Aluminum Extrusions 3
ImprovedQuality of Aluminum Extrusions
ImprovedQuality of Aluminum Extrusions
Aluminumextrusions are designed aluminum pieces that are produced from heatedaluminum blocks then pushed through a die to create particulardesigns. Aluminum extrusions can be developed in many of sizes anddifferent shapes whereby a die is easily created. This extrudedaluminum provides structural strength, durability, and it can befully recyclable (Sheppard, 1999, p. 34). The extruded aluminumbegins with solid, aluminum cylindrical forms called billets. Othertimes, the aluminum can be used in its pure nature, but often has tobe blended with copper, manganese, manganese or silicon for creationof alloys that has particular properties. Alloys, depending on theblend, can be provide increased resistance to corrosion, improvedconductivity or increased strength, but often one factor increasecreates a trade-off for decrease in another.
Aluminumextrusions can be used for numerous purposes, which include thingssuch as aluminum-framed desks in modernized offices and displaycabinets in a number of stores. Every vehicle type virtually containsaluminum extrusions, which includes boats, cars, trains, andbicycles. In addition, tools and home appliances take advantage ofexcellent aluminum products that weigh and cost less to transportthan those ones that are made with different types of metals, butstill provides long-lasting service (McQueen, 2011, p. 109). Theincreased attention on green building has also forced leadingarchitects and contractors to use more products of extruded aluminumproducts. Extruded aluminum is corrosion-resistant and flexible, andcan be easily recycled therefore can be used more than once inconstruction projects. Therefore, the purpose of this researchproposal is give insights on how the quality of aluminum extrusionscan be improved.
HowAluminum Extrusions can be improved in Quality
Theglobal market for extruded light metal aluminum is rapidly changing.A lot of users are starting to become more knowledgeable on thecapability of pure aluminum extrusions and world class extruders. Thespecified profiles required have never been manufactured before, andtolerance are becoming uncommonly tight, while surface finishes thatwere required before now requires secondary operation (Xu, 2012, p.50). Because of this, there is need to improve the quality of theextrusions and the extruders.
Firstly,before working on aluminum die, the work has to go through grindingand polishing. Generally, work tape is required to be polished finelyto a mirror finish. Examine the verticality and flatness of the moldtape before assembling it. Shi et al. (2012, p. 56) cautioned thatwhether the quality of the nitride is good or bad, a decision shouldbe made on the polished finish to some extent of the work tape. Inaddition, the mold cavity has to be cleaned by use of brush andhigh-pressure gas, no impurities or dust, or it could result tovulnerability to working tape strain which is driven by metal flow,and thus result to roughness and crossed defects to surfaces ofextruded aluminum profile products.
Secondly,holding time for the mold in extrusion production is roughly 2 to 3hours, but could not exceed eight hours, or else hardness of the moldwork tape nitride layering will be reduced, turn the surface profilerough, and also cause wear at work, which will result to seriouscross and many other defects.
Figure1: The starting point: 5000 hooks
Thirdly,correct use of alkaline cleaning method should be used. After themold is unloaded, the temperature of the mold stands at 600 degrees,and if immediately immersed in the alkaline, since temperature ofalkaline water stands lower than mold temperature, and if thetemperature of the mold drops quickly, then the mold is develops acracking phenomenon. The correct way to increase the quality is toplace the mold at 150 to 180 degrees in the air, and then afterunloading is immersed in the alkaline.
Fourthly,optimize the process of extrusion according to Kalpakjian &Schmid (2014, p. 99). In order to scientifically extend the qualityof the aluminum extrusions die, rational use of the mold productionremains one aspect of the all process that not ignored. Sinceextrusion die working conditions is very poor, production of extrudedaluminum profiles must take into consideration reasonable measures toensure organization of the mold performance.
Thenext step ensures that before using extrusion die, there is need forthe die to process more reasonable surface for the process fornitriding treatment. According to Xu (2012, p. 65), nitridingtreatment surface enables the mold to improve greatly the surfacehardness for maintenance of sufficient toughness, for purposes ofreducing generation of heat. Since surface nitriding is hard to doonce, nitriding treatment done 3 or 4 times must be done on the moldduring the process, which generally require thickness of the nitrideto about 0.15mm.
McQueen(2011, p. 110) advices selection of appropriate extruder forproduction However, before extrusion production, there is need forfull calculation of profile cross-section, which according tocomplexity degree of the cross-section profile, size, thickness, andextrusion co-efficient to measure the extruder’s tonnage size. Inaddition, aluminum extrusion profile machine is ever-changing, andthus the aluminum extrusion industry is now developed. Again,aluminum has vital importance of good strength and light weighttherefore there are many industries that use aluminum profilesinstead of using the original long lasting material.
Accordingto Schippert (1934, p. 121), extruded aluminum surface appearance andsurface quality is of a certain nature that in a number of cases thatinvolves application, extruded aluminum finishing is not needed. Thisis due to the fact that aluminum has a very good resistance tocorrosion, and thus surface treatments are not necessary forprotection. However, there are other reasons for treatment ofaluminum surfaces proposed for quality aluminum extrusions, whichinclude: Color, hardness, better resistance to corrosion, betterresistance to wear, electrical insulation, and reflectivity.
Forextruded aluminum parts, the following processes are required forimproved quality. To begin with, mechanical surface treatments are atechnique required. These are grinding, polishing, and tumbling.Grinding is a treatment that should be used to improve the extrudedaluminum surface quality. The technique when applied leaves a finestriation behind on the grinding direction. The surface finishingcould then result to achievement a range from a medium, fine orcoarse. After the surface undergoes grinding, it should then befollowed with anodizing. According to Sheppard (1999, p. 127),grinding should be done before painting for further improvement ofachievable surface finish.
Secondly,the extruded aluminum surface should be polished. This would resultin determining the quality and gross specific requirements andrequests. After the surface is finally polished, it must then beionized by a process of bright ionizing in order to achieve glossfinish. Finally, there is barrel polishing, which is better known astumbling. It should often be employed as a process of deburring thatwould ensure surface finishes ranges from the matt to gloss (AluminumExtruders Council, 1998, p. 45).
Anodizingis the process of increasing translucent aluminum oxide film or thethickness of natural film that is already present. It should be knownthat aluminum surfaces after anodized will be able to achieveincreased resistance to corrosive effects. To ensure this isachieved, alkaline to acidic levels should be between four and nine.The strong and alkaline substances should not be used on alkalinesurfaces since the surface could be subject to damage. According toKaiser Aluminum And Chemical Sales, Inc et al. (1963, p. 154), thiskind of damage has been observed in the construction sites wherebythe extruded aluminum parts may come into contact with the gypsum,cement, and lime. To prevent this, visible surfaces should be coveredwith tape.
Paintingand power-coating should also be employed for increased quality ofextruded aluminum. Painting will offer a limited choice ofrepeatability and colors, while power-coating remains the best methodof aluminum finishing. While in the pre-treatment phase, pickling anddegreasing the surface should be performed. For good adhesion andresistance to corrosion, chemical treatments, either chrome-based orchrome-free should be used. On the other hand, when there is no limitto colors, power coatings should be applied on the surfaces ofextruded aluminum and then cured without application of solvents.However, in wet coat plants, it would result in high level use ofpaint that could easily be lost as a result of evaporation. Powercoating is therefore recommended since it would use the powder up to98 percent. The unused powder must then be recalculated through areclamation system.
Figure2: Side by side comparison of a good product and a poor qualityproduct. On the left is rejected on the left is accepted.
Finally,profile designs must be done in cases where extrusion stripes andlines are noticeable on the aluminum surface. To do this, aluminumfinishing should be performed in decoration form in order to hide theimperfections. To do this will result in the formation of designstage, which could result to the following benefits: (1)imperfections are easily hidden by decorations, (2) protection isoffered against the damages that might come up during handling andmachining, and (3) aesthetic design is offered. By offering a moredecorative, aesthetic pattern on the plain aluminum surfaces, it willresult in the decorations hiding the joints elegantly, which couldmake it part of the fluted design (Saha, 2000, p. 89).
TestingProcedures for Aluminum Extrusions
Forquality production of extruded aluminum, many extruders must be madeto change their approach to productivity. Extrusion process parts aretoo often considered individually without putting into considerationthe influence that could be brought by the components or the goal ofall the parts of the whole process that works together as part of thecoordinated system. Therefore, for increase in quality of extrudedaluminum, the extrusion process should be regarded to be a successionof the mini-systems, with each promising two or three parts, whichmost closely affect each other’s performance in development andproduct research (Hatzenbichler, T., & Buchmayr, 2010, p. 101).
Accordingto Australasian Asian Pacific Conference on Aluminum Cast HouseTechnology, & Whiteley (2013, p. 111), in the extrusionproduction process, the mini-system operation of neither thecontainer nor the dummy block should be individually studied. Itshould first be considered to be a small system that works closelybetween each other. For effective functioning of the mini-system, itshould be dependent on the temperature and conditions of thecontainer. If the hardness is lost in the container and is turnedinto a belly or may be distorted in a way, the dummy block operationswill be negatively affected in a way.
Figure 3: The rejected Hooks
Forquality extruded aluminum, the dummy block as to work properly. Thisis achieved when a thin alloy film must remain in between thecontainer and the block at all the time during the process ofextrusion. However, Saker (1993, p. 65) noted that a problem couldresult during the process of heating since the dummy block couldexpand. The operation block during extrusion will operate at theexact same temperature as the container and the billet. A lot of careshould therefore be taken in order to preheat the block to theoperating temperature before it is immersed in the hot container. Itmust be noted carefully that for every 93 degrees difference thatstands between the operating temperature and initial blocktemperature, a 20 cm dummy block will therefore expands by about0.0025cm (Lumley, 2010, p. 76).
Inevery functioning machine, there are instances of wear and teartherefore, the dummy block should be examined often as much asquality production of extruded aluminum remains the first priority.Faunce et al. (2013, p. 12) noted that most tear occurs naturally onthe dummy block frontal side. The block should therefore be returnedto be re-shelled by the supplier, or replaced. Subsequently, acost-effective or efficient alternative is to replace the shell’sfront lid with powerful steel that expands the wear ring that couldeasily be replaced.
Inconclusion, the global market demands for production of high qualityextruded aluminum. To achieve this, it has to undergo a number ofprocesses which include processes of billets production, aluminumextrusions a finishing, and systems approach to quality extrudedaluminum. Since extrusion is known to be a holistic process, all thestages must be adhered to, including the production process thatshould be considered a cohesive system, which comprises of themini-systems that should work together. In addition, the wholeprocess demands good alignment, physical and well as thermal forsuccessful extrusion process. Since extrusion process is considered asystem, in a competitive market, production of high-quality aluminumextrusions should be made a priority for success.
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