Contour processing of mechanical parts machining
1, unannotated shape tolerance should be in line with the requirements of GB1184-80.
2, the unnoticed length size allowable deviation ± 0.5mm.
3, not note the radius of rounded corners R5.
4, not noted chamfer are C2.
5、Sharp corner chamfering blunt.
6、Sharp edge chamfering blunt, remove burr flying edge.
Mechanical parts processing surface treatment
1、The machined surface of the parts should not have scratches, abrasions and other defects that damage the surface of the parts.
2、The machined thread surface should not have defects such as black skin, bump, messy buckle and burr. Before painting, all steel parts must be free of rust, oxide, grease, dust, mud, salt and dirt.
3、Before removing rust, remove grease and dirt from the surface of steel parts with organic solvent, alkali, emulsifier, steam, etc.
4、The time interval between the surface to be coated by shot blasting or manual rust removal and the primer coating shall not be more than 6h.
5, riveted parts in contact with each other's surface, before the connection must be coated with a thickness of 30 ~ 40μm anti-rust paint. The edge of the lap joint should be closed with paint, putty or adhesive. The primer damaged due to processing or welding should be repainted
Heat treatment of mechanical parts processing
1, by tempering treatment, HRC50～55.
2, medium carbon steel: 45 or 40Cr parts for high-frequency quenching, 350 ~ 370 ℃ tempering, HRC40 ~ 45.
3、Carburizing depth 0.3mm.
4、High-temperature aging treatment.
Technical requirements after precision machining
1, precision machining of the parts after placement shall not be placed directly on the ground, should take the necessary support, protection measures.
2, processing surface is not allowed to have rust and affect the performance, life or appearance of the bump, scratch and other defects.
3, rolling precision machining of the surface, after rolling shall not have the phenomenon of peeling.
4, the final process after heat treatment of the parts, the surface should not have oxide skin. After precision machining of the mating surface, tooth surface should not be annealed
Sealing treatment of mechanical parts processing
1、The seals must be soaked with oil before assembly.
2、Strictly check and remove the sharp corners, burrs and foreign objects left when the parts are machined before assembly. Ensure that the seals are not scratched when they are installed.
3、After bonding, the excess adhesive should be removed.
Gear technical requirements
1、After the gear is assembled, the contact spot and side gap of the tooth surface should conform to the provisions of GB10095 and GB11365.
2, gear (worm wheel) benchmark end face and shaft shoulder (or positioning sleeve end face) should fit, and check with 0.05mm stopper does not enter. And should ensure that the gear benchmark end face and axis perpendicularity requirements.
3、The combination surface of gear box and cover should be in good contact.
Bearing technical requirements
1、The assembly of rolling bearings is allowed to be heated by oil for hot installation, and the temperature of oil shall not exceed 100℃.
2、The outer ring of the bearing and the semi-circular hole of the open bearing housing and bearing cover are not allowed to have jamming phenomenon.
3, bearing outer ring and open bearing seat and bearing cover of the semicircular hole should be in good contact, with color inspection, and bearing seat in symmetry in the center line 120 °, and bearing cover in symmetry in the center line of 90 ° range should be uniform contact. In the above range with the plug ruler check, 0.03mm plug shall not be plugged into the outer ring width of 1/3.
4, bearing outer ring assembly and positioning end bearing cover end face should be contacted evenly.
5、The rolling bearing should be flexible and smooth after assembled and rotated by hand.
6、The combination surface of the upper and lower shaft tile should be tightly fitted and checked with 0.05mm plug gauge not into.
7、When fixing the shaft tile with the locating pin, it should be drilled and reamed and matched with the pin under the condition of ensuring the opening and closing surface of the tile mouth and end surface and the end bread of the relevant bearing hole. The pin shall not be loosened after it is inserted.
8, spherical bearing bearing body and bearing seat should be uniform contact, using the coloring method to check, the contact should not be less than 70%.
9, alloy bearing lining surface into yellow is not allowed to use, in the specified contact angle is not allowed to have the phenomenon of leaving the nucleus, in the contact angle outside the area of the nucleus shall not be greater than 10% of the total area of non-contact area.
Screws, bolts and nuts technical requirements
1、When fastening screws, bolts and nuts, it is strictly prohibited to strike or use unsuitable spinning tools and wrenches. Screw slot, nut and screw, bolt head must not be damaged after tightening.
2, the fasteners specified tightening torque requirements, must be used torque wrenches, and fastened according to the specified tightening torque.
3, the same part with multiple screws (bolts) fastening, the screws (bolts) need to be crossed, symmetrical, gradual and uniform tightening.
4, flat key and shaft keyway on both sides of the surface should be uniform contact, the mating surface shall not have a gap.
Patch welding technical requirements
1、The defects must be completely removed before welding, the bevel surface should be repaired smooth and round, there should be no sharp corners.
2、According to the defective situation of cast steel parts, the defective patch welding area can be removed by shovel digging, grinding, carbon arc gas planing, gas cutting or mechanical processing.
3、Sticky sand, oil, water, rust and other dirt around the filler area and bevel within 20mm must be thoroughly cleaned.
4、In the whole process of welding, the temperature of the preheating area of the cast steel parts must not be lower than 350°C.
5、Welding in the horizontal position as far as possible, if the conditions allow.
6、When welding, the welding rod should not do too much lateral swing.
7, cast steel parts surface stack welding, the overlap between the welding channel shall not be less than 1/3 of the width of the welding channel.
Casting technical requirements
1, casting tolerance zone symmetry in the basic size configuration of the blank casting.
2, the casting surface is not allowed to have cold partition, cracks, shrinkage and penetrating defects and serious defective class defects (such as under-casting, mechanical damage, etc.).
3、Castings should be cleaned up, no burrs, flying edge, non-machining indicates that the sprue should be cleaned up flush with the surface of the casting.
4, castings on the non-machined surface of the castings and signs should be clear and legible, the location and font should be in line with the requirements of the drawings.
5, the roughness of the non-machined surface of the casting, sand casting R, not more than 50μm.
6, castings should be cleared of sprues, flying spurs, etc. The residue of the sprue on the non-machined surface should be leveled and
polished to meet the surface quality requirements.
7、Castings on the sand, core sand and core bone should be cleared.
8, the casting has an inclined part, its size tolerance zone should be along the inclined side of the proportional configuration.
9, castings on the type of sand, core sand, core bone, succulent, sticky sand, etc. should be shovel grinding smooth, clean up.
10, the wrong type, tab casting deviation, etc. should be corrected to achieve a smooth transition, a guarantee of appearance quality.
11、The wrinkles on the non-machined surface of the casting, the depth is less than 2mm, and the spacing should be more than 100mm.
12, machine products castings of the non-machined surface are required to be shot peening or roller treatment, to achieve the requirements of cleanliness Sa2 1/2 level.
13、Castings must be treated with water toughness.
14、The surface of the casting should be flat, and the sprue, burr and sticky sand should be cleared.
15、Castings are not allowed to have cold partition, cracks, holes and other casting defects that are detrimental to use.
Technical requirements of forgings
1、Each ingot should have sufficient removal amount of spout and riser to ensure no shrinkage and serious deflection of forgings.
2、The forgings should be forged and formed on the forging press with sufficient capacity to ensure that the forgings are fully forged inside.
3, forgings are not allowed to have cracks, folding and other appearance defects that affect the use of the naked eye. 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 shall be cleaned up and rounded transition.
4, forgings do not allow the existence of white spots, internal cracks and residual shrinkage.
Assembly technical requirements
1、The use of sealing filler or sealant is allowed when assembling the hydraulic system, but it should be prevented from entering the system.
2, into the assembly of parts and components (including outsourced parts, outsourcing parts), must have the inspection department's
certificate of compliance before assembly.
3, the parts must be cleaned and cleaned before assembly, there should be no burrs, flying edges, oxide, rust, chips, oil, coloring agents and dust, etc.
4, before assembly should be zero, parts of the main fit size, especially interference with the size and accuracy of the relevant review.
5, the assembly process parts are not allowed to bump, touch, scratch and rust.
6, taper pin assembly should be with the hole should be color coated check, the contact rate should not be less than 60% of the fit length, and should be evenly distributed.
7, spline assembly while contacting the number of tooth surface not less than 2/3, the contact rate in the direction of the length and height of the key teeth shall not be less than 50%.
8, the sliding fit of the flat key (or spline) after assembly, the phase fittings move freely, there shall be no uneven loosening and tightening.
9, all the tubes before assembly should remove the tube end flying edge, burr and chamfering. Use compressed air or other methods to clear
the debris and floating rust attached to the inner wall of the tube.
10、Before assembly, all steel pipes (including prefabricated pipes) should be degreased, pickled, neutralized, washed and rust-proofed.
11, assembly of pipe clamps, standoffs, flanges and joints with threaded connections fixed parts to tighten to prevent loosening.