Computer-implemented system and method for synthesizing a fixture layout for a part to be manufactured

Patent metadata

Field	Value
Publication number	US-9235658-B2
Application number	US-201313843025-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jan 12, 2016
Grant date	Jan 12, 2016

Abstract

Automated fixture layout is approached in two distinct stages. First, the spatial locations of clamping points on the work piece are determined to ensure immobility of the fixtured part under any infinitesimal perturbation. Second, spatial locations are matched against a user-specified library of reconfigurable clamps to synthesize a valid fixture layout or configuration that includes clamps that are accessible and collision free. The spatial locations matching during the second stage can be the same spatial locations chosen in the first stage to ensure immobility, or a different set of spatial locations.

First claim

What is claimed is:

1. A computer-implemented system for synthesizing a fixture layout for a part to be manufactured, comprising:
at least one computer processor and associated memory;
a potential configuration comprising a plurality of locations on the boundary of the part against which to contact a plurality of fixture elements configured to be affixed to a base plate;
a determination module to determine a collision free region about each of the locations comprising basis vectors and collision free distances along each of the basis vectors;
a part definition module to define a part envelope comprising a geometric representation of a region defined about the boundary of the part;
a part identification module to identify a part clearance needed by each of the fixture elements to avoid interference with the part envelope when affixed to the base plate;
a catalog comprising a multiplicity of fixture elements specific to a manufacturing facility and configurable to fixture the part;
a filter module to filter each candidate fixture element listed in the catalog that exceeds the part clearance in at least one dimension of the candidate fixture element, and to remove from further consideration the filtered candidate fixture elements;
a transformation computation module to compute using the at least one computer processor, for each of the candidate fixture elements listed in the catalog and not filtered, a transformation between the part and the base plate, and to align the part with the base plate by the transformation; and
an elimination module to eliminate both the candidate fixture elements that are listed in the catalog and not filtered and attachment points of those candidate filter elements to the base plate, which are situated where that fixture element would overlap with another of the remaining fixture elements, the candidate fixture elements and their attachment points remaining after overlap elimination comprising a fixture layout, wherein a plane is defined at a contact point of the plurality of locations and basis vectors X and Y defined by configuration of the attachment points on the base plate, such that the basis vector X comprises an access vector of the candidate fixture element and s comprises spacing of the attachment points on the base plate to determine a transformation with a form closure point (x,y) comprising a position of a location projected onto the base plate, by the expression:

If
⁢

⁢

(

y
⁢
mod

⁢

⁢
s

)

>

(

s
2

)

,
then

offset
=

s
-

(

y
⁢
mod

⁢

⁢
s

)

else

offset
=

-

(

y
⁢
mod

⁢

⁢
s

)

where offset comprises a distance by which to shift the part along the Y basis vector and providing an optimized configured fixture layout model that ensures part stability.

2. A system according to claim 1 , further comprising:
a distance specification module to specify access collision free distance as a positive direction; and
a distance identification module to identify thickness and width collision free distances through ray tracing respectively along the basis vectors for thickness direction and width direction,
wherein the access collision free distance, the thickness collision free distance, and the width collision free distance comprise the collision free distances.

3. A system according to claim 1 , further comprising:
an access module to access a model of the part that defines the boundary of the part;
a trimming module to trim the model of the part with a plane defined at each of the locations and the set up vector and to retain a solid rendering of the part taken from below the plane;
an extraction module to extract an outer contour of the solid rendering of the part projected onto a plane defined on the surface of the base plate; and
a clearance determination module to determine the part clearance through ray tracing from the outer contour along the access direction.

4. A system according to claim 1 , further comprising:
an evaluation module to evaluate form closure of the potential configuration over the part when fixtured by the plurality of fixture elements when affixed to the base plate and in contact with the part at the plurality of the locations comprised in the potential configuration; and
a disqualification module to disqualify the potential configuration if the form closure is absent.

5. A system according to claim 1 , further comprising:
a dimension determination module to determine dimensions of a bounding box peripherally traced about the boundary of the part; and
a base plate selection module to select the base plate sized to at least fit the bounding box's dimensions.

6. A system according to claim 1 , wherein the transformation computation module computes, for each of the candidate fixture elements listed in the catalog and not filtered, the transformation between the part and the base plate that positions a face of the candidate fixture element in contact with one of the locations and a mounting feature of the candidate fixture element in contact with an attachment point on the base plate.

7. A system according to claim 1 , further comprising:
a candidate selection module to select the candidate fixture elements in the catalog based on criteria comprising availability, smallest size and lowest forces.

8. A system according to claim 7 , further comprising:
an element selection module to further select the minimal number of the candidate fixture elements listed in the catalog with a minimal number of changes of the fixture elements between each consecutive step in the sequence.

9. A system according to claim 1 , further comprising:
a process retrieval module to retrieve a sequence of process steps through which the part is to be manufactured, each of the process steps in the sequence requiring fixturing o

Assignees

• Palo Alto Res Ct Inc

Inventors

• Nelaturi Saigopal
• Rangarajan Arvind
• Kurtoglu Tolga
• Fritz Christian

Classifications

• G06F30/00

  Computer-aided design [CAD] · CPC title

• G05B2219/35043

  Tool, fixture design · CPC title

• G05B2219/36315

  Library for shapes of tool holders, fixtures, chucks · CPC title

• G05B2219/35025

  Design and manufacture jig · CPC title

• G05B2219/35218

  From cad data derive fixture configuration and assembly program · CPC title