Concept:
Process called sheet metal sheet metal processing. Specific example, the use of sheet production chimney, drum, tank oiler, ventilation pipes, elbow the size of the first, day garden areas, funnel-shaped, the main processes are cutting, bending buckle side, bending, welding, riveting, etc., need some knowledge of geometry. Sheet metal is sheet metal parts, that is, by stamping, bending, stretching and other means to process the parts, a general definition is the same thickness in the processing of parts corresponding to the casting, forging parts, machined parts.
Sheet Metal material selection
Sheet Metal and General materials used in cold-rolled plate (SPCC), hot-rolled plate (SHCC), galvanized steel (SECC, SGCC), copper (CU) brass, copper, beryllium copper, aluminum (6061,6063 , hard aluminum, etc.), aluminum, stainless steel (mirror, drawing surface, matte), according to the role of different products, different materials used, it generally takes from product use and its costs up for consideration.
1. Cold rolled SPCC, mainly used in electroplating and paint parts, low cost, easy to shape, material thickness ≤ 3.2mm.
2. Hot-rolled plate SHCC, material T ≥ 3.0mm, also plating, paint parts, low cost, but difficult to shape, mainly used for flat pieces.
3. Galvanized sheet SECC, SGCC. SECC Electrolytic board material points N, P material, N is not expected to be the main surface treatment, high cost, P material used for coating parts.
4. Copper; major role with conductive materials and parts, the surface is plated with nickel, chrome, or no treatment, the high cost.
5. Aluminum; general use surface chromate (J11-A), oxidized (conductive oxidation, chemical oxidation), high cost, there are silver-plated, nickel-plated.
6. Aluminum;-sectional structure of complex materials and parts, used extensively for a variety of plug box. Surface treatment with aluminum.
7. Stainless steel; mainly used without any surface treatment, and high cost.
Note sheet metal to start
Expansion plan is based on the parts diagram (3D) to start the plan (2D)
1. Expansions to be together, to facilitate savings in materials and processing
2. Reasonable choice to ask gap and wrapping methods, T = 2.0 the following question gap 0.2, T = 2-3 Q-gap 0.5, edging and side bag with a long way short side (door type)
3. Reasonable to consider dimension tolerance: the negative balance to go in the end, take half are poor; hole shape dimensions: positive difference to go in the end, take half of the negative difference.
4. Burr direction
5. Pumping teeth, riveted, tearing, red bumps (package), the direction of such position, draw the cutaway view
6. Check the material, thickness, the thickness tolerance
7. Special point of view, within the radius of the bend angle (typically R = 0.5) determined to try to start off
8. There are error-prone (similar to the asymmetry) should focus on prompt local
9. Size and more places to add Enlargement
10. Protection of areas that need to be sprayed, said
Sheet metal machining process
According to sheet metal structures, processes can vary, but generally does not exceed the following points.
1, cutting: cutting a variety of ways, mainly in the following ways
①. Shears: Shears cut the use of simple materials and parts of the material, it is primarily to prepare for the mold off the metal forming process, low cost, accuracy of less than 0.2, but can only process non-porous material or non-beveled corners of the block of material.
②. Punch: is the use of punch, one or more sub-steps will be part of the plate after the commencement of the flat pieces of materials and parts stamping forming various shapes, which takes advantage of the short working hours, high efficiency, high precision, low cost for mass production, However, to design the mold.
③. NC-cutting, NC cutting of the first to write NC programs, the use of programming software, the expansion plan will be drawn into the preparation of NC machine tools can identify the number of pull programs, these programs allowed under the knife in the step of blanking plate structure shape flat pieces, but its structure by the tool structure actions, low cost, accuracy in 0.15.
④. Laser cutting, laser cutting method is the use, in large flat shape of the structure will cut its flat out, with the NC cutting program as the laser to be prepared, it can be of various shapes of flat pieces of complex, high cost, accuracy at 0.1.
⑤. Saw: The main use under aluminum, square tube, map tube, rod material and the like, low cost, low accuracy.
1. Fitter: sink hole, tapping, reaming, drilling countersinking angle is generally 120 ℃, used for pop rivets, 90 ℃ for countersunk head screws, tapping inch bottom outlet.
2. Flange: also known as pumping holes, turn the hole, is a small hole on the base pumping into a slightly larger hole, and then tapping the key with the thickness of thin sheet metal processing, to increase its strength and thread turns , to avoid sliding teeth, generally used for relatively thin thickness, the hole-week normal shallow flange thickness unchanged, allow 30-40% of the thickness of the thin, highly available large flange than normal high 40 - 60% of the height, thin with a 50% squeeze may be the largest flange height, when the thickness is large, such as the thickness of 2.0, 2.5 and above, can be directly tapping.
3. Punch: is the use of mold forming manufacturing processes, the general processing of a punch punching, cutting angle, blanking, punching the convex hull (bump), red tear, pumping hole, forming, and processing methods, the processing necessary to have appropriate mold to complete the operation, such as blanking punching mold, the convex hull mold, tearing mode, pumping hole mold, molding, etc., operating mainly pay attention to the location, direction.
4. Riveting: Riveting of this company, mainly clinching nuts, screws, captive, etc., it is by hydraulic pressure riveting machine or punch to complete the operation, to be riveted to the sheet metal pieces, as well as riveting up way, the need to pay attention to direction.
5. Bending; bending is the 2D flat pieces, fold the success of D parts. The process requires folding bed and the corresponding bending mold to complete, it also has some bending sequence, the principle is to not produce interference under the knife before folding, after the fold will produce interference.
l is the number of bending of the following six times T = 3.0mm thickness calculated width, such as: T = 1.0, V = 6.0F = 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 Brake mold classification, straight knives, machetes (80 ℃, 30 ℃)
l aluminum bending, cracks, increase the width style to increase the lower mold die R (annealing to avoid cracking)
l Bending Notes: Ⅰ surface, required plate thickness, quantity; Ⅱ Ⅲ bending direction of the bending angle; Ⅳ bending dimensions; Ⅵ appearance, chrome plating of materials and parts must not have creases.
Relationship between bending and riveting process, under normal circumstances, after clinching the first bend, but after clinching materials and parts must be folded to interfere pressure, and some are bending - riveted - and then bending and other processes.
6. Welding: Welding definition: the welded materials from atoms and molecules from the lattice to form one of Beijing
① Type: a fusion welding: welding, CO2 welding, gas welding, manual welding
b pressure welding: spot welding, butt welding, welding hit
c brazing: electric welding of chromium, copper wire
② welding: aCO2 gas shielded arc welding
b Welding
c-point welding
d robot welding
Choice of welding method is based on actual requirements and the material may be, in general, CO2 gas shielded welding class for welding iron daub; welding for stainless steel, aluminum welding class, and robotic welding, can save time, improve efficiency and welding quality, reduce the work intensity.
③ welding symbols: Δ angle welding, Д, I type welding, V-welding, soldering unilateral V-(V) with a blunt edge V-welding (V), welding (O), plug or slot weld welding (Π) , curling, welding (χ), with the blunt side of a unilateral V-welding (V), the U-shaped with blunt welding, with a blunt J-welding, weld the back cover of every welding
④ arrow lines and fittings
⑤ welding missing and loss prevention measures
Spot: strong enough to play bump, impose welding area
CO2 welding: production rate, energy consumption, low cost, and strong resistance to rust
TIG: melting depth, welding slow, low efficiency, high production costs, with a clip of tungsten defect, but with the advantages of good quality welding can weld non-ferrous metals such as aluminum, copper, magnesium and so on.
⑥ welding deformation of reasons: lack of preparation prior to welding, an additional fixture
Welding jig poor to improve the process
Poor welding sequence
⑦ welding distortion effect Dhamma: Dhamma flame effect
Vibration method
Hammering method
Artificial aging method
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Cathy 
Cathy
sales@gzhch.com
