or supplementing pressure oil each time, please take out filter and put it on container, clean it with gasoline and dry it with compressed air. If it is not cleaned, it may cause dirt to enter fuel tank.

After machine starts running for 2 weeks, please take out oil filter and clean it every three months to keep oil pump suction pipe unblocked. If filter screen on oil filter is blocked by objects, it will cause oil pump to generate noise.
Oil filter cleaning steps:
1) Open fuel tank cap and take out oil filter.
2) Put oil filter on a container, add some gasoline, wash filter with a brush, then dry inner and outer parts of filter with compressed air.
3) Reinstall oil filter and replace fuel tank cap.

After cooler has been used for a period of time, scale will adhere to inner wall of cooling pipe of cooler, resulting in a decrease in heat transfer efficiency and an increase in pressure oil. Therefore, cooler should be cleaned every 6 months. Cooler disassembly and cleaning steps:
1) Make sure that pressure oil in tank has been completely pumped out.
2) Make sure that water gate for cooling water supply is closed.
3) Put container on connecting part of pressure oil and cooling water, so that it is convenient to hold water and oil when oil pipe and water pipe are removed.
4) Remove cooling water pipe and pressure oil pipe on cooler.
5) Remove screws fixing cooler on machine.
6) Drain all pressure oil and cooling water in cooler.
7) Loosen fixing screws of outer covers on both sides of cooler, and take out outer covers.
8) Take out heat dissipation copper tube and barrier plate.
9) Use a copper brush to clean inner and outer parts of hot copper pipe.

When injection molding works normally, temperature of pressure oil is best kept at 30 to 50 degrees Celsius. Excessive pressure oil temperature may cause following phenomena:
1) Oxidation is accelerated and quality of pressure oil deteriorates;
2) Decrease in the concentration of pressure oil may lead to a decrease in lubricating function, oil pump and oil valve may be easily damaged;
3) Oil sealing ring is easy to harden, reducing oil sealing function.

Mold clamping part is an important lubricating place, including large and small hinge edges, sliding feet and guide rods. Due to continuous reciprocating friction for a long time, if there is no proper lubrication, parts will wear out quickly, which directly affects performance and quality of mechanical parts.

 

To ensure that lubrication system is functioning properly, please check following points:
1) In general use, it is recommended to set parameters for lubrication, and drain oil for 3-5 seconds every 10 injection cycles.
2) Every four months or 500,000 cycles, lubricating oil needs to be replaced and oil return, oil suction filter and oil tank should be cleaned.
3) Under normal use, oil storage will gradually decrease, and oil storage needs to be checked every week.
4) Regularly check whether motor works normally.
5) Keep oil tank and lubricating oil clean, avoid mixing lubricating oil with water. If there is water, please take out throat plug of oil drain hole at the bottom of lubricating oil tank, and drain water.
6) In addition, lubricating grease nozzles (grease nozzles) are used for mold screw nuts, tie bar copper parts, sliding feet, drive shafts of melted plastic motors, front and rear (T-slot) guide rails of injection table, and electric motor bearings. Please fill grease (butter) regularly, and it is recommended to refill grease (butter) once a month.
Note: Do not use pressure oil as lubricating oil, because viscosity of the two is different. If it is used for cost saving, it will cause wear and tear on hinge.

Moving or rotating part of clamping structure is prone to wear due to lack of lubricating oil. If you can pay attention to smooth flow of lubricating oil supply to each rotating part of clamping structure, and always pay attention to screws or nuts used for firmness, damage or failure of mold clamping part will be reduced. In addition, following points should be noted:
1) Sufficient lubricating oil can prevent wear of hinge part.
2) Regularly check whether lubricating transparent throat of centralized lubrication system of machine hinge is smooth and whether it is broken or damaged.
3) Regularly check whether there is any bad wear on hinge part, and whether there is iron powder seeping out.
4) Keep slide rails of mobile formwork clean and lubricated.
5) Keep surface of four Corinthians clean.
6) Do not use bad molds, which will wear out machine hinge and cause Corinthian pillar to break.
7) Do not use excessive clamping force, it will cause unnecessary deformation of mold and cavity. But also can cause service life shortening or damage of machine hinge, mold and Corinthian column.
8) Do not use a mold that is too small, too small a mold will generate high bending stress on mold plate, and long-term use will cause mold plate to burst.

Note following points:
1) Do not activate melter motor to melt glue when melter barrel has not reached preset temperature.
2) When using reverse cable, make sure that plastic in melt is completely melted, otherwise screw will be damaged when screw is retreated, rubber head kit or components of transmission system will be damaged.
3) Except for plastics and plastic additives, do not put anything else into hopper. If a large amount of nozzle material is used, a hopper magnet should be added to prevent metal fragments from entering melt cylinder.
4) When disassembling or replacing nozzle, bolt rubber ring, injection glue meson, and fixing screws on head, it is necessary to apply a layer of high temperature resistant lubricating oil. If not, screw part will be oxidized and it will be difficult to remove in the future .
5) If you use (PVC, POM) and other plastics, please inject all plastics in plastic tube before each shutdown, then use PE, PP plastics to clean plastic tube.
6) When temperature of melt cylinder is normal but black spots or discoloration of melt continue to be found, check whether injection screw, bolting rubber ring and injection meson are worn.
7) Periodically check whether screw on injection piston rod is loose.

1) Generally, electric motors use air cooling to dissipate heat. Too much dust accumulation will cause difficulty in dissipating heat. Dust around external hub and fan blades should be cleaned once a year.
2) When electric motor makes abnormal noise, check whether bearing is worn, and replace it immediately if worn.
3) Use a 500V megohmmeter to measure whether insulation resistance of coil is above 1MΩ.

Mold thickness adjustment device should be used regularly to adjust mold plate back and forth from the thickest to the thinnest to ensure smooth movement. If machine produced by same mold is used for a long time, this inspection must be carried out to avoid failure during mold adjustment, and at the same time apply lubricating grease to mold adjustment gear and chain.

1) Check pressure hose and see if outer skin is damaged.
2) Check nozzle of pressure hose for looseness.

Center point of injection nozzle has been adjusted before machine leaves factory. If you do not replace melt barrel or clean injection screw, please do not adjust it arbitrarily.
Adjustment steps:
1) Prepare a caliper. If mold has been installed on machine, disassemble mold first.
2) Press 'Injection platform forward' key to make injection platform advance until nozzle and clamping plate are on same plane, and loosen four fixing screws of injection platform.
3) Use a caliper to measure whether horizontal and vertical distances between center hole of nozzle and positioning ring of clamping plate are equal.
4) If horizontal distances are not equal, use an appropriate tool (such as a wrench) to adjust with side of nozzle as force point and side of center hole of head plate as fulcrum.
5) If vertical distances are not equal, fine-tune four height adjustment screws.
6) Re-measure horizontal and vertical distance between center hole of nozzle and positioning ring of clamping plate, if there is any deviation, repeat steps 4 to 5.
7) Retighten four fixing screws.

 

In order to ensure normal operation of machine and reduce occurrence of failures. Maintain high performance, service life, safe operation of machine and shorten downtime caused by failure. Regular maintenance checks must be carried out on machine. Maintenance inspection can be divided into daily, weekly, monthly, semi-annual and annual maintenance.

1) Make sure that emergency stop button can cut off part of motor power of oil pump.
2) Keep injection molding machine and machine body clean.
3) Check whether temperature needle and heating cylinder are operating normally.
4) Check whether mold locking can be terminated when safety door is opened. Manual and fully semi-automatic mode-locking were used for testing.
5) Check whether mold is firmly installed on clamping head plate and moving mold plate.
6) Check whether there is water leakage in each cooling water delivery pipe, and tighten leaking pipe.
7) Check that all cover panels are firmly installed on machine.
8) After starting up and running for a period of time, check whether oil temperature has risen above 50 degrees Celsius. Check cooling water temperature of supply cooling, oil temperature should be maintained at 30-50 degrees Celsius.
9) Check whether mechanical safety lock is operating normally.

1) Check whether lubricating throats are broken or damaged.
2) Check whether pulleys of the limit card system of each safety door are worn.
3) Check whether screws of moving parts of machine are loose, and retighten them if any.

1) Check whether electrical components and wiring are loose, and if so, tighten them again.
2) Check whether working pressure of hydraulic system is too low or too high.
3) Check whether there is any oil leakage in each part of the whole machine. If there is, tighten oil hose joint of oil leakage or replace oil seal of damaged hydraulic component.
4) Check whether system pressure gauge is operating normally.

 

1) Check whether installation of each galvanic wire and heating cylinder is stable.
2) Check whether installation of each electronic ruler and proximity switch is stable.
3) Recheck nozzle center degree.

1) Check whether relay inside electric box and contacts of electromagnetic contactor are aging, and replace them with new ones if necessary.
2) Check whether wire connections inside electrical box and outside fuselage are secure.
3) Clean inner and outer walls of copper pipe of cooler.
4) Check whether four Corinthian screw nuts on clamping head plate are installed firmly and whether they are loosened.
5) Check linear ratio of speed and pressure, and readjust if necessary.
6) Check all parts of machine for oil leakage.
7) Check whether working pressure of hydraulic system is too low or too high.
8) Clean oil tank.

1) Check whether fixing screws of safety mechanism are tightened.
2) Clean inner and outer walls of copper pipe of cooler.
3) Clean fuel tank.
4) Clean dirt on oil filter and clean dust on air filter.
5) Check whether pressure oil needs to be replaced, take a sample of pressure oil and send it to laboratory for testing. If pressure oil deteriorates, it must be replaced with new oil.
6) Clean dust on the surface of motor fan blade and outer socket, and inject lubricating grease on bearing.
7) Check exposed wires of fuselage, if damaged, it must be replaced.
8) Check if there is any noise in bearing combination of oil pressure motor, refill grease or replace new bearing.
9) Recheck fuselage level.
10) Recheck parallelism between clamping head plate and moving mold plate.
11) Check linear ratio of speed and pressure, and readjust if necessary.
12) Check whether working pressure of hydraulic system is too low or too high.
13) Check whether there is oil leakage in each part of the whole machine