Stretch Forming by Linetec

Stretch Forming by LinetecPeople have been bending and curving metal for centuries, but stretch forming, born from the aerospace industry, maintains precise dimensions throughout a curve and produces perfectly contoured products while limiting, or even eliminating, wrinkling inside the arc.

Stretch forming is the process of forming sheets and profiles by the combined application of tensile and bending forces. Stretch forming keeps the extrusion under constant tension while wrapping it around a form, or die, to make parts into simple or complex contoured curves.

To deliver these stretch forming services, Linetec has teamed with Southern Stretch Forming, headquartered in Texas. The company will provide a full scope of bending capabilities on Linetec’s campus in Wausau, Wis., including annealing and tempering to soften and harden aluminum.

STRETCH FORM CAPABILITIESStretch Forming by Linetec

Linetec and Southern Stretch Forming will work together, striving to meet every need of our customer. However, there may be some cases that an extrusions configuration are not suitable for curving/stretch forming. Below are some broad overview capabilities, if your needs are outside of these capabilities contact us directly at sales@linetec.com for assistance.

    • Maximum arc length of 260 inches (larger lengths reviewed on individual basis
    • Curved shapes up to 10 inches in width
    • Full annealing and tempering
    • Ability to manufacture and stretch form brake metal
    • Custom die/tooling
    • Thermal improvement services on curved metal, both thermal strut and poured thermal barriers

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For more information on Linetec and our stretch forming services, visit our website, www.linetec.com.

Stretch Forming by Linetec now available

Aluminum finishing, curving and thermal improvement services all provided at a single location

As building projects continue to push the limits in vision and design, Linetec continues to expand its value-added services. Linetec will soon offer stretch forming, which allows architectural product manufactures to have their metal building components curved and finished in one location.

SSFF-bending-project-photo“Customers needing material to be curved can send the parts to Linetec or have it pulled from their material stored and managed in Linetec’s inventory program. This offers customers quick-turn bending services. Utilizing the company’s dedicated fleet of trucks ensures the finished, curved material, along with the rest of the project, arrives free from damage, on schedule and backed with an industry-leading warranty

Stretch Forming by Linetec alleviates the worry and hassle of multiple points of contact and brings tremendous value. Customers can ship us their aluminum for bending and then, have it finished in the same place to retain the full finish warranty. This saves shipping costs and transit time, as well as reduces material handling and packaging to minimize the opportunity for damage.

To deliver the new stretch forming services, Linetec has teamed with Southern Stretch Forming. Southern Stretch is headquartered in Texas with production facilities in California and Pennsylvania. The company will provide a full scope of bending capabilities on Linetec’s campus in Wausau, Wis., including annealing and tempering to soften and harden aluminum. Facility site preparation, equipment deployment and other logistics are underway.

When we realized stretch forming would be of benefit to customers, we sought out a partner with an equal reputation in their industry; a quality company with a strong reputation for customer service and reliability. We are glad to have Southern Stretch Forming  as that partner.”

Southern Stretch Forming’s president, David Arthur, notes that the feeling is mutual, “We have very high regard for Linetec and are pleased to have established a strong collaborative relationship with their team.”

Arthur explains, “In simplest terms, stretch forming is a way of bending metal into a desired shape, usually curved, by heat treating it then pressing it over a die. Stretch forming turns a straight aluminum extrusion into a vital component of contemporary structures — a hotel skylight, a mall archway or a skyscraper’s glass and metal facing. Stretch forming frees architects, designers and builders to realize forms as graceful as they are sturdy and functional.”

Expanding services to enhance architectural metal components is nothing new to Linetec. We continually invest in these innovative, value-added services to support our customers’ short-term needs and long-term goals.

For more information about Stretch Forming by Linetec, finishing and other services, please call 888-717-1472 or visit www.linetec.com.

Fabricating After Finishing – Not Recommended

Bending and forming of high-performance PVDF coated aluminum – often referred to as post forming- is a common practice by many in the industry. However, the three largest architectural paint manufacturers, Akzo Nobel, PPG and Valspar do not recommend  this practice. They caution that great care should be taken if the aluminum is formed after painting.

All three paint manufacturer warranties state that the warranty is void if any fabricating operation damages the coating, or damages the substrate to an extent that the coating film is compromised, delaminated or degradated.

Akzo Nobel, PPG and Valspar offer several warnings against post forming finished aluminum:

  • Post forming the coated aluminum substrate will open small micro cracks in the
    paint and pretreatment, which will leave the bare substrate at risk for failure. While PVDF coatings are  flexible, they are not super flexible; as a result, when forming  the substrate, stress is put on the coating either at the surface (adhesion failure) or within the coating (cracking) and corrosion can set in.
  • Warming the aluminum prior to bending, with a purpose to increase flexibility of the

    Fracturing of mil aluminum

    aluminum and its coating, can cause the surface to soften and make it much more susceptible to scratching and marring.

  • Bending of heavy extrusions that have been heat-treated can result in cracking the aluminum and paint film.
  • Improper set-up of press/brake or forming die can damage the paint film.
  • Fracturing or cracking is not necessarily related to the paint coating, but can, and often is, related to the aluminum alloy and the flexibility of the aluminum in post-forming. The aluminum has a tendency to fracture and crack underneath the paint film.
  • Severe bending on a small radius can cause cracking of the aluminum substrate, which will result in cracking of the paint film.   .

Here is an example of brake metal that was post formed. A series of AAMA 2605 tests
were conducted including cross hatch, direct impact and pencil hardness. These test results indicate no issues with the paint, its application, or performance. Although the paint was compromised on the bend, all testing passed – even that done right next to the bend area.

It is always best practice to form the aluminum prior to painting.