Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-07-07
2002-12-03
Trammell, James P. (Department: 2161)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C707S793000, C700S160000, C700S118000, C700S181000
Reexamination Certificate
active
06490498
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an integrated support system for supporting sheet metal machining. More particularly, it relates to a sheet metal machining information system adapted to centrally collecting, and reutilizing sheet metal machining data fed back from the shop floor in order to efficiently accumulate and exploit the know-how of skilled operators and simultaneously to shift the operation of arrangements from the actual machining phase to the design phase to improve the quality of sheet metal products and the rate of operation of machine tools.
2. Description of the Related Art
Generally, the sheet metal machining is a two-phased process including a design phase that utilizes CAE (computer aided engineering) in the office and an actual machining phase on the shop floor. The office is provided with CAE equipment (also referred to as automatic programming unit) having CAD/CAM functions, whereas the shop floor is equipped with various machine tools for producing sheet metal products including those for punching, laser machining and bending objects to be machined (hereinafter “works”). The machine tools are controlled by NC data, (i.e., machining programs for controlling the machine tools) prepared in the office by means of the CAE equipment. The CAE equipment and the control terminals of the machine tools are connected with each other by way of private lines.
Now, the conventional procedure of sheet metal machining will be summarily discussed below.
Firstly, the design phase procedure in a manner as described below in terms of reception of a new order.
To begin with, in the design phase, a three faces design drawing is prepared for the ordered product. And the data on the three faces design drawing (FIG.
1
(A)) and machining are entered to the CAD equipment. As a result, a development elevation (FIG.
1
(B)) is produced to provide reference data for actual machining operations.
More specifically, for preparing a development elevation, the CAD operator has to perform various operations including checking the flanges and other components for interferences, determining the attribute values relating to different machining operations including bending and judging if each of the operations is feasible or not, with confirming the values of the important dimensions in the three face design drawing and with imagining a three-dimensional form of the product on the basis of the drawing. The operation of preparing a development elevation is often referred to as brain development for good reason. Then, pictures will be synthetically produced for the different faces of the product, employing the brain development.
Attribute values will be determined for various different machining operations including bending operations in the synthesizing process. Of the attribute values for the machining operations, the stretch of the work due to a bending operation is typically determined by referring to a table of stretch data stored in the office or the data provided by skilled operators. The bending-related attributes may include the stretch and the angle, the lines and the profiles of the ridges and recesses produced at and around each of the bends of the work.
Then, the CAM apparatus (also referred to as automatic programming unit) assigns arrangement data for producing the product to the development elevation prepared in CAD equipment including data for allocating machine tools and outputs NC data including G codes for controlling the allocated machine tools in the form of perforated tapes. Thus, the NC data prepared in the design phase are selected and finalized on the basis of predetermined standard data and by referring to the data provided by skilled operators. Then comes the machining phase.
Only the NC data including the three faces design drawing and the tapes prepared in the design phase for the sheet metal product are provided for the machining phase along with an letter of machining instruction because the data on the development elevation produced in the design phase are poorly accurate and reliable. Thus, the data on the development elevation are not utilized in the machining phase, so that its not provided for machining site.
In the machining phase, a punching and laser machining step comes first. Arrangements have to be made for the machining phase before actual machining operation. The operation of making arrangements is divided into two major stages. In the first stage of arrangement, the NC tapes are entered and dies are selected and arranged in position, while clamps are aligned and other operations necessary for starting the machining process are performed, the first stage of arrangement is setting operation. In the second stage of arrangement, the NC data produced by the design phase are checked for verification and, if necessary, some of them may have to be modified to meet the requirements specific to the shop floor.
The operation of checking and verifying the NC data is conventionally conducted in an NCT (numerically controlled turret punch press) step (for punching and laser machining operations as an arrangement). And it is necessary to preliminarily perform a test punching and laser machining operation for the verification stage because no data on the development elevation are provided.
After the test punching and laser machining operation, a skilled operator typically performs a series of operations for verifying the NC data including laying a blank (produced by cutting a sheet or a rod of the material to given dimensions so that it may be used for the subsequent operations including bending) on a base sheet (work sheet) and testing if the three faces design drawing can be used to successfully produce a development elevation, using the three faces design drawing and the blank, by way of brain development as in the case of the design phase. Data including the stretch of the work due to a three-dimensional bending operation may have to be appropriately taken into consideration to precisely specify the right spots for piercing. Thus, the provided data have to beverified for the NCT/laser machining step. In other words, with a conventional system, the operation of verifying the data on the development elevation has to be repeated in the machining phase in order to prevent defective development (i.e., a situation where a final product having a desired profile is not obtained).
It is also necessary to make arrangements for a bending operation. More specifically, a skilled operator typically performs a series of operations for verifying the data on the development elevation again by way of brain development, referring to the three faces design drawing on the basis of a three-dimensional image he or she has in the brain and taking the bending sequence into consideration. The arrangements will be finalized by the skilled operator for the bending order (i.e. , bending sequence), the selection of the die to be used for bending and other bending-related operations according to the result of the brain development.
A set of bending-related attributes such as stretch will also have be determined as part of arrangement information. The stretch of a work has to be determined by carefully taking complex factors into consideration, including the wear, the warp and the rate of spring back of the dies on the shop floor. Thus, the bending-related attributes have conventionally been determined on the basis of the know-how of the skilled operators on the shop floor. Then, the parameters such as the L-value and the D-value of the NC data to be used for bending operations are modified, if necessary, to define data for the positional relationship between each die and the work to be machined on the basis of the bending-related attributes and the arrangement data. As used herein, the L-value refers to the distance to be moved for abutment from the center of the die and the D-value refers to the displacement of the die necessary for the bending the work after the work and the die are brought to contact with each other.
The operators on the shop
Amada Company Limited
Backer Firmin
Greenblum & Bernstein P.L.C.
Trammell James P.
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