Patent Application
20100038037
1. Field of the Invention
This invention relates to extruded sheets and, more particularly, to an apparatus for continuously applying a film to a bottom side of an extruded sheet layer.
2. Background Art
Extruded sheets are formed for a multitude of different uses. Certain products require the application of a film layer to the bottom side of an extruded sheet layer.
In one known system configuration for making sheets of this type, film rolls are stored downstream of a roll stack and film is guided therefrom continuously upstream to an appropriate lamination location on the roll stack. This film supply location may add undesirably to the overall lengthwise extent of the system and may further require an elaborate structure to both route the film to the roll stack and thereafter route the extruded layer with the applied film past the roll supply station to the downstream end of the apparatus where the end product is accumulated.
This type of equipment has also generally been made with a fixed, skeletal frame between the upstream and downstream ends thereof. A film supply station, extruder assembly, roll stack, etc. are all integrated into this framework. While this configuration performs effectively, in the event that there is a malfunction, or regular maintenance needs to be conducted, it may be difficult to access particular components. For example, if access to the roll stack is required, portions of the extruder may have to be disassembled to make this possible.
While these problems have existed and persisted for years, the industry has contended with them because there have not existed viable alternatives to these basic structures that would address and potentially overcome the noted problems.
In one form, the invention is directed to an apparatus for applying a film to a bottom side of an extruded sheet. The apparatus has an upstream end and a downstream end to which a completed product is directed. The apparatus has: an extruder assembly for forming an extruded sheet; a roll stack assembly with a first plurality of rolls against which an extruded sheet is formed by the extruder assembly and guided as the extruded sheet is advanced towards the downstream end of the apparatus; and a first station for a supply of film that can be applied to the bottom side of an extruded sheet formed by the extruder assembly at the roll stack assembly. The first station is upstream of the roll stack assembly.
In one form, the apparatus may be provided in combination with a supply of film at the first station.
In one form, the extruder assembly projects over the supply of film at the first station.
In one form, at least part of each of the extruder assembly and first station for the supply of film is incorporated into a first module that is a unit that is separate from the roll stack assembly.
In one form, the first module further has a second plurality of rolls against which film from the supply can be placed selectively in a manner to alternatively guide film from the supply towards: (a) a first primary lamination/nip point on the roll stack assembly; and (b) a second/secondary lamination/nip point on the roll stack assembly that is spaced from the first/primary lamination/nip point.
In one form, the first/primary lamination/nip point is above the supply of film.
In one form, the first module includes a second plurality of rolls against which film from the supply can be placed selectively in a manner to guide film from the supply towards a first lamination/nip point on the roll stack assembly. The extruder assembly includes a sheet die that is configured to deliver material to form an extruded sheet with a top side and bottom side at the first lamination/nip point at which the film can be applied to the bottom side of the extruded sheet.
In one form, the first module further includes a second plurality of rolls against which film from the supply can be placed selectively in a manner to guide film from the supply towards one lamination/nip point on the roll stack assembly. The extruder assembly has a sheet die that is configured to deliver material to form an extruded sheet with a top side and bottom side at another lamination/nip point that is upstream of the one lamination/nip point. The film is capable of being applied to the bottom side of the extruded sheet.
In one form, the apparatus may be provided in combination with an extruded sheet formed by the extruder assembly.
In one form, the extruded sheet is made from a plastic material.
In one form, the roll stack assembly is part of a second module that is a unit that is separate from the first module.
In one form, the supply of film includes a first roll of the film on the first module.
The supply of film may include a second roll of the film on the first module.
In one form, the extruder assembly has a lengthwise extent between upstream and downstream ends of the first module and the film rolls reside within the lengthwise extent of the extruder assembly.
In one form, the film is directed in a downstream direction up to and against one of the rolls in the first plurality of rolls at the first/primary lamination/nip point.
In one form, the film is directed in a downstream direction up to and against one of the rolls in the first plurality of rolls at the second/secondary lamination/nip point.
In one form, the apparatus has a substantially straight configuration between the upstream and downstream ends.
In one form, the second module additionally has at least one pull roll that is configured to draw a web, including the film and an extruded sheet formed by the extruder assembly, in a downstream direction.
In one form, at least one of the first and second modules is movable relative to the other of the first and second modules to expose, for access, upstream components on the second module and downstream components on the first module.
In one form, the roll stack has a widthwise extent and the first and second modules are relatively repositionable to expose the full widthwise extent of the roll stack.
In
The apparatus 10 consists of an extruder assembly 26, of conventional construction, for delivering an appropriate material, such as plastic, to form the extruded sheet 16.
The apparatus 10 further consists of a roll stack assembly 28 made up of a plurality of rolls, and in this case, three chrome rolls 30,32,34 against which the extruded sheet 16 is formed by the extruder assembly 26. The extruded sheet 16 is guided by the rolls 32,34 as it is advanced towards the downstream end 20 of the apparatus 20.
The apparatus 10 further consists of an unwind station at 36 in which one, and in this case two, separate rolls 38,40 of film 12 are mounted. One of the rolls 38,40 is active, with the other available as a backup upon exhaustion of film 12 from the one roll. The unwind station 36 is located upstream of the roll stack assembly 28.
The apparatus 10 is made up of separate first and second modules 42,44 that are self-contained units, each separate from the other. As explained below, at least one of the modules 42,44 is movable relative to the other to permit strategic access to components with the apparatus 10 in a down state.
The first module 42 consists of a frame 46 with a stepped base 48, with a higher base portion 50 and a lower base portion 52.
The film rolls 38,40 are separately mounted upon stands 54,56, respectively, in conventional fashion. A guide roll assembly 58 resides between the stands 54,56 to direct film 12 from either roll 38,40 in a transverse path initially downwardly and then horizontally towards the downstream end 20 of the apparatus.
The extruder assembly 26 has a conventional construction and is supported cooperatively by the base portion 50 and separate vertical supports 60,62 projecting upwardly from the lower base potion 52. The extruder assembly 26 has a sheet die 64 with a material discharge 66 for delivery of material against the roll 32 at a primary lamination/nip point 68 at a vertical location between the rolls 30,32.
As depicted, a main extruder component 70, supported upon the base portion 50 and vertical supports 60, projects over and spans fully the lengthwise extent of the unwind station 36 and the film rolls 38,40 thereat. Thus, the film rolls 38,40 lie fully within the lengthwise extent of the extruder assembly 26, and more specifically the main extruder component 70, so as to afford a compact, lengthwise design. At the same time, the film rolls 38,40 reside at a convenient height for installation and replacement.
The apparatus 10 further includes a pull roll assembly 72 at the downstream end of the apparatus 20. At least one roll 73 on the assembly 72 is designed to draw the completed product 22, in web form, away from the roll stack assembly 28 and towards the downstream end 20 of the apparatus 10.
A plurality of strategically placed rolls 74,76,78,80,82 is provided downstream of the rolls 30,32,34 to control web tension and situate the web 22 to be pulled and advanced by the pull roll assembly 72.
The first module 42 has a plurality of rolls, including the rolls 86,88,90,92, defining the guide roll assembly 58, and rolls 96,98,100,102, 104,106, in addition to the rolls on the guide roll assembly 58, against which film 12 from the rolls 38,40 can be trained to direct the film 12 selectively in a downstream direction to either the primary lamination/nip point 68, previously described, or a secondary lamination/nip point 110, between the rolls 34,102 beneath the primary lamination/nip point 68. In each configuration, the film 12 is directed in a downstream direction up to and against each of the lamination/nip points 68,110.
In one configuration, shown in
Alternatively, as shown partially in dotted lines in
Typically, at the primary lamination/nip point, molten polymer discharging from the sheet die 64 is combined with the film 12. This produces a very strong bond. However, lamination at this location may not be appropriate when the film 12 is temperature-sensitive or very high temperature polymers are used. Under those circumstances, the film 12 may be prone to melting or otherwise becoming damaged due to the high temperatures encountered at the primary lamination/nip point 68. The secondary lamination/nip point 110 thus offers an alternative location whereby the temperature problems can be avoided while still producing an effective bond between the applied film 12 and extruded sheet 16.
As depicted in
At least one, and potentially both, of the modules 42,44 are moveable, each relative to the other, to produce a system configuration that allows access to components directly between the modules 42,44.
In
Alternatively, the modules 42,44 can be relatively angularly moved, as depicted by the dotted line position for the second module 44 in
In
Further, the depicted path for the film 138 makes it difficult to set the system up. One exemplary problem area, in terms of training the film 138 around/against rolls that will establish its path, is at the bottom chrome roll on the roll stack assembly 134.
As can be seen, the components on the apparatus 130 are all integrated into the same skeletal framework 150 that extends fully between the upstream and downstream ends of the apparatus. As a result, if access to a sheet die 152 is required, a substantial disassembly of components may be required to allow this to occur.
The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.
