Guide for Periodic Maintenance of Hollow Blow Molding Machine

What is included in the regular maintenance of the extrusion blow molding machine?
Regular maintenance is an important part of the maintenance of the extrusion blow molding machine, including 3-6 months, 12 months and 36 months of regular maintenance, which are generally referred to as minor repairs, medium repairs and overhauls.
(1) The main content of minor repairs
①Clean the feeding pipe of the feeding system and replace the seals.
② Clean up the vacuum system.
③The machine head leakage treatment and the maintenance and cleaning of the filter replacement device.
④ Check and deal with the leakage of cooling water, lubricating oil and other pipelines and fittings.
⑤ The working oil of the hydraulic system should be supplemented in time to ensure that the oil level is in the middle of the oil standard. In order to ensure that the working oil has a suitable viscosity, it is recommended to use 32# mill hydraulic oil when the ambient temperature is low, and 46# mill hydraulic oil when the ambient temperature is high.
⑥ Every half month to one month, the oil level window of the reducer should be observed. If the oil level is lower than the specified value, an appropriate amount of 220 intermediate hydraulic gear oil (LCKC220) should be added in time. After the new machine is started, the lubricating oil should be replaced once within 300-600h. The replacement time needs to be when the reducer stops until the lubricating oil has not cooled down, and the box body should also be flushed with the same quality lubricating oil.

(2) The main content of the intermediate repair
When the extrusion blow molding machine is repaired, in addition to the minor repairs, there are mainly the following aspects.
①Check the surface of the screw, screw spline (or flat key) and clean it.
②Check or replace the porous plate and filter replacement device, repair the surface of the pallet, and adjust the clamping force.
③Check the tooth surface condition and contact condition of the gear in the reduction box, measure the backlash, clean the dirty oil at the bottom of the reduction box, eliminate the oil leakage of the sealing parts such as the oil seal, and change the oil.
④Check the concentricity and wear of the connecting sleeve (or spline sleeve) between the output shaft of the reducer and the screw
⑤Check the main motor bearing and add grease.
⑥Check the electric heater and electric control part
⑦Hydraulic system inspection, including: changing the working oil according to regulations; cleaning or replacing the filter device; checking the performance of each valve and replacing it if necessary; checking the servo system as required to ensure the quality of the parison.

(3) The main content of the overhaul
In addition to the content of the medium repair, the overhaul also includes the following aspects.
① Disassemble and pull out the extruder screw. When disassembling the screw of the extruder, it should be noted that the material in the barrel must be completely melted, and the melted material in the barrel must be extruded before disassembly. In the process of pulling out the screw, the screw should be prevented from deforming and bruising, and the steel wire rope used should be covered with a rubber tube. To clean up materials and carbon deposits on the screw surface, the tools used are copper rods, copper plates and copper brushes. Measure and record the outer diameter of each section of the screw, measure the straightness of the screw, and straighten it if necessary. Measure the fit clearance of screw splines or flat keys, record wear and remove burrs. The outer diameter of the screw, the general allowable limit of wear is less than 2mm. The straightness deviation of the screw axis should not be lower than the 8-level accuracy specified in GB/T1184, otherwise it should be corrected. The part where the chromium plating layer falls off can be repaired by brush plating or spray plating.
② Check and repair the scratched parts on the inner surface of the barrel.
③Check and adjust the coaxiality of the barrel to the output shaft of the reducer, as well as the levelness of the barrel and reducer, measure and record the gap between the screw and the barrel. The level deviation of the front and rear ends of the barrel is less than or equal to 0.05mm/m, and the tilt direction is the same.
④Disassemble and inspect bearings, lubricating oil pumps, oil distributors, seals and moving parts.
⑤Disassemble and check the main reducer, repair the gear tooth surface, adjust the gap of each part, check or replace the wearing parts such as the bearing oil seal, clean the oil tank and change the oil.
⑥Disassembly inspection or repair of feeder and feeder motor
⑦Overhaul the hydraulic system, thoroughly clean, inspect and test all hydraulic components (especially pumps and valves), and replace those that fail to meet the requirements.

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