Preparation before the assignment
(1) Work data: including general assembly drawings, component assembly drawings, part drawings, material BOM, etc. Until the end of the project, the completeness, neatness and completeness of process information records of the drawings must be ensured.
(2) Workplace: Parts placement and component assembly must be carried out in the designated workplace. The site for the placement and assembly of the whole machine must be clearly planned. Until the end of the entire project, all workplaces must be kept neat, standardized and orderly.
(3) Assembly materials: Before the operation, the assembly materials specified in the assembly process must be in place on time. If some non-critical materials are not in place, the operation sequence can be changed, and then a material expediting form can be filled out and submitted to the purchasing department.
(4) Before assembly, the structure, assembly technology and process requirements of the equipment should be understood.
Basic Specifications
(1) Mechanical assembly shall be carried out in strict accordance with the assembly drawings and process requirements provided by the design department. It is strictly forbidden to modify the work content or change the parts in an abnormal manner.
(2) The parts to be assembled must be those that have passed the quality inspection department's acceptance. If any unqualified parts are found during the assembly process, they should be reported in a timely manner.
(3) The assembly environment must be clean and free of dust or other contaminants. Parts should be stored in a dry, dust-free place with protective pads.
(4) During the assembly process, the parts shall not be bumped or cut, the surface of the parts shall not be damaged, or the parts shall not be obviously bent, twisted or deformed. The mating surfaces of the parts shall not be damaged.
(5) For parts that move relative to each other, lubricating oil (grease) should be applied between the contact surfaces during assembly.
(6) The mating dimensions of the mating parts must be accurate.
(7) During assembly, parts and tools should be placed in designated facilities. In principle, parts and tools should not be placed on the machine or directly on the ground. If necessary, protective mats or carpets should be laid at the placement location.
(8) In principle, stepping on the machinery is not allowed during assembly. If stepping is necessary, protective mats or carpets must be laid on the machinery. Important parts and non-metallic parts with low strength are strictly prohibited from being stepped on.
Connection method
(1) Bolted connection
A. When tightening bolts, adjustable wrenches must not be used, and no more than one identical washer should be used under each nut. After countersunk screws are tightened, the screw head should be embedded in the machine part and should not be exposed.
B. Generally, threaded connections should have anti-loosening spring washers. When tightening multiple symmetrical bolts, they should be tightened gradually in a symmetrical sequence. For strip-shaped connectors, they should be tightened gradually and symmetrically from the middle outwards.
C. After the bolt and nut are tightened, the bolt should protrude 1-2 threads above the nut; when the screw is used to fasten moving parts or for maintenance without disassembling the parts, thread-locking adhesive should be applied to the screw before assembly.
D. For fasteners with specified tightening torque requirements, a torque wrench should be used to tighten them to the specified torque. For bolts without specified tightening torque, the tightening torque can be referenced in the Appendix.
(2) Pin connection
A. The end face of the locating pin should generally be slightly higher than the surface of the part. After the tapered pin with a threaded end is installed into the relevant part, its large end should be sunk into the hole.
B. After the cotter pin is installed into the relevant parts, its tail should be separated by 60°-90°.
(3) Key connection
A. The two sides of the keyway of the flat key and the fixed key should be in uniform contact, and there should be no gap between their mating surfaces.
B. When a key (or spline) with clearance fit is assembled, there should be no uneven tightness when the relatively moving parts move along the axial direction.
C. After assembly, the contact area of hook keys and wedge keys should not be less than 70% of the working area, and the non-contact parts should not be concentrated in one place; the length of the exposed part should be 10%-15% of the length of the inclined plane.
(4) Riveting
A. The materials and dimensions of the riveting must meet the design requirements, and the machining of the rivet holes should comply with relevant standards.
B. The surface of the riveted parts must not be damaged or deformed during riveting.
C. Unless otherwise specified, there should be no loosening after riveting. The head of the rivet must be in close contact with the riveted parts and should be smooth and round.
(5) Expansion sleeve connection
Expansion sleeve assembly: Apply lubricating grease to the expansion sleeve, place it into the hub hole, insert the mounting shaft, adjust the assembly position, and then tighten the bolts. The tightening sequence should be based on the slit opening, tightening symmetrically from left to right in sequence to ensure the rated torque value is reached.
(6) Tight-fitting connection
The tapered end of the set screw and the recess should both be 90°, and the set screw should be aligned with the recess and tightened.
Rolling bearing assembly
(1) Before the bearing is assembled, there must be no dirt or contaminants in the bearing seat.
(2) When assembling bearings, a layer of lubricating oil should be applied to the surface of the mating parts. The end of the bearing without a model number should face inward, i.e., towards the shaft shoulder.
(3) Special presses should be used when assembling bearings. Direct impact is strictly prohibited. When installing bearings, the magnitude, direction and position of the force should be appropriate. The protective frame or rolling elements should not be subjected to force. The force should be even and symmetrical to ensure that the end face is perpendicular to the shaft.
(4) The inner ring end face of the bearing should generally be close to the shaft shoulder (shaft clip). After the outer ring of the bearing is assembled, the contact between the bearing cap at its positioning end and the washer or outer ring should be uniform.
(5) After the rolling bearing is installed, the relative moving parts should rotate flexibly and easily. If there is any jamming, the cause of the problem should be checked and analyzed and dealt with accordingly.
(6) During the bearing assembly process, if the hole or shaft fit is found to be too loose, the tolerance should be checked; if it is too tight, it should not be forcibly assembled. The cause of the problem should be checked and analyzed and appropriate measures should be taken.
(7) The axial clearance of single-row tapered roller bearings, thrust angular contact bearings and double-direction thrust ball bearings shall meet the requirements of the drawings and process during assembly.
(8) For bearings that use grease and their mating surfaces, an appropriate amount of grease should be injected after assembly. For bearings with an operating temperature not exceeding 65℃, ZG-5 grease can be used according to GB491-65 "Calcium-based Grease"; for bearings with an operating temperature higher than 65℃, ZN-2 or ZN-3 grease can be used according to GB492-77 "Calcium-based Grease".
(9) The temperature rise of ordinary bearings during normal operation should not exceed 35°C, and the maximum temperature during operation should not exceed 70°C.
Assembly of linear bearings
(1) Before assembly, the inside of the bearing should be coated with grease.
(2) When the bearing is pressed into the support, a special installation tool should be used to press it against the outer ring end face. It is not allowed to directly hit the bearing to avoid deformation.
(3) The fit between the bearing and the support must meet the tolerance requirements. If it is too tight, the guide shaft and the bearing will be interference fit, which will damage the bearing; if it is too loose, the bearing will not be able to be fixed in the support.
(4) When the guide shaft is installed into the bearing, it should be aligned with the center and inserted gently. If it is inserted at an angle, the balls will fall out and the cage will deform.
(5) When the bearing is installed in the support, it is not allowed to rotate. Forcing it to rotate will damage the bearing.
(6) Set screws are not allowed to be directly tightened onto the outer ring of the bearing, otherwise deformation will occur.
Assembly of linear guide rails
(1) The guide rail installation area must be free of dirt, and the flatness of the installation surface must meet the requirements.
(2) When there is a reference edge on the side of the guide rail, it should be installed close to the reference edge. When there is no reference edge, the sliding direction of the guide rail should be consistent with the design requirements. After the guide rail fixing screws are tightened, the sliding direction of the slider should be checked for deviation. Otherwise, it must be adjusted.
(3) If the slider is driven by a transmission belt, after the transmission belt and the slider are fixed and tensioned, the transmission belt must not be pulled at an angle. Otherwise, the pulley must be adjusted so that the driving direction of the transmission belt is parallel to the guide rail.
Assembly of sprockets and chains
(1) The fit between the sprocket and the shaft must meet the design requirements.
(2) The geometric center planes of the teeth of the driving sprocket and the driven sprocket should coincide, and their offset should not exceed the design requirements. If not specified in the design, it should generally be less than or equal to 2‰ of the center distance between the two sprockets.
(3) When the chain meshes with the sprocket, the working side must be tightened to ensure smooth meshing.
(4) The sag of the non-working side of the chain should meet the design requirements. If not specified in the design, it should be adjusted by 1% to 2% of the center distance between the two sprockets.
Gear assembly
(1) When meshing gears are assembled, the axial misalignment shall not exceed 1 mm when the gear rim width is less than or equal to 20 mm; and the axial misalignment shall not exceed 5% of the rim width when the gear rim width is greater than 20 mm.
(2) The installation accuracy requirements for cylindrical gears, bevel gears and worm gear drives shall be determined according to the accuracy and size of the transmission components in JB179-83 "Accuracy of Involute Cylindrical Gears", JB180-60 "Tolerance of Bevel Gear Transmissions" and JB162-60 "Tolerance of Worm Gear Transmissions".
(3) The gear meshing surfaces must be properly lubricated according to technical requirements, and the gearbox must be filled with lubricating oil to the oil level line according to technical requirements.
(4) The noise of the gearbox under full load shall not exceed 80dB.
Assembly of timing pulleys
(1) The shafts of the driving and driven synchronous pulleys must be parallel to each other, and there must be no skew or wobbling. The tilt error should not exceed 2‰.
(2) When the width of the two pulleys is the same, their end faces should be on the same plane, and the axial misalignment of the two pulleys shall not exceed 5% of the width of the rim.
(3) When assembling a timing belt, the pulleys should not be pried in forcibly. Instead, the belt should be assembled by shortening the center distance between the two pulleys. Otherwise, the tensile layer of the timing belt may be damaged.
(4) The timing belt tensioner should be installed on the slack side for tensioning, and two fastening bolts should be used to fix it.
Assembly of flat belts
(1) Before installation, all conveying surfaces should be leveled.
(2) The line connecting the center points of the pulleys should be adjusted to be on the same vertical plane, and the axes should be parallel to each other.
(3) The conveying direction of the flat belt should be installed in accordance with the arrow direction marked on the belt, otherwise it will affect its service life.
Assembly of motors and reducers
(1) Check whether the motor model and the reducer model are correct.
(2) Before assembly, clean the connection between the motor shaft and the speed reducer.
(3) Before tightening the motor flange bolts, rotate the motor to correct the concentricity of the motor shaft and the reducer coupling, then connect the motor flange to the reducer and tighten the fixing bolts diagonally.
(4) During the assembly of the servo motor, the encoder at the rear of the motor should be protected from external force, and it is strictly forbidden to strike the servo motor shaft.
(5) Installation of the servo reducer:
A. Move the sealing screws on the outside of the reducer flange to facilitate adjustment of the clamping screws.
B. Unscrew the clamping screws, connect the motor flange to the reducer, and tighten the positioning bolts diagonally.
C. Tighten the clamping ring with appropriate torque, and then tighten the sealing screw.
D. Loosen the motor flange bolts, jog the servo motor shaft or rotate the motor shaft by hand a few times to correct the concentricity of the motor shaft and the reducer coupling.
E. Finally, connect the motor flange to the reducer and tighten the positioning bolts diagonally.
Rack adjustment and connection
(1) The height of the frame in different sections should be adjusted to the same height according to the same reference point.
(2) All rack wall panels should be adjusted to the same vertical plane.
(3) After each section of the frame is adjusted to the correct position and meets the requirements, the fixed connecting plates between them should be installed.
Assembly of pneumatic components
(1) The configuration of each pneumatic drive device must be strictly connected in accordance with the air circuit diagram provided by the design department. The valve body, pipe joint, cylinder and other components must be checked for accuracy when connected.
(2) Connect the inlet and outlet of the main intake pressure reducing valve according to the direction of the arrow. The water cup and oil cup of the air filter and oil mist lubricator must be installed vertically downward.
(3) Before piping, the cutting powder and dust inside the pipe should be thoroughly blown away.
(4) The pipe fitting is screwed in by thread. If the pipe thread does not have thread sealant, it should be wrapped with PTFE tape. The wrapping direction should be clockwise when viewed from the front. The PTFE tape should not be mixed into the valve. When wrapping the PTFE tape, one thread should be left unwound.
(5) The air pipes should be arranged neatly and aesthetically, and cross arrangement should be avoided as much as possible. 90° elbows should be used at bends. When fixing the air pipes, do not subject the joints to additional stress, otherwise air leakage will occur.
(6) When connecting the solenoid valve, pay attention to the function of each port number on the valve: P: main air intake; A: air outlet 1; B: air outlet 2; R (EA): exhaust corresponding to A; S (EB): exhaust corresponding to B.
(7) When assembling the cylinder, the axis of the piston rod should be consistent with the direction of load movement.
(8) When using linear bearings for guidance, after the front end of the cylinder piston rod is connected to the load, there must be no resistance during the entire stroke, otherwise the cylinder will be damaged.
(9) When using a throttle valve, attention should be paid to the type of throttle valve. Generally speaking, it can be distinguished by the large arrow marked on the valve body. The large arrow pointing to the threaded end is for cylinder use; the large arrow pointing to the pipe end is for solenoid valve use.
Assembly inspection work
(1) After each component is assembled, it must be checked according to the following items. If any assembly problems are found, they should be analyzed and dealt with in a timely manner.
A. Ensure the completeness of the assembly work, check the assembly drawings, and inspect for any missing parts.
B. Verify the accuracy of the installation positions of each part by checking against the assembly drawings or the requirements described in the above specifications.
C. The reliability of each connection part, whether each fastening screw meets the torque required for assembly, and whether special fasteners meet the requirements to prevent loosening.
D. The flexibility of moving parts, such as conveyor rollers, pulleys, guide rails, etc., when manually rotated or moved, whether there is jamming or obstruction, whether there is eccentricity or bending, etc.
(2) After the final assembly is completed, the main inspection is the connection between the assembled parts. The inspection content is based on the "four properties" specified in (1) as the measurement standard.
(3) After the final assembly is completed, the iron filings, debris, dust and other contaminants of the machine should be cleaned to ensure that there are no obstructions in the transmission parts.
(4) During the trial run, carefully monitor the startup process. After the machine starts, immediately observe whether the main working parameters and moving parts are moving normally.
(5) The main working parameters include the speed of motion, the smoothness of motion, the rotation of each transmission shaft, temperature, vibration and noise, etc.
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