Maintain
Roll Inventory
Working
with engineering and the roll vendors, roll shop management
plans and executes roll procurements. Not only are inventory
levels of rolls involved, but so are the chemical and physical
specifications. Through analysis of roll performance, procurement
decisions are made with an eye toward minimizing roll investment
through increased roll life longevity.
[QMOS]
supports this function by providing production and grinding
performance histories for each roll and the ability to display
this information in ways that illustrate trends and suggest
root causes.
Prepare
Rolls
In this process, the surface of the rolls are prepared, (ground,
textured, and chromed), when they are received as new inventory,
and each time they are changed out of the mill.
Measurement
results from these operations, (crown, roughness, diameters,
etc.), are automatically captured by [QMOS] for later procurement
analysis and automatic communication to the mill.
Create
Roll Schedules
I
n response to mill production schedules, roll schedules are
created to plan roll assembly and staging.
This
activity is supported by [QMOS] by bringing together the mill
production schedule and roll inventory information into one
place for roll schedule creation.
Assemble
Roll Sets
Work rolls and backup rolls must be assembled into sets, (two
rolls plus chocks, bearings, and seals), before they can be
used in the mill.
These
assemblies are recorded into the [QMOS] system for use by roll
shop personnel to keep track of what is ready for production,
and the mill software to easily identify what is being loaded
into the mill.
Move
Rolls To Production
After assembly, rolls are moved to staging areas as they proceed
to the mill.
Each
time that a roll is moved, its new location is recorded in [QMOS].
When a mill queries [QMOS] about a work roll or backup roll
set about to be loaded into the mill, the roll shop system automatically
supplies the necessary identity and measurement data needed
by the mill.
Disassemble
Rolls
After the completion of a run for each roll, the rolls are changed
out of the mill, and disassembled in preparation for the supporting
roll components, (chocks, bearings, and seals), to be maintained,
and the rolls’ surfaces to be ground.
As
the rolls are changed out, the mill system automatically sends
production information to [QMOS] for inclusion in its roll history.
Maintain
Roll Components
The individual parts of the roll assemblies and sets are inspected.
At this point, items are replaced and bearings rotated where
necessary.
The
accumulated production history of bearings in the [QMOS] database
is used to assist in the rotation process. The disassembly of
the roll assemblies is reflected in [QMOS] to maintain an up-to-date
record of the location and status of the components. This can
also be scheduled.
[QMOS]Flat
Roll
Shop
Roll Grinding activity is automatically scheduled based on mill
activity. When rolls are removed from the mill and de-chocked,
the next step in the usual process is to grind the rolls so
that they are ready to use the next time that they are required.
When the operator records that chocks have been removed from
the rolls, he is given the option to automatically create a
roll grinding work order. The rolls will then be scheduled for
roll grinding at the next available time.
Similarly,
rolls can be scheduled for grinding based on when they are next
planned for use in the mill. The roll grinding schedule is calculated
to allow sufficient lead time to complete the process in time
to have the rolls chocked and ready for the mill before they
will be required.
A
list of standard procedures or steps required to grind each
roll is accessible, providing an instant “how to”
manual for all shop personnel. Users can track which steps have
been completed, so that the supervisor and other workers all
know the current status of the job. This feature also provides
a list of SOP’s which then conform to ISO standards.
Some shops’ roll grinding procedures include external
processes for things such as chroming and for other finishing
processes or repairs. [QMOS] handles all of this seamlessly.
Each roll may be sent to any number of vendors for a variety
of reasons. Results from each process can be recorded, including
the external cost and the quality of the work done. The whereabouts
of each roll is always known, as well as the status of each
roll for each step in the roll grinding process.
When
a roll is finished being ground, new roll diameters and roll
surface readings are recorded in [QMOS]. Any roll which is ground
more or less than expected is flagged, requiring the operator
to acknowledge and explain what has happened. Hardness readings
can be noted, and saved for further analysis. Information on
sub-surface conditions such as cracks and bruises can also be
stored. The grinder operator responsible for grinding the roll
is saved. A full historical profile of each roll is saved, detailing
all roll grinding results and suitable for investigation and
historical analysis.
Grind Wheel performance is tracked by recording specific activity
and use of each grind wheel. The amount of wear on the wheel,
and the number of rolls ground and the total amount ground off
all rolls are all attributable back to each individual grind
wheel. Detailed reports are available depicting grind wheel
inventory and performance and can be tracked by vendor.
Roll
Scheduling
Rolls are scheduled for the mill based on roll availability
and the upcoming production schedule. The best Work Rolls and
Backup Rolls are recommended at each stand, based upon the crown
and texture required in each stand. Roll changes must take place
whenever the rolls in the mill are not appropriate for the upcoming
production, or when they are worn. [QMOS] is able to compare
the expected usage on the current rolls with the upcoming rolling,
The system will suggest that the rolls be changed based upon
comparisons with historical data concerning the usual amount
of use by similar rolls when they wear out. The operator is
given a view of the whole mill cross referenced with upcoming
production, providing the easiest and most efficient means of
roll scheduling.
The coil width being used is also considered, in order to prevent
marking or scoring on the finished product. [QMOS] checks for
the expected finished product width to determine if the rolls
might cause a problem due to a change in coil width.
Roll
Inventory
All roll purchasing, scrapping, and depreciation is handled
by [QMOS]. Worn or broken rolls which need to be scrapped, and
[QMOS] records details of the roll status, and removes the rolls
from the active roll inventory.
As
rolls wear or break, and they are due to be replaced, [QMOS]
prepares the necessary Purchase Order for ordering the replacement
rolls. When new rolls are received and accepted, they are then
added to active roll inventory and can be used in the mill.
When the roll diameter is reduced due to roll grinding, [QMOS]
automatically depreciates roll values accordingly. An end of
month Account Summary is produced which shows opening and closing
roll inventory balances, as well as the details of roll consumption
during the month.
Many
other reports are available, including those which illustrate
roll performance by supplier, or by roll material, and activity
of the roll shop for a period of time or for a specific grinder
operator.
Stand Building & Tear Down
Once rolls have been ground and are ready for use, they must
be chocked and built into the correct stand. Stand Building
activity is scheduled and tracked through the Bearing &
Chock Inventory module. [QMOS] tracks which chocks and bearings
were used on each roll, and who did the work. Rolls can be built
up for a specific stand for upcoming production, or as a spare
in case of premature roll wear or breakage.
Later, when the rolls come out of the mill, they are de-chocked.
The operator records this activity, which then breaks the relationship
between the rolls and the chocks. When this is done, the operator
is given the option to automatically create a roll grinding
work order, beginning the entire process again.
A
list of standard procedures or steps required to build and tear
down each stand is accessible, providing an instant “how
to” manual for all shop personnel. Users can track which
steps have been completed, so that the supervisor and other
workers all know the current status of the job. This feature
also provides a list of SOP’s which then conform to ISO
standards.
Bearing
& Chock Inspection
Bearing and Chock inspections carried out periodically enable
the setup shop to track various measurements, such as bearing
bore and chock width across liners. When the bearing is assembled
into the chock, the load zone used is recorded, as well as the
employee who performed the inspection. Also any chock parts,
seals and assorted hardware can be recorded on the work order.
This can also be used for historical data tracking.
Again, a list of standard procedures or steps required to inspect
bearings and chocks is accessible, which provides a manual for
all shop personnel. This provides a list of SOP’s which
then conform to ISO standards.
Interfaces
A number of interactive processes between [QMOS] and other systems
and equipment have been automated at Worthington Steel, including
roll grinders and the mill operation system.
Roll
Grinding Interface
Worthington uses two Waldrich-Seigen grinders in the roll shop.
As roll grinding takes place, a user-friendly interface allows
grinding results to be automatically transferred from the grinders
directly to [QMOS]. A complete roll diameter profile is captured,
along with Eddy Current crack and bruise data. The only user
intervention required is to ensure that the correct roll number
is entered.
This
interface allows complete accuracy for recording roll grinding
results, and occurs instantaneously upon completion of the roll
grinding process.
Mill
System
When the mill system calls for new rolls for any stand, roll
diameters are passed from [QMOS], along with other roll information
required for mill setup. The mill system operator does not need
to manually enter any further roll data in order to set up the
mill to run.
As
coils are produced, the tonnage and length of steel produced
are immediately passed back to [QMOS]. [QMOS] then keeps track
of the amount of steel rolled by each work roll and backup roll
each time it is used in the mill. Tonnage and length rolled
is stored for each roll over its entire life, and since it was
last ground. This data provides meaningful analysis of roll
usage and performance.
The
roll tonnage is also applied directly to the chocks and bearings
used with each roll. Bearing and Chock maintenance and inspection
schedules can be set up based on their usage, to try to prevent
or limit bearing failure. Tonnage is stored for each chock and
bearing over its entire life, and since the last inspection.
When
rolls are changed in the mill, [QMOS] is immediately notified.
The tons and length rolled stop accumulating on the rolls, and
begin to accrue to the new rolls, chocks, and bearings. A work
order to tear down the stand is automatically created.
Analytical
Power of [QMOS]
The
tonnage and length of steel produced that are passed back to
[QMOS] as coils are produced provides data for meaningful analysis
of roll usage and performance. Reports showing roll cost per
ton can be printed for whichever rolls or time period required.
A Roll History Report can be used to spot interesting results
and trends in terms of roll wear or roll value when generated
by supplier or by roll material. Reports detailing the performance
and usage of grind wheels, or grind wheel suppliers, can also
be prepared and measured in the same fashion.
A
periodical Roll Grinding Report will show overall roll grinding
activity. It can also be produced for a particular lathe operator,
which is useful to identify the need for additional training
or a possible change required to standard procedures.
From
the historical roll profile, it’s possible to review and
graph roll hardness as the roll wears. This has proven particularly
useful when analyzing the causes of roll breakage. Production
of the Roll Hardness Profile has become a part of standard routines
whenever a roll breaks or wears prematurely.
Summary
The
[QMOS]FLAT Roll Shop Management System is a client server application
runs on Windows family of products. Oracle is used as the data
base management system using UNIX, or NT platform. This System
is currently used by Worthington Steel, Decatur AL for planning
roll shop events, monitoring shop activity, helping operators
make decisions during the shift, and for performing analysis
and viewing trends to allow for consistent improvement to the
processes.
The
system has provided improved roll shop efficiency which has
lead to a reduced investment in roll and roll related inventory,
and increased roll life. The quality of the finished rolled
product has improved by utilizing more accurate roll results
from the grinders. There is now an increase in mill productivity,
directly resulting from roll shop scheduling improvements.