Abstract:
A numerically controlled machining center for performing work on a workpiece including a plurality of magazines holding a plurality of tools, each magazine positioned a first distance from an adjacent magazine, a plurality of spindles equal to the number of magazines and movable relative to one another independent of the positions of the magazines, the spindles movable apart from one another in a tool loading position to accommodate large magazine sizes and movable toward one another in a working position to allow the tools to work close together to minimize waste, and a table for supporting a workpiece.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 61/656,621 filed Jun. 7, 2012, the entirety of which is incorporated by reference herein. 
    
    
     TECHNICAL FIELD AND BACKGROUND OF THE INVENTION 
     The present invention relates generally to the field of machine tools, and more particularly, to the field of automated machining centers utilizing multiple tools that simultaneously operate on one or more workpieces. 
     Machine tools have been in use for centuries. Rotary filing machines date at least to the eighteenth century with milling machines appearing a short time thereafter. Automation began in the early twentieth century, and by the late twentieth century computers were commonly utilized to control automation. Presently, it is common for a numerically controlled automated machine tool to operate with multiple tools functioning at the same time on one or more workpieces. 
     For instance, in a manufacturing process where milling of a workpiece is necessary, the workpiece is typically held on a table and the machine utilizes one, two, three, four, or more spindles each securing a tool. The spindles may be connected to one another and move together in parallel motion. The table may move in the x-y plane and the spindles of the machine along the z axis. The table may also move in the x-y plane as well as along another axis or multiple other axes and/or the spindles may also move in the x-y plane. Thus, it is possible to machine a 2-D or 3-D workpiece along multiple axes. 
     As refinement of the computer driven automation of machine tools has advanced, so has the ability to adapt machines for multiple tools. Rather than having multiple machines wherein the spindles of a particular machine each hold only one tool, spindles may be made adaptable to multiple tools. For some time, tools in a spindle were required to be manually changed, for instance, if a tool became damaged or required sharpening/adjustment or if a different tool was desired. With advances in computerized automation, a machine may contain a magazine of tools wherein the spindle is adapted to cooperate with the magazine and automatically change tools as programmed. Magazines are typically located near the spindle, contain multiple tools, and are rotatable such that as it rotates a tool can be removed from the spindle and a different tool placed in the spindle. Spindles may be moved between use and loading positions. 
     Because a spindle may be adaptable to many different sizes and types of tools, the size of the magazines can vary. When magazines are large in order to contain a large number of tools, they gain flexibility in being able to perform many different functions with individual spindles acting in a single machine tool. A magazine may be supplied with tools allowing the spindle to drill, cut, grind, mill, punch, etch, etc., by rotating the magazine to a different position. However, by adding tools to a magazine and thereby increasing magazine size, efficiency of the operation on the workpiece may suffer because large magazines require spindles to be separated by a greater distance. In other words, spacing between spindles is directly impacted by magazine size. Spacing can become an important factor with respect to waste material from a workpiece. For example, four spindles may operate on a flat workpiece, with each spindle cutting a portion of the workpiece. Because of the minimum spacing required between spindles, voids are present between spindles in which the workpiece cannot be worked on, resulting in waste product. 
     Thus, there exists a need for a machining center that permits a wide range of tools to be utilized by each spindle while permitting multiple spindles to function at a relatively close distance to one another, thereby reducing waste. 
     BRIEF SUMMARY OF THE INVENTION 
     It one aspect, the presented invention is directed to a numerically controlled machining center configured to reduce the waste associated with performing work on a workpiece. 
     In another aspect, the machining center includes a plurality of machine tool spindles (hereinafter “spindles”), wherein each spindle is movable and configured to access at least one magazine of a plurality of magazines holding a plurality of tools for working the workpiece. 
     In a further aspect, the center of each of the magazines is located at a first distance apart from the center of an adjacent magazine or magazines. 
     In a further aspect, each spindle is configured to load a selected tool from a magazine and then detach and move toward (i.e. closer) to an adjacent spindle such that once positioned, the center of each spindle is a second distance apart from the center of an adjacent spindle, wherein the second distance is less than the first distance. 
     In a further aspect, loaded, adjacent spindles are closer together than their respective magazines are to adjacent magazines. 
     In a further aspect, the machining center is configured to operate in a tool loading position where the magazines rotate and tools are changed, a working position where tools do work to a workpiece, and an intermediate position where the spindles move through a series of positions from the loading position to the working position or from the working position to the loading position. 
     In a further aspect, in the intermediate position the spindles move in the direction toward one another (i.e., closer together) before starting work on the workpiece, or move away from one another (i.e., further apart) after performing work on the workpiece. 
     In a further aspect, a machining center is provided herein wherein magazines and spindles are respectively arranged in a plane or in a plurality of parallel planes. 
     In a further aspect, a machining center is provided herein wherein the second distance can be programmed to vary from one spindle to another adjacent spindle. 
     In a further aspect, the workpiece is held by a table positioned beneath the spindles that may be numerically programmed to automatically move along one or more of the x and y axes. 
     In a further aspect, the table moves along a plurality of axes and/or at various angles with respect to the spindles. 
     In a further aspect, each of the plurality of spindles may move along one or more of the x, y and z axes. 
     In a further aspect each of the plurality of spindles may move along a plurality of axes and/or at various angles with respect to the table. 
     In a further aspect, the plurality of spindles are surrounded by a debris vacuum system for removing bits of debris collected as a byproduct of the machining process during the working position. 
     To achieve the foregoing and other aspects and advantages, in one embodiment provided herein is a numerically controlled machining center for performing work on a workpiece including a plurality of magazines wherein each magazine holds a plurality of tools for performing work on the workpiece, wherein each magazine is positioned at a first distance from an adjacent magazine determined by the size, number and types of tools held in each magazine, a plurality of spindles, equal in number to the plurality of magazines and mounted for movement relative to one another independent of the positions of the magazines, the plurality of spindles operable for grasping and securing a tool from the magazines while the spindles are spaced from one another, wherein each spindle is moveable to a second distance apart from an adjacent spindle when work is performed on the workpiece, the second distance being less than the first distance for permitting the spindles to work relatively close together to minimize waste, and a support for holding the workpiece. 
     In a further embodiment, the plurality of spindles are movable between a loading position for loading a tool, a working position for performing work on the workpiece, and an intermediate position between the loading position and the working position, wherein the plurality of spindles are farthest apart in the loading position and closest together in the working position. 
     In a further embodiment, the first distance is measured between centers of adjacent magazines and the second distance is measured between centers of adjacent spindles, and wherein the second distance is less than the first distance when the plurality of spindles are positioned in the working position. 
     In a further embodiment, the machining center includes a CNC controller and a PLC controller for controlling rotation of the plurality of magazines, tool loading and movement of the plurality of spindles relative to the magazines and to one another, among other functions. 
     In another embodiment, provided herein is a numerically controlled machining center for performing work on a workpiece including a plurality of magazines holding a plurality of tools, each magazine positioned a first distance from an adjacent magazine, a plurality of spindles equal in number to the number of magazines and movable relative to one another independent of the positions of the magazines, the spindles movable configured to move apart from one another in a tool loading position and movable toward one another in a working position to allow the tools to be spaced apart during tool loading to accommodate for a large magazine size and work close together to minimize waste, and a table for supporting a workpiece. 
     In a further embodiment, the distance between adjacent magazines is greater than the distance between adjacent spindles when the adjacent spindles are positioned in the working position, and the distance between adjacent spindles is greater in the tool loading position than in the working position. 
     In yet another embodiment, provided herein is a method for controlling the loading and movement of spindles in a machining center including the steps of providing a machining center including a plurality of magazines each holding a plurality of tools, a plurality of spindles equal in number to the plurality of magazines and movable relative to the magazines and one another independent of the positions of the magazines, and a table for supporting a workpiece, providing a CNC controller and a PLC controller for controlling rotation of the plurality of magazines, tool loading and movement of the plurality of spindles relative to the magazines and to one another, transferring tools from the plurality of magazines to the plurality of spindles in a loading position of the machining center, and moving the plurality of spindles apart from one another as the plurality of spindles move between the loading position and a working position for performing work on the workpiece. 
     Additional features, aspects and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein. It is to be understood that both the foregoing general description and the following detailed description present various embodiments of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, aspects and advantages of the present invention are better understood when the following detailed description is read with reference to the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a machining center according to one embodiment of the invention and including four spindles, four magazines, a table and two workpieces; 
         FIG. 1A  is a perspective view of a machining center according to another embodiment of the invention and including six spindles, six magazines, a table and two workpieces; 
         FIG. 2  is a top plan view of the machining center of  FIG. 1 ; 
         FIG. 3  is a front elevation view of the machining center of  FIG. 1 ; 
         FIG. 4  is a side elevation view of the machining center of  FIG. 1 ; 
         FIG. 5  is a front perspective view of a machining center illustrating the spindle loading position; 
         FIG. 6  is a front perspective view of a machining center illustrating an intermediate position wherein a tool has been loaded and spindles moving closer together and towards the workpiece; 
         FIG. 7  is a front perspective view of a machining center illustrating first distance (D1) between magazine centers and second distance (D2) between spindle centers in the intermediate position; 
         FIG. 8  is a front perspective view of a machining center illustrating a working position and x- and y-axis movement; 
         FIG. 9  is a front perspective view of a machining center illustrating an intermediate position wherein the plurality of spindles move apart and in a direction away from the workpiece; and 
         FIG. 10  is a front perspective view of a machining center illustrating an intermediate position wherein tools have completed work on the workpiece and are returning to the loading position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the representative embodiments set forth herein. The exemplary embodiments are provided so that this disclosure will be both thorough and complete, and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use and practice the invention. Like reference numbers refer to like elements throughout the various drawings. 
     Referring now to the drawings,  FIGS. 1-4  illustrate a machining center  10  generally including a plurality of spindles  11 , a plurality of magazines  20 , a plurality of tools  31  in each magazine  20 , a table  40 , a set of table rails  41 , a set of spindle rails  12 , a plurality of workpieces  50 , a debris collection hood  60 , and a debris collection conduit  61 . Each spindle  11  is loaded with a preselected tool  32  from the plurality of tools  31 . The machining center  10  is shown  FIGS. 1-4  in a tool loading position with the spindles  11  acting in cooperation with the magazines  20 . Tools  31  are loaded into a magazine  20  and are ready to be transferred from the magazine  20  to the spindles  11 . 
     One or more workpieces  50  are loaded onto the table  40 . Table  40  has table rails  41  that allow the table to move along the y axis. The machining center  10  may additionally be configured to move the table along one or more the x, y and z axes. The plurality of spindles  11  move along a set of spindle rails  12  along the x axis. The machining center  10  may also be configured to move the spindles along one or more of the x, y and z axes, as shown in  FIG. 6 .  FIGS. 1-4  also show debris conduits  61  that carry debris collected from debris collection hoods  60  as the spindles  11  and tool  32  perform work on the workpieces  50 .  FIG. 1A  shows an alternative embodiment of a machining center including additional spindles  11 . 
     The spindles  11  of the machining center  10  are configured to be numerically programmed to move closer to each other after disengaging from the magazines  20 .  FIGS. 5-10  show various stages of movement of the spindles between a tool loading position (see  FIGS. 5 and 6 ) and a working position (see  FIGS. 7 and 8 ), through a series of intermediate positions (see  FIG. 9 ). In other words, the spindles  11  are positioned farthest apart in the tool loading position to accommodate for large magazine size and spacing, and closest together in the working position to permit the tools to operate close together to minimize waste. In the intermediate positions the tools may be moving apart and/or in the direction of one of the magazines and the workpiece. 
       FIG. 5  shows the machining center  10  where the spindles  11  have begun to disengage from the magazines  20 . Tools  31  remain in the magazines  20  and tools  32  have been loaded into the spindles  11 . The magazines  20  are, and remain throughout the movement, a first distance D1 apart from one another. Distance D1 may be determined by one or more of magazine size, tool size, types of tools in the magazines, number of tools in the magazines, etc. 
       FIG. 6  shows the machining center  10  where the spindles  11  have begun to move downward and towards the right as part of the intermediate position. The distance D1 between the magazines  20  remains the same. 
       FIG. 7  shows the machining center  10  where the spindles  11  have moved further downward and to the right such that the distance D2 between the spindles is smaller (i.e., less) than the distance D1 between the magazines  20 . The tools  32  in the spindles  11  are nearly in contact with the workpiece  50  resting on the table  40 . Also, the debris collection hood  60  surrounds the tool  32  so as to prepare to collect debris produced from the machining process. This debris will be collected through the debris collection hood  60  and be passed and channeled through the debris collection conduits  61 . 
       FIG. 8  shows the machining center  10  in the working position where tools  32  are loaded in the spindles  11  and are performing work on the workpiece  50 . The debris collection hoods  60  are vacuuming debris and passing the debris through the debris collection conduit  61 . The magazines  20  remain the same distance D1 apart and the spindles are a smaller distance D2 apart from one another. The table  40  moves the workpiece  50  along a y axis. The spindles  11  move together along the spindle rails  12  along an x axis. The magazines  20  remain loaded with additional tools  31 . 
       FIG. 9  shows the machining center  10  in the intermediate position, returning from the working position shown in  FIG. 8  to the loading position of  FIG. 5 . The tool  32  that has completed working on the workpiece  50  is still loaded in the spindle  11 . The debris collection hood  60  is moving upward with the spindle  11 . Tools  31  remain in the magazine  20  and are ready to be loaded into the spindles  11  once the spindles  11  reach the loading position and unload existing tools  32  back into the magazines  20 . 
       FIG. 10  shows the machining center  10  in the intermediate position, returning from the working position shown in  FIG. 8  to the loading position shown in  FIG. 5 . The spindles  11  are moving upward and to the left. The tool  32  that has completed working on the workpiece  50  is still loaded in the spindle  11 . The debris collection hood  60  is moving upward and leftward with the spindle  11 . Tools  31  remain in the magazines  20  and are ready to be loaded into the spindles  11  once the spindles  11  reach the loading position and unload existing tools  32  back into the magazines  20 . 
     Each magazine  20  and spindle  11  may be provided with a respective computer numeric controlled (CNC) controller and respective programmable logic controller (PLC), which may also be single controllers with different channels. The controllers receive signals (information) relating to the current status and positional information of the spindles and magazines. On the basis of this information, the PLC controller controls the removal of a tool from, and the return of a tool to, its respective magazine and the loading and unloading of the spindles. CNC and PLC controllers are well known in the field of machine control. 
     The foregoing description provides embodiments of the invention by way of example only. It is envisioned that other embodiments may perform similar functions and/or achieve similar results. Any and all such equivalent embodiments and examples are within the spirit and scope of the present invention and are intended to be covered by the appended claims.