Patent Publication Number: US-10759073-B2

Title: Cutting machine

Description:
RELATED APPLICATIONS 
     This application is related to Australian Provisional Patent Application No. 2015904093 entitled “Cutting machine” and filed on 8 Oct. 2015 in the name of Precision Foam Technologies Pty Ltd, the entire content of which is incorporated as if fully set forth herein. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     Field of the Disclosure 
     The present disclosure relates to a cutting machine for cutting foam products. 
     Background of the Disclosure 
     In the foam product manufacturing industry, foam products are cut to a desired shape in a number of different ways. Complex shapes often require multiple pieces of foam to be individually cut and then bonded together to form the complex shape. 
     One method of producing integral complex shapes in a consistent manner involves compression cutting, which is used to cut foam products out of foam blocks or sheets. The foam is cut while being compressed between two surfaces, typically between a compression plate and a template or between a roller and a moving template. The foam expands into the template and by cutting the foam adjacent the template, the foam that has expanded into the template can be cut away. This leaves a complimentary pair of foam by-products that generally reflect the shape of the template. 
     As the foam is compressed between the compression member and the template, the foam expands into recesses in the template and consequently, different portions of the foam product undergo different degrees of compression, depending on the depth of recesses in the template. This creates a varying compression profile in the foam product. Accordingly, as the foam product is cut, the varying compression profile in the foam product creates a cut profile that generally reflects the shape of the template. 
     The definition of surface details that can be achieved with compression cutting becomes more limited as the density of the foam increases. This is due to the rapidly increasing compressive forces required as foam density increases. 
     The high levels of compression lead to high levels of abrasive pressure between the cutting blade and the compressed foam material. This can result in abrasion of the foam surface and can create undesirable dust. The high density of foam material presented to the cutting blade results in accelerated wear of the blade and blade supporting structures on a compression cutting machine. 
     A high level of compression can also cause excessive levels of distortion of the foam material, above that required to generate a particular profile and this can contribute to undesirable variation in the profile of the cut part. 
     It is also not possible to cut certain complex shapes using compression cutting, due to the compressive forces required to force the foam material into small cavities in the template. It is also difficult to produce products that require fine detail interior apertures passing through the product. 
     There is a need in the art to substantially overcome or at least ameliorate one or more of the above disadvantages, or to provide a useful alternative. 
     SUMMARY 
     Embodiments of the disclosure pertain to a cutting machine. 
     In a first aspect, the present invention provides a cutting machine having: a blank holder adapted to receive a foam blank, the blank holder comprising: a first component having a die projection formed on a front surface of the first component; a second component having a cutting surface, an opposite back surface, and an aperture passing from the cutting surface through the second component to the back surface, the aperture corresponding in cross-sectional shape to the external shape of a desired cut foam product; and a third component having an uninterrupted planar cutting surface and an opposite back surface, the third component being releasably securable in a deployed location in the aperture of the second component, wherein the cutting surfaces of the second and third components are coplanar and form a peripheral aperture between the second and third components, the aperture extending around the entire lateral periphery of the third component; and a cutting blade, wherein at least one of the cutting blade and the blank holder is mounted for movement relative to the other; wherein at least one of the first component and the second component is mounted for movement relative to the other and the third component remains located in the aperture of the second component during said movement, wherein said movement ranges between a first configuration, in which the first and second components are distal to one another, and a second configuration, in which the first and second components are proximal to one another, with the front surface of the first component opposing the back surface of the second component, and in which the die projection of the first component is aligned with the aperture of the second component, so as to press foam material of the foam blank through the aperture to protrude beyond the cutting surfaces; wherein the cutting blade is adapted to pass across the cutting surfaces of the second and third components in the second configuration to cut the protruding foam away from the foam blank; and wherein the die projection has raised or flared edges on a leading edge of the die projection with respect to a blade vector of the cutting blade. 
     In a preferred embodiment, the blank holder is mounted for movement relative to the cutting blade, which remains in a fixed position. 
     Preferably, the first component is mounted for movement relative to the second and third components. 
     In a preferred embodiment, the first component is a base plate, the second component is an outer plate and the third component is an inner plate and wherein the base plate is mounted in the blank holder for sliding movement between the first configuration and the second configuration. 
     Preferably, the inner plate is independently moveable between a retracted position in which the inner plate is spaced away from the outer plate and a deployed position in which the inner plate is located within the aperture of the outer plate. 
     In a preferred embodiment, the inner plate has a stem extending substantially normal to the back surface and the base plate has a central hole adapted to receive the stem of the inner plate. 
     Preferably, the blank holder further comprises a locking mechanism adapted to lock the stem of the inner plate to the blank holder and retain the inner plate in the deployed position. 
     In a preferred embodiment, the cutting machine further comprises an electromagnetic carrier adapted to electromagnetically hold the inner plate, the electromagnetic carrier being movable to move the inner plate between the retracted and deployed positions. 
     Preferably, the blank holder includes a blank support adapted to receive and locate a foam blank between the first component and the second component in a predetermined alignment with the aperture of the second component. 
     In a preferred embodiment, the die projection has raised or flared edges on a leading edge of the die projection with respect to the cutting blade. 
     Preferably, the cutting machine further comprises a compression member adapted to apply a compressive force, normal to the cutting surfaces, to foam material of the foam blank projecting through the peripheral aperture while the cutting blade passes across the cutting surfaces. 
     These and other embodiments, features and advantages will be apparent in the following detailed description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full understanding of embodiments disclosed herein is obtained from the detailed description of the disclosure presented herein below, and the accompanying drawings, which are given by way of illustration only and are not intended to be limitative of the present embodiments, and wherein: 
         FIG. 1  depicts a cut foam product; 
         FIG. 2  is a tailored foam blank for producing the cut foam product of  FIG. 1 ; 
         FIG. 3  is an exploded view of isolated components of a cutting machine; 
         FIG. 4  depicts a cutting machine for cutting the foam product of  FIG. 1  from the foam blank of  FIG. 2 ; 
         FIG. 5  depicts the cutting machine of  FIG. 4  in a further configuration; 
         FIG. 6  is a schematic cross-sectional view of a portion of the cutting machine in a first configuration; 
         FIG. 7  is a cross-sectional view of a portion of a cut foam product resulting from the configuration shown in  FIG. 6 ; 
         FIG. 8  is a schematic cross-sectional view of a portion of the cutting machine in a second configuration; 
         FIG. 9  is a cross-sectional view of a portion of a cut foam product resulting from the configuration shown in  FIG. 8 ; 
         FIG. 10  is a schematic cross-sectional view of a portion of the cutting machine in a third configuration; 
         FIG. 11  is a cross-sectional view of a portion of a cut foam product resulting from the configuration shown in  FIG. 10 ; 
         FIG. 12  is a schematic cross-sectional view of a portion of the cutting machine in a fourth configuration; 
         FIG. 13  is a cross-sectional view of a portion of a cut foam product resulting from the configuration shown in  FIG. 12 ; 
         FIG. 14  is a schematic cross-sectional view of a portion of the cutting machine in a fifth configuration; and 
         FIG. 15  is a cross-sectional view of a portion of a cut foam product resulting from the configuration shown in  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a complex foam product  100  that can be produced using a particular embodiment of a cutting machine of the present disclosure. The complex foam product  100  has a generally ring-shaped body  102  with a central aperture  104 . An upper surface  106  of the foam product  100  has curved edges  108 , a series of radial channels  110  and a semi-circumferential groove  112  formed in the upper surface  106 . 
     The first step in producing the complex foam product  100  is to design a tailored blank of foam material  200 , as depicted in  FIG. 2 . For best results, the tailored blank  200  should have an outer shape that reflects a general approximation of the basic outer shape of the foam product  100 . For example, the tailored blank  200 , shown in  FIG. 2 , is disc-shaped and has a central hole  202  extending through the tailored blank  200 . Forming an appropriately shaped tailored blank  200  minimises foam waste and helps to avoid unintended distortion in the tailored blank during the protrusion phase of the cutting process, which can affect the quality of the cut foam product  100 . 
     The foam product  100  is cut from the tailored blank  200  using the cutting machine  300  depicted in  FIGS. 4 and 5 .  FIG. 3  depicts some of the basic components of the cutting machine  300 , which includes a first component, referred to hereinafter as a base plate  302 , a second component referred to hereinafter an outer plate  304 , and a third component referred to hereinafter as an inner plate  306 . 
     The base plate  302  has a die projection  310  projecting from a front surface  315  of the base plate  302 . The die projection  310  has a shape designed to produce the required features of the desired cut foam product  100 . In this example, the die projection  310  comprises a ring shaped projection  312  having an upper surface  314  with a series of radial channels  316  and a semi-circumferential groove  318 . The base plate  302  also has a central hole  320 , passing through the base plate  302 . 
     The outer plate  304  has a front cutting surface  321 , an opposing back surface  322  and a circular aperture  325  with a slightly larger diameter than the die projection  310 . The aperture  325  determines the external size and shape of the desired cut foam product  100  and can be any shape or size desired. 
     The inner plate  306  has a front surface  323  and an opposing back surface  327  and has a slightly smaller diameter than the internal diameter of the ring-shaped die projection  310 . Likewise, the inner plate  306  can be any shape or size in order to produce apertures in the cut foam product  100  having specific shapes and sizes. Multiple inner plates  306  can also be used to produce multiple apertures in the cut foam product  100 . 
     The cutting machine  300  is depicted in  FIG. 4 , in a blank loading configuration. The cutting machine  300  has a blank holder  324  incorporating the outer plate  304 . The base plate  302  of the cutting machine  300  is mounted for sliding movement relative to the blank holder  324 , with the base plate  302  remaining parallel to the outer plate  304  and moving normal to the front surface  315  of the base plate  302  and the front surface  321  of the outer plate  304 . The die projection  310  is axially aligned with the circular aperture  325  and the base plate  302  is axially movable between a distal position, in which the base plate  302  is spaced away from the outer plate  304  such that a tailored foam blank  200  can be loaded between the outer plate  304  and the base plate  302 , and a proximal position, in which the base plate  302  compresses the tailored foam blank  200  between the base plate  302  and the outer plate  304 . 
     Although not shown in the drawings, a custom shaped bracket is provided on the rear surface of the outer plate  304  within the blank holder  324 . The custom bracket is shaped to receive the tailored blank  200  and to hold it in correct alignment with the aperture  325  against the inside surface of the outer plate  304 . 
     The inner plate  306  is attached, or integral with, a stem  326 . The inner plate  306  and stem  326  are electromagnetically held by an electromagnetic carrier  328 , which is axially movable between a retracted position, shown in  FIG. 4  in which the electromagnetic carrier  328 , inner plate  306  and stem  326  are spaced away from the blank holder  324 , and a deployment position, in which the electromagnetic carrier  328  is adjacent to the plane defined by the front surface  321  of the outer plate  304 . In the deployment position, the electromagnetic carrier  328  locates the inner plate  306  in the circular aperture  325 , such that the front surface  323  of the inner plate  306  is coplanar with the front surface  321  of the outer plate  304  and the stem  326  passes through the central hole  320  in the base plate  302 . This position is depicted in  FIG. 5  and forms a peripheral aperture  329  between the inner plate  306  and outer plate  304 , which extends around the entire lateral periphery of the inner plate  306 . A releasable locking mechanism, such as a bolt or clamp, is provided in the blank holder  324  to engage the stem  326  and lock the stem  326  and inner plate  306  in a deployed position.  FIG. 5  shows the inner plate  306  and stem  326  in the deployed position, once the electromagnetic carrier  328  has been demagnetised and returned to the retracted position. 
     The cutting blade  330  is depicted in  FIGS. 4 and 5  and is typically a smooth-edge ground bevel blade. The cutting blade  330  and the blank holder  324  are movable one relative to the other such that the cutting blade  330  passes across the front surfaces  321 ,  323  of the outer plate  304  and inner plate  306 . In one embodiment, the cutting blade  330  is stationary and the blank holder  324  moves relative to the cutting blade  330 . In other embodiments, a moving cutting blade  330  and a stationary blank holder  324  may be employed. 
     A compression member  332  is movable between a retracted position, as shown in  FIG. 4  in which the compression member  332  is distal to the blank holder  324 , and a deployed position, in which the compression member  332  is proximal to the blank holder  324 . 
     In operation, a tailored foam blank  200  is loaded into the custom shaped bracket on the inside of the outer plate  304  and held in place by the bracket. The electromagnetic carrier  328  then moves from the retracted position to the deployment position and locates the inner plate  306  and stem  326  in the deployed position. The locking mechanism is then used to lock the stem  326  in the blank holder  324  and maintain the inner plate  306  in the deployed position. The electromagnet in the carrier  328  is then switched off, releasing the inner plate  306  from the electromagnetic carrier  328  and the electromagnetic carrier  328  is moved back to the retracted position as shown in  FIG. 5 . 
     The base plate  302  is then moved toward the outer plate  304 , compressing the tailored blank  200  between the base plate  302  and the outer plate  304  and inner plate  306 , causing the foam to protrude through the peripheral aperture  329  between the outer plate  304  and the inner plate  306 . This is shown in cross-section in  FIG. 6 . The compression member  332  is then moved from the retracted position to the deployed position, pressing into the protruding foam. This is shown in cross-section in  FIG. 8 . 
     The blank holder  324  is then moved into a cutting alignment position such that the cutting blade  330  is directly adjacent to the front surface  321  of the outer plate  304 . The blank holder  324  is then moved across the cutting blade  330  in a transverse direction, such that the cutting blade  330  runs across the front surfaces  321 ,  323  of both the outer plate  304  and the inner plate  306 . In doing so, the cutting blade cuts through the protruding foam along the plane defined by the front surfaces  321 ,  323  of the outer and inner plates  304 ,  306 , resulting in the cut foam product  100  being cut from the tailored foam blank  200 . 
       FIG. 7  and  FIG. 9 , respectively, depict cross-sections of the foam product  100 ,  100   a  that result from cutting the same foam blank in the cutting machine  300 , without applying the compression member  332 , as depicted in  FIG. 6 , and by applying the compression member  332 , as depicted in  FIG. 8 . As can be seen by comparing the cut foam products  100 ,  100   a , and their corresponding grooves  112 ,  112   a , applying the compression member  332  results in a deeper, more defined groove  112  than not applying the compression member  332 . This is because more of the foam material is pressed into the corresponding groove feature  318  of the die projection  310 . 
     When the foam blank  200  is compressed between the base plate  302  and the outer plate  304 , the foam material between the edges of the die projection  310  and the edges of the aperture  325  experiences a lower compressive force, creating the curved edges  108  of the cut foam product  100 . For certain applications, it may be desirable to provide a cut foam product  100  with more or less of a rounded edge profile.  FIG. 10  depicts a cutting machine, in which the die projection  310  is provided with a shim portion  340  that extends laterally, so that the edge of the shim portion  340  approximately aligns with the edge of the peripheral aperture  329 . This results in more of the foam material at the edges being pressed into and through the peripheral aperture  329 , which results in the cut foam product  100   b , as depicted in cross-section in  FIG. 11 , having less rounded and more defined edges  108   b . It also allows the cut foam product  100   b  to be produced from a much smaller tailored blank  200   b , which provides the benefit of improved material yield. The shim portion  340  may be one or more components added to the die projection  310  or may be integrally formed as part of the die projection  310 . 
     The cutting blade  330  runs continuously in a longitudinal running direction such as indicated by the arrows in  FIG. 4 . During cutting of the foam product  100 , the running direction of the cutting blade  330  and the relative movement of the tailored blank  200  across the cutting blade  330  (or the blade  330  across the blank  200 ) creates a blade vector V, being the resultant force, acting on the tailored blank  200 . The force of the blade vector V applied by the cutting blade  330  can have a distorting effect on the tailored foam blank  200 . The degree of distortion can be a function of the foam material hardness or stiffness. As shown in exaggerated example in  FIGS. 12 and 13 , this can result in the cut foam product  100   c  having a slightly deformed or irregular shape to the leading edge  108   c  of the cut foam product  100   c . In order to correct this issue, as shown in  FIGS. 14 and 15 , the present disclosure provides a cutting machine  300  having a die projection  310  with an asymmetric profile. Relative to the blade vector direction V, the leading edges  350  of the die projection  310  are raised or flared to provide slightly greater protrusion of the foam blank  200  at each leading edge  350 . As shown in  FIG. 14 , the raised or flared leading edges  350  of the die projection  310  result in the same or corresponding surface profile at the leading edge  108   d  as the trailing edge  109   d  of the cut foam product  100   d . The asymmetric profile balances the effect of the blade vector V and produces a symmetrical and evenly cut foam product  100   d . Alternatively, or in conjunction, the corresponding trailing edges may be relieved relative to the blade vector V to provide the same effect. The application of such an asymmetric die projection allows faster cutting strokes thereby improving cutting cycle times and improving the economics of the cutting process. 
     As the cutting blade  330  approaches the end of the cutting process, only a small amount of foam material joins the cut foam product  100  to the foam blank  200 . In this situation, the lateral force of the cutting blade  330  can draw extra foam material through the aperture  325  causing the cut foam product to have an undesired variable surface shape and dimension. This can be prevented by having a stop member abutting the protruding foam material, in a direction opposed to the base plate  302  near where the cutting blade exits the foam material. 
     Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.