What should be paid attention to during the installation of motor assembly line?

The installation quality of motor assembly line directly determines the motor production efficiency, product qualification rate and equipment service life. The installation process needs to be carried out around the three cores of "precision control, safety compliance and process adaptation", and the specific precautions can be subdivided into the following six key dimensions:

First, preliminary preparation: avoid "blind construction" and ensure foundation adaptation.

Planning before installation is the core to avoid the later problems, and the following three points need to be confirmed:

Verification of site and basic conditions

Ground bearing: according to the total weight of the assembly line (including equipment, tooling and materials), confirm that the ground bearing is more than or equal to the design requirements (usually 500 kg/㎡ for light assembly lines and 1000 kg/㎡ for heavy ones), so as to avoid ground settlement and line inclination caused by long-term use;

Space size: reserve "feeding and discharging buffer space" at both ends of the wire body (usually ≥1.5m) and "operation and maintenance space" at both sides (single side ≥0.8m), and confirm that the ceiling height can meet the lifting requirements (if heavy parts such as motor stator/rotor are involved in lifting, a clearance of ≥2m shall be reserved);

Environmental adaptation: If the assembly line contains precision inspection stations (such as motor insulation test and dynamic balance test), it is necessary to confirm that the temperature and humidity (normal temperature 20-25℃, humidity 40%-60%) and dust concentration (≤ 0.5 mg/m) of the site meet the standards to avoid environmental impact on the inspection accuracy.

Check equipment and drawings.

Check the model, specification and quantity of parts (such as conveying roller, positioning fixture, tightening machine and testing instrument) one by one according to the assembly line design drawings (including assembly drawing, electrical schematic drawing and station layout drawing) to ensure that there is no wrong hair and missing hair (for example, the model of pressure sensor of motor bearing press-fitting station should be consistent with the design);

Check the integrity of key components: for example, the rollers of the conveying chain are not deformed, the surface of the guide rail is not scratched, and the encoder of the servo motor is not damaged, so as to avoid rework after installation due to component defects.

Tools and personnel preparation

Tool accuracy: Prepare installation tools that meet the accuracy requirements, such as torque wrench (accuracy 3%), level meter (accuracy 0.02mm/m) and laser centering instrument (used for the alignment of motor and conveying shaft), and check the effectiveness of tools in advance;

Personnel qualification: Installers should be familiar with motor assembly process (such as determining rotor assembly sequence and winding wiring specification), and electrical wiring personnel should hold electrician certificates to avoid potential safety hazards or assembly errors caused by unprofessional operation.

Second, mechanical installation: strictly control the "precision error" to ensure the stable operation of the wire body.

The mechanical part is the skeleton of the assembly line, and it is necessary to focus on controlling the three core indicators of "levelness, coaxiality and positioning accuracy":

Installation of wire frame: first level, then fix.

Calibrate the wire frame along the conveying direction (longitudinal direction) and vertical direction (transverse direction) with a level instrument to ensure that the horizontal error within each meter length is ≤0.5mm (when the total length exceeds 10m, the cumulative error is ≤3mm), so as to avoid the transportation jam caused by frame inclination;

When using expansion bolts to fix the frame, they should be installed according to the design spacing (usually ≤1.5m/piece), and the bolt tightening torque should meet the requirements (such as M12 bolt torque ≥ 45 nm) to prevent the bolts from loosening due to long-term vibration.

Installation of conveying system: reducing the risk of "jamming"

Conveying roller table/chain: calibrate the coaxiality of adjacent roller tables (error ≤0.1mm) and the tension of the chain (sag ≤2% span) to ensure that there is no abnormal sound or jamming during operation; In case of belt conveying, it is necessary to adjust the belt deviation (unilateral deviation ≤5mm/10m) to avoid belt wear or material deviation;

Positioning fixture: After installation, the flatness (≤0.05mm) and parallelism (≤0.1mm/m) of the fixture positioning surface shall be detected with a dial indicator to ensure accurate positioning of the motor housing/rotor and other workpieces and avoid subsequent assembly dislocation.

Installation of process equipment: adapting to "assembly accuracy"

Press-fitting equipment (such as bearing press-fitting machine): it is necessary to calibrate the concentricity between the press head and the workpiece (error ≤0.03mm) and test the control accuracy of press-fitting force (error ≤ 5% set value) to prevent parts from being damaged due to too tight press-fitting and abnormal sound caused by too loose press-fitting;

Tightening equipment (such as bolt tightening machine): After installation, it is necessary to check the torque accuracy (error ≤ 3%), and ensure the coaxiality between the tightening shaft and the bolt (≤0.05mm) to avoid the bolt slipping or the torque is not up to standard, which will lead to the bolt loosening when the motor is running.

3. Installation of electrical system: Avoid "potential safety hazards" and ensure signal stability.

Electrical system is the "nerve" of assembly line, which needs to give consideration to safety compliance and signal transmission reliability;

Wiring Specification: Avoid "Messiness" and "Interference"

Power lines (such as motor power lines) and signal lines (such as sensor and encoder lines) are wired separately (with a distance of ≥150mm), and the signal lines need to be shielded by metal pipes to prevent signal distortion caused by electromagnetic interference of power lines;

Cable fixation: use clamps to fix cables every 300-500mm along the frame of the line to avoid cable sagging and friction with moving parts; The joint should be waterproof (such as damp in the workshop) and dustproof, and wrapped with heat shrinkable tube to prevent poor contact.

Grounding and insulation: ensuring "personal safety"

Grounding resistance: the wire frame, equipment shell and electrical control cabinet shall be grounded separately, and the grounding resistance shall be ≤ 4Ω; If precision testing equipment is involved, independent grounding (grounding resistance ≤1Ω) is required to avoid common ground interference;

Insulation test: after installation, use megohmmeter to test the insulation resistance of power circuit (≥0.5MΩ) and control circuit (≥1MΩ) to prevent electric shock caused by electric leakage.

Installation of electrical components: ensure "reliable function"

Sensors (such as photoelectric sensors and proximity switches): the installation position should be accurate (the detection distance error is less than or equal to 5%), and the sensitivity should be adjusted to avoid false triggering (such as missing workpieces) or not triggering (such as multiple workpieces);

Control cabinet: It is installed in a ventilated and dust-free area, with reasonable layout of internal components (heat dissipation components are far away from relays) and clearly marked terminals (such as "Motor 1 power line" and "Positioning sensor signal") to facilitate later maintenance.

Fourth, safety protection: implement the "fool-proof design" to reduce operational risks.

Motor assembly line involves mechanical movement and electrical energy consumption, so safety protection measures should be fully implemented:

Physical protection: isolate "dangerous areas"

Moving parts: chains, gears and other moving parts on both sides of the wire body need to be equipped with protective nets/shields (mesh ≤12mm, height ≥1.2m), and protective doors need to be equipped with interlocking devices (the wire body will stop immediately when the door is opened);

High-altitude station: If there is an assembly station higher than 1.5m, it is necessary to install guardrail (height ≥1.1m) and anti-skid pedal to prevent people from falling.

Electrical safety: set up "double protection"

Overload protection: each motor loop should be equipped with circuit breakers (overload current is 1.2-1.5 times of rated current) and thermal relays to prevent the motor from being burnt out due to overload;

Emergency stop: the line body is provided with an emergency stop button (red, prominently installed) every 10-15m, and the emergency stop signal needs to be directly connected to the main control loop, so as to ensure that the line body is powered off immediately after being pressed without delay.

Warning sign: define "risk warning"

Clear signs (such as "Be careful to pinch your hands", "Do not cross" and "High-voltage danger") shall be posted on protective doors, emergency stop buttons and high-voltage areas. The size of the signs shall be ≥100mm×100mm, and the colors shall be in sharp contrast (white characters on red background/black characters on yellow background).

V. Preliminary check after installation: avoid "putting into production with errors"

After the installation is completed, static and dynamic verification shall be carried out to find problems in advance:

Static verification: Confirm that "the hardware is up to standard"

Re-test key accuracy: such as wire levelness, fixture positioning accuracy and electrical insulation resistance to ensure that it meets the design requirements;

Check the tightness of components: retighten all connecting bolts (such as frame bolts and equipment fixing bolts) with a torque wrench to avoid looseness during installation.

Dynamic commissioning: testing "operational stability"

No-load test run: run for 1-2 hours with no-load after power-on, and observe the running speed of the wire body (error ≤ 2% set value), no jamming noise, and no overheating (temperature rise ≤ 40℃) of electrical components (such as sensors and motors);

Load trial run: Run for 4-8 hours according to the design load (such as placing one motor to be assembled at each station), test the bearing capacity of the conveying system and the coordination of the process equipment (such as no delay in the process connection of press-fitting-tightening-testing), and record the stability of key parameters (such as press-fitting force and tightening torque).

VI. Documentation and Training: Guarantee "Post-maintenance"

In the final stage of installation, it is necessary to improve the documentation and personnel training to lay the foundation for subsequent operation and maintenance:

Documentation: Retaining "Traceability Basis"

Arrange installation records: including equipment inventory table, accuracy test report, electrical wiring diagram and commissioning parameter record table, and file them for preservation;

Handover of technical data: hand over design drawings, equipment specifications and spare parts list to customers/users, and specify the maintenance period (such as chain lubrication once every three months and sensor calibration once every six months).

Personnel training: ensure "correct operation"

Operation training: instruct the on-site operators to be familiar with the starting and stopping of the wire body, parameter adjustment, and common fault handling (such as the emergency stop operation when the material is stuck and the calibration method of sensor misoperation);

Maintenance training: explain the principle of electrical circuit, the disassembly process of mechanical parts (such as the replacement method of conveying roller table) and the replacement cycle of key parts to maintenance personnel to avoid equipment damage due to improper maintenance.

To sum up, the installation of motor assembly line needs to run through the whole process requirements of "accuracy, safety and compliance", and every step needs to strictly control the details, so as to ensure that the operation goal of "high efficiency, stability and low failure rate" can be achieved after the assembly line is put into production.