MATPROCESS

MATPROCESS is a company, formed by professionals with long experience, for supporting the improvement, in the field of metal working, of the:

• production management,
• maintenance management,
• processes automation,
• energy optimization,

The experiences are in different  MATerial PROCESSes  :

AFC  : Automatic Flatness Control

MATPROCESS can provide complete revamping of the flatness control system. Starting with the signals from the rotors of the shape meter, manages in close loop , the hydraulic actuators , tilting , bending and the sprays system for the working rolls in order to control the shape of the strip in the cold mill.

Hardware and Software

 The system consists in a PLC that, with the signals received from the rotors of the flatness roll (at the moment not supplied), compared to the flatness reference curve assigned by the operator through a touch screen, calculate the strip flatness error.Three corrective actions are generated in the cold mill to manage the strip flatness through 2 PID regulator, the tilting and bending control and N four state control for the 2/3 N spray zone.

ATEC:Atomatic Tight Edges Control.

Induction roll edge heater / Hot oil sprays

MATPROCESS offers a systems in order to manage the tight edges looking for improving quality and production rate with more percentual of reduction at each pass. The tight edges in the strip are connected with the quarter buckles, W profile, as the result of the elastic deformation of the working roll (wr) supported by the backup roll (br) under distributed load, with poor thermal gradient profile in the working rolls, and flattening. If you observe in the monitor the shape of the first part of the coil rolled after wr change , you see this  W shape.

 It normaly happens after work rolls are changed, in the first part of the coil, the wr have low temperature and is not possible to generate, with the spray cooling, a thermal gradient in the wr quarters or , when from one pass to another there is a big rolling load variation. In this condition, W the bending is frozen (if the bending try to remove tight edges, moving in negative direction, the quarter buckles grows) only the cooling have the chance to generate thermal gradient in the quarter. In order to generate the thermal gradient, with the spray cooling opened at the quarter of the wr to reduce the quarter bukles, it needs time and when this appen for the bending is possible to move in negative direction to reduce the tight edges. During this time we generate quarter bukles and tight edges in the rolled strip.

To fasten the flatness correction it' s possible to heat the work roll (wr) outside the strip width, where the tight edges are. There are two systems to do this, spraying hot oil or activating inductor  in order to generate thermal gradient that grow the diameter of the wr , reducing  the tight edges.

In this condition, without tight edges, the bending goes in positive removing the quarter buckles. All this functionality are driven by the AFC software presented above. 

ABSC : Automatic Bending Support by Cooling.

MATPROCESS provides solutions in order to automatic managing the bending in the following conditions:

During cold rolling, a big change of the paschedule, width [mm] or/and load [N], generates a request of bending over the maximum +/- 100% with flatness problems (central bags, lateral waves) for the first part of the coil.The automatic flatness control (AFC) remove the flatness problem through the cooling sistem, but it has need time, the first part of the coil is without flatness, 100/500 meter of strip.

 During passchedule changes, width change and load change, with this functionality ABSC, the bending is continuosly drived in a predetermined gap near +10% +15%, with the cooling management, generating a predetermined thermal crown in the working rolls, in this manner there is at disposal for the bending the +/- 90% of the full scale for overcome the big variation in width and load. This moves the limits of the paschedule assembling semplifying it and remove flatness problems in those phases.

 MATPROCESS develops mathematical models for:

CMM : Cold Mill Model

1. Excel file
2. Data entry for fix technicals Mill data like rolls dimension , motors data, etc.
3. Data entry for different alloys for define yield strength vs hardening (flow stress)
4. Paschedule generation with intermediate annealing.

      a-free, with introduction of the entry, exit thichness

               at varius passes, width , alloy

      b-costant reduction for minimize the total lenght of the

                rolled material (contact time reduction), 

                 with introducion only the N° of passes, width , alloy.

      5. CMM cold mill model calculates :

     a-Entry exit thickness for costant reduction [mm]

     b-Entry exit tension [N] in the respect of, wr slipping,

        minimum friction

     c-Arc of contact [mm] , wr flattening, rolling load [N]

     d-Friction μ (Avitzur)  

     e-Exit coil temperature [°C]

     f-Productivity [Ton/h]

     g-Energy consuption [kwh/ton]

PLM : Paint Line Model for 2 curing ovens description.

1-Excel file

2-Data entry for fix technicals Paint Line data like max speed [m/1'], max exaust air capacity[Nm^3/h], curing ovens lenght [m], thermal capacity[kwh/m^2], minimum oxigen level[%], LEL[%,grs/m^2], etc.

3-Data entry for different paint type, primer and finish, solvent [grs/m^2], peack metal temperature PMT [°C], etc

4-Process data entry, strip alloy, thickness [mm], width [mm] and:

      a-free, with introduction of the zones curing ovens

         temperature [°C], linee speed [m/1'], for research the

         strip PMT [°C] and particular temperature profile in the

         zones. 

      b-for maximize the productivity [ton/h], with introduction

         the PMT [°C]. The sistem calculate the strip speed

         [m/1']  for reach the PMT in the last zone with the

         max temperature for each zones.

5-PLM paint line model calculates :

     a-PMT[°C] , strip profile temeprature in the ovens zones

        [°C].

     b-Line speed [m/1'].

     c-Exaust, fresh, hot air flow rate [Nm^3/h].

     d-Level Explosion Limit LEL [%], Oxigen level O2 [%].   

     e-Thermal energy consuption [kwh/ton].

     f-Productivity [Ton/h].

 ABCFF : Automatic Bending Control Feed Forward.

MATPROCESS provides software/hardware solutions in order to improve bending control, managing it in automatic mode in the following phases:

1-phases where the flatness contol is not in operation, during strip introduction to the recoiler in rolling and speed under 60m/1'.

2-phases where the rolling load changes, during acceleration and deceleration and when changing gauge at coil heads and tails.

Normaly in those two phases the bending reference is under manual operator control.

The "ABCFF Automatic Bending Control FeedForward" in those fases is a good helper for the operator, improving fasten speed up and reduce quality problem in the strip and work rolls like off flatness, holes, strip break, signs and scratches .

ABCFF is a matematical model, installed in the PLC, that with signals from rolling load, strip width, work rolls diameter and actual bending, it calculates the mechanical deflection and the thermal profile  of the working rolls for generate the correct bending reference.

 WR profile=y(x)=(f)mechanical deflection+(g)thermal deflection=

=f(Roll Load(N);Strip Width(mm);WR diam(mm);Bending(N/%))+g(delta T(°C)).

AVCM AVoid Chatter Mark in cold rolling. Matprocess Vibration Monitoring

Chatter mark on the strip are the transversal thickness variation (2/3 um micron deep) perpendicular to the rolling direction  with a pass of 20/25 mm.

 The chatter mark in the strip is a common quality problem for the cold rolling mill where the production speed is more than 350 m/1'.

It appears when the stand, the working rolls and back-up rolls goes in resonance.

Connected to this quality problem in the strip there is a back-up rolls lif reduction.

The tendency towards resonance is always present in the mill and a lot of are the possible causes:

1. Lubrication condiction in the bite
2. Rolling speed
3. Unbalanced element (spindles, rolls, joints, ironing roll)
4. Misalignment, looseness, 
5. Gear boxes defects (toots, shafts, bearings)
6. Back-up rolls shape grinding
7. Chocks
8. Abnormal AGC control
9. Strip tension variation
10. Eccentric Motor Rotors, Fans
11. SCR’s
12. Material alloy, material hardness, rolling load
13. Incoming quality or shape issues from Hot Mills

 Due to this several causes is very difficult to eliminate the mill resonance generating the chatter marks on the strip.

A good strategy is to place in the mill a vibration monitor system (provided by Matprocess) to detect the beginning of the resonance condiction and act in the mill a partial speed slow down since the resonance disappear.

In this way whe produce a good material without chatter and increase the back-up rolls life with a little productivity reduction.

In this condictions is possible now search and try to remove the causes.

In the picture above there are the output of the Matprocess vibration monitor system that interface the operator and mill for showing the beginning of the resonance condiction with three level green, yellow, red.