Mechanical drawings - summary of technical requirements
General technical requirements
1. Remove the oxide scale from the parts.
2. On the processing surface of the parts, there should be no scratches, abrasions and other defects that damage the surface of the parts.
3. Remove burr flash.
Heat treatment requirements
1. Quenched and tempered, HRC50~55.
2. The parts are quenched at high frequency, tempered at 350~370°C, HRC40~45.
3. Carburizing depth 0.3mm.
4. Carry out high-temperature aging treatment.
Tolerance requirements
1. The shape tolerance of the unmarked should meet the requirements of GB1184-80.
2. The allowable deviation of the unmarked length dimension ± 0.5mm.
3. The casting tolerance zone is symmetrical to the basic size configuration of the blank casting.
Edges and corners of the part
1. The radius of the fillet R5 is not injected.
2. The chamfers of the uninjected are all 2×45°.
3. Sharp angles/sharp corners/sharp edges are blunt.
Assembly requirements
1. Each seal must be soaked in oil before assembly.
2. The assembly of rolling bearings allows the use of oil heating for hot charging, and the temperature of the oil shall not exceed 100 °C.
3. After the gear is assembled, the contact spots and backlash of the tooth surface should meet the provisions of GB10095 and GB11365.
4. Sealing packing or sealant is allowed when assembling the hydraulic system, but it should be prevented from entering the system.
5. The parts and components (including purchased parts and outsourced parts) that enter the assembly must have the certificate of the inspection department before they can be assembled.
6. The parts must be cleaned and cleaned before assembly, and there shall be no burrs, flash, oxide scale, rust, chips, oil, colorants and dust, etc.
7. Before assembly, the main fitting size of the parts and components, especially the interference fit size and related accuracy, should be reviewed.
8. The parts are not allowed to be bumped, bumped, scratched and rusted during the assembly process.
9. When tightening screws, bolts and nuts, it is strictly forbidden to strike or use unsuitable screws and wrenches. After tightening, the screw groove, nut and screw, and bolt head must not be damaged.
10. Fasteners that stipulate the tightening torque requirements must use a torque wrench and be fastened according to the specified tightening torque.
11. When the same part is fastened with multiple screws (bolts), each screw (bolt) needs to be crossed, symmetrical, gradual and evenly tightened.
12. When the taper pin is assembled, it should be colored and checked with the hole, and its contact rate should not be less than 60% of the fit length, and it should be evenly distributed.
13. The two sides of the flat key and the keyway on the shaft should be in uniform contact, and there should be no gap on the mating surface.
14. The number of tooth surfaces in contact with spline assembly at the same time shall not be less than 2/3, and the contact rate shall not be less than 50% in the length and height direction of the key teeth.
15. After the flat key (or spline) of the sliding fit is assembled, the phase fitting moves freely, and there shall be no uneven tightness
Phenomenon.
16. After bonding, the excess adhesive that flows out should be removed.
17. The semicircular hole of the outer ring of the bearing and the open bearing seat and the bearing cover is not allowed to be stuck.
18. The outer ring of the bearing should be in good contact with the semi-circular hole of the open bearing seat and the bearing cover, and when it is checked by coloring, it should be in uniform contact with the bearing seat in the range of symmetry in the centerline of 120° and the bearing cover in the range of symmetry of the centerline of 90°. When inspected with a feeler gauge within the above range, a feeler gauge of 0.03mm must not be stuffed into 1/3 of the width of the outer ring.
19. After the outer ring of the bearing is assembled, it should be in uniform contact with the end face of the bearing cover at the locating end.
20. After the rolling bearing is installed, it should be flexible and stable to rotate by hand.
21. The joint surface of the upper and lower bearings should be tightly fitted, and it should not be checked with a 0.05mm feeler gauge.
22. When fixing the bearing with the dowel pin, the hinge and distribution pin should be drilled under the condition of ensuring that the tile mouth surface and the end face are flush with the opening and closing surface of the relevant bearing hole and the end bread. The pin must not be loosened after being driven.
23. The bearing body of the spherical bearing should be in uniform contact with the bearing seat, and the contact should not be less than 70% by coloring.
24. When the surface of the alloy bearing lining is yellow, it is not allowed to be used in the specified contact angle, and the nucleation area outside the contact angle shall not be greater than 10% of the total area of the non-contact area.
25. The end face of the gear (worm gear) datum should fit with the shaft shoulder (or the end face of the positioning sleeve), and it should not be checked with a 0.05mm feeler gauge. And the perpendicularity of the gear datum end face and the axis should be ensured.
26. The joint surface of the gearbox and the cover should be in good contact.
27. Strictly inspect and remove the sharp angles, burrs and foreign objects left during the processing of parts before assembly. Ensure that the seal is not scratched when it is inserted.
Casting requirements
1. There are no cold separations, cracks, shrinkage holes, penetrating defects and serious defects (such as undercasting, mechanical damage, etc.) on the surface of the casting.
2. The casting should be cleaned, there should be no burrs, flash, and the gating riser on the non-processing indication should be cleaned flush with the surface of the casting.
3. The casting words and marks on the non-machined surface of the casting should be clearly legible, and the position and font should meet the requirements of the drawing.
4. The roughness of the unmachined surface of the casting, sand casting R, is not more than 50μm.
5. The casting should be cleared of gating risers, flying spurs, etc. The residual amount of the gate riser on the non-processed surface should be shoveled and polished to meet the surface quality requirements.
6. The molding sand, core sand and core bone on the casting should be cleaned.
7. If the casting has an inclined part, its size tolerance zone should be symmetrically arranged along the inclined surface.
8. The molding sand, core sand, core bone, fleshy, sticky sand, etc. on the casting should be shoveled and smoothed and cleaned.
9. The wrong type and boss casting deviation should be corrected to achieve a smooth transition and ensure the appearance quality.
10. The wrinkles on the non-machined surface of the casting, the depth is less than 2mm, and the spacing should be greater than 100mm.
11. The non-machined surface of the castings of machine products needs to be shot peened or pulleyed to meet the requirements of cleanliness Sa2 1/2.
12. Castings must be treated with water toughness.
13. The surface of the casting should be smooth, and the gate, burr, and sticky sand should be cleaned.
14. Castings are not allowed to have casting defects such as cold separation, cracks, and holes that are detrimental to use.
Paint requirements
1. Rust, scale, grease, dust, mud, salt and dirt must be removed from the surface of all steel parts that need to be painted before painting.
2. Before rust removal, use organic solvents, lye, emulsifiers, steam, etc. to remove the grease on the surface of steel parts.
Dirt.
3. The time interval between the surface to be coated and the primer after shot peening or manual rust removal shall not be more than 6h.
4. The surface of the riveting parts in contact with each other must be coated with anti-rust paint with a thickness of 30~40μm before connection. The overlapping edges should be closed with paint, putty, or adhesive. Primers damaged due to processing or welding are to be repainted.
Plumbing Requirements
1. All tubes should be de-flashed, burrs and chamfered before assembly. Use compressed air or other methods to clear the debris and floating rust attached to the inner wall of the pipe.
2. Before assembly, all steel pipes (including prefabricated pipes) should be degreased, pickled, neutralized, washed and anti-rust.
3. When assembling, tighten the parts fixed with threaded connections, such as pipe clamps, bearings, flanges and joints, to prevent loosening.
4. The welding parts of the prefabricated pipes should be tested under pressure.
5. When the piping is replaced or transferred, the pipeline separation port must be plugged and sealed with adhesive tape or plastic pipe to prevent any debris from entering, and the label must be attached.
Repair weldment requirements
1. Before welding, the defects must be completely removed, and the groove surface should be smooth and smooth, and there should be no sharp corners. 2. According to the defects of steel castings, the defects in the welding area can be removed by shoveling, grinding, carbon arc gouging, gas cutting or machining.
3. The sand, oil, water, rust and other dirt within 20mm around the welding area and the groove must be thoroughly cleaned.
4. In the whole process of welding, the temperature of the preheating zone of the steel casting shall not be lower than 350°C.
5. If conditions permit, weld in a horizontal position as much as possible.
6. When repairing welding, the electrode should not swing too much.
7. When the surface of the steel casting is surfacing welding, the overlap between the weld beads shall not be less than 1/3 of the weld bead width. The welding flesh is full, and the welding surface is free of burns, cracks and obvious nodules. The appearance of the weld is beautiful, and there are no defects such as meat bite, slag addition, porosity, cracks, and spatter; The welding wave is uniform.
Forging requirements
1. The nozzle and riser of the ingot should have enough amount of removal to ensure that the forging has no shrinkage holes and serious deflection.
2. The forging should be forged on a forging press with sufficient capacity to ensure that the inside of the forging is fully forged.
3. Forgings are not allowed to have visible cracks, folds and other appearance defects that affect the use. Local defects can be removed, but the cleaning depth shall not exceed 75% of the machining allowance, and the defects on the non-machined surface of the forging should be cleaned up and smoothly transitioned.
4. Forgings are not allowed to have white spots, internal cracks and residual shrinkage holes.
Requirements for machined parts
1. The parts should be inspected and accepted according to the process, and can be transferred to the next process only after the previous process is inspected. 2. The machined parts are not allowed to have burrs.
3. The finished parts should not be placed directly on the ground, and necessary support and protection measures should be taken. The processing surface is not allowed to have defects such as rust and bumps, scratches and other defects that affect performance, life or appearance.
4. The surface of rolling and finishing shall not peel after rolling.
5. After heat treatment in the final process, there should be no oxide scale on the surface. There should be no annealing on the finished mating surface and tooth surface
6. The processed thread surface is not allowed to have defects such as black skin, bumps, random buckles and burrs