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Sheet Metal Processing Process Flow
- Jun 01, 2018 -

Selection of materials

Sheet metal processing and manufacture materials commonly used ((SPCC)), hot rolled plate (SHCC), galvanized sheet (SECC, SGCC), copper (CU), brass, copper, beryllium copper, aluminum plate (6061, 5052, 1010, 5052, 6063, hard aluminum, etc.), stainless steel (mirror, wire drawing, fog), according to the product function is different, choose different materials, usually need to consider its utility and cost from the product.

1. Cold rolling SPCC, mainly used for plating and baking, low cost, easy to be formed, material thickness less than 3.2mm.

2. Hot rolled sheet SHCC, material T greater than or equal to 3.0mm, is also used for plating, baking paint, low cost, but difficult to be formed, mainly for flat plate.

3. Galvanized sheet SECC, SGCC. SECC electrolytic plates are divided into N materials and P materials. N materials are mainly not processed on the surface and have high cost.

4. Copper; The main use of conductive action materials, its surface treatment is nickel plating, chromium plating, or no treatment, high cost.

5. Aluminum plate; Surface chromate (j11-a), oxidation (conductive oxidation, chemical oxidation), high cost, silver plating, nickel plating.

6. Lu: xingcai; The material parts with complex cross section structure are widely used in various kinds of cases. Surface treatment with aluminum plate.

7. Stainless steel; Mainly used without any surface treatment, high cost.

Drawing review

To write the process flow of parts, the first thing is to know the various technical requirements of part drawings. Then the surface audit is the most important part of the part process.

1. Check that the drawing is complete.

2. Graphic view relationship, whether clearly marked, complete, marked dimensions.

3. Assembly relations, assembly requirements for key dimensions.

4. The new and old versions differ.

5. Translation of foreign language drawings.

6. Table code name conversion.

7. Surface problem feedback and burial.

8. material

9. Quality requirements and process requirements

10. A quality control seal shall be affixed to the official issue.

Matters needing attention

The expansion diagram is a plane diagram (2D) expanded according to part diagram (3D).

1. The expansion method should be suitable, and it should be convenient to save materials and processing

2. Reasonable selection of clearance and edge wrapping methods: T= below 2.0 clearance 0.2, T=2-3 clearance 0.5, long edge wrapping short edge (door panel type)

3. Reasonable consideration of tolerance profile size: negative difference to the end, positive difference to walk half; Hole size: positive difference to go to the end, negative difference to go half.

4. Burr direction

5. Pull teeth, riveting pressure, tearing, punch and convex point (package), etc., and draw a section view

6. Check material, plate thickness, board thickness tolerance

7. For special angles, the radius within the bending Angle (general R=0.5) should be tried and expanded

8. Points that are prone to error (similar asymmetries) should be highlighted

9. Where there are more dimensions, a larger image should be added

10. The place to be protected by spraying shall be indicated

Machining process

According to the difference of sheet metal parts structure, the process flow can be different, but the total number is not more than the following points.

1. Feeding: there are various feeding methods, mainly including the following

(1). Shearing machine: it is a simple material part of shearing bar, which is mainly prepared for die blanking and forming. The cost is low and the precision is less than 0.2.

(2). Press: is the use of punch points step or more open after the tablet on plate parts blanking forming various shapes, its advantage is cost time is short, high efficiency, high precision, low cost, suitable for mass production, but to design mold.

(3). NC NC blanking, the first to write all NC blanking NC machining program, using the programming software, pull map of writing into a number of NC machine tool can identify the program, make it according to the program step a knife on the plate blanking shape of the flat piece, but its structure by the cutting tool structure, low cost, precision at 0.15.

(4). Laser cutting, is the use of laser cutting way, in the structure of large flat it flat shape cut out, as well as NC blanking to write laser program, it can be a variety of complex shapes under flat parts, high cost, accuracy in 0.1.

(5). Sawing machine: mainly used aluminum profile, square pipe, round pipe, round bar material and so on, low cost, low precision.

1. Pliers: sinking, tapping, reaming, drilling

Sink hole Angle generally 120 ℃, for rivets, 90 ℃ for countersunk head screws, tapping the imperial bottom hole.

2. Flanging: also called pumping hole, hole, is in a small hole on the smoke into a larger hole, tapping again, mainly with the thickness of thin sheet metal processing, increase the strength and the screw thread turns, avoid sliding tooth, commonly used in thickness is thin, its around the normal shallow flanging, basic did not change, the thickness of thin thickness is allowed in the 30-40%, larger than normal flanging height can be obtained high height of 40-60%, with crowded thin 50% when, can get the biggest flanging height, when the thickness is bigger, such as the thickness of above the 2.0, 2.5, etc, can be directly tapping.

3. Press: is the use of mold forming processing working procedure, general processing of punching and cutting Angle, blanking, punching convex hull (convex point), salt tear, suction hole and forming processing, the processing needs to have the corresponding mold to finish operation, such as punching blanking die, convex BaoMo, tearing mode, pumping hole pattern, forming mould, etc., operating mainly pay attention to the position, direction.

4. Pressure riveting, riveting for the purpose of this company, mainly has the pressure riveting nut, screw, not to take off, etc, it is done through hydraulic pressure riveting machine or punch operation, the riveting to the sheet metal parts, and rose riveting way, need to pay attention to the direction.

5. Bending; Bending is folding 2D flat parts into 3D parts. Its processing needs to have the folding bed and the corresponding bending mold to complete, it also has certain bending order, its principle is to the next knife does not produce interference first folds, will produce interference later folds.

For example, T=1.0, V= 6.0, F=1.8, T=1.2, V=8, F=2.2, T=1.5, V=10, F=2.7, T=2.0, V=12, F=4.0

L mold classification, folding bed straight knife, curved knife (80 ℃ and 30 ℃)

When l aluminum plate is bent, there are cracks, which can increase the width of lower die groove and increase the upper die R (annealing can avoid cracks).

Note: when l bending Ⅰ diagram, plate thickness, number; Ⅱ bending direction

Ⅲ bending Angle; Ⅳ bending size; Ⅵ appearance, electroplating chromium chemical materials are not allowed to have creases.

The relationship between bending and riveting process is that, in general, after riveting is pressed, it is bent after bending, but after riveting of material parts, it is necessary to first fold and then press, and some of them need bending - riveting - bending.

6. Welding: welding definition: the atoms and molecules of the welded material are formed in one unit from jingda lattice distance

Welding a: argon arc welding, CO2 welding, gas welding, manual welding

B pressure welding: spot welding, butt welding and butt welding

C brazing: electric chrome welding, copper wire

Vacuum welding method: a CO2 gas shielded welding

B argon arc welding

C spot welding

D robot welding

The selection of welding method is based on actual requirements and materials. Generally speaking, CO2 gas shielded welding is used for steel plate welding. Argon arc welding is used for welding stainless steel and aluminum plates by robot, which can save working hours, improve working efficiency and welding quality, and reduce working intensity.

(3) the welding symbol: Δ fillet welding, Д, type I welding, v-shaped welding, single side welding V (V) with a blunt edge V (V) welding, point welding (O) and plug welding or groove welding (∏), edge welding (χ), with a blunt edge unilateral v-shaped weld (V), with a blunt U welding, welding with blunt J type, backing, when welding

Superior arrow lines and connectors

Missing welding and preventive measures

Spot welding: it is not strong enough to punch the convex point and impose the welding area

CO2 welding: high productivity, low energy consumption, low cost and rust resistance

Argon arc welding: low dissolution depth, slow dissolution rate, low efficiency, high production cost, with tungsten clamp defect, but with good welding quality, can weld non-ferrous metals, such as aluminum, copper, magnesium, etc.

1/2 welding deformation reason: insufficient preparation before welding, need to increase fixture

Welding fixture bad improvement process

Poor welding sequence

Tool welding distortion correction method: flame validity correction method

Method of vibration

Hammering method

Artificial time imitation