Method and apparatus for separating and reclaiming trim from a lamination machine

A device for separating layers of laminate trim includes a pair of nip rollers defining a feed path for a laminate, at least two winders and a drive system for the winders. The winders are preferably arranged on an upstream side of the nip rollers. The device can be provided at the output of a lamination machine to receive longitudinal trim portions cut from a laminate being formed by the lamination machine, so as to provide continuous delamination of trim exiting the lamination machine. In the case of a three (or multiple) layer laminate, the device can include a third winder (or additional winders) for collecting a middle layer of the laminate.

TECHNICAL FIELD 
The invention relates to a method and apparatus for separating and 
reclaiming trim from a lamination machine, and particularly to an improved 
device and method for separating layers of side trim of an aluminum 
composite material. 
BACKGROUND OF THE INVENTION 
Discussion of the Background 
Aluminum-polyethylene composite laminates, as well as other types of 
composite laminates, are useful for a number of architectural 
applications, because the laminates combine light weight with high 
strength. These laminates may be used as finished surfaces or for all or 
portions of the interior or exterior surfaces of a building or an 
automobile. 
In the field of composite material manufacturing, a lamination machine is 
used to produce a composite material consisting of, for example, a layer 
of polyethylene sandwiched between layers of sheet aluminum. U.S. Pat. No. 
4,994,130 to Ichikawa et al. teaches a lamination machine which includes 
pay off reels 3 and 3' that are used to feed the sheet aluminum to 
preheaters 6 and 6', then to hot press bonding rollers 2 and 2' where a 
synthetic resin sheet is pressed between the aluminum sheets, and thereby 
bonded to the aluminum sheets with a thermally activated adhesive. The 
lamination machine typically uses large rolls of sheet aluminum and 
extruded polyethylene to form long continuous sheets of composite 
material. In order to ensure a uniform or complete distribution of 
polyethylene between the aluminum sheets, it is common to extrude the 
polyethylene so that it is slightly wider than the aluminum sheet rolls. 
Therefore the composite laminate leaving the laminating machine will 
typically have a small amount of polyethylene projecting from the edge of 
the material. In order to ensure that the edge of the final product is 
flush, the longitudinal edge of the sheet is trimmed off as it leaves the 
lamination machine, and the trimmed laminate is then cut laterally to form 
panels. The continuous longitudinal trimming the edge of the laminate 
results in large amounts of trim material, that heretofore have been 
wasted. 
Since the materials which form composite materials, such as aluminum-resin 
composites, can be expensive, particularly in large volumes, it is 
desirable to recycle both the metal and the resin components. In the past, 
panels or sheets of such composite materials have been recycled. In 
recycling such sheets, for example, when the metal sheets include 
aluminum, it is important to separate the aluminum from the thermoplastic 
resin prior to melting the thermoplastic resin, since melting of the 
aluminum-thermoplastic resin leads to conversion of the aluminum to 
aluminum oxides and a poor yield of recovered aluminum. It is known to 
separate aluminum polyethylene laminate composite utilizing a two stage 
process, in which the laminate is first heated and then pressed between 
picking rolls. See U.S. Pat. No. 5,500,072 to Fujimura et al. col. 1, 
lines 58-67. However, this method is not effective when the aluminum sheet 
is relatively thick or is composed of less pure and less flexible 
aluminum. Furthermore, it has been found that heating the laminate for 
separating requires a large amount of energy, and is not conducive to a 
continuous separating process. 
U.S. Pat. No. 5,500,072 to Fujimura et al. teaches a method and apparatus 
for separating aluminum sheets from thermoplastic resins that are cut into 
panels. Fujimura et al. teach a method and apparatus which includes 
feeding the cut laminate through embossing rollers, then through a heating 
zone. When the material emerges, "it separates spontaneously into its 
component metal sheets 4 and resin core 3 upon cooling." See Fujimura et 
al. at column 6, lines 4-6. However, a process which requires heat 
consumes a substantial amount of energy, and is therefore costly, and 
contrary to the purpose and desirability of recycling, particularly with a 
relatively small width trim (e.g., trim separated from the longitudinal 
edges of a laminate). 
U.S. Pat. No. 5,194,109 issued to Yamada teaches a method for recovering 
scraps of a multilayer plastic sheet or film. With the Yamada method, the 
scrap is heated to a temperature lower than the softening point of the 
base material layer so that the inter-laminar peeling strength of the 
adhesive resin is lower than the strength of the weakest layer in the 
lamination, and the multilayer scrap is separated into at least two scrap 
layers. Yamada utilizes heating rolls, a pair of separation rolls 
downstream from the heating rolls, and rollers which are used to take-up 
the outer layers of the heated and separated laminate. Yamada also teaches 
that heating can be performed by hot air or infrared rays. See column 4, 
lines 61-63. However, this method also suffers from the high energy 
requirements of heating the laminate trim. 
Thus there remains a need for a method and apparatus for separating sheet 
metal-thermoplastic resin laminate trim composites into their component 
metal sheets and thermoplastic resin sheets. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an apparatus and method 
for simplifying the separation of layers of a laminate. 
It is another object of the invention to provide an apparatus and method 
for separating layers of a laminate without the need for heating the 
laminate prior to separation. 
It is a further object of the invention to provide for the continuous 
separation of layers of a laminate trim which is generated by a lamination 
machine. 
It is yet another object of the invention to provide an apparatus and 
method for separating layers of a laminate trim, and which automatically 
takes up the slack in the laminate trim. 
The above and other objects and advantages are achieved in accordance with 
the present invention by providing a pair of nip rollers arranged to 
define a path for receiving a laminate trim between the nip rollers and a 
pair of winders arranged to roll layers of the laminate trim that leave 
the nip rollers. The winders are provided on an upstream side of the nip 
rollers so that the layers of the laminate trim are curled at least 
90.degree. from the feeding path of the laminate trim into the nip 
rollers, and a drive system rotates the pair of winders. 
In a presently preferred form of the invention, drive motors transmit a 
predetermined torque to the winders to ensure stability in the 
delaminating procedure such that the likelihood of the layers of the 
laminate trim breaking during the separating process is minimized. The 
predetermined torque is chosen based on the width of the laminate trim. 
Preferably, the predetermined torque is chosen so that the trim is 
separated at a maximum rate, yet not so high as to rupture the laminate 
trim entering the nip rollers. Furthermore, by providing the winders with 
a predetermined torque, the speed of the winders changes according to the 
applied load. Therefore, when there is slack in the trim entering the nip 
rollers, the speed of the winders increases due to the reduced tension in 
the laminate trim, which thereby causes the winders to pull the laminate 
trim at a higher speed and eliminate slack. 
Preferably, the separating assembly is provided at the output of a 
lamination machine so that the trim produced by the laminating machine is 
continuously fed to the separating assembly. Arranged as such, the present 
invention provides continuous delamination of the trim as it leaves the 
laminating machine. This arrangement can be advantageous in efficient 
handling of the trim and, in at least some circumstances, it can be easier 
to separate the layers when the adhesive used to bond the layers of the 
laminate trim has not been allowed to cure. 
Preferably, the winders are provided with quick release end covers which 
allow the winder to be partially disassembled so that the trim components 
wound upon the winder can be removed without removing the winder from its 
shaft. This allows the process of delamination to be performed nearly 
continuously with a minimal time delay for emptying the winders.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A trim separator 10 for separating the layers of a laminate trim according 
to the invention is illustrated in FIG. 1. It includes a frame 12 with 
uprights 14 which are configured to mount the winders 16, 18 and 20, and 
nip rollers 22 with known structures such as shafts and bearings (not 
shown). As seen in FIG. 6, nip rollers 22 are preferably tapered so as to 
ensure that laminate trim 34 remains between rollers 22. This embodiment 
is designed to separate the layers of a three layer laminate, for example, 
a laminate having an upper layer 24 and a lower layer 26 made of aluminum, 
with an inner layer 28 made of polyethylene. In this example, the inner 
layer 28 is bonded to the outer layers 24 and 26 with an adhesive 30 (FIG. 
5). 
In order to collect the separated layers of such a three layer laminate 
trim, the present embodiment is provided with three winders. However, it 
is also possible to utilize only two winders 16 and 18 to separate the 
layers of a two layer laminate trim, or additional winders for separating 
multiple layers of a laminate trim. In the FIG. 1 embodiment, winders 16 
and 18 are provided on an upstream side of a plane P which is tangential 
with a leading edge of nip roller 22 and substantially perpendicular to a 
path 32 defined by nip rollers 22 for receiving laminate trim 34. Winders 
16 and 18 are configured to be fed with the outer layers 24 and 26 of 
laminate trim 34. Such an arrangement of winders 16 and 18 ensures that 
the layers 24 and 26 can be peeled away from layer 28 such that a 
peel-away angle B can approach 90.degree. (FIG. 5) 
By inducing a severe peel-away angle B, the present invention benefits from 
the natural tendency of material under bending to undergo tensile strain 
at its outer surface (i.e., the outer side with respect to the bending 
direction or, in other words, the side facing away from the roller around 
which the layer is bent), thereby inducing a shear stress in the adhesive 
layer 30. More particularly, when a member is subjected to bending, the 
outer surface of the member is subject to a maximum tensile stress while 
the inner surface is subjected to a maximum compressive stress. As shown 
in FIG. 5, layer 24 is subjected to a maximum tensile stress on surface 40 
at approximately the cleavage point 42 (where adhesive 30 ruptures upon 
delamination). The tensile stresses are indicated by arrow T while the 
compressive forces are labeled as arrows C. The effect of the tensile 
stress of surface 40 on adhesive 30 at the cleavage point 42 results in a 
strain or elongation of surface 40 relative to the inner layer 28 at 
cleavage point 42 causing a shearing stress in the area surrounding 42 in 
the adhesive. This shearing stress is combined with the tensile stress 
caused by the winders 16 and 18 pulling layers 24 and 26 away from layer 
28. The combination of this shearing stress and the tensile stress 
cooperate to rupture adhesive 30. Thus, in accordance with one aspect of 
the invention, by arranging winders 16 and 18 such that the peel-away 
angle B is approximately 90.degree. (or greater) when cleavage point 42 is 
approximately between nip rollers 22, the tensile forces along surface 40 
are sufficient such that it is not necessary to heat the laminate trim to 
separate the layers of the laminate trim. 
During operation, the cleavage point typically does not remain at a 
constant position relative to nip rollers 22, and thus the cleavage point 
does not remain between nip rollers 22 at all times. In fact, the cleavage 
point 42 may move downstream from nip rollers 22. For example, during 
operation, delamination may occur over short intermittent lengths, with 
the cleavage point traveling downstream slightly to the point 43 shown in 
FIG. 7, and then a separation/delamination can occur and the trim will be 
separated back to point 41 of FIG. 7. Furthermore, the delamination of the 
top and bottom layers does not always occur at the same point along the 
feed path, for example, as shown in FIG. 8 (where delamination occurs at 
cleavage points 47 and 45). Therefore, it is preferable to arrange the 
winders 16 and 18 such that the point of delamination is kept in proximity 
to nip rollers 22, so that delamination remains under control and cleavage 
points remain predictable. To do this, winders 16 and 18 should be 
arranged so that layer 24 and 26 leaving nip roller 22, downstream from 
cleavage point 41, 42, 43, 45, 47 make contact with nip rollers 22 before 
reaching winders 16 and 18. This can be achieved by arranging winders 16 
and 18 such that winding angle D, which is the angle between feeding path 
32 and winding path 33 along which layer 24 follows from nip roller 22 to 
winder 16, is between 10.degree. and 80.degree., and preferably between 
25.degree. and 60.degree., as shown in FIG. 10. 
The presently preferred arrangement provides improved results over the 
prior art. For example, as shown in FIG. 9, if winding rollers 4 are 
arranged on a downstream side of separation rollers 5, the outer layers of 
the laminate may not encounter sufficient bending forces, and thus, less 
than optimal results are achieved. For example, if a particular area in 
adhesive layer 30 is of a strength such that a peel-away angle B of 
approximately 90.degree. is needed to create sufficient shear stresses to 
rupture the adhesive, layer 28 might not separate from layer 24 or the 
separation could be incomplete, and therefore, layers 24 and 28 may 
together enter winder 4 and thereby require the apparatus to be stopped 
and re-threaded. Alternately, heating of the laminate could be required, 
making the equipment more expensive to manufacture and operate. On the 
other hand with the presently preferred arrangement, since winders 16 and 
18 are arranged on an upstream side of a plane P, layers 24 and 26 can be 
exposed to a greater peel-away angle so that separation of the laminate 
layers is improved and more reliable. 
If the layers are separated before the adhesive has completely cured, 
separation of the layers of the laminate trim is substantially easier. 
Therefore, trim separator 10 is preferably arranged at or near the 
discharge of trimmer of a laminating machine 46. As shown in FIG. 1, the 
laminating machine 46 includes a trimmer 48 which is configured to 
continuously trim the excess material at the edge of a laminate 50 leaving 
machine 46. Preferably, the laminate trim 34 leaving the trimmer 48, is 
directly fed to guide 36 adjacent nip rollers 22. The adhesive used for 
bonding sheet aluminum material with polyethylene, typically requires at 
least from 15 minutes to one hour to cure. Therefore, by providing the 
trim separator 10 at the discharge of trimmer 48, the present invention 
provides a method and apparatus which avoids the need for heating the 
laminate trim before separation. 
Two trimmers 48 are typically used so that both longitudinal edges of a 
laminate 50 leaving a lamination machine 46 can be trimmed. In that case, 
two trim separators 10 are used, one separator 10 provided downstream from 
each trimmer 48, as shown in FIG. 2. 
Because it is preferable to provide trim separator 10 at the discharge of 
trimmer 48, it is most efficient to drive winder 16, 18 and 20 with a 
varying speed so that any slack in a laminate trim 34 leaving trimmer 48 
can be automatically taken up. Therefore, controller 52 is provided to 
drive DC motors 54, 56 and 58. More particularly, a predetermined amperage 
is provided to the DC motors, so that each DC motor will transmit a 
predetermined torque through its output shaft. Alternatively, winders 
16,18 and 20 may be driven by a single motor (not shown) coupled to a 
multiple output transmission (not shown) or a multiple output torque 
converter (not shown). By controlling the motors 54, 56 and 58 as such, 
the speeds of the winders 16, 18 and 20 are automatically varied to 
maintain a predetermined tension in lamination layers 24, 26 and 28 
according to the load transmitted to motors 54, 56 and 58 through laminate 
trim 34. This arrangement is particularly advantageous if the trim 
separator 10 is shut off while laminating machine 46 is running, since 
slack then begins to form in laminate trim 34. If the trim separator 10 is 
then turned on with the slack remaining in laminate trim 34, there is 
chance that laminate trim 34 will become tangled. However, with winders 
16, 18 and 20 provided with a predetermined torque by motors 54, 56 and 
58, the speed of winders 16, 18 and 20 vary according to the tension of 
laminate trim 34. Preferably, the torque selected is such that the 
resulting speed of the winders is faster than the output speed of the 
lamination machine so that slack in laminate trim 34 will be taken up, and 
a positive tension is thereby maintained in laminate trim 34 leaving the 
lamination machine 46. However, the maximum possible torque selected and 
therefore the maximum possible amperage chosen, will be limited by the 
width of the laminate trim 34 entering the nip rollers 22, i.e., narrow 
laminate trim will be ruptured if an excessive torque is applied to 
winders 16, 18 and 20. Once the slack is taken up, the tension in the trim 
imposes a load upon the winders and thereby slows the winding speed to 
match the output speed of the lamination machine. 
As the winders 16, 18 and 20 are filled with either aluminum or 
polyethylene layers, the diameter of the spool changes. However, the 
linear speed of laminate trim 34 leaving lamination machine 46 is 
typically constant, unless there is slack between machine 34 and nip 
rollers 22. Therefore, the rotational rate of winders 16, 18 and 20 and 
therefore motors 54, 56 and 58, will gradually fall as the individual 
layers of laminate trim 34 gradually accumulate on winders 16, 18 and 20. 
Accordingly, it is important that drive motors 54, 56 and 58 can be 
subjected to such speed changes without damage. Therefore, drive motors 
54, 56 and 58 are preferably DC motors provided with constant amperage 
circuits. Such a configuration has a distinct advantage over a AC motor 
drive in that a DC motor provided with a predetermined amperage and 
voltage can be significantly loaded and therefore slowed without being 
damaged, unlike an AC motor. 
In a presently preferred form, controller 52 includes a constant amperage 
circuit. By way of example, a SECO DC DRIVE, model number SE2000, 
manufactured by WARNER ELECTRIC which can be operated in a torque control 
mode or a speed control mode. Each drive provided in controller 52, is 
preferably provided with an amperage meter 51, an amperage adjustment knob 
53, and a speed pot knob 55. Amperage adjustment knob 53 allows a user to 
designate or adjust the amperage output by the drive and therefore the 
torque produced by the corresponding DC motor. Similarly, speed pot knob 
55 allows a user to designate or adjust the maximum voltage output by the 
circuit and therefore the maximum capable speed of the corresponding DC 
motor. 
In operation, laminate trim 34 leaving lamination machine 46 is initially 
split into individual layers 24, 16 and 18 by hand, and the layers are 
threaded through guide 36 and nip rollers 22. Layers 24 and 26 are 
respectively threaded onto winders 16 and 18 while inner layer 30 is 
threaded onto winder 20. Alternatively, the laminate trim 34 may be stored 
on off-line spool 64 and fed to nip roller therefrom. 
Once the winders have been threaded with the laminate trim 34, controller 
52 is switched on, a predetermined amperage is selected for each winder, 
and the speed potentiometers (pots) are set to the maximum speed (100%). 
Setting the speed pots to 100% causes the drives to be saturated so that a 
maximum voltage is output to the motors 54, 56 and 58 is maintained. 
Although the speed pots may be set to a percentage lower than the maximum 
(100%), doing so would limit the maximum speed achieved by the winders and 
thereby limit the ability of the winders to absorb slack formed in the 
laminate trim 34 leaving machine 46. Therefore, in the presently preferred 
embodiment, the speed pots are set to the maximum speed thereby saturating 
the speed pots so that any slack formed in the laminate trim 34 is 
absorbed as quickly as possible. 
After setting the speed pots, an amperage is selected based on the width of 
the laminate trim 34 to be separated so that the trim 34 is separated at a 
maximum speed without being ruptured. Presently, an amperage of 2.0 amps 
is used to power each of the motors 54, 56 and 58, with the laminate made 
of aluminum and polyethylene, and with the aluminum layer approximately 
one-quarter inch wide. 
As the winders begin to fill, the diameter of the core of the winders 
becomes larger due to the accumulation of material. This results in an 
effective change in the outer diameter of the winder. Because motors 54, 
56 and 58 are provided with a predetermined amperage, the rotational rate 
of motors 54, 56 and 58 will gradually fall as the accumulation of 
material increases the diameter of winders 16, 18 and 20 without damaging 
motors 54, 56 and 58. Furthermore, when there is slack in laminate trim 34 
entering nip rollers 22, the rotational rate of motors 54, 56 and 58 will 
approach the maximum possible speed due to the voltage saturation of the 
drive and the lack of tension in laminate trim 34, thereby removing slack 
present in laminate trim 34. 
Since winders 16, 18 and 20 are provided with a predetermined torque, the 
tension in trim 34 falls incrementally as the effective diameters of 
winders 16, 18 and 20 increase. Winders 16, 18 and 20 could be provided 
with a compensation device for increasing the torque provided to winders 
16, 18 and 20 in response to the falling tension. However, the change in 
tension as the effective diameters of winder 16, 18 and 20 is negligible. 
Therefore, it is preferable to use a predetermined amperage, and therefore 
torque, throughout the delamination process yielding a relatively constant 
tension in trim 34 and layers 24, 26 and 28. 
The winders are run until they are filled with a strip of a layer of the 
laminate trim. At that time, an operator can stop the winders by actuating 
stop lever 57. The operator then cuts any one of the layers downstream 
from the nip roller 22, empties the winder, and re-threads the layer onto 
the empty winder. Thereafter, controller 52 can then be turned back on and 
the separating process will continue. 
In order to maximize the efficiency and speed of emptying winder 16, 18 and 
20, the construction of the winders is made such that the outer cover 60 
is releasably mounted on core 61 and held in place by quick release wheel 
62. The core of winder 16, 18 and 20 is preferably tapered so that when 
the cover 60 is removed, the wound material can easily be removed from 
winder 16, 18 or 20 in the direction of R as shown in FIG. 3. Preferably, 
core 61 is made from rods 63 arranged in a tapered fashion between back 
plate 59 and cover 60 such that the core 61 is narrower at cover 60 than 
at back plate 59. By constructing core 61 from rods, a user can easily 
insert a hook or a hand into the interior of core 61 and pull the wound 
material off the core 61 by pulling in the direction of arrow R. 
In an alternative embodiment, laminate trim 34 may be separated "off line". 
In other words, laminate trim 34 may be stored on a spool 64 temporarily, 
then fed to trim separator 10. Winder 64 is therefore preferably provided 
with a DC motor 66 and a constant amperage circuit so that spool 64 can be 
used to accumulate trim and provide a predetermined tension to laminate 
trim 34 in order to avoid tangling of laminate 34 leaving the lamination 
machine 46. Used as such, spool 64 can be used to temporarily hold 
laminate trim 34 if the separator should be down for maintenance or 
repairs, and the trim accumulated on the spool can then later be run 
through the separator. In addition, if the separator is to service more 
than one laminating machine, the separator can continuously receive and 
separate the trim from one laminating machine, while the trim from another 
laminating machine is wound upon a spool 64. The trim on spool 64 could 
then later be run through the separator when the first machine is down. 
Although the spool 64 can be utilized to store trim which is later 
delaminated, as discussed earlier, it is presently preferred to delaminate 
the trim as it is received directly from the laminating machine. 
Referring now to FIG. 6, controller 52 is shown connected to motors 54, 56 
and 58. Preferably, controller 52 supplies motor 54, 56 and 58 with a 
predetermined amperage which thereby causes motor 54, 56 and 58 to output 
a predetermined torque. Controller 52 can also be used to control braking 
motor 66 so that off-line spool 64 is provided with a predetermined 
braking torque by using a constant amperage circuit in a similar fashion 
to those used to control motors 54, 56 and 58. 
As should be apparent from the foregoing, the present invention provides an 
advantageous delaminating arrangement, which is particularly suitable for 
delaminating a laminate trim received from a lamination machine. The 
invention is particularly advantageous in that it allows for recycling of 
trim cuttings which have, in the past, been wasted. The invention is also 
advantageous in that separation can be accomplished without requiring heat 
in separating the laminate layers. The invention can be utilized for 
separating a laminate trim which has been stored upon a spool, however in 
the preferred arrangement, the trim delaminating arrangement is provided 
directly downstream from a lamination machine so that the trim is 
continuously delaminated as it is received from the lamination machine. 
Obviously, numerous modifications and variations of the present invention 
are possible in light of the above teachings. It is therefore to be 
understood that, within the scope of the appended claims, the invention 
may be practiced otherwise than as specifically described herein.