Patent Application
20070198123
This invention broadly relates to a system and method for measuring at least one characteristic of a machining tool in a numerically controlled (NC) machine or machining operation using a smart image acquisition device. This invention further broadly relates to a system and method for using the acquired data generated by the smart image acquisition device to control the operational use of the measured machining tool by the NC machine, or to determine the operational condition of the measured machining tool or NC machine.
Automatic numerical controlled machines are used to perform a variety of machining operations, such as milling, boring, drilling, reaming, honing, and threading. For each such operation, the exact location, amount of material to be removed, finished dimension, diameter and depth of holes to be machined, etc., are predetermined and translated into a numerical program or code which is stored on magnetic tape, perforated tape, cards, other data storage device (e.g., computer hard disk), etc. The machine is thus “numerically controlled” (NC) to perform many machining operations automatically without the requirement for human operators in constant attendance. See, for example, U.S. Pat. No. 4,151,642 (Holland et al.), issued May 1, 1979; commonly assigned U.S. Pat. No. 4,382,215 (Barlow et al.), issued May 3, 1983; commonly assigned U.S. Pat. No. 4,816,729 (Carlson), issued Mar. 28, 1989; and commonly assigned U.S. Pat. No. 5,189,624 (Barlow et al.), issued Feb. 23, 1993, for some illustrative NC machines and systems.
Although cutting or other removal of material occurs automatically in NC machining systems, numerous manual operations may still be required, primarily for measuring the machined dimensions, for making cutter adjustments using an ordinary numerical control cutter offset, etc. For example, manual measurements and adjustments of the cutting tool may be necessary to take into account a large number of variables, such as wear of the cutting tool, repositioning and/or replacement of the cutting tool, as well as dimensional changes of the cutting tool, the work piece or the machine itself due to such factors as heating, deflection under load, etc.
In a typical operation carried out with an NC machining tool such as a cutting tool, certain adjustments (e.g., tool offsets) may need to be manually implemented by the operator after the machine is set up for the manufacture of a particular work piece or part. Prior to the start of the machining operation, the operator may need to advance the cutting tool to a tool setting surface and determine the tool position by manually measuring the space between the tool and the reference surface. This is may done with a piece of shim material, or the like and such measurements may then form the basis for manually making tool offsets. Where the machining tool includes a tool mechanism such as a multiple tool turret, this operation may need to be carried out separately for each tool, as well as for each of the axes (of motion) of the machine. Prior to making the final or finishing cut for a particular work piece surface, the various dimensions of the semi-finished work piece surface may need to be measured by using a hand-held gauge. This enables the operator to determine the required offset of the cutting tool which is used for the finishing cut. After the finishing cut is made, the work piece may need to be checked again with the hand-held gauge in order to measure the conformance of the actual dimensions of the finished surface to the desired dimensions.
Many NC machining operations may also require dimensional information about the machining tool, for example, the particular gauge length of a cutting tool, to be entered into the NC machining control. The gauge length may be manually measured prior to loading of the machining tool and manually entered into the NC machining control. Manual measurement operations are individually very time-consuming and take up a significant amount of the total time required to machine a particular work piece to the desired dimensions, thus limiting the manufacturing capacity of the machining tool. Any reduction of the capacity of the machining tool becomes a matter of economic significance because of the costs associated with NC machining systems.
In addition, all such manual operations are prone to introduce errors into the manufacturing process. Instead of using manual measurements, the relevant characteristic of the machining tool, for example the gauge length of a cutting tool, may be measured on the NC machine using a tool probe. See U.S. Pat. No. 4,151,642 (Holland et al.), issued May 1, 1979, which discloses a tool probe assembly for measuring the dimensions of a machining tool. In addition to gauge length, other dimensional characteristics of the cutting tool, such as the diameter, corner radius, etc., may also be measured by a tool probe to ensure that the correct tool has been loaded by the NC machine. Tool probing may be performed under the control of the NC machine controller and thus comprise part of the NC machine system. Probing tools on the NC machine tend to be more accurate and less prone to error for identifying correct gauge lengths when compared to manual methods. Even so, tool probing is still a relatively slow process for gauging the length and other characteristics of a machining tool, such as a cutting tool. See also commonly assigned U.S. Pat. No. 4,571,841 (Campbell), issued Feb. 25, 1986 and U.S. Pat. No. 4,592,146 (Campbell), issued Jun. 3, 1986, for other pre-gauging devices for cutting tools.
Accordingly, it would be desirable to provide a system and method for machining tools, such as cutting tools, of an NC machine that has the ability to: (1) measure the relevant characteristics of the machining tool, such as gauge length, etc., more quickly than manual methods or conventional tool probes; (2) with a degree of accuracy at least comparable to that of conventional tool probes; as well as (3) to determine (e.g., verify) from such measurements: (a) whether the machining tool is appropriate or correct for the machining operation to be performed; (b) the appropriateness of other operational uses of the machining tool; (c) how the operational uses of the machining tool should be controlled; or (d) what the operational condition of the machining tool and/or NC machine is.
An embodiment of this invention is broadly directed at a system comprising:
Another embodiment of this invention is broadly directed at a system comprising:
Another embodiment of this invention is broadly directed at a method comprising the following steps:
Another embodiment of this invention is broadly directed at a method comprising the following steps:
As used herein, the term “numerically controlled machine” or “NC machine” refers to a machine that carries out one or machining operations with one or more machining tools where the machining operation(s) to be performed is predetermined and translated into a numerical code, computer instructions, etc., which may be stored on magnetic tape, perforated tape, computer cards, computer software, computer hardware, etc. Illustrative examples of NC machines are disclosed, for example, in U.S. Pat. No. 4,151,642 (Holland et al.) issued May 1, 1979; commonly assigned U.S. Pat. No. 4,382,215 (Barlow et al.), issued May 3, 1983; commonly assigned U.S. Pat. No. 4,816,729 (Carlson), issued Mar. 28, 1989; and commonly assigned U.S. Pat. No. 5,189,624 (Barlow et al.), issued Feb. 23, 1993, the relevant disclosures of which are incorporated herein by reference.
As used herein, the term “NC machine controller” refers to that component or portion of the NC machine that controls the operation of the NC machine.
As used herein, the term “machining tool” refers to any tool used by a NC machine to carrying out a machining operation. Some examples of machining tools include but are not limited to, mills (e.g., cutting mills, end mills, etc.), reamers, drills, bores, honing devices, threading devices, lathes, etc.
As used herein, the term “measured machining tool” refers to a machining tool measured by a smart image acquisition device.
As used herein, the term “transaction” refers to a request transmitted to a smart image acquisition device as to which characteristics and measurements of the machining tool are to be obtained. A transaction may also include an identification number (ID), known characteristics of the tool, how the tool is to be positioned and/or oriented for measuring characteristics, etc.
As used herein, the term “characteristic” refers to any parameter, quality, shape, configuration, design, size, length, width, thickness, height, composition, property, structure, feature, attribute, arrangement, order, orientation, etc., or any combination thereof of a machining tool that may be measured by a smart image acquisition device.
As used herein, the term “relevant characteristic” refers to any characteristic measured by a smart image acquisition device that may be used to control the operational use of a machining tool, or may be used to determine the operational condition of a machining tool or NC machine.
As used herein, the term “smart image acquisition device” refers to a device that is capable of taking, obtaining, acquiring, generating, etc., an image of a machining tool being measured and optionally converting that image into a format (e.g., digital format) such that measurement data that is taken, obtained, acquired, generated, etc. by the smart image acquisition device may be evaluated, for example, by a machining tool program. Suitable smart image acquisition devices include, but are not limited to smart cameras, etc.
As used herein, the term “data” refers to any information, image, etc., taken, acquired, obtained, generated, etc., by measuring one or more characteristics of a machining tool by using a smart image acquisition device.
As used herein, the term “acquired data” refers to any relevant characteristic taken, generated, obtained, etc., by a smart image acquisition device (e.g., smart camera) from those portions of the measured machining tool in the field of view of the smart image acquisition device that may be transmitted to a machining tool program.
As used herein, the term “using acquired data” refers to evaluating, assessing, manipulating, transforming, converting, employing, etc., the acquired data that is transmitted to a machining tool program.
As used herein, the term “machining tool program” refers to computer software used in controlling the operational use of a machining tool by the NC machine, or determining the operation conditional of a machining tool or NC machine.
As used herein, the term “operational use” refers to any machining operation that may be performed by the machining tool and that may be controlled by a machining tool program.
As used herein, the term “control operational use” includes but is not limited to regulating, monitoring, limiting, restricting, increasing, decreasing, changing, etc., the degree, manner, type, etc., of a machining operation performed by a machining tool, including not using the machining tool or stopping use of the machining tool.
As used herein, the term “operational condition” refers to the state, condition, readiness, etc., of a machining tool, NC machine, or both for performing a machining operation.
As used herein, the term “verify” refers to determining, confirming, validating, substantiating, corroborating, etc., from acquired data whether or not a measured machining tool is ready or appropriate (e.g., the correct tool) for operational use, or whether or not the measured machining tool or NC machine is in operational condition.
As used herein, the term “correct machining tool” refers to a measured machining tool that has been verified from acquired data to be the appropriate, proper, suitable, etc., machining tool for operational use by the NC machine or machining system.
As used herein, the terms “gauge length” and “gage length” are used interchangeably herein to refer to a measurement of a linear dimension of a machining tool, for example, a length measured from the mechanical interface of the tool assembly to the control point on the tool, etc.
As used herein, the term “runout” refers to the amount of wobble, warp, etc., that occurs as a machining tool (e.g., a drill, reamer, end mill, etc.) revolves, rotates, spins, etc.
As used herein, the term “machining operation” refers to an action, function, etc., carried out by a machining tool. Machining operations that may be carried out by a machining tool include, but are not limited to one or more of: drilling, boring, milling, grinding, reaming, cutting, lathing, finishing, fabricating, assembling, shaping, etc.
As used herein, the term “machining step” refers to any procedure, process, practice, etc., carried out by a machining tool. Machining steps include, but are not limited to one or more of: drilling, boring, milling, grinding, reaming, cutting, lathing, finishing, fabricating, assembling, shaping, etc.
As used herein, the term “machining system” refers to a system comprising one or more machining operations.
As used herein, the term “machining method” refers a method comprising one or more machining steps.
As used herein, the term “machining station” refers to a given point, place, position, etc., in the machining system where one or more machining operations may be carried out.
As used herein, the terms “transmission,” “transmitting”, “transmit” and the like refer to any type, manner, etc. of providing, supplying, inputting or otherwise transmitting data. Transmission of data herein may be carried out electronically, including the use of wired electronic methods, wireless electronic methods or combinations thereof. Electronic transmissions may be carried out by a variety of local or remote electronic transmission methods, such as by using Local or Wide Area Network (LAN or WAN)-based, Internet-based, or web-based transmission methods, cable television or wireless telecommunications networks, or any other suitable local or remote transmission method.
As used herein, the term “computer” may refer to a personal computer (portable or desktop), server, mainframe computer, etc.
As used herein, the term “software” refers to any form of programmed machine-readable language or instructions (e.g., object code) that, when loaded or otherwise installed, provides operating instructions to a machine capable of reading those instructions, such as a computer or other computer program reader.
As used herein, the term “comprising” means various operations, steps, data, stations, tools, devices, etc., can be conjointly employed in this invention. Accordingly, the term “comprising” encompasses the more restrictive terms “consisting essentially of” and “consisting of”
An embodiment of the system of this invention broadly comprises: (a) an NC machine having at least one machining tool; (b) a smart image acquisition device that measures at least one relevant characteristic of the machining tool to provide acquired data on the measured machining tool; (c) optionally a machining tool program that uses the acquired data to control the operational use of the measured machining tool by the NC machine or to determine the operational condition of the measured machining tool or the NC machine.
An embodiment of the method of this invention broadly comprises: (a) providing a machining tool from an NC machining operation; (b) measuring at least one relevant characteristic of the machining tool with a smart image acquisition device to provide acquired data on the measured machining tool; (c) optionally using the acquired data to control the operational use of the measured machining tool by the NC machining operation or to determine the operational condition of measured machining tool or NC machine.
The embodiments of the system and method of this invention are based on the discovery that smart image acquisition devices (e.g., smart cameras) may be used to: (1) measure at least one relevant tool characteristic of a machining tool (e.g., gauge length of a cutting tool) more quickly than manual methods or tool probes; (2) measure the relevant tool characteristic(s) with a degree of accuracy at least comparable to conventional tool probes; (3) provide acquired data on the measured machining tool that may be used to: (a) control the operational use of the measured machining tool by the NC machine (e.g., whether or not the measured machining tool is the correct machining tool to select for use in the NC machine or machining operation), or (b) determine the operational condition of the machining tool or NC machine.
A schematic diagram of a specific embodiment of a system comprising an NC machine having a machining tool, for example, a cutting tool, that uses as smart image acquisition device, for example, a smart camera, to measure the relevant characteristics of the machining tool for controlling the operational use of the cutting tool (e.g., to verify the selection of the correct tool) is further illustrated by reference to
As shown in
Transaction 40 is transmitted by system 10, as indicated by arrow 42, to smart camera 34. In response to transaction 40, smart camera 34 obtains one or more images of one or more relevant characteristics of tool 26, as indicated by double headed arrow 44. These transmitted images 44 are often converted by smart camera 34 into digital measurements. Image(s)/measurement(s) 44 obtained by smart camera 34 provide acquired data that is transmitted, as indicated by arrow 46, to a machining tool program 36. Tool program 36 then uses the acquired data 46 that is received, as indicated by arrow 50, to control the operational use of tool 26 by machine 18 (e.g., providing instructions to the NC machine controller), for example, to determine whether or not tool 26 is the correct tool for use by machine 18, whether tool 26 and/or machine 18 are in operational condition, etc.
Referring to
Tool 26 may be positioned and/or oriented within field of view 52 prior to a request (e.g., transaction 40) from system 10 to determine the position and/or orientation of tool 26. Each tool 26 may have one or more control points 80, two of which shown in
Once tool 26 is positioned, a transaction 40 (which may include a transaction ID number, known tool characteristics, how tool 26 is to be positioned or oriented for measuring characteristics, identity of tool 26, etc.) may be transmitted (as indicated by arrow 42) by system 10 to smart camera 34 as to which characteristics and measurements are to be obtained of tool 26 by smart camera 34. The resulting measurements obtained by smart camera 34 are then transmitted as acquired data 46 to machining tool program 36. Tool program 36 uses acquired data 46 to control the operation of tool 26 by machine 18, or to determine the condition of tool 26 and/or machine 18. For example, tool program 36 may evaluate the measurements obtained by smart camera 34 and from that evaluation, determine, for example, whether or not tool 26 is the correct tool to use (e.g., whether effective diameter of 26 tool is acceptable and within tolerance), whether tool 26 is mounted correctly by machine 18, whether tool 26 is positioned and/or oriented correctly for use (and how to update or adjust the positioning and/or orientation of tool 26 if it is not), whether the incorrect positioning and/or orienting of tool 26 indicates or suggests machine 18 requires maintenance or repair, etc.
In an embodiment of a measurement of all or most of the relevant characteristics of tool 26 (as illustrated by
As illustrated in
From the above measurements, smart camera 34 may provide the following acquired data 46, as illustrated in
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by system 10, these discovered errors may be listed along with their associated codes, with any unused characteristics that may not have valid values being returned with a value of 0.
In an embodiment illustrating “length only” tool measurements, again for a tool 26 wherein the length fits completely within field of view 52, system 10 may transmit a “length only tool measurement” transaction 40 (referred to hereafter as “ID 02”) to smart camera 34. ID 02 may include the following known characteristics of tool 26 that are transmitted to smart camera 34:
Using the data provided by transaction ID 02, the following acquired data 46 may be obtained by smart camera 34 from tool 26 and transmitted to tool program 36:
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by system 10, these discovered errors may be listed along with their associated codes, with any unused characteristics that may not have valid values being returned with a value of 0.
In an embodiment illustrating width only tool measurements, again for a tool 26 wherein the width fits completely within field of view 52 (as in
Using the above checks and characteristics provided by transaction ID 03, the following acquired data 46 may be obtained by smart camera 34 from tool 26 and transmitted to tool program 36:
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by system 10, these discovered errors may be listed along with their associated codes with any unused characteristics that may not have valid values being returned with a value of 0.
When a tool 26 does not fit completely within field of view 52, as illustrated in
The potential measurements for corner radius 174 shown in
The identification of the respective tool sides (e.g., top side 122 and bottom side 124) of tool 126 as positioned in field of view 120 may be transmitted with transaction ID 04 to smart camera 34. Values may also be preassigned for the respective tool sides, such as 1 for the bottom side 124, or 2 for top side 122. For the data included in transaction ID 04, smart camera 34 may provide the following acquired data 46, as illustrated in
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by system 10, these discovered errors may be listed along with their associated codes with any unused characteristics that may not have valid values being returned with a value of 0.
In an embodiment illustrating “length only” tool measurement of tool 126, control point(s) 130 of tool 126 may be placed on the length target plane 154 and the tool radius target plane 152. System 10 may transmit a “length only tool measurement” transaction 40 (referred to hereafter as “ID 05”) to smart camera 34. A transaction ID 05 may be assigned to identify the measurements required. Transaction ID 05 may include performing a “length deviation from nominal” by gathering the following data:
The identification of the respective tool sides (e.g., bottom side 124 or top side 122) of tool 126 as positioned in field of view 120 may be transmitted to smart camera 34 (as described above) as part of transaction ID 05, for example, a value such as 1 for the bottom side 124, or 2 for top side 122. Using the data provided by transaction ID 05, the following acquired data 46 may be obtained by smart camera 34 from tool 26 and transmitted to tool program 36:
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by the system 10, these discovered errors may be listed along with their associated codes with any unused characteristics that may not have valid values being returned with a value of 0.
Radius measurements may only apply when the width of the tool (e.g., tool 126) do not fit within or inside the field of view (e.g., field of view 120). Bottom side 124 of tool 126 may be placed on, or approximate to, tool radius target plane 152. The radial deviation 156 of tool 126 may be checked where length target plane 154 intersects any part or portion of tool 126 (when tool 126 is also positioned to intersect target plane 154 in field of view 120). System 10 may transmit a transaction 40 (referred to hereafter as “ID 06) to smart camera 34 to perform a measurement of radial deviation 156, using the following characteristics of tool 126 and providing the following measurement of radial deviation 156:
If no errors have been detected, system 10 may be set to reflect an error code of 0. When errors are found by system 10, these discovered errors may be listed along with their associated codes with any unused parameters that may not have valid values being returned with a value of 0.
A specific embodiment of a method that uses system 10 for verifying the correct selection of a machining tool is illustrated by a flowchart shown in
As further shown in
If an error message is discovered in step 314 as part of acquired data 46, tool program 36 may halt or terminate, the use of tool 26 and the operation of machine as indicated by step 322, until the discovered error is corrected or otherwise resolved appropriately.
While
An embodiment of a smart camera 34 and associated components that may be used herein is illustrated in
While specific embodiments of the system and method of this invention have been described, it will be apparent to those skilled in the art that various modifications thereto can be made without departing from the spirit and scope of this invention as defined in the appended claims.
