Visual quality characteristics of aluminum sheet and plate has been compiled by the technology committee of the sheet and plate division as a reference for those who have an interest in these rolled products and who may have a need to know the terminology commonly used in this largest segment of the aluminum industry. The demand for aluminium extrudates are growing and extruders are pressurized to extrude products as fast as possible without lowering the quality of the product. The objectives of this work are to determine the root causes of streak defects on an anodized aluminium extrusion weld and its associated microstructural features in the alloy and to eliminate the defects. Ppt extrusion powerpoint presentation free to download. A manufacturer of the flexible packaging material used to. Owing to the considerable deformation associated with extrusion operations, a number of defects can occur in extruded products. During the execution of this work, the defects of the extrusion process were typified. Product defects in aluminum extrusion and their impact on operational cost vol. Back end or extrusion defect streaks are caused by ingot skin or container skin being extruded on or near to the section surface.
Aluminum is often selected for its electrical conductivity, which is nearly twice that of copper on an equivalent weight basis. Visual quality characteristics of aluminum sheet and plate. The aluminium extrusion process begins with heating aluminium billets in a furnace up to 750 or 900 degrees fahrenheit 398 482celsius 3. Troubleshooting the extrusion process hanser publications.
These defects differ from transverse welds in that they normally occur at the back end of an extruded length and are not confined to feeder plate or hollow extrusions. The extrusion process converts a solid plastic feedstock material into a molten viscous fluid, and then to a finished solid or flexible film product for practical use. Commercial hot extrusion of aluminum involves different operations, such as billet preheating and shearing, loading and deformation, stretching and roll correction, age hardening, and paintinganodizing. Compared to steel profiles, aluminium extrusions can be made more complex and material can be added where it is needed. They are often of different native language, but mostly use the english language for their correspondence. Keywords hot metal forming, aluminum extrusion, anodizing, painting, product defects, origin of defects, defect classification, metal flow patterns, operational. Pdf product defects in aluminum extrusion and their. Aluminium is particularly well suited to the extrusion process due to its excellent plasticity at extrusion. The identification and prevention of defects on finished. Technical and economic viability of the process depends on reduction of defects that. Direct extrusion finds application in the manufacture of solid rods, bars, hollow tubes, and hollow and solid sections. The proposed inspection system can be applied in industry for online monitoring of aluminium extrusion processes and the inspection of defects arising in extruded products. During the aluminium extrusion, defects are largely responsible for decreasing.
This defect occurs at the front of all extrusions except the first with any solid profile produced with a pocket or welding chamber and all hollow shapes. Member companies operate almost 200 plants in the united states and many conduct business worldwide. The requirements of high conductivity and mechanical strength can be met by use of longline, highvoltage, aluminum steelcored reinforced transmission cable. Defects classification in 6xxx aluminum extrusions. The most important and common method used in aluminum extrusion is the direct process. In this lesson, extrusion defects have been explained. Study of surface cracking during extrusion of aluminium alloy aa 2014 z. Important extrusion parameters and conditions are exit temperature, extrusion. It is a cast or forged steel that supports for extrusion tooling and so it is designed for minimum deflection under load. Direct extrusion finds application in the manufacture of solid rods, bars, hollow tubes, and hollow and solid sections accord. Aluminum extrusion plants around the globe are turning to best practices programs to improve productivity, quality, and consistency of performance in the key elements of the extrusion process.
The form of aluminium can be classified as not liquid, but rather a malleable solid at the time of extrusion. Thus, defects lead to increased production costs, delays in delivery and increase of the scrap percentage. The evaluation of defects in the aluminium extrusion. The demand for and application of aluminum extrusion in architecture and in the manufacture of automobiles, small machine components, struc. Real world data from local industry is used for partial cost analysis. Aluminum extrusions are popular in the automobile, aircraft, and construction industries. Aim of the current study is to study the production line of an aluminum alloy wheel manufacturing industry and to improve the quality of production using quality control tools. Fdeahp analysis to reduce defects in an aluminium extrusion industry arun mathews varikatt, dr. Our production units in south africa are based in midrand and pietermaritzburg.
The defects can be classified into the following categories, illustrated in figure 6. Pdf commercial hot extrusion of aluminum involves different operations, such as billet preheating and shearing, loading and deformation. Previous experiments suggest that this type of defect is caused by. Some cross sections, when extruded, will produce undesirable force distributions and metal flow. Pdf product defects in aluminum extrusion and their impact on. The effects of nitrogenliquid and gaseouson aluminum. The origin of streaks on aluminium alloy extrusions. Because of its versatility and netshape ability, extrusion is a very common manufacturing process, especially for aluminum alloys. Casexpert a process planning system with feature based.
Product defects in aluminum extrusion and their impact on operational cost. Hot metal forming, extrusion, anodizing, painting, defects, origin, classification, flow. Unfortunately, the systems and procedures used to implement these standards are often too complex or ineffective. It can be caused by a single source or the cumulative effect of several factors. Some defects may originate in the substrate metal as a result of the thermomechanical fabrication process used to produce the sheet or extrusion or during handling and storage of the material before finishing. The thermal conductivity of aluminum alloys, about 50 to 60%. Global advisory group gag guidance terms and definitions 200901 3 47 introduction the market of many aluminium products is global and involves a global communication between the stakeholders, e. Study of surface cracking during extrusion of aluminium. Extrusion defects may arise in extruded products from the starting material or billet, the deformation process itself, or from other postprocessing corrective measures. Detection, causes and cures edward cohen, edward cohen consulting, inc. Analysis of product defects in a typical aluminum extrusion facility. Extrusion defects surface cracking also called hot shortness if temperature, friction or speed is too high, intergranular cracks occur common in aluminum, magnesium, and zinc alloys bamboo defects are periodic surface cracks that develop.
Extrusion is a process used to create objects of a fixed crosssectional profile. Aluminium is recognised as one of the material shaping the automobiles of the future. Ordinary tools saws and drills can be used for that purpose. Tappi flexible packaging troubleshooting short course. This study shows the systematic approach to find the root cause of a major defects in aluminium castings using defect. Pdf commercial hot extrusion of aluminum involves different operations, such as billet preheating, and shearing, loading and deformation. The aluminum association the aluminum association, based in washington, dc, with offices in detroit, mi, represents u. Product defects in aluminum extrusion and their impact on. The extrusion was initially etched in sodium hydroxide solution and, subsequently, anodized in sulphuric acid solution. Care of aluminium objectives general the extrusion process hulamin extrusions is the leading supplier of aluminium extrusions in southern africa, supplying extrusions and components to the architectural sector and engineering industry. The two main advantages of this process over other manufacturing processes are its ability to create very complex crosssections, and to work materials that are brittle, because the material only encounters compressive and shear stresses. Chris rauwendaal isbns 9781569904701 1569904707 hanser hanser publishers, munich hanser publications, cincinnati sample chapter 1.
Extrusion is the method that produces the largest volume of plastic products extruded products are generally long uniform and solid or hollow complex crosssections 2 sheet and film extrusion other types tubing, electrical wire coating, pipes to extrude thin film, air is forced into an. Classification of main faults in the production process of. Keywords extrusion press, guideways, linear motion guideways. Surface cracking internal cracking piping defect 4. This process cause gas porosity,shrink porosity,etc casting defect. Sheppard surface cracking is generally recognised as one of the main defects occurring during the process of aluminium extrusion, especially in the case of the so called hard aluminium alloys. Capral aluminium limited is regarded as an innovator in the application of aluminium extrusion technology for the automotive industry aluminium and extrusion. During the aluminium extrusion, defects are largely responsible for decreasing the quality of the finished product profiles which requires the duplication of work. Defects defect is any form of deviation of the products characteristic from the specification set up by the manufacturing process. Aluminium can be formed both in heated and cold state. An attempt is made in the first part of the paper to describe various types of product defects in commercial aluminum extrusion.
Aluminum extrusion technology in modern industries, both in the united states and elsewhere, continues to be a subject of discussion and evaluation concerning its application to the working environment. Irregularities during the process of extrusion these are mainly due to non uniform flow and stress distribution number of defects depends upon. Abstract aluminium extrusions are popularly used in transportation, construction, energy, electrical, manufacturing and defence industries. Aluminum extrusion quality for anodizing characteristic. The figure below illustrates a complex profile made stiffer and with added material where needed. The aluminum is used as a raw material for extrusion. Aluminum extrusion is an ingenious forming process that designers rely on to create profiles that challenge their creativity and imagination and meet exacting, specific needs. Troubleshooting the extrusion process a systematic approach to solving plastic extrusion problems 2nd edition maria del pilar noriega e. Extrusion is a continuous solid state deformation process which is widely used in the aluminium industry.