XX month XX-XX month XX
Internship purpose
Through the two-week practical training, to have a certain understanding of the sheet metal and the sheet metal processing process, the sheet metal primary processing has a certain operating skills, in accordance with the requirements of the instructor to produce sheet metal works.
The understanding of the terminology of sheet metal
1 Definition of sheet metal: Sheet metal is a comprehensive cold working process for sheet metal (usually below 6mm), including shearing, punching/cutting/compounding, folding, welding, riveting, splicing, molding and so on.
2 mechanical properties of metals: the mechanical properties of metals refers to the ability of metal materials to resist a variety of applied loads, often including: elasticity and stiffness, strength, plasticity, hardness, impact toughness, fracture toughness and fatigue strength, etc., which are extremely important indicators to measure the performance of materials. Sheet metal is also the use of mechanical properties of metal processing.
3 Basic deformation of sheet metal: bending, flanging, calendering, partial molding, expansion
4 Sheet metal samples: basic samples, production samples, standard samples
5 The three elements of the production of sheet metal parts for aircraft
(1) Reasonable sheet metal forming process;
(2) Advanced molds;
(3) Efficient Forming equipment;
6 on the way the four types of heat treatment:
Annealing: refinement of grain homogenization of the material tissue composition, reduce hardness, improve plasticity, de-stressing, to prevent cracking
Normalizing: annealing of the special case, the purpose is the same, the cooling rate is different.
Quenching: preparation for tempering
Tempering: reduce brittleness, eliminate internal stresses, to prevent deformation and cracking in the process of use
7 Theoretical mold line: Theoretical mold line is drawn on the metal plate or gelatin plate 1:1 of the theoretical shape of the aircraft parts of the map, which also has a structural axes, datum lines, etc. drawn. The role is to coordinate the theoretical shape of the part plane and each cut surface, and as the original basis for manufacturing all the basic samples of the cut surface.
8 structural mold line: is drawn on a metal plate or gelatin plate on a part of the cut 1:1 internal structure, the role is to coordinate the cut of all parts of the structure of the shape, and as the original basis for manufacturing the cut of all production samples to ensure that the cut of the full set of coordination between the process equipment.
9 sample plate: aircraft sheet metal parts of the sample plate is the mold line on the 1:1 product data and shape transferred to the product parts or process equipment on the "excessive tool" to play a role in the coordination between the parts or process equipment.
10 scribing: in the material to be processed to draw the processing boundaries of the line containing points, called scribing.
11 manual bending: refers to the manual operation of the sheet material along the straight line or curve bending into a certain angle or radian method.
12 hemming: the process of shrinking the wool fibers to become shorter is called hemming, processing of convex curved edges are generally used hemming.
13 basic methods of hemming: folding pliers folding, cradling the edge, with a rubber beaters hemming, shrinking machine hemming.
14 put edge: in the process of molding to make the edge of the material thinner stretching operation.
15 pulling edge: the flat material will be made out of a certain height of the curved edge of the curved parts of the method is called pulling edge, is divided into the outer edge and the inner edge of the pulling edge, as well as the composite pulling edge.
16 arch: the plate material made by hand into a concave and convex surface shape of the part is called arch, divided into cold arch and hot arch two methods.
17 crimping: in order to increase the rigidity and strength of the edge of the part, the edge of the part will be crimped process is called crimping, can enhance the strength, rigidity and aesthetic effect.
18 types of crimping: clip wire crimping, hollow crimping.
19 bite seam: the edge of two pieces of sheet material or a piece of sheet material of the two sides of the bending buckle, and press each other way.
20 methods of biting seam: vertical single biting seam, vertical double biting seam, horizontal single biting seam, horizontal double biting seam.
21 (2) release: the method of drawing out the unfolding plan in 1:1 scale is called release.
21 (1) the basic principle of release: the projected dimensions of a complex part part in accordance with the actual unfolding, and subsequently combined into a complete unfolded shape.
22 The basic method of release: parallel line expansion method, triangle expansion method, ray expansion method, straight line equalization method, circumferential equalization method.
23 Sheet metal part correction: eliminating unnecessary deformation to achieve the required shape of the operation
24 Rubber forming: the use of rubber as a general-purpose convex (or concave) mold for sheet metal parts forming method, is one of the soft mold forming methods.
25: rubber molding features: good productivity, good surface quality, rubber instead of concave mold role.
26 compression bending: the method of mechanical pressure on the metal material to produce bending moment, so that the method of bending molding.
27 roll bending: roll bending is the plate or profile, through the rotation of the roller to make it a process of bending. Where the cylindrical structure or arc-shaped components, generally use the roll bending process to molding processing. Roll bending is divided into two-dimensional bending and three-dimensional bending.
28 around the bend: one side of the woolen material to tighten in the rotating mold, and the woolen material lateral pressure, so that the woolen material around the mold bending and forming process.
29 bending: bending is the metal sheet, tube and profile bending into a certain curvature, shape and size of the workpiece of the press molding process. Bending is widely used in the manufacture of high-pressure vessels, boiler ladle, boiler tubes, hull of the steel plate and bone ribs, a variety of utensils, instruments and components, as well as cabinet inserts.
30 bending classification: according to the characteristics of the process, bending can be divided into top bending, bending, roll bending and bending.
Which pressure bending is the most commonly used bending method.
31 bending equipment: most of the general-purpose mechanical presses or hydraulic presses, but also special bending presses. Commonly used roll bending equipment is the coiler
32 bending method: the plate is placed between the drive roller and the pressure roller, the drive roller positive and negative direction of the exchange of rotation, so that the plate reciprocating motion. Adjust the pressure roller to make it gradually down, you can bend the plate into the required curvature of the cylindrical, conical and hyperbolic curvature of the smaller. One end of the press-down roller can be raised to facilitate the unloading of the workpiece.
33 bending notes: for higher precision requirements, length and radius of curvature requirements of larger, smaller transverse size requirements of the bending parts, can be in a special bending machine for bending. When bending, the full thickness of the plate are subject to tensile stress, thus only producing elongation deformation, unloading the deformation caused by the spring back small, easy to ensure precision.
34 molding process: molding process is divided into cold molding and hot molding;
35 cold molding process: the material is not heated in the case of punching and shearing, bending, stretching, etc., the processing method called cold molding;
36 hot molding process: thermoplastic plastic sheet material into a variety of products of a class of more special processing methods,
37 the difference between the two: Cold molding and hot molding is mainly for forging. Workpiece blanks in the unheated state of forging is cold molding, in the heated state of forging is hot molding, hot molding and temperature forging and hot forging, the temperature is different.
38 Shot Peening: Shot Peening is the use of high-speed spherical projectile spray attack exposing the surface layer, so that it produces plastic deformation of an aircraft sheet metal special process processing methods.
39 Shot Peening Usage: Shot Peening is used for large-scale overall wall plate type of molding, its main advantage: no molds, only a set of cut surface samples, in line with the accuracy of the cut surface samples gap of 0.3-0.5mm, especially suitable for large-scale wings, fuselage, the rocket's overall wall plate molding.
40 shot peening: shot peening, also known as shot peening, is to reduce fatigue of parts, one of the effective ways to improve the life of the shot peening is the high-speed projectile stream sprayed onto the surface of the spring, so that the surface of the spring plastic deformation occurs, and the formation of a certain thickness of the reinforced layer, the reinforced layer of the formation of a high level of residual stress, due to the existence of compressive stress on the surface of the spring, when the spring is subjected to loads can offset a portion of the stress resistance, thus improving the spring. A part of the stress resistance, thus improving the fatigue strength of the spring.
Three equipment in the internship
(a): shearing machine
1 shearing machine definition: shearing machine is a blade relative to the other blade for reciprocating linear motion shear plate machine. Is borrowed from the movement of the upper blade and the fixed lower blade, the use of reasonable blade clearance, various thicknesses of metal plate shear force, so that the plate according to the required size fracture separation. Shearing machine belongs to a kind of forging machinery, the main role is the metal processing industry. The products are widely used in aviation, light industry, metallurgy, chemical industry, construction, shipbuilding, automobile, electric power, electrical appliances, decoration and other industries to provide the required special machinery and complete sets of equipment.
2 shearing machine classification: special shears, slant blade shears, flat blade shears, multi-purpose shears (combined punching and shearing machine, plate bending and shearing machine)
(B): bending machine
1 bending machine definition: is a machine capable of bending thin plates, its structure mainly includes bracket, table and clamping plate, the table is placed on the bracket, the table is formed by the base and the pressure plate. The worktable is placed on the bracket, the worktable consists of the base and the pressure plate, the base is connected to the clamping plate through the hinge, the base consists of the seat shell, the coil and the cover plate, the coil is placed in the depression of the seat shell, the top of the depression is covered with a cover plate. The coil is energized by a wire when in use, and the energized wire generates a gravitational force on the platen, thereby realizing the clamping of a thin plate between the platen and the base. Because of the electromagnetic force clamping, the platen can be made into a variety of workpiece requirements, and can be processed for workpieces with sidewalls, and the operation is very simple.
2 bending machine classification: bending machine is divided into manual bending machine (also divided into mechanical manual bending machine and electric manual bending machine, hydraulic bending machine), hydraulic bending machine and CNC bending machine. If the synchronization can be divided into: torsion axis synchronization, machine-hydraulic synchronization, and electro-hydraulic synchronization.
Hydraulic bending machine according to the movement can be divided into: the upper dynamic type, the lower dynamic type.
(C): roll bending machine
1 roll bending machine definition: the plate through the roll bending way to obtain different degrees of bending machinery and equipment.
2 roll bending machine classification: three-axis roll bending machine, four-axis roll bending machine, multi-axis roll bending machine.
A few of the deepest experience on the practical training
1 discipline and punctuality.
2 practical training tools should be counted before and after use, not more and not less.
3 Do not wear gloves when operating rotating equipment.
4Single person operation, safety first.
5Speeding up the sanding speed can improve the surface roughness.
6 Knocking bending into rows, even force is one of the ways to ensure the quality of curved surface curvature.
7Pipe clamps when bending by hand with a cloth can reduce the degree of surface damage.
8When the pneumatic drill is used, keeping the drill bit upright can greatly reduce the chance of not hitting off.
9For sheet metal processing in pairs, you can take one material plate scribing, the other laminating, and processing together at the same time, can improve the degree of cooperation.
10 Effective mediation of the shearer blade clearance can improve the quality of the shear opening.
Summary of the internship
Through this internship, I know: sheet metal is irreplaceable in the field of machinery, sheet metal has a light weight, high strength, electrically conductive (able to be used for electromagnetic shielding), low cost, large-scale mass production of good performance, etc., and is now widely used in the field of aviation, electronics and electrical appliances, communications, automotive industry, medical equipment and other fields. Secondly, as the application of sheet metal becomes more and more extensive, the design of sheet metal parts has become a very important part of the product development process. Mechanical engineers must be proficient in the design of sheet metal parts, so that the design of sheet metal meets the functionality and appearance of the product and other requirements, and also makes the stamping die manufacturing simple and low-cost. And we, as sheet metal processors, also bear an important responsibility to ensure the quality of parts, reduce the scrap rate, is our main learning aspect. Sheet metal processing, basically belongs to the one-time molding, can not be secondary molding, so once the inappropriate will not be able to use again to produce the part. Although this internship is only a very short two weeks, to our internship is not particularly deep, mainly to give us a simple experience of sheet metal manual processing skills, while familiar with the operation of some commonly used sheet metal material and processing of several mechanical equipment. Shears are often used to cut large pieces of sheet metal to the required size. Through the adjustment can be obtained by different angles of the bending parts. At the same time I have developed a personal competence in processing simple bending surfaces by hand.
Through this 10 days of practical training operation, gave me more practical sexy view, I will work and study in the future I will combine the theory and practice, so that it will be very helpful to their own cognition. Knowledge is more full of me, ability to make me more abundant. Thank you for all the growth this internship has brought me.