There are many machining methods, and the types of machined workpieces are also various. Different types of workpieces have different machining methods, and different types of workpieces also have different machining technical requirements.
General technical requirements for machining of castings：
1. Cold shuts, cracks, shrinkage cavities, penetrating defects and serious incomplete defects (such as under casting, mechanical damage, etc.) are not allowed on the surface of castings.
2. The casting shall be cleaned without burrs and flash. The pouring and riser on the non machining indication shall be cleaned and flush with the casting surface.
3. The cast words and marks on the non machined surface of the casting shall be clear and legible, and the position and font shall meet the requirements of the drawing.
4. The roughness of the non machined surface of the casting, sand casting R, is not greater than 50 μ m。
5. The pouring riser and flying thorn shall be removed from the casting. The residue of pouring and riser on the non machined surface shall be leveled and polished to meet the surface quality requirements.
6. The molding sand, core sand and core bone on the casting shall be removed.
7. If the casting has inclined parts, its dimensional tolerance zone shall be symmetrically configured along the inclined plane.
8. The molding sand, core sand, core bone, fleshy, sticky sand, etc. on the casting shall be spaded, ground and cleaned.
9. The wrong type and the casting deviation of the boss should be corrected to achieve a smooth transition and ensure the appearance quality.
10. The depth of the folds on the non machined surface of the casting shall be less than 2mm, and the spacing shall be greater than 100mm.
11. The non machined surface of machine product castings shall be shot blasted or roller treated to meet the requirements of cleanliness SA2 1/2.
12. Castings must be subject to water toughening treatment.
13. The casting surface shall be flat, and the gate, burr, sand sticking, etc. shall be removed.
14. Castings are not allowed to have cold shuts, cracks, holes and other casting defects that are detrimental to use.
Conventional technical requirements for forging machining：
1. The nozzle and riser of forgings shall have sufficient cutting amount to ensure that forgings are free from shrinkage and serious deflection.
2. Forgings shall be forged on a forging press with sufficient capacity to ensure that the inside of forgings 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. Defects on the non machined surface of forgings shall be cleaned and smoothly transited.
4. Forgings are not allowed to have white spots, internal cracks and residual shrinkage cavities.
Conventional technical requirements for machining of Weldments：
1. The defects must be completely removed before welding, and the groove surface should be flat and smooth without sharp corners.
2. The defective areas of weldments can be removed by shovel excavation, grinding, carbon arc gouging, gas cutting or machining.
3. Sand, oil, water, rust and other dirt within 20mm around the welding area and groove must be thoroughly cleaned.
4. In the whole process of welding, the temperature of preheating zone shall not be lower than 350 ° C.
5. If conditions permit, weld at the horizontal position as far as possible.
6. During repair welding, the welding rod should not swing laterally.
7. During surface stacking welding, the overlap between 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.
8. The weld appearance is beautiful, and there are no defects such as meat biting, slag addition, pores, cracks, splashes, etc; The welding wave is even.
Conventional technical requirements for machining of cutting parts：
1. The parts shall be inspected and accepted according to the processing procedure, and can be transferred to the next procedure only after the previous procedure is qualified.
2. The processed parts are not allowed to have burrs.
3. The parts after finishing shall not be placed directly on the ground, and necessary support and protection measures shall be taken. The machined surface shall be free of rust and other defects such as bumps and scratches that affect performance, service life or appearance.
4. There shall be no peeling on the surface after rolling and finishing.
5. The surface of parts after heat treatment in the final process shall be free of oxide skin. The mating surface and tooth surface after finishing shall not be annealed
6. The machined thread surface is not allowed to have defects such as black skin, bump, disorderly buckle and burr.
Different workpieces have different technical requirements for machining. Only by following the conventional technical requirements, can we better ensure the quality of workpieces.
(Editor: we are Shenzhen perfect precision products Co., Ltd., specializing in providing laser cutting, bending, stamping, spinning, welding and other high-quality sheet metal processing services. With 15 years of experience and a 3000 square meter factory, we have an experienced engineering team, with iso9001:2015 quality system and imported machines from the United States and Japan. You can send us inquiries below.)