Roll forming , also spelled rollforming , is a rolling type that involves continuous bending of long sheets of metal sheets (usually rolled steel) into desired sections. Strips pass through sets of reels mounted on consecutive booths, each set only doing an additional part of the bend, until the desired cross section (profile) is obtained. Roll forming is ideal for producing constant profile parts with long and large lengths.
Video Roll forming
Overview
Various cross-sectional profiles can be produced, but each profile requires a carefully crafted set of tools. The scroll design begins with the flower pattern , which is a sequence of cross-section profiles, one profile for each stand. The contour scroll then comes from the profile of the flower pattern. Due to the high cost of roll sets, computer simulations are often used to develop or validate the roll design and optimize the forming process to minimize the amount of standing and material pressure in the final product.
Roll-shaped parts may have advantages over similar shape extrusions. The rolls of the formed parts may be much lighter, with thinner walls perhaps than in extrusion processes, and stronger ones, which have worked hardened in cold conditions. Parts can be finished or painted. In addition, the roll forming process is faster and requires less energy than extrusion.
Roll forming machines are available that produce different sizes and thickness of the material using the same coil. Size variations are achieved by making the spacing between rolling variables with manual adjustment or computerized controls, allowing fast switching. This special plant is prevalent in the light gauge framing industry where metal buttons and standard profile tracks and thickness are used. For example, a single plant may be able to produce metal buttons from different web (eg 3-5/8 "to 14 inches), flange (eg 1-3/8" to 2-1/2 ") and lips (eg Dimensions 3/8 "to 5/8"), from different gauges (eg 20 to 12 GA) from galvanized steel sheets.
Rolls form lines can be arranged with multiple configurations to punch and cut off the inside of continuous operation. To cut parts down to lengths, lines can be set to use a die pre-cut where a single blank runs through a roll mill, or a post cut die where the cutoff profile after the roll forming process. Features can be added in holes, notches, embossments, or sliding shapes by punching in a roller line. Features of this section can be done in pre-punch applications (before roll forming starts), in mid-line punching applications (in the middle of roll forming line/process) or post menching applications (after roll forming is completed). Some roll forming lines combine just one of the blow or cutoff apps above, others combine multiple or all apps in a single line.
Process
Roll forming is, among the manufacturing processes, one of the simplest. It usually starts with a roll of large metal sheets, between 1 inch (2.5 cm) and 20 inches (51 cm). in width, and 0.004 inches (0.10 mm) and 0.125 inches (3.2 mm) thick, supported on uncoiler. These strips are inserted through the entry guides to align the material precisely as it passes through the milling roll, each set of rolls forming the bend until the material reaches the desired shape. The roll set is usually mounted one on top of another on a pair of horizontal parallel shafts supported by stand (s). Side windings and cluster rolls can also be used to provide higher precision and flexibility and to limit the pressure on the material. Strips that are shaped can be cut extending forward from rolling rolls, between factories, or at the end of a roller line.
Geometric possibilities
Geometric possibilities can be very wide and even include closed shapes during uniform sections. Typical sheet thicknesses range from 0.004 inches (0.10 mm) to 0.125 inches (3.2 mm), but they can exceed that. Length is barely affected by the scrolling process. The width of the section is usually not smaller than 1 inch (2.5 cm), but they can exceed 20 inches (51 cm). The main limitation is the depth profile, which is generally limited to less than 4 inches (10 cm) and is rarely greater than 6 inches (15 cm) due to the pressure provided by the roll and the difference in surface velocity increases with depth.
- Tolerance can usually be held in Ã, Â ± 0.015 inches (0.38 mm) for the width of the cross sectional shape, and Ã, Â ± 0.060 inches (1.5 mm) for depth.
Production Level
The level of production depends heavily on material thickness and bend radius; but is also affected by the number of stations or steps required. For a turning radius of 50 times the thickness of a 0.7 inch (18 mm) low carbon steel thick material may range from 85 feet per minute (26 m/min) through eight stations up to 55 feet per minute (17 m/min) to 12 stations or 50 feet per minute (15 m/min) through 22 stations.
The time for a product to take shape can be represented by a simple function: t = (L n? D)/V , where L is the length of the piece being formed, n is the number of standing forms, d is the distance between stands, and V is the velocity of the strip through the roll.
Generally the rolling line can run from 5 to 500 feet per minute (1.5 to 152.4 m/min) or higher, depending on the application. In some cases, the limiting factor is a punching or cutoff application.
Other considerations
While dealing with manufacturing, things to consider are, for example, lubrication, the effect of processes on material properties, cost, and of course safety.
Lubrication provides an important barrier between the die roll and the workpiece surface. This helps reduce the wear and tear of the chisel and lets things move faster. This table shows the various types of lubricants, their applications, and metals that are ideal for use.
The effect of the process on material properties is minimal. Physical and chemical properties are almost unchanged, but this process can cause work hardening, microscopy, or thinning in corners when discussing the mechanical properties of the material.
The cost of roll forming is relatively low. When calculating the cost of the process of things such as time of arrangement, equipment and equipment costs, load/load time, direct labor rates, overhead rates, and amortization of equipment and tools should be considered.
Security is also a bit of a problem with this process. The main hazards to consider are dealing with moving workpieces (up to 800 feet per minute (240 m/min)), high-pressure rolls, or sharp, shaved metal edges.
Maps Roll forming
See also
- Sheet metal
- Passed-skin
- Structural scrolling
- Bead tube
- Roll bent
- Roll slides roll machine form
References
Note
Bibliography
- Halmos, George T. Roll Forming Handbook, CRC Press, 2005. ISBNÃ, 0-8247-9563-6
- Dobrev, Atanas; George T. Halmos (1993). "Roll shaping into the 21st century". Society of Manufacturing Engineers.
- Todd, Robert (1994). Manufacturing Process Reference Guide . New York: Industrial Press inc. ISBNÃ, 0-8311-3049-0.
Source of the article : Wikipedia
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