What is the main process of sheet metal processing in most factories that manufacture and process profiles?

Common sheet metal parts processing process

First, material selection.

The commonly used materials for sheet metal processing are porcelain cold-rolled sheet (SPCC), hot-rolled sheet (SHCC), galvanized sheet (SGCC SECC), copper (CU), brass, red copper, beryllium copper, aluminum sheet (606 1, 6063, hard aluminum, etc. ), aluminum profile, stainless steel (mirror surface, wire drawing surface, etc.

The choice of materials is different, and the use and cost of the product should generally be considered.

1.SPCC cold-rolled steel plate.

Mainly used for electroplating and baking paint parts.

Low cost, easy molding, and material thickness ≤ 3.2 mm

2.SHCC hot rolled steel plate.

Materials with T≥3.0mm are also baked by electroplating, which has low cost, but it is difficult to form, and flat parts are mainly used.

3.SECC and SGCC galvanized sheets. SECC electrolytic plate is divided into n material and p material.

N materials are mainly not surface treated.

The cost is high, and P material is used for spraying parts.

4. copper; Conductive materials are mainly used, and their surface treatment is nickel and chromium plating, or no treatment, which is costly.

5. aluminum plate; Generally, surface chromate (J 1 1-A) and oxidation (conductive oxidation and chemical oxidation) are used, which are costly, including silver plating and nickel plating.

6. Aluminum profiles; Materials with complex cross-sectional structure are widely used in various boxes. Surface treatment is the same as aluminum plate.

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

Second, drawing review, to write the process flow of parts, we must first know the various technical requirements of parts drawings; Then drawing review is the most important link in the preparation of part process flow.

1. Check whether the drawings are complete.

2. Whether the relationship between drawings and views is clearly marked.

Complete, marked with size units.

3. Assembly relationship, assembly requires key dimensions.

4. The difference between the old and new layout.

5. Translation of foreign maps.

6. Table code conversion.

7. Feedback and burying of drawing problems.

8. Materials

9. Quality requirements and process requirements

10. The officially released drawings must be stamped with the seal of quality control.

Third, start the precautions.

The developed drawing is a plan (2D) developed according to the part drawing (3D).

1. Expansion modes should be combined.

It is necessary to promote material saving and machinability.

2. Reasonable selection of clearance and edging mode, with clearance of 0.2 below T=2.0 and clearance of 0.5 below T=2-3. The wrapping method adopts long side and short side (door panel).

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

4. Burr direction

5. Tooth extraction, riveting, tearing, punching bumps (bags), etc. , and draw a sectional view.

6. Check the material, thickness and thickness tolerance.

7. For special angles, the inner radius of the bending angle (generally R=0.5) should be enlarged according to the trial bending.

8. Errors (similar asymmetry) should be emphasized.

9. Enlarge the picture where there are many sizes.

10. The places that need spray protection shall be marked.

Four, sheet metal processing technology, according to the differences in the structure of sheet metal parts, the technology can be different, but the total does not exceed the following points.

1, blanking: There are many blanking methods.

There are mainly the following ways

(1) Shearer: It is a simple material that is sheared by shears. Mainly for die blanking. The cost is low, and the accuracy is lower than 0.2, but only strips or blocks without holes and corners can be processed.

(2) Punch machine: The flat parts after the parts are unfolded are punched into various shapes on the plate by a punch machine in one or more steps. Its advantages are short working hours, high efficiency, high precision and low cost, and it is suitable for mass production, but it needs to design dies.

③.NC numerical control blanking.

During NC blanking, the NC machining program should be written first, and the unfolded drawings should be written into recognizable programs of NC drawing machine tools by using programming software, so that flat parts with various shapes can be stamped on the flat plate step by step according to these programs, but the structure is affected by the tool structure.

Low cost.

The accuracy is 0. 15.

(4) Laser blanking, that is, laser cutting is used to cut the structural shape of the flat plate on the large flat plate.

Just like NC blanking, it is necessary to write a laser program, which can blank all kinds of complex flat parts, and the cost is high.

The accuracy is 0. 1.

⑤. Sawing machine: mainly uses lower aluminum profiles, square tubes, drawn tubes, round bars, etc., with low cost and low precision.

1. fitter: reaming, tapping, reaming and drilling.

The counterbore angle is generally 120℃, which is used for rivets and 90℃ for countersunk screws.

Tap the English bottom hole.

2. Flanging: also known as hole drawing and hole turning, it is to draw a slightly larger hole on a smaller bottom hole.

Heavy tapping, mainly with thin sheet metal processing.

Increase its strength and number of thread turns to avoid slipping teeth. It is generally used for shallow flanging of thin plate thickness and normal hole circumference, and the thickness is basically unchanged. When the thickness is allowed to be reduced by 30-40%, the height is 40-60% higher than the normal flanging height, and when the thickness is reduced by 50%, the maximum flanging height can be obtained.

When the thickness of the plate is large, such as 2.0 or more, it can be tapped directly.

3. Stamping: This is a processing procedure formed by a die. Stamping processing generally includes punching, corner cutting, blanking, punching convex hull (bump), punching and tearing, punching and forming. Its processing needs corresponding dies to complete the operation, such as punching blanking die, convex die, tearing die, punching die, forming die and so on. , the operation mainly pays attention to the position and directionality.

4. Riveting: As far as our company is concerned, there are mainly riveting nuts and screws, which are riveted to sheet metal parts by hydraulic riveting machine or punching machine, and there are also riveting methods, so attention should be paid to directionality.

5. bending; Bending is to fold a 2D plane part into a D part. Its processing needs folding machine and corresponding bending die to complete, and there is also a certain bending sequence. Its principle is that the next knife folds first without interference, and folds after interference.

L the number of bent strips is 6 times of the calculated slot width of the plate thickness below T=3.0mm, such as T= 1.0, V=6 .0 F= 1.8, T= 1.2, V=8, F=2.2 and t =/kloc-.

F=4.0

L Classification of folding bed molds, straight knives and curved knives (80℃, 30℃)

L aluminum plate has cracks when bending, so the width of the lower die groove can be increased and the upper die R can be increased (annealing can avoid cracks).

L Matters needing attention in bending: I drawings, required plate thickness and quantity; Two bending directions

ⅲ bending angle; Ⅳ bending size; ⅵ Chromium plating materials are not allowed to have wrinkles.

Generally speaking, the relationship between bending and riveting process is riveting before bending, but some parts will interfere after riveting, so they must be folded before pressing, and some processes such as bending, riveting and bending are needed.

6. Welding: Definition of welding: The distance between atoms and molecules of the material to be welded is integrated with the crystal lattice of Jingda.

① Classification: A fusion welding: argon arc welding, CO2 welding, gas welding and manual welding.

Pressure welding: spot welding, butt welding and collision welding.

Brazing: electrolytic chromium welding, copper wire.

② Welding method: AC02 gas shielded welding.

argon arc welding

C point welding, etc.

Robot welding

The choice of welding method depends on the actual requirements and materials. Generally speaking, CO2 gas shielded welding is adopted for iron plate welding. Argon arc welding is used to weld stainless steel and aluminum plate. Robot welding can save working hours, improve working efficiency and welding quality, and reduce working intensity.

③ Welding symbol: δ fillet welding.

д, I type welding.

V-welding, single-sided V-welding (V) blunt edge V-welding, spot welding (O), plug welding or groove welding (∏), edge welding (χ) and single-sided blunt edge V-welding (V).

Blunt u-welding, blunt j-welding, back welding and butt welding.

④ Arrow line and connector

⑤ Welding defects and their preventive measures

Spot welding: insufficient strength will bump and impose the welding area.

CO2 welding: high productivity, low energy consumption, low cost and strong rust prevention ability.

Argon arc welding: penetration, slow penetration speed.

Low efficiency and high production cost.

It has the defect of tungsten inclusion, but it has the advantage of good welding quality and can weld non-ferrous metals.

Such as aluminum, copper, magnesium, etc.

⑥ Causes of welding deformation: insufficient preparation before welding, requiring additional fixtures.

Improvement process of welding fixture defects

Wrong welding sequence