MDI elastomer is the core of polyurethane elastomer products production, high precision equipment, relying on precise metering, constant temperature material supply and high pressure casting to form the finished product. MDIs have high reactivity of raw materials and are prone to crystallization and solidification residues. Inadequate maintenance can easily lead to pipeline blockages, measurement error, casting bubbles, uneven output, etc.. These problems directly affect product quality, accelerate pump bodies and valve wear, increase equipment failure rate and downtime costs. Systematic and periodic maintenance is the key to ensure stable operation of equipment, prolong service life and maintain stable product yield. The layered maintenance procedures of MDI casting machines are introduced in detail, and industry-standard cleaning intervals for material tanks and pipes are specified.
I. Daily Routine Maintenance (required before and after start-up)
Daily maintenance focuses on inspection, cleaning and parameter verification, which are the basis for preventing short-term production failures. Before starting each day, operators must check the raw material levels in cylinders A and B to prevent the machine from drying out due to a material shortages. At the same time, they must verify temperature control systems to ensure that storage tanks and delivery pipelines are in a temperature range suitable for MDI materials, thus avoiding high viscosity due to low temperatures or degradation of materials due to high temperatures. Secondly, the operator should check pressure parameters to confirm that circulation and casting pressures are normal and that sensors and pressure gauges display accurate readings. At the end of production, the remaining material on the head and discharge nozzle surface of the casting must be cleaned, and dust and oil stains on the surface of the body must be wiped down to maintain a clean working environment. At the same time, inspect for leakage or loosening pipeline connections and valves and, if so, correct the tightening components in a timely manner to prevent material leakage or air/moisture ingress and to ensure that the equipment is in good basic operating condition.
II. Weekly Specialized Maintenance (inspection of worn parts and basic cleaning)
Weekly maintenance is focused on filtration systems, moving parts and sealing structures, in particular to address issues related to material impurities and component wear. First, filter screens must be removed from the A and B material lines to remove impurities and gel deposits; this prevents screen blockages that could lead to unstable output or measurement imbalances, and damaged filters must be replaced in a timely manner. Secondly, moving partssuch as pump bodies, drive bearings and sliding guide rail should be inspected and special grease applied to minimize mechanical wear. At the same time, the pipe seal and joint gaskets are thoroughly inspected for aging, deformation or microleakage. Due to the high permeability of MDI raw material, seal degradation can easily lead to leakage failures; therefore, proactive inspection and replacement is required. Finally, calibrate the reference dispensing parameters to ensure that the equipment's mixing ratio accuracy meets production standard.
III. Monthly In-Depth Maintenance (Core Cleaning of Material Tanks and Pipelines)
Material slots and transfer pipelines are the focus of MDI foundry maintenance and are prone to common faults and must be cleaned in strict accordance with a standard cleaning schedules. Under normal continuous production conditions, material tanks, transfer pipelines and circulation lines need to be thoroughly cleaned once a month. For intermittent production involving a daily start stop cycle, cleaning is recommended every 20 days. If the machine is idle for more than three days, the pipe must be specially cleaning process before it can be restarted. During cleaning process, the residue is removed from the container and recycled through the pipe with a specialized environmental solvent to completely remove the adherent resin residues and solidified particles, thus preventing buildup that could clog the pipe or impair the flow of the material. In addition, remove and clean precision components-such as casting heads, mixing chambers, and check valves-to eliminate air bubbles or poor curing caused by residual mixing. After cleaning, the pipe is blow-dried to prevent residual solvents from reacting with the MDI raw material.
IV. INTRODUCTION Annual Comprehensive Overhaul and Maintenance (System-Wide Performance Optimization)
The entire machine is overhauled every year to ensure long-term stability. This process requires the complete emptying material tanks, the complete removal of piping system, thorough cleaning and descaling, and the replacement of aging pipes, damaged filters and worn seals. Replace hydraulic oil and lubricants; verify accuracy of heating systems, temperature probes and pressure sensors; calibrate casting flow and mixing ratio. In addition, check pump wear and tear, replace serious wear or aging core components in a timely manner, eliminate potential faults, and restore the equipment to the original factory operating accuracy.
Emergency maintenance procedures under special operating conditions.
In addition to regular maintenance, additional upkeep is required under special operating conditions. Pipeline cleaning cycles must be shortened to once every two weeks when the equipment is operating at full power, in a hot, humid workshop environments, or in production where raw materials are frequently replaced. If the equipment is idle for more than 72 hours, raw materials must be drained from the pipes, the system must be sealed and stored, and the pipes and material tanks must be thoroughly cleaned before reopening, preventing crystallization, solidification and blockage of the pipes. If the production process appears slow, pressure instability, batch defects, etc., it is necessary to immediately stop the inspection, clean pipe impurity, do not wait for the scheduled maintenance interval.
VI. INTRODUCTION Maintenance summary and core values
Maintenance of the MDI elastomer casting machine follows the core principles of "daily inspection, weekly maintenance, monthly pipeline cleaning, annual maintenance," with monthly cleaning of material tanks and piping a top priority. Standardization and periodic maintenance can effectively solve industry pain points such as residual MDI material jamming, mixing ratio deviations and product defects, thus stabilizing product quality, significantly reducing equipment failure rate and maintenance cost, extending equipment service life, and ensuring continuous, efficient and compliant operation of production lines.