| Hand Forming | ||||
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The simplest type of curving as it applies to aluminum extrusions is hand forming that uses simple hand tools, an arbor block and radius gage. It can be easily managed in-house and is a good method of last resort curving for simple, low quantity production. |
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Fig. 2 Bending alone |
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| Compression bending | ||||
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Another common type of curving is
compression bending that uses a modified tube bender to wrap the
aluminum extrusion around a radius form block. This method is fast and
when one has the exact same item to be repeated in quantity, it is very
cost-effective. Also, if there is no need for the use of a mandrel, the
compression-bending process offers unlimited use of length capabilities. |
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Fig. 2 Bending plus stretching |
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| Roll Forming | ||||
| Roll forming is the third common method that involves using a three- or four-roller system either vertically or horizontally, placing the part between the rolls, and pinching to achieve the desired shape. It is a process which has low tooling costs and can usually form a painted or anodized part. Another advantage is that it also offers competitive pricing for small part runs. | ||||
| Stretch wrap forming | ||||
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The final method of stretch wrap forming involves the curving and stretching of a metal part. The extrusion is stretched past its yield point to create a part that is in an elastic state. This means that a part is deformed permanently. The idea is to hold the profile by wrapping it around a form block. This method has many advantages, including: excellent, repeatability of parts, little or no distortion, ue of longer lengths, and a relatively low scrap rate. Most important, stretch wrap forming is ideal for forming compound curves and multi-radii parts. Multi-assemblies are also easily achieved by stretch forming, and price per part costs can dramatically be reduced in quantity orders. |
