铝挤压机培训资料1docx.docx

1、铝挤压机培训资料1docxAluminum Profile ExtrusionShandong University2010.06ContentsChapter1 Process of Extrusion of Aluminum1.1 Process OverviewThe aluminum extrusion process really begins with the design process, for it is the design of the product-based on its intended use-that determines any of the ultimat

2、e production parameters. Questions regarding machinability, finishing, and environment of use will lead to the choice of alloy to be extruded. The function of the profile will determine the design of its form and, hence, the design of the die that shapes it.Once the design questions have been answer

3、ed, the actual extrusion process begins with billet, the aluminum material from which profiles are extruded. The billet must be softened by heat prior to extrusion. The heated billet is placed into the extrusion press, a powerful hydraulic device wherein a ram pushes a dummy block that forces the so

4、ftened metal through a precision opening, known as a die, to produce the desired shape.Fig. 1.1 This is a simple diagram of a typical horizontal hydraulic extrusion press; the direction of extrusion here is from left to right.That is a simplified description of the process known as direct extrusion,

5、 which is the most common method in use today. Indirect extrusion is a similar process, but with some important differences. In the direct extrusion process, the die is stationary and the ram forces the alloy through the opening in the die. In the indirect process, the die is contained within the ho

6、llow ram, which moves into the stationary billet from one end, forcing the metal to flow into the ram, acquiring the shape of the die as it does so.The extrusion process has been likened to squeezing toothpaste out of a tube. When pressure is applied at the closed end, the paste is forced to flow th

7、rough the open end, accepting the round shape of the opening as it emerges. If the opening is flattened, the paste will emerge as a flat ribbon. Complex shapes can be produced by complex openings. Fig. 1.2 These photos show a new length of extrudate, just emerging from the press (left) and the produ

8、ction of a profile in progress (right).注释：Main cylinder silind 主液压缸Hydraulic pressure hadr:lk 液压Press column klm 柱式压机Container 挤压筒Dummy block dmi: 挤压垫Ram 挤压杆Billet 坯料Front platen 挤压机前牌坊，前挤压盘Runout table 输出辊道Ribbon ribn 带状物Squeeze skwi:z 榨取, 挤出1.2 BilletBillet is the starting stock for the extrusion

9、operation. Extrusion billet may be a solid or hollow form, commonly cylindrical, and is the length charged into the extrusion press container. It is usually a cast product but may be a wrought product or powder compact. Often it is cut from a longer length of alloyed aluminum, known as a log.Alloys

10、are metals composed of more than one metallic element. Aluminum extrusion alloys contain small amounts (usually less than five percent) of elements such as copper, manganese, silicon, magnesium, or zinc. These alloying elements enhance the natural properties of aluminum and influence the extrusion p

11、rocess.Billet length varies according to a number of factors, including the desired length of the finished profile, the extrusion ratio, the length of the run-out, and the requirements of the extrusion press. Standard lengths may run from about 26 inches (660 mm) up to 72 inches (1,830 mm). The outs

12、ide diameter may range from 3 inches (76 mm) to 33 inches (838 mm); 6-inch (155 mm) to 9-inch (228 mm) diameters are the most common.注释：Copper kp，kp(r) 铜Manganese mni:z 锰Silicon silikn 硅Magnesium mgni:zi:m, -m 镁Zinc zik 锌Wrought r:t 制造的; 形成的; 精炼的, 锻成的Metallic mitlik 金属的1.3 Dies and ToolingDies can b

13、e made to form a virtually limitless array of shapes and sizes. Several factors influence the actual cost and lead-time of a specific die; the best combination of product performance, quality and cost is achieved when the product designer, the die maker, the extruder, and the purchaser recognize eac

14、h others requirements and work together.A typical extrusion operation will make use of a die assembly, including the die itself, which, together with a backer, is enclosed within a die ring, placed in front of a bolster, with a sub-bolster behind, all held together as a unit by a tool carrier. The b

15、acker, bolster, and sub-bolster provide the necessary support for the die during the extrusion process.Fig.1. 3 This diagram shows the components that typically make up a die slide, the tooling assembly, for a solid die.注释：Platen 挤压机前牌坊，挤压盘Bolster blst 前垫Backer 模垫Die 模具Die ring 模套Stem 挤压杆Dummy block

16、 挤压垫Liner 挤压筒内衬Container 挤压筒Die slide 模架Pressure ring 压力垫圈Horse shoe 马蹄形止口The extrusion die, itself, is a steel disk (normally H13) with an opening, the size and shape of the intended cross-section of the final extruded product, cut through it.Dies are broadly grouped as solid (or flat) dies, which

17、produce solid shapes, and hollow dies, which produce hollow or semi-hollow shapes. Combinations of solid, semi-hollow, and/or hollow shapes may be incorporated into a single die.A solid die may have one or more orifices or apertures through which the softened alloy is forced (extruded). Multiple ape

18、rtures in a single die produce multiple extrusions with each stroke of the press.Solid dies may, on occasion, be used to produce hollow profiles by means of a fixed or floating mandrel. The use of a mandrel for extruding a hollow shape through a flat die usually involves the use of hollow billets, c

19、ylindrical source stock that may have been cast or bored. Piercing mandrels, however, do not require the use of cored billet.Fig.1. 4 A solid die, as shown here, produces shapes without any enclosed voids and/or semi-hollow conditions.注释：Orifices :rfs, r- 模孔Apertures ptju 模孔Mandrelmndril 心轴、模芯Pierci

20、ng mandrel 穿孔针A semi-hollow die extrudes a shape that is nearly hollow, partially enclosing a void, the area of which (the area of the die tongue) is large in comparison with the gap where the tongue is connected to the main body of the die.While a solid or semi-hollow die is a single piece, it requ

21、ires support from additional tools called backers and bolsters. Depending on the complexity of the extruded shape, the total cost of the extrusion tooling may include charges for these supplemental tools.Fig.1. 5 A semi-hollow die also produces shapes without enclosed voids; however, unlike a solid

22、die, it produces shapes with a tongue ratio of 3:1 or greater.Hollow dies take a variety of forms. Bridge, porthole, and spider dies, for example, include a fixed stub mandrel as an integral part of the die. Each type of hollow extrusion die serves certain functions and carries its own advantages an

23、d disadvantages. The manufacturing methods and costs vary widely. The choice of design, and even manufacturing methods, will depend on the profile, press and container size, and production requirements.Fig.1. 6 A hollow die produces shapes with one or more enclosed voids. The die shown here, when us

24、ed together with a mandrel and other support tooling, produces a profile with six voids.The most common types of hollow dies are the porthole and pancake. They typically are the most cost effective and easiest to manufacture, allowing the designer to be much more creative in the placement and shapin

25、g of the ports and feed. They are also the easiest for CNC Machining (Computer Numeric Control), which allows for the die maker and die corrector to quantify any alterations for production improvements on future dies.A critically important characteristic of extrusion dies is that the effective beari

26、ng length controls the metal flow through the die. The objective is to have all parts of the profile emerge from the die at the same speed. The longer the bearing length, the greater the resistance to the flow of aluminum and the shorter the bearing length, the less resistance to flow. Through effec

27、tive design, the thick parts of a profile can be slowed through the use of longer bearings to match the speed of the thinner parts with short bearings.注释：Porthole p:thl, prt- 分流孔Pancake 饼状Bearing bri 工作带Resistance ri zistns 抵抗, 反抗, 抵抗能力Profile prufail 型材1.4 Direct Extrusion OperationFig. 1.7 This di

28、agram shows the basic steps involved in extruding an aluminum profile.Once the shape of the final product has been identified, the proper alloy selected, and the die prepared, to make ready for the actual extrusion process, the billet and extrusion tools are preheated. During extrusion, the billet i

29、s still solid, but has been softened in a heating furnace. The melting point of aluminum varies with the purity of the metal, but is approximately 1,220 Fahrenheit (660 Centigrade). Extrusion operations typically take place with billet heated to temperatures in excess of 700F (375C), and-depending u

30、pon the alloy being extruded-as high as 930F (500C).The actual extrusion process begins when the ram starts applying pressure to the billet within the container. Various hydraulic press designs are capable of exerting anywhere from 100 tons to 15,000 tons of pressure. This pressure capacity of a pre

31、ss determines how large an extrusion it can produce. The extrusion size is measured by its longest cross-sectional dimension, sometimes referred to as its fit within a circumscribing circle diameter (CCD).As pressure is first applied, the billet is crushed against the die, becoming shorter and wider

32、 until its expansion is restricted by full contact with the container walls. Then, as the pressure increases, the soft (but still solid) metal has no place else to go and begins to squeeze out through the shaped orifice of the die to emerge on the other side as a fully formed profile.About 10 percent of the billet, including its outer skin, is left behind in the container. The complete