Three color material high-speed injection molding machine is the core equipment for producing multi-color plastic products (such as two-color handles and three color toys), and its maintenance needs to be taken into accountHigh speed operation stability, multi-color material switching accuracy, mold lifeThree core requirements. From the followingDaily maintenance, key component maintenance, fault prevention, safe operation, spare parts managementFive dimensions are developed, combined with the process characteristics of high-speed injection molding machines (firing rate ≥ 300mm/s) and multi-color materials (such as ABS+PC+TPU), to provide a systematic solution:

1、 Daily maintenance: Ensure the basic condition of the equipment

1. Cleaning and dust prevention (after each shift of production)

• Body and electrical control cabinet：
  • Use compressed air (pressure 0.3-0.5MPa) to blow away dust on the surface of the machine body (especially in the injection unit and mold area), to prevent dust from entering the hydraulic system or electronic control components (dust concentration should be controlled at ≤ 5mg/m ³ to avoid short circuit risks);
  • Use a vacuum cleaner (with HEPA filter) to clean the inside of the electrical control cabinet, and do not wipe it with a damp cloth (to prevent corrosion of the circuit board caused by condensed water).
• Hopper and dryer：
  • Clean the residual materials in the three color material hopper (use a soft bristled brush to avoid scratching the inner wall), and check the filter screen of the dryer (if blocked, it will cause the moisture content of the material to exceed the standard, such as PC material, which needs to have a moisture content of ≤ 0.02%);
  • The temperature of the dryer should be set according to the material requirements (such as ABS 80-85 ℃, TPU 60-70 ℃), and temperature fluctuations should be recorded for each shift (with an error of ≤± 2 ℃).

2. Lubrication and rust prevention (before daily production)

• Guide rails and sliders：
  • Apply high-speed grease (such as KLUBER ISOFLEX TOPAS NB 52) to the X/Y/Z axis guide rails (such as linear guides), covering the contact surface of the guide rails but not in excess (excessive amount may cause dust accumulation);
  • Check the fastening bolts of the slider (refer to the equipment manual for torque values, such as 12-15N · m for M8 bolts) to prevent loosening during high-speed operation.
• hydraulic system：
  • Check the hydraulic oil level (between the upper and lower limits of the oil gauge), and if the oil level is too low, replenish it (the oil type should be the same as the original hydraulic oil, such as Shell Tellus S4 MX 46);
  • Observe the color of the hydraulic oil (normally it should be light yellow, if it turns black, it needs to be replaced immediately to avoid oil sludge blocking the valve core).

2、 Key component maintenance: extending core life

1. Glue injection system (multi-color material core)

• Screw and barrel：
  • Cleaning switchWhen changing the color of the material, use specialized cleaning agents (such as polyester cleaning agents) to clean the screw to avoid carbonization of residual materials (carbides can scratch the inner wall of the material cylinder, causing glue leakage);
  • Wear detectionEvery quarter, use an endoscope to inspect the root of the screw (easily worn area) and the inner wall of the barrel. If the diameter of the screw is worn by more than 0.5mm or the inner diameter of the barrel is worn by more than 1mm, it needs to be replaced (the cost of the screw is about 20000 to 50000 yuan per piece, and the cost of the barrel is about 30000 to 80000 yuan per piece);
  • temperature controlThe temperature of the three color material nozzle needs to be independently controlled (such as ABS 220-240 ℃, PC 280-300 ℃, TPU 190-210 ℃), and the temperature sensor should be calibrated with an infrared thermometer every shift (with an error of ≤± 3 ℃).
• measurement system：
  • Check the sealing of the Back Pressure Valve (leakage can cause inaccurate measurement, and if the proportion deviation of multi-color materials is greater than 5%, the product will be scrapped);
  • Monthly calibration of measuring sensors (tested with standard weights, with an error of ≤± 0.1g, otherwise PID parameters need to be adjusted or sensors need to be replaced).

2. Mold and ejector system

• mold maintenance：
  • cooling water circuitCheck the cooling water flow rate (≥ 5L/min) and temperature (recommended 15-20 ℃) of the mold every shift. If the flow rate is insufficient, clean the water nozzle (scale blockage can cause uneven mold temperature and product deformation);
  • Top needle lubricationApply high-temperature resistant grease (such as Molykote X-5-1) to the top pin of the mold every 5000 molds (to avoid the top pin getting stuck and causing damage to the mold);
  • Cleaning of parting surfaceClean the residual adhesive on the parting surface with a copper scraper (steel tools are prohibited to avoid scratching the mold), and clean it once per shift (the accumulation of residual adhesive can cause a flash thickness greater than 0.1mm).
• Ejection mechanism：
  • Check the sealing ring of the ejector cylinder (if there is a leak, it will cause insufficient ejector force and deformation of the product), and replace the sealing ring every six months (cost about 200-500 yuan/set);
  • Adjust the ejection speed (to match the mold opening speed, with an error of ≤ 10%) to avoid product whitening caused by high-speed ejection.

3. Hydraulic and Electrical Systems

• hydraulic valve：
  • Clean the proportion valve (such as MOOG servo valve) filter screen every quarter (blockage can cause pressure fluctuations and affect the accuracy of glue injection), and use an ultrasonic cleaning machine (frequency 40kHz) to clean for 10 minutes;
  • Check the noise of the hydraulic pump (normally ≤ 75dB, if abnormal, replace the bearings or pump body).
• electrical components：
  • Check the cooling fan of the servo drive (if it stops, it will cause the drive to overheat and trigger an alarm), and clean the fan dust every month;
  • Calibrate the encoder (such as the Heidenhain encoder) signal (every six months) to ensure a position accuracy of ≤ 0.01mm (otherwise it may cause misalignment of multi-color materials).

3、 Fault prevention: reduce downtime risk

1. Common faults and solutions

Fault phenomenon	Possible reasons	Solution
Uneven mixing of multi-color materials	Mismatched screw speed and insufficient back pressure	Adjust the screw speed (such as ABS 150-200rpm, PC 100-150rpm) and increase the back pressure to 5-10MPa
Injection pressure fluctuation>5%	Hydraulic oil contamination, proportional valve malfunction	Replace hydraulic oil (every 2000 hours), clean or replace proportional valve
Mold temperature deviation>3 ℃	Damaged heating tube, blocked cooling water circuit	Replace the heating tube (power needs to match the mold requirements), clean the cooling water circuit with citric acid (concentration 5%, cycle for 2 hours)
Abnormal vibration of equipment	Coupling wear and loose foundation	Replace the coupling (such as an elastic coupling, with an allowable deviation of ± 0.1mm), tighten the foundation bolts (torque must meet the requirements of the equipment manual)

2. Preventive maintenance plan

• dailyCheck the hydraulic oil level, lubricate the guide rail, and clean the hopper;
• weeklyCalibrate the temperature sensor and check the cooling water circuit of the mold;
• monthlyClean the proportional valve filter and check the electrical connections;
• quarterlyReplace hydraulic oil filter element and detect screw wear;
• every yearOverhaul equipment (disassemble and clean all components, replace sealing rings, calibrate encoders).

4、 Safe operation: Avoid personal and equipment damage

1. Pre operation inspection

• safety device：
  • Check if the safety grating (such as SICK grating) is sensitive (test method: cover the grating with your hand, and the equipment should stop within 1 second);
  • Confirm that the emergency stop button (E-Stop) can be triggered normally (the device should stop all actions within 0.5 seconds after pressing).
• Electrical safety：
  • Check if the power cord is damaged (if the skin cracks, it needs to be replaced), and if the grounding wire is reliably connected (grounding resistance ≤ 4 Ω);
  • The distribution box needs to be equipped with a leakage protector (operating current ≤ 30mA, operating time ≤ 0.1s), and the sensitivity should be tested once a month.

2. Precautions during operation

• Prohibited matters：
  • It is strictly prohibited to adjust the position of the ejector pin when the mold is closed (which may cause damage to the mold);
  • It is strictly prohibited to touch the nozzle during injection (surface temperature can reach over 300 ℃, which may cause burns).
• Temperature monitoring：
  • The temperature of the material barrel needs to be displayed in real time (such as a digital thermometer). If the temperature is abnormal (>set value 5 ℃ or<set value 3 ℃), the machine should be stopped immediately for inspection;
  • The temperature of the mold needs to be monitored by a thermocouple (with an error of ≤± 1 ℃) to avoid material decomposition caused by excessive temperature (such as toxic gases produced by PC material decomposition).

3. Post operation processing

• Power outage and cleaning：
  • After turning off the device power, wait for 15 minutes for the hydraulic system to release pressure (to avoid injury from residual pressure);
  • Hang a "No Closing" warning sign and clean up the oil stains around the equipment to prevent slipping.

5、 Spare parts management: ensuring quick response

1. Key spare parts list

Spare Part Name	Low inventory level	replacement cycle	Supplier Information
Screw (three color universal)	1 piece	According to the wear and tear condition	XX Screw Manufacturing Factory (Phone: XXX)
Proportional valve (MOOG)	2 of them	3 years	XX Hydraulic Components Company (Phone: XXX)
Heating tube (500W)	5 pieces	2 years	XX Electric Heating Element Factory (Phone: XXX)
Encoder (Heidenhain)	1 piece	5 years	XX Automation Company (Phone: XXX)

2. Inventory warning and procurement

• When the quantity of spare parts is ≤ low inventory, the procurement process must be initiated within 3 working days (to avoid downtime for more than 24 hours due to missing parts);
• Spare parts should be stored by model (such as hydraulic parts, electrical parts, mechanical parts) and labeled with replacement dates and supplier information.