Used slitting lines
Contents
Slitting lines - more than just splitting stripsThe classic structures and functions of slitting lines
Performance of slitting lines
Special applications of slitting lines
How can the automation of slitting lines look like?
Tools and equipment for slitting lines
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Slitting lines - more than just splitting strips
title="Buy used slitting lines" Slitting lines, also known as slitters, are an important type of machine for the entire industry. As a rule, the slitting lines are operated by subsuppliers (e.g. service centers). From there, slit strips are delivered to the automotive industry, for example, so that they can be processed into products such as stamped articles or rims on press lines or in forming machines.
There are slitting lines in the metal industry, plastic film industry or also paper industry. In this article slitting lines for the metal industry are considered. Slitters are used for metals made of steel, aluminum and other non-ferrous metals.
The slitting lines belong to the field of manufacturing technology, more precisely to the manufacturing process "material separating". Strips, so-called rings, are cut from a wide metal bundle, also known as a coil. The cutting is done by circular knife shears.
The classic structures and functions of slitting lines
The basic arrangement of a slitting line is a horizontal material flow, either from right to left or from left to right. The information relates to the position from the operator's side. The operator's side with the control panels is freely accessible by the operator. The side opposite the operating side is referred to as the drive or motor side. This area is not accessible if the current safety rules are observed in normal and automatic operation of the slitting line.
The structure of a slitting line consists of many individual machines, which are connected to one another with tables and rollers.
It starts with a ring or coil storage. This can be designed as a ramp or as a carousel. The input of the coil to the storage is executed by a crane or self-driving vehicles. Coil stores can be designed with or without floor rollers.
From the coil storage, the coil made free from the binding tape, the coil is transported by a lifting coilcar onto the decoiler, equiped with a pressure roller and coil bending device. The coil eye (inside diameter of the coil) is aligned with the decoiler mandrel by the lifting function of the coilcar. It is important that the diameter of the coil eye matches the decoiler mandrel. The mandrel is adapted to the coil eye diameter by using screwed segments. Also wide range decoiler mandrels are existing. This mandrels can work without segments.
After aligning and tensioning the coil inside the coileye, the strip is unwound by rotating the decoiler mandrel and transported to the strip feeder (pinchroll) and the straightening machine via a telescopic table. A strip center control positions the center of the strip on the center of the line by shifting the decoiler. In some cases, the strip is not moved in the center of the line, but rather a strip edge is positioned on a defined side of the line. The basic functions of the slitting line are not influenced by this.
Cropping shears are usually used after the pre-straightening machine. The crop shears make a straight initial cut. The cut sheet metal is transported into a retractable scrap box via a scrap switch on the transfer table. It is of course also possible to cut several sheets of scrap that are defined in length and convey them to the scrap box. When the slitting process has to start, the wide strip must be conveyed on over the transfer table.
Before the slitting shear is reached, the wide strip is centered on laterally positioned rollers. Then a roller bridle calms the strip. A measuring wheel arranged in front of the slitting shear monitors the speed of the strip.
The wide strip then moves into the slitting shear. The shafts of the shear are built up with knives, rings and spacers and the knife set is clamped axial (hydraulically or mechanically). The knife change options are versatile. There is the manual assembly, the CNC assembly, the knife changing device with a knife turnstile or the knife construction robot.
In the trimming operation the two outer strips are scrap. This scrap is discharged downwards and can be wound up with a strip winder or shredded with a scrap cutter. In both cases, the scrap ends up wrapped or shredded in containers.
The inner strips that do not belong to the two scrap strips are conveyed by means of a transfer table to beart reduction rollers, a pinchroll and / or to a strip end press.
The strips are then picked up by a movable braking unit, i.e. the beginnings of the strips are clamped and moved in the direction of the recoiler. The alternative are folding tables that cover the loop pit so that the strips can be driven towards the braking carriage. If the strips are clamped in the brake unit, the loop pit must be released. In the case of tables, the tables are folded down.
After that, the horizontal course of the stripes is over for the time being. Via a roller cage in the inlet of the loop pit and a roller cage in the outlet, the slitted strips are fed into the pit in a defined loop. This is necessary to compensate the different lengths of the strips coming up after slitting and rewinding. This effect is generated by the not constant thickness of the strip in cross direction.
The horizontal course of the stripes is ensured again in the braking carriage. There the strips are driven evenly by a pinchroll until they leave the braking carriage / frame at the end. In order to ensure an even position of each individual strip, an additional cropping shear is usually installed at the end of the braking carriage / frame.
Another important facility after the loop pit are the separating shafts (separators). The number varies. The first separation is usually on the underside of the roller cage at the end of the loop pit. One or two more separating shafts are installed on the braking carriage. In many cases it makes sense to provide a further separation on the recoiler. In addition to the strip guide, the separation ensures that the strips are spaced apart from one another.
When all strips are cropped and neatly separated, a strip clamping device lifts all strips to the correct height in order to push them into the clamping slot of the recoiler mandrel by moving forward the braking carriage. The clamping slot of the rewinding mandrel closes and the mandrel expands to the inner diameter of the rings. The required inner ring diameter can be adapted using screwed segments.
After start winding on the recoiler mandrel, it is important that a tension between recoiler mandrel and braking unit is built up. This strip tension can be generated by a felt press, brake rollers, roller bridles or belt brake frames. The use of an S-roll or a deflector roll at the end of the braking carriage is also common. The contact angle of the strips on the last rollers supports the stable strip guidance.
The recoiler with the mandrel winds up all the strips at the same time until the desired or maximum permissible outer coil diameter is reached. Once that has happened, the line stops. A pressure roller, which is mounted on the recoiler, is placed on the rings to prevent the rings from opening. A final crop cut is made before the strips are completely wound up.
Depending on the width of the raw material and the weight of the coil, the recoiler mandrel must be equipped with a mandrel counter support on the operator's side. For loading or unloading the recoiler mandrel, the mandrel counter support is swiveled, moved or sunk, depending on the design. Of course, this also applies to the decoiler.
After the winding process has ended, there are various options for continuing the process:
1. The recoiler is used as a manual tying area for the circumferential strapping of each individual ring. A coilcar with support arms then takes over the rings from the de-expanded mandrel and transports them to a turnstile
2. A coilcar with its own pressure bar and piano fingers takes the unstrapped rings from the de-expanded mandrel and transports the rings to a turnstile, also equiped with a pressure arm and piano fingers, for manual or automatic external strapping
The rings can be transported from the turnstile to a packaging line using a tilting table, or they can be removed from the turnstile using a crane.
Pneumatics, hydraulics, electrics and controls are other indispensable components for the function of a slitting line.
Performance of slitting lines
Slitting lines are also available for various materials for thickness ranges from less than 0.1 mm to areas of one inch. Most systems have a thickness range of 0.3 to 4 mm. In terms of width, the most current systems are between 950 and 1750 mm. However, systems from 450 to 2800 mm are available.
The speed ranges depend heavily on the material thickness. Systems from 0.3 to 4 mm are usually designed in two speed steps. In the thicker area the line speed is 150 ... 200 m / min., In the thinner area it is 300 ... 400 m / min. Thicker materials have to run slower.
Special applications of slitting lines
A slitting line can also be used for the following special applications if the equipment of the slitting line has been selected accordingly:
1. Rewinding lines, a strip is rewound to keep the inside of the coil as the outside
2. Side trimming lines, the slitting shear is only equipped with two sets of knives and only cuts the strip at the edges in order to obtain a straight edge and a defined width
3. Side trimming lines, a pure trimming shear with a center slitting device - here a coil can be split into a maximum of two rings with a defined width.
4. Inspection lines, when rewinding the top and / or the bottom of the strip is checked. This can be done purely visually at an inspection stand with the help of one or two mirrors, or automatic inspection systems with camera or laser systems are used.
Depending on the design of the individual machines within the slitting line, all possible combinations can of course also be made. In practice, it is possible to equip a slitting line as a rewinding system with a trimming device and inspection stand.
Equipping a slitting line with a slitting shear plus side trimming shear is also conceivable and has already been implemented in practice. The advantage of such a combination is that the system can run in trimming operation while the knife frame is being equipped with a new set of knives.
This list does not claim to be complete. There are hardly any limits to the growing automation and the connection with other parts of the system, such as a packaging line.
How can the automation of slitting lines look like?
As in many other areas, the possible degree of automation is also a question of investment. Slitting lines can be automatically linked with coil preparation stations and packaging systems. Manual interventions are then no longer necessary for feeding in the coils and removing the rings.
The operator then mainly takes on control tasks and work such as adjusting and setting up. The personnel deployed must be very qualified.
Typical automation features for slitting systems are:
· Coil preparation station with and without automatic strap removal
· Automatic width and thickness measurement
· Automatic knife change in frame construction or just changing the knife sets via a pusher device and a knife turnstile
· Knife construction robots or CNC shears
· Automatic setting of the separators
· Automatic oiling and de-oiling or brushing machines
· Automatic surface inspection equipment
· Process optimization through better division of the safety zones
This list does not claim to be complete.
Tools and equipment for slitting lines
In the case of slitting lines, the term tools mainly refers to the knives or knife sets. On the one hand, knife sets (round knives with rubber rings and spacer sleeves) are required for the slitting shears, on the other hand, long knives are required for the crop shears.
In addition, there are operating materials such as felts for the braking press, brushes and oils.
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tramao offers you a large selection of new and used slitters or slitting lines. You will also find the right service companies for repairs and spare parts procurement on tramao.de.
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Not to be forgotten is our range of tools and tool sets.
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