1. What does the term "temper designation" of aluminum extruded material mean? The temper of the material is determined by a combination of hardness and strength imparted to a metal by mechanical or thermal treatments and is characterized by certain metallurgical structures and mechanical properties. The temper designation system is based on the sequences of basic treatments applied to produce the various tempers -- including: F - (As Extruded); O - (Annealed); H - (Strain-Hardened); and T - (Thermally Treated). The complete temper designation system is extensive and your nearby Shapemaker extruder should be consulted for complete details.
2. Which Rockwell Hardness Tester settings can be used for checking aluminum? Rockwell F, E, and K. Rockwell B is not suitable because it does not measure the T-5 range completely.
3. The cost of running my semi-hollow extrusion is almost cost prohibitive. Do you have any suggestions to reduce the cost? To reduce the cost of your extrusion, reduce the ratio between the void area and the gap. Any improvements in reducing the size of the void will reduce pressure on the die tongue and provide easier extrusion. Another way to reduce the void is to increase the wall thickness. While the weight per foot will be greater, it is possible that the price per foot will be less. Also consider widening the gap. If the gap can be enlarged enough, it may classify the extrusion as a solid shape.
4. How do I determine which is the right aluminum alloy for my part? It's possible that several alloys and tempers would be suitable for your part. Selection is usually made on the basis of structural or fabrication requirements. It's a good idea to look for the most economical alloy among several that may be suitable to your specific application. The choice of alloy is best arrived at by consultation with your extruder.
5. We use an extrusion in 6063-T5 alloy and temper, and we want to use 6063-T6 instead. Will that improve the deflection strength of the extrusion? It will have a minor effect on the deflection strength of the extrusion. A better solution is to use a higher strength alloy such as 6061-T6, or totally redesign the extrusion in order to achieve better results.
6. In reference to the Question above, concerning "deflection strength" and alloys 6063-T5 vs. 6063-T6, please clarify: are deflection and strength two different issues? Yes. Deflection and strength are two distinct problems. Deflection requires shape design; strength requires alloy and temper selection. Deflection is controlled by shape design, i.e. the deeper the shape in the plane of bending, the less the deflection. A 6063-T5, 6063-T6 and 6061-T6 alloy of equal proportion and same shape will deflect the same under identical loads as illustrated in the following formula:
   
   Maximum deflection at center
   (PL³)
   (48 El)
   
   Strength, on the other hand, is greatly related to which alloy and temper are used in terms of allowable stress. Since stresses depend on the application, an engineer should always be consulted for the correct stress to use for all critical applications.
7. Our company manufactures a box from aluminum extrusions and sheet. It needs five extrusions, sheet, rivets, etc., and is very labor-intensive. Can you improve on this for us? Yes. The basic box can be made of two extrusions with screw bosses, one lid and one base. Extruded ends or aluminum sheet can then be screwed onto the ends of the extruded lid and base (utilizing the screw bosses). This method saves a lot of parts and labor.
8. I'm in the market for some extruded aluminum heat sinks. Which alloy is best for this type of application? The purpose of any heat sink material is the dissipation of heat. Although all aluminum is capable of this, the specific alloy 6063 works best, when all aspects of aluminum in this application are considered. This alloy finishes well, and is machinable to most user needs. It's one of the most cost-effective alloys for this purpose. This alloy's characteristics lend themselves well to the sharp corners and tight spaces of some heat sink designs.
9. Can an extrusion provide enough heat dissipation to cool my electrical components? With only copper, silver and gold having better thermal conductivity, aluminum historically provides the most cost-effective solution while the extrusion can be designed to allow the maximum cooling area where it's most needed. Designing in serrated surfaces greatly increases the cooling area.
10. Why is the aluminum extrusion process better able to produce products that meet "load" conditions? Because of the relatively lower cost of tooling with aluminum extrusion, the shape can be designed to place material in the optimal locations to produce the strongest possible section for a given load. In addition, material can be "designed out" of low-stressed areas to produce a more cost-effective shape.
11. What advantage is there to using an aluminum extrusion over an aluminum casting? The integrity of an extrusion is much more consistent than that of a casting. Castings are inherently more porous due to their manufacturing process, and this results in more material used for structural applications.
12. How can I achieve maximum application of my aluminum product today and not have it obsoleted by replacement materials a year from now? The very nature of extrusions allows them great flexibility. While no one can make promises on the future, today's extrusions are adaptable to virtually any material, with few exceptions.
13. Why use aluminum? Why use aluminum in its extruded form? Few commercial metals can be extruded in as wide a variety of configurations with desirable combinations of physical properties as can aluminum. Aluminum extrusions provide a high strength-to-weight ratio, close tolerances, ease of joining, good machinability, excellent corrosion resistance, high electrical conductivity and excellent thermal properties.
14. Can I save production costs by designing with aluminum extrusions? The "tools" required for aluminum extrusion -- dies and related elements -- are relatively inexpensive compared with those necessary for other production methods. Initial investment may be quickly amortized and even a fairly small production run may pass the "break even" point, thus economically justifying the use of extrusion.
15. What is the reflectivity of extruded aluminum? By definition, reflectivity is the ability to reflect light and other electromagnetic radiation. Aluminum has high reflectivity, 80% or more for visible light, and 90% or more for infrared radiation.
16. Are aluminum extrusions recyclable? Aluminum extrusions have substantial scrap value and can be recycled. That's an advantage that may appeal both to a potential buyer's pocketbook and to his concern for environmental protection. Recycling aluminum takes only five percent as much energy as producing new aluminum.
17. Will aluminum extrusions function satisfactorily in extremely low-temperature situations? The many advantages of extruded aluminum are not impaired by exposure to low-temperatures. Aluminum actually gains strength as temperature is reduced, making is a most appropriate material for Arctic, space or cryogenic applications.
18. My finished products need to be resilient. Is extruded aluminum a good choice for my design? Aluminum products can deflect under loads and shocks and spring right back. This resilience not only protects the form of an aluminum product, but it can be "designed-in" as a deliberate and very important product function wherever flexible strength is valued.
19. Our product is used in food packaging. Is extruded aluminum suitable for this application? Solid aluminum alloys are non-toxic and are used widely in food preparation and packaging, and in chemical processing and handling. In addition, they have a smooth, non-porous, easily cleaned surface which will not absorb bacteria sustaining food materials.
20. Is extruded aluminum adversely affected by ultraviolet radiation from sunlight? Sunlight includes ultraviolet (electromagnetic) radiation, which causes tanning or sunburn in human skin and which may cause chemical or structural changes in some commercial materials. Aluminum, however, reflects ultraviolet radiation and is not damaged by it.
21. Combustibility is a major factor in the design of exterior trim for our product. How does extruded aluminum stack-up to other materials? Extruded aluminum will not burn, which makes it safer than many other materials, such as wood, paper and plastic, for design applications. And unlike other materials, extruded aluminum does not emit any toxic, hazardous fumes when exposed to high temperatures.

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