A Tolerance Technology-Oriented Method for Automatically Establishing Datum Reference Frame
A technology of datum reference and method establishment, applied in instrumentation, geometric CAD, calculation, etc., can solve problems such as backwardness and difficulty in CAD/CAPP/CAM integration, and achieve strong operability
Active Publication Date: 2018-11-09
HANGZHOU DIANZI UNIV
View PDF4 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
[0004] Due to the complexity of computer-aided tolerance technology, the research on tolerance design technology, especially three-dimensional tolerance design technology, is far behind the research on CAD, CAPP and CAM, making it difficult to integrate with current CAD / CAPP / CAM
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0038] The preferred embodiments of the present invention will be described in detail below.
[0039] by image 3 hole in Taking the determination of the DRF of the position degree tolerance as an example, the determination method of the construction element is illustrated. According to rule 1, the base plane A is F p . The second datum (hole B) derives an axis l, and the known construction element at this time is F p , according to the first algorithm in the first column of Table 1, l and F can be calculated p The intersection point determines P o , the remaining undetermined construction elements are L a , therefore, it is necessary to enter the table again to determine L a Algorithm column, since the current l cannot determine L a , the algorithm ends. For the axis l derived from the third datum feature (hole C), directly enter to determine L a Algorithm column, the algorithm that satisfies the combination condition at this time is the second algorithm in the sec...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses an automatic establishment method of a datum reference frame facing to a tolerancing technology. The automatic establishment method comprises the steps of: (1) acquiring geometric tolerance marking information from a three-dimensional CAD (Computer Aided Design) model of a part; (2)determining a derivative geometric element of each datum element in a datum system to form a derivative geometric set of current datum elements; (3) directly determining all derivative datum geometries of first datum elements as construction elements; (4) operating all derivative geometric elements of second datum elements by using a recursive determination algorithm of the construction elements, determining effective derivative geometries and remaining construction elements of the datum system, and storing effective results into a known construction element set; (5) verifying the effectiveness of a datum; when an effectiveness problem exists, offering an error prompt message and exiting a program flow; (6) carrying out operations of the steps (4) and (5) on third datum elements; (7) checking completeness of the constrained freedom degree of the datum system, if an undetermined construction element exists, offering the error prompt message, and deciding whether the program flow continues.
Description
technical field [0001] The invention belongs to the technical field of computer-aided tolerance design (CAT), in particular to a method for automatically establishing a datum reference frame for automatically analyzing tolerances in mechanical product design models. Background technique [0002] The datum reference frame is an orthogonal coordinate system used in tolerancing technology to define the position of the target geometric features. The datum reference frame is used to determine the position of the ideal geometry of the target feature relative to the actual geometry of the datum feature. The datum reference frame is generated according to the actual geometry of all datum elements in the datum system of geometric tolerance, and the coordinate axes and coordinate planes of the datum reference frame are generated by calculating the outline elements and central elements of the simulated datum elements through certain rules. The establishment of the datum reference fram...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/50
CPCG06F30/13
Inventor 吴玉光顾齐齐
Owner HANGZHOU DIANZI UNIV