Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 9
APPARATUS FOR T~E ASSEMBLY OF STACKS OF PRESS
MATERIALS IN THE MANUFACTURE OF LAMINATED SHEETS
The invention relates to apparatus used in the manufacture of
laminated sheets with a platen press, preferably a multi-layer platen
press, for the assembly of stacks of press materials which are made of a
lower metal foil, a substrate mat positioned thereon, and an upper metal
foil placed on top of the substrate mat and are assembled on a metallic
pressure sheet, for the positioning of the stacks of press materials onto
a metallic transport sheet which carries an underpadding, and for the
depositing of a cover padding and metallic cover sheet onto the stacks of
press materials.
In conventional installations of this type, the transport and
pressure sheets and the paddings are reused and cleaned, if required.
Damaged sheets and paddings can be removed from circulation and
replaced. The term "substrate mat" refers to a type of starting material
for the manufacture of laminated sheets used particularly in electrical
engineering or electronics and especially in the production of printed
circuits. Substrate mats are generally made of glass fibre fabrics or
glass fibre felts impregnated with a synthetic resin, for example an
epoxy resin. Generally, a number of stacks of press materials and
pressure sheets inserted therebetween are assembled in layers on the
transport sheet, for example in the sequence transport
sheet/underpadding/pressure sheet/lower metal foil/substrate mat/upper
metal foil/the next pressure sheet/lower metal foil/substrate mat/upper
metal oil/another pressure sheet/... and so on... It is understood by a
person skilled in the art that each substrate mat and, thus, each
finished, laminated sheet is provided on either one or both sides with a
metal foil, preferably a copper foil. The transport sheets are each
loaded with a pile including the stacks of press materials and the
intermediate pressure sheets and fed together therewith into the platen
press according to the cycle time of the press. The cover padding and
the metallic cover sheet are positioned onto the pile on its way into the
platen press. The resulting covered pile is then loaded into the platen
press on the transport sheet and compressed therein to a stack of
finished laminated sheets.
In conventional apparatus, the complete assembly of a covered pile
to be pressed including the underpadding, the first pressure sheet, one
or more stacks of press materials including at least one metal foil and a
subs~rate mat, the intermediate pressure sheets~ the cover padding and
the cover sheet is carried out on the transport sheet. ~owever, that
method is time consuming, especially since the copper foils are very
sensitive and must be manipulated very slowly and carefully. As a
result, conventional apparatus of the above described type have cycle
times which are determined by the sum of the individual operations of the
apparatus. Consequently, the cycle times are substantially longer than
the cycle time of the associated plate press, which in turn depends on
the time required for the physical and chemical processes that take place
during pressing and for loading and unloading of the plate press.
It is now an object of the invention to provide an apparatus of the
above described general type which can be operated at a significantly
reduced cycle time and preferably at the cycle time of the plate press
respectively used.
This object is achieved in an apparatus wherein the time consuming
depositing of the metal foils onto the respectively ~mderlaying pressure
sheet or substrate mat is carried out away from the transport sheet and
the metal foil/pressure sheet and metal foil/substrate mat combinations
are subsequently layed-down onto the transport sheet for assembly of a
stack of press materials.
Accordingly, the invention provides apparatus used in the
manufacture of laminated sheets in a platen press, preferably a
multi-layer platen press, for the assembly of at least one stack of press
materials on a pressure sheet, which stack includes a lower metal foil, a
substrate mat positioned thereon and an upper metal foil placed on top of
the substrate mat, for the positioning of the stack and the supporting
pressure sheet onto a transport sheet and for the subsequent depositing
of a cover padding and cover sheet thereonto. The apparatus includes a
metallic pressure sheet transfer conveyor having a first metal foil
pull-in station for depositing the lower metal foil onto the pressure
sheet; a substrate mat transfer conveyor having a second metal foil
pull-in station for depositing the upper metal foil onto the substrate
mat; and an assembly statlon for assembling the pressure sh~et carrying
2~2~
the lower metal foil and the substrate mat carrying the upper metal foil
on the transport sheet into a stack of press materials, which assembly
station is integrated into a transport sheet circulating arrangement and
has a padding lay-on station for depositing the underpadding directly
onto the transport sheet. The pressure sheet transfer conveyor and the
substrate mat transfer conveyor enter the assembly station on opposite
sides thereof and transverse to the transport direction of the transport
sheets in the transport sheet circulating arrangement. A transport
conveyor for transport sheets carrying the under padding and at least one
stack of press materials connects the assembly station with the platen
press. A series of stacks of press materials with intermediate pressure
sheets are arranged in a pile on the transport sheet carrying the
underpadding. The apparatus also includes a cover padding and cover
sheet lay-on tool for placing of the cover pad and the cover sheet onto
the pile of press materials stacks during its transport to the platen
press. The covered pile as such is compressed in the platen press.
Tools for loading and unloading of the platen press and the operation of
the circulation pathways for the transfer sheets, the press sheets and
the paddings are known in the art.
Even when very thin and, thus, very sensitive metal foils are used,
especially short cycle times are achievable with a preferred embodiment
wherein the metal foil pull-in stations for the depositing of the lower
metal foil onto the pressure sheet and the upper metal foil onto the
substrate mat respectively are provided with a lay-down conveyor, a
suction beam and a suction source associated with the lay-down conveyor.
In that embodiment, each metal foil is pulled onto the lay-down conveyor
by means of the suction beam, the depositing conveyor is moved over the
substrate and then the metal foil is deposited and sucked down onto the
respective underlayer (pressure sheet or substrate mat) by a reverse
movement of the lay-down conveyor and simultaneous suction of air from
the gap between the metal foil and the underlayer.
In another preferred embodiment, the metal foil pull-in stations of
the pressure sheet transfer conveyor and the substrate mat transfer
conveyor as well as the assembly station are enclosed in a clean room
which contains little or practically no dust. Electrostatic cleaning
arrangements for the surface of the underlayer are preferably provided at
the entry of the transfer conveyors into the clean room. The metal foils
are preferably copper foils.
It is an advantage of an apparatus in accordance with the invention
that it can be operated as a short cycle apparatus at very short cycle
times so that its cycle time can be adjusted to that of the associated
platen press. The cycle time of the platen press depends on the physical
and chemical processes which take place during the compressing of the
stacks of press materials and includes the time required for loading and
unloading of the platen press. The apparatus in accordance with the
invention can operate at very short cycle times because of the pressure
sheet transfer conveyor and the substrate mat transfer conveyor which
cooperate with the assembly station as described above. This is
advantageous compared to a conventional installation as described above
wherein the complete assembly of the stacks of press materials including
the pressure sheets, the paddings and the cover sheet is carried out
directly on the transport sheet.
A preferred embodiment of the apparatus in accordance with the
invention will now be further described by way of example only and with
reference to the attached drawingsJ wherein
Figure 1 is a top plan view of one half of a short cycle apparatus
in accordance with the invention; and
Figure 2 illustrates the other half of the short cycle apparatus
shown in Figure 1.
The apparatus shown in the drawings is used in the manufacture of
laminates, more exactly laminated sheets in a platen press, preferably a
multi-layer platen press, and is adapted for the assembly of at least one
stack of press materials consisting of a lower copper foil l, a substrate
mat 2 positioned thereon and an upper copper foil 3 positioned on top of
the substrate mat, each stack of press materials being placed onto a
metallic pressure sheet 4, and for the depositing of the stack of press
materials and the underlaying pressure sheet onto a metallic transport
sheet 5 which carries an underpadding 6 thereon. Of course, it will be
appreciated by the art skilled person that a cover padding 7 and a
metallic cover sheet 8 are placed on top of the stack of press materials
before it is loaded together with the pressure sheet 4 into the platen
press (not shown) on the transport sheet 5. The platen press is
~2~
positioned to the right of Figure 2. A conveyor S connects the apparatus
with the platen press. At least one stack of press materials which
includes the lower copper foil 1, the substrate mat 2 positioned thereon
and the upper copper foil 3 placed on top of ~he substrate mat is loaded
onto a transport sheet 5. However, it is also possible to stac~ several
stacks of press materials and intermediate pressure sheets 4 to a pile of
stacks of press materials, to place the cover padding and cover sheet on
top of the pile and to compress it in the platen press. This is possible
even when the stacks of press materials each include only one copper foil.
Figures 1 and 2 illustrate an assembly station 9 which is integrated
into a transport sheet cycle tnot shown) that includes an underpadding
lay-on station 10 for the underpadding 6. Some sections of the transport
sheet cycle are shown. Figure 2 shows the pressure sheet transfer
conveyor 11 which is provided with a first copper foil pull-in station 12
for the depositing of the lower copper foil 1 onto the pressure sheet 4.
Figure 1 shows a substrate mat transfer conveyor 13 which is provided
with a second copper foil pull-in station 14 for the depositing of the
upper copper foil 3 onto the substrate mat 2. It becomes apparent from
combined Figures 1 and 2 that the pressure sheet transfer conveyor 11 and
the substrate mat transfer conveyor 13 enter into the assembly station 9
at opposite sides thereof and transverse to the transport direction of
the transport sheets 5. The transport direction of the transport sheets
5 is indicated by the solid arrows in the Figures. The transport
conveyor S for transport sheets which are provided with the under padding
6 and support a pile of one or more stacks of press materials thereon is
connected to the assembly station 9 and leads to the platen press (not
shown). A cover padding 7 and a metal cover sheet 8 are positioned onto
the one or more stacks of press materials on their way to the platen
press by way of a cover padding and cover sheet lay-on tool 15 indicated
in Figure 2. As indicated in thick, broken lines in Figures 1 and 2, the
first copper foil pull-in station 12 for the depositing of the lower
copper foil 1 onto the pressure sheet 4 and the second copper foil
pull-in station 14 for the depositing of the upper copper foil 3 onto the
substrate mat 2 are both provided with a lay-down conveyor l6, a suction
beam 17 and a suction source 18 associated with the lay-down conveyor.
Suitable lay-down conveyors 16 are known in the art and so is the
transport of copper foils and other foils by means of suction beams (see
German Patent 29 32 845). ~lowever, the suction source 18 was added. The
construction is such that the copper foils 1 and 3 are pulled onto ~he
lay-down conveyor by the suction beams 17, the lay-down conveyor 16 is
moved over the pressure sheet 4 or substrate mat 2, and the copper foils
1, 3 are deposited and sucked down onto the respective pressure sheet 4
and substrate mat 2 by reverse movement of the lay-down conveyor,
simultaneous removal of the conveyor from above the pressure sheet 4 or
substrate mat 2 and suction of air from under the respective copper foil
1, 3. The first copper foil pull-in station 12 of the pressure sheet
transfer conveyor 11, the second copper foil pull-in station 15 of the
substrate mat transfer conveyor 13, and the assembly station 9 are all
enclosed in a clean room 19 which contains little or no dust. The
transfer conveyors 11, 13 enter into the clean room 19 and electrostatic
cleaning equipment for the surface of the substrate mats is provided at
their respective entry 20 into the clean room.
