Maintaining a 15-year relationship with supplier Salvagnini
Group (Vicenza,
Italy), the decision was easy for the Verona, Italy-based appliance
maker. “They were known as the most experienced supplier in the
field of flexible automation,” Giovanni Simoni, technical production
director of Polin, explains. “For this reason we contacted them.
They provide effective and efficient services to support the machinery.” Installing
an integrated system comprising a tray store, an S4 punching and shearing
center, and an automatic P4 panel bender, Polin says it is able to
control several production functions at various rates to accommodate
order demand.
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A fully automated system from supplier Salvagnini
Group (Vicenza, Italy) controls production rates
according to order demand with a computer-controlled
storage system. |
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Storage
Smarts
The flexible system starts with a shelved “store” where an
operator specifies an internal code and quantity for the sheet material
and enters the data through a terminal located next to the store. Capable
of holding 376 pallets with a maximum capacity of 3,000 kg (approx. 6,600
lbs), the stores can hold material for use on the flexible system in
addition to material needed for other production systems.
To ensure an efficient and fluid production run, the store’s Automatic
Storage and Retrieval System (ASRS) automatically checks to see if the
needed material is available when a production list is loaded into the
system. If the material is already in the store, all operations are performed
by the automated system. According to Salvagnini, production is interrupted
only when the material required on the current production list is not
in the store. In this case, the operator can decide to either load a
different production list or continue running the initial list, as the
required material may have been loaded during the time the warning message
was sent. In addition, the control system keeps track of material on
multiple levels, including current stored material and material that
is available but earmarked for future production. For every batch that
is sent to the system, the software displays a table that shows used
and available material inventories.
One aspect of the flexible system is that material can be sent to any
part of the system at any time. “You need a flexible system in
the beginning because you’re starting from the metal sheet, and
you have to obtain many kinds of parts,” Nicola Vanzo, project
manager for Salvagnini, tells APPLIANCE. “One part can go to the
press brake, another is going to go to the welding system, another part
to assembly. You have to follow all of your production, which can require
a different material.” As a result, Polin has assigned internal
codes to different materials. Therefore, once the operator enters a production
list, the system automatically reads an ASCII file and sends the pallet
to the appropriate designated system area. Unused material is sent back
to the store for future use. Machined parts can be stored using the same
code system as the sheet material and can later be sent to another system
area by the same initial store methods as well.
| Ing.
Polin & C. (Verona,
Italy) produces its commercial ovens on an automated
system from Salvagnini Group. The appliance maker
says it is planning on installing additional systems
from the supplier. |
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Precise
Punching & Systematic
Shearing
Equipped with an automatic feed station, the system’s punching
center contains a patented head fitted with an independent actuating
hydraulic press that comes in contact with every point of the sheet,
eliminating any need for rotation. Patented angular sheer-equipped independent
blades with an automatic clearance adjustment function can cut the material
in any length and in any order according to longitudinal and transverse
axes. Polin’s punching and shearing center is equipped with 40
hydraulic presses with a 33-diam maximum punch and four presses with
maximum tool dimensions of 90 by 70 mm (3 1/2 by 2 3/4 in). The punching
press can also be equipped with additional presses and rotary pressing
units to enable embossing.
Polin’s shearing system consists of two fixed 400-mm (15 3/4-in)
lower blades that meet to form a point parallel to the axis of the manipulator.
Two upper blades feature an inclined cutting edge in respect to the lower
blades and are fitted with a blankholder. Incoming blanks can be cut
into multiple sheets in various sizes without scrap. The supplier says
its punching and shearing system can be used with both magnetic and non-magnetic
sheet metal with a maximum thickness of 3.5 mm. Covered with changeable
brushes, the work table and conveyer are said to be quiet and help reduce
damage to the sheet metal before unloading. This, according to Mr. Vanzo,
is a cost savings to Polin. “If you don’t have an automatic
store like we have at Polin, you need a main person to take care of that
[function],” he says. “Now, the customer is able to follow
the feeding of the machine automatically, without an operator.”
Bending Options
Punched parts are inserted into the system’s panel bender by a
controlled manipulator, where the blankholder is closed on the bottom
blade to lock the part in place. The top blade then moves to perform
downward bends, while the bottom blade consequently creates upward bends.
Once bending is performed on one side, the manipulator takes the sheet
out of the press, rotates it, and inserts the other side. Various bends
can be performed, including flattened, radiussed, tubular, and partial.
The supplier says the machine is self-tooling, and complete retooling
can be completed within 90 sec. In addition, Polin asked that the bender
have the ability to cut during the cycle to produce narrow panels traditionally
manufactured on forming machines. To achieve this, the sheet is cut by
moving the bottom blade after the top has already bent the sheet, whereas
traditionally, the part is bent by moving the top blade. The supplier
says the cutting option can cut a solid sheet with a maximum thickness
of 2 mm or 1.2 mm for stainless steel.
Hi-Tech Handling
With the flexible system, Polin says the largest benefits of using the
supplier’s system is increased productivity and reduced costs and
labor. “We reduced costs by increasing productivity,” says
Mr. Simoni. “Unmanned production through fully automated solutions
cancelled all possible non-value-added work. That is, time and resources
spent on areas of the manufacturing process, meaning people moving parts
back and forth and feeding or unloading machines.”
The automated handling is integrated into each part of the system. In
the store, the production list software initiates the handling of material
and moves packs of sheet metal while also preparing and ordering other
pallets for upcoming orders. In both the punching and shearing system
and the bending system, a universal destacker, capable of feeding sheets
ranging from 0.5 and 3.5 mm in thickness, removes the sheets from a pack
and feeds the appropriate machines. Magnetic separators or a series of
air blasts separate the sheets as six suction cups lift the shorter side
of the sheet to the feeder pincher. A safety device checks to ensure
that only one sheet has been fed, and the pincher then transfers the
sheet to the worktable.
Sheets are centered on the worktable by preset guides and by an optical
sensor that detects the end of the sheet as it passes the worktable.
Once the sheet is gripped by the manipulator, it is not released until
after the designated machine operations are complete. In order to allow
all the punches in the head to reach every position on the sheet, one
half of the sheet is machined at a time. Scrap is collected from under
the machinery and is conveyed to its own container. In addition, exit
paths are programmed and a stacker containing two pairs of magnetic belts
transfers and places the parts on top of each other. For non-magnetic
parts, two sets of rollers, mounted on two oscillating longitudinal beams
below the stacker, push the sheets on the belt until the stacker moves
the parts.
Parts leaving the bender are stacked and can be programmed to return
to the store and can be recalled when requested by a production list.
The bender is also equipped with the same centering and unloading stations
as the punching and shearing system. Once a part has gone through the
bender, a motorized roller table and inclinable rake slide the part to
a cushioned stop. From here, the parts are then lifted and stacked.
Challenging Rewards
The completely automated system, according to Polin, has resulted in
several benefits since its installation. “Advantages have been
numerous,” Mr. Simoni tells APPLIANCE. “From reduction of
personnel costs, to increased ability to react to market demands, to
increased flexibility allowing smaller stock [leading], to increased
production.” The appliance maker says that due to the automated
system, both material quality and productivity have increased, as room
for error has decreased with fewer workers handling the material.
There were, however, minor challenges associated with the project that
both the appliance maker and its supplier worked to overcome. The first
involved efficiently fitting the flexible system into Polin’s production
facility in Verona. “We had to revise the layout of the system
to make it fit exactly in Polin’s plant,” Mr. Vanzo says. “The
customer not only asked us to have it fit correctly, but to install the
machine following the flow of the material.” This was a challenge,
as the facility was older and could not be rebuilt to accommodate the
new machinery. The answer, Mr. Vanzo says, was placing the punching and
shearing system in line with the panel bender and integrating the two
with the automatic store.
In addition, Mr. Simoni of Polin says the conceptual ideas associated
with the new system were also a challenge for the company. “We
had to conceive products and the production process in a different way,” he
says. “We were used to press brakes and other traditional, non-automated
machines.”
Even so, the appliance maker says that by using the new system, its final
products ended up being produced with fewer parts and screws, and welding
was also drastically reduced. “Production has become faster, and
the flexibility of the machines allow us to have a much shorter time-to-market.
We have increased the range and the number of products we can offer our
customers every year,” Mr. Simoni says. “We had to think
differently from the way that we were used to. We had to think automated.”
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