Levelling and Cut to Length Lines

FIMI Machinery has commissioned lines able to level high-strength steel coils up to 2.000 N/mm2 yield strength, achieving perfect levelling quality and a level of internal tension dimension to meet the special demands of laser cutting.

These performances of excellence are possible thanks to the application of a levelling philosophy, which is based on the progressive contribution of several levellers in series, adjusted to generate a kind of tension levelling.

Depending on the production range, FIMI’s levelling and cut to length lines are equipped with a minimum of two machines, a pre-levelling and a levelling machine, up to a maximum of three machines, i.e. pre-levelling machine with two levelling machines in series.

Main Features

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Material thickness range

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Maximum strip width

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Maximum sheet length

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Maximum tensile strength

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Maximum coil weight

Patents

TDDS®
Torque Dynamic Distribution System

This is a FIMI patented system, already applied on several lines, necessary for levelling both high strength steel strips and non-ferrous strips with a very delicate surface.

This system is based on the application of special sliding couplings on each exit shaft of the drive unit distributor, as connecting elements to the shafts that transmit motion to the levelling rolls.

The couplings work in an oil bath, in a special tank, to ensure adequate lubrication and cooling conditions. They are made of special materials that guarantee the possibility of continuous sliding during the entire levelling process, rather than only occasional and sudden sliding when a certain high torque value is reached, as well as any sliding coupling available on the market with a protection function against torque overloads.

The purpose of this system is not primarily to protect the mechanical parts from overloading (which is in any case a function intrinsically guaranteed by the system), but to obtain a sort of distribution of the levelling torque on all the working rolls and a sort of independence, as regards the rotation speed of each roll compared to others.

In this way, each roll can assume its own speed, different from the other rolls and dependent on the strip bending being levelled in the area of contact with the roll itself.

In addition, the torque required for levelling is shared quite homogenously among all rolls, avoiding torque conflicts between the various working rolls and significantly raising the resistance limit of the processable material with the same diameter of the levelling rolls.

The result is no sliding between the working rolls and the strip surface, resulting in a much longer life of the working rolls and no scratches on the strip surface.

The sharing of levelling torque among the rolls allows less power consumption (because all the rolls are giving a positive contribute for levelling without braking or fighting against the others) and, the possibility to process materials with ultra-high strength mechanical properties that otherwise couldn’t be processed by traditional levelling drive system, because the levelling torque through the most loaded rolls would break them.

Media

Product range

The levelling and cut to length lines for automotive applications are specially designed to meet the surface quality requirements and tight sheet size tolerances demanded by automotive sector. Typical thicknesses range from 0.3 to 3.5 mm, while the material processed is both steel and aluminium, including high strength.

This type of cut to length line is equipped with a special and innovative rotary shear with tilting mould holders and an automatic mould changing device.

This solution allows the assembly of equipment for various types of cutting (orthogonal and/or inclined rectilinear for trapezoidal sheets or rectilinear for various shapes). Used for both carbon steel up to 3.0 mm thick and aluminium up to 5.0 mm thick.

These are combined line configurations, equipped with Slitting shear for cutting into strips (max 5 strips) and subsequent cutting shear for cutting the strips into sheets.
Typical applications are the household appliance and automotive sectors.

The levelling and cut to length lines for high-strength (HSS) and ultra-high-strength (UHSS) hot-rolled steels were successfully developed to meet the growing market demand to reduce material thickness and simultaneously increase the strength. The traditional configuration of these plants would have never been able to process such HSS and UHSS material; therefore, FIMI developed a special patented system, TDDS® for the levelling units and a levelling philosophy that allowed the required performance to be achieved.

Cut to length lines for hot-rolled high-strength steels are becoming increasingly popular in recent years, due to the growing demand for heavy sheet metal for structural applications, wagons, ships, etc. These lines also make use of the patented TDDS® system developed by FIMI for its levellers to gently remove internal material tension. In some special cases requested by customers, an in-line Skin Pass Mill can be added to the line to increase surface quality.

They are characterised by solutions aimed at the highest productivity (process speeds up to 180 m/min), maximum respect of the strip surface and the production of sheets with very tight geometric tolerances in width, length and squaring.

These type of cut to length lines, both for thin and thick aluminium, are often characterised by machines, devices and technical solutions particularly dedicated to the nature of this metal, the way it is produced in upstream processes and its fields of application.

These are implementations of cut to length lines either with the insertion of a recoiler upstream of the cutting shear, to be able to recoil, totally or partially, the trimmed and levelled strip; or with the insertion of a slitting shear upstream of the cutting shear, to be able to cut several sheets simultaneously.

Our proven expertise in the levelling of high-strength and thick steel extends to aluminium: a single levelling machine is equipped with 1 to 3 cassettes to perform ‘laser cut’ quality levelling in the desired thickness range; cassette change is semi- or fully automatic. Entry and exit pressure rolls are complementary and are used for multi-sheet and reverse levelling. Our experience also extends to brushing and vacuum cleaning, a ‘must’ to consider when levelling high-strength steel. The infeed and outfeed roller conveyors are designed to match the desired sheet length.

The entry and exit roller conveyors are designed to match the desired sheet length.

This is a levelling line with feeder + loop configuration for press feeding, a typical application for the moulding of automotive parts. They are characterised by high production capacity, highest product quality both in terms of flatness and dimensional tolerance as well as with respect to the strip surface and a high automation content.

The line consists of:

Entry Group

Coil Stocking and automatic loading with vertical and horizontal centring.
Automated strap removal devices, both off-line and on board of the decoiler.
Devices of various configurations for opening the strip head.
Static and dynamic strip centring with head straightening.
Cropping, automatic dividing and scrap handling.

Trimming

Edge trimming from 0,1 a 25,4 mm.
Possibility of integration with central cut.
Scrap winding devices, both in foil and coils.
High efficiency scrap cutters.
Customised solutions for scrap handling.

Levelling

Levelling is at the heart of the technological process of cut to length lines and it is the function where FIMI has dedicated the most research and development activity, defining innovative solutions that represent the state of the art in the sector and are essential to be able to process the most modern materials, developed by the most advanced steel mills.

Cut to Length

Different types of shears are available for cut to length lines, depending on the type of material to be processed and the production capacity required.