Used Straighteners for Sale — 490

Straightening – Increases the quality of finished workpieces

Metal can be very easily processed and metal products can be produced with high precision. This is the case for components of a clock mechanism and the lower construction of machines and devices. The production of construction elements contains two processes: casting an entire component; and joining together series components. When casting components, in order to reach the required precision it is necessary to undertake post-production metal cutting processes. Straightening or welding cast parts is not possible. Cast components are generally monolithic and because of their course, crystallised internal structure. Thereby, no subsequent bending processes are used for these products.

Due to the post-processing stage, rolled and drawn components have a relatively finer internal crystal structure. This means that these components can be thoroughly processed through bending, pressing and straightening.

A sheet metal straightening machine is necessary for several reasons. Products manufactured using thermal processes, like continually cast beams, welded components like steel pipes or welded steel profiles, can contain irregular internal tensions after they cool down. Stress pointsare weak points in a construction and can act as a breaking point. These are removed from a workpiece using heat treatment in a furnace. After the annealing process, the workpiece is no longer dimensionally stable but more or less strongly distorted. Straightening benches are used to re-establish the required stability within the workpiece. Another application for straightening machines is to repair cold warped construction like automobiles that have been in an accident. In addition to tubes and profiles, high-end straighteners be used to transform single sheet metal workpieces into smooth and straight components. Bars and shafts are brought into a precisely straight form using special roll straightening machines.

Straightening is really important during the production of bent mass series products. For example, galvanised steel angles need to be shaped into the 90° angle before the galvanising process. Zinc is too brittle and cannot be bent afterwards. Ripping open the zinc layer can result in losing the protective layer against corrosion. Undesired warpage can occur during galvanization (particularly zinc and chrome plating) because it is a heat treatment. However, straightening machines can be used to lightly re-bend a galvanised component

The structure and function of a straightening machine

Straighteners are used to bend targeted points on a bent construction so far, so that when they spring back, they are fall into the desired form. In order to achieve this, the single components need to be bent so far from one another that the reformation effect occurs at the desired point. A straightening bench uses stops, measurable points and hydraulic pressing cylinders. A sheet metal straightener works with particularly wide hydraulic stamps. High-end straightening machines support the straightening process with a supply of hot air.

Working with a straightener requires a high level of experience. Metal cannot often be bent beyond a certain point. With every bend, the bending point hardens, which can result in fatigue fractures. This is particularly relevant for cold damaged constructions like the bodies of automobiles after an accident. These can be visually and optically made stable again using straightening. However, the strength of the base structure will be lost through excessive straightening. This needs to be taken into consideration before undertaking the straightening process. In this instance, it is usually more common to replace the damaged frame.

A special process is roller straightening. Components that need to be very straight are usually finished on roll straightening machines. This includes components like shafts, full-floating axles and tools like drills. These are clamped into a lathe chuck and then straightened by two roller stamps, while being rotated. Upper and lower stamps continue to grip the rotating component until the lens system no longer registers any deflections. Nowadays, this process is supported by a computer and monitored by a camera. The qualities and levels of precision that can be achieved today were not possible before the introduction of the computer assisted straightening processes.

Sheet metal straightening machines have several intermeshing rollers with numerous hydraulic stamps. They roll sheet metal through cold or hot processes, so that they can be fully taken from the machine again. Nowadays, these processes can be automatic. Metalworking facilities, particularly those that are used to produce welded constructions, can be made more efficient through the use of straightening machines. Within construction facilities, the quality of the delivered products is very important. Contrary to cut or wrongly cut products, straighteners on sale can be used to transform crooked and wavy products into ones that can be used again. If a metal straightener is applied before the construction process, an approximate quality can be produced that pre-products of other companies can be compared and swtiched with. This prevents the need for post-production straightening or interrupting workflows due to a component that does not fit correctly.

Suppliers of straighteners for sale

Straightening benches that are used to straighten finished constructions are available from CELETTE, BLACKHAWK and DOZER.

Roll straightening machines, which are also called bar straightening machines, are used to straighten holes and shafts. These are available from the companies HÄMMERLE, KIESERLING, WIRTH and BRONX.

Straightening machines for sheet metal and moulded components are available from the companies ARKU, LOOSE, DAHLHAUS, SKET and WILHELMSBURGER. These machines are also called roll straighteners.