Process flow of sheet metal processing
1. cold rolled plate SPCC, mainly used in electroplating and paint, low cost, easy molding, material thickness is less than 3.2mm.
2. hot rolled plate material SHCC, T = 3.0mm, is also used in electroplating, paint, low cost, but difficult to molding, mainly for flat pieces.
3. galvanized sheet SECC, SGCC. SECC electrolysis board is divided into N material, P material, and N material is not treated mainly for surface treatment, and the cost is high. P is used for spraying parts.
4. copper; the main use of conductive material, the surface treatment is nickel plating, chromium plating, or not to be treated, high cost.
5. aluminum plate; usually with surface chromate (J11-A), oxidation (conductive oxidation, chemical oxidation), high cost, silver plating, nickel plating.
6. aluminum profile; a complex section of the material, a large number of inserts in a variety of boxes. The surface is treated with the same aluminum plate.
7. stainless steel; it is mainly used without any surface treatment, and the cost is high.
In order to write the process flow of parts, first of all, we must know all kinds of technical requirements of the part drawing, and the drawing surface review is the most important link in the writing of the process flow of parts.
1. check whether the surface of the map is complete.
2. graph surface view relationship, marking whether clear, complete, dimensioning units.
3. assembly relationship, assembly required key dimensions.
4. the difference between the old and the new layout.
5. translation of foreign language.
The 6. table is in the code conversion.
7. feedback and burial of the problem.
9. quality requirements and technological requirements
10. the quality control seal must be added to the surface of the official issue.
Matters needing attention
The expansion diagram is a plane diagram (2D) unfolded based on the part diagram (3D)
1. unfolding should be combined to facilitate the saving of materials and processability
2. the reasonable choice of gap and the way of the edge, the following clearance of 0.2, T=2-3 gap 0.5, the way of the edge of the long side of the short side of the package (door type).
3. reasonable consideration of the dimension of tolerance: the negative difference is in the end, and the positive difference is half; the size of the hole shape: the positive difference is in the end and the negative difference is half.
4. burr direction
5. drawing teeth, riveting, riveting, punching point (bag), and other position direction, drawing a sectional view
6. check material, plate thickness, plate thickness tolerance
7. in a special angle, the inner radius of the bending angle (general R=0.5) must be tested and unfolded
8. places with error prone (similar asymmetries) should be highlighted
9. places with more size should be added to the big picture
10. the need for spraying protection must be expressed
According to the differences in the structure of the sheet metal parts, the process flow can be different, but the total number is not more than the following.
1, blanking: there are various kinds of blanking methods, mainly in the following ways
1. Shears: shears shear strip has the advantages of simple materials, it is mainly for the mold blanking forming preparation process, low cost, accuracy is less than 0.2, the strip or block but can only be processed without orifice cutting angle.
2. Punching machine: punching and shaping various parts and materials by using punching machine in one or more steps to expand parts after plate development, and its advantage is short time consuming, high efficiency, high accuracy and low cost. It is suitable for mass production, but we need to design moulds.
The.NC NC material, NC material under the first to write CNC machining program, using the programming software, the expansion plan will be drawn into the preparation of NC number of pull machine can identify the program, so that under these programs step knife. Each shape plate in plate blanking, but its structure is subject to. The tool structure of low cost, accuracy to 0.15.
(4) laser cutting is to cut out the shape of the flat plate on the large plate by means of laser cutting. With the same way as NC cutting, we need to write laser programs, which can be used for all kinds of complex shapes. The cost is high and the accuracy is 0.1..
Sawing machine: the main use of aluminum profile, square tube, round pipe, round bar, and so on, low cost, low precision.
1. fitter: sinking, tapping, reaming, drilling
Sink hole angles of 120 DEG C, for rivet, 90 DEG C for countersunk head screws, tapping the bottom inch.
2. flange: also called smoke hole, through hole, holes in the base is a small pump into a larger hole, then tapping, mainly used in thick sheet metal processing relatively thin, increasing its strength and number of threads, to avoid slipping, generally used for plate thickness is thin, the hole of Zhou Zhengchang shallow flanging, thickness did not change, allowing a thickness of 30-40%, high high 40-60% level than normal flanging, squeeze 50% thin, can get maximum flanging height, when the plate thickness is large, such as 2, 2.5 above the plate thickness, can be directly tapping.
3.: punch mold forming manufacturing processes, general punch processing punching, blanking, cutting, convex hull (bumps), red tear, smoke hole, forming and other processing methods, processing needs corresponding mold to complete the operation, such as punching, blanking die, die bulge and tear die, die, drawing hole forming mold, the operation of the main attention to the location, direction.
4. pressure riveting: pressure riveting of the company, the main pressure riveting nut, screw loose, etc., it is through the hydraulic pressure riveting machine or punch to complete the operation, the riveted to the sheet metal, and rivet, should pay attention to the direction of.
5. bending; bending is the part of the 2D plate, folded into 3D. The processing needs of folding bed and a corresponding bending mold, it also has some bending sequence, the principle is the a first folding knife does not produce interference, interference.
Application of machining parts in sheet metal workshop