Simulation of the machining of a workpiece

Patent metadata

Field	Value
Publication number	US-RE48940-E
Application number	US-201816184157-A
Country	US
Kind code	E1
Filing date	Nov 8, 2018
Priority date	Nov 3, 2011
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

It is provided a computer-implemented method for simulating the machining of a workpiece with a cutting tool having a cutting part and a non-cutting part. The method comprises providing a modeled volume representing the workpiece and a trajectory of the cutting tool; determining a colliding sweep of the cutting tool, wherein the colliding sweep represents the volume swept by the non-cutting front of the cutting tool when the cutting tool follows the trajectory; testing a collision with the workpiece according to the determining step. Such a method improves the simulation of the machining of a workpiece with a cutting tool.

First claim

The invention claimed is:

1. A computer-implemented method for simulating the machining of a workpiece on a CAM system, wherein the method comprises:
by a processor and associated memory:
providing in the CAM system (i) a modeled volume representing a subject workpiece, (ii) a cutting tool having a cutting part and a non-cutting part, the non-cutting part having a non-cutting front, and (iii) a trajectory of the cutting tool;
determining a colliding sweep of the cutting tool, wherein the colliding sweep represents volume swept by the non-cutting front of the cutting tool when the cutting tool follows the trajectory, and wherein determining the colliding sweep comprises dissociating motion of the cutting part and motion of the non-cutting part, and the dissociating motion includes determining volume swept by the non-cutting front when the cutting tool is moving to follow the trajectory at a given time t, wherein the non-cutting front comprises a set of points with instantaneous speed vectors at the given time t that are oriented towards an exterior of the moving cutting tool, wherein at the given time t, the non-cutting front Front(t) is a subset of S outer defined by:
Front(t)={xϵS outer ;<Rot(t)n(x),∂/∂tTraj(t)x>≥0},

Front
⁡

(
t
)

=

{

x
∈

S
outer

;

〈

Rot
(
t
)

⁢

n
(
x
)

,

∂

∂
t

⁢

Traj
⁡

(
t
)

⁢
x

〉

≥
0

}

,

 wherein S outer is a boundary of the cutting non-cutting part, <u,v> denotes a scalar product between vectors u and v, Traj(t) denotes a trajectory of the cutting tool at the given time t, and Rot(t) denotes a rotation component of the trajectory at the given time t; and
testing a collision with the subject workpiece resulting from the determined colliding sweep, the testing comprising: determining whether the colliding sweep intersects the workpiece, and if the colliding sweep is determined as intersecting the workpiece, detecting a collision.

2. The method of claim 1 wherein the method further comprises determining a protective front of the cutting tool; and
wherein determining the colliding sweep comprises determining both volume swept by the non-cutting part and volume swept by the determined protective front.

3. The method of claim 2 , wherein the subject workpiece is represented by a set of dexels, each dexel comprising a set of segments representing the intersection between a line and the subject workpiece, and wherein testing the collision comprises, for a respective dexel:
determining segments of the set of segments of the respective dexel that intersect the volume swept by the determined protective front,
updating the respective dexel based on the determined segments, and
evaluating if the determined segments as updated intersect the volume swept by the non-cutting part.

4. The method of claim 3 , wherein the cutting part is convex, the determined segments are ordered, and updating the respective dexel comprises:
shortening a segment of minimal order that intersects the volume swept by the determined protective front,
shortening a segment of maximal order that intersects the volume swept by the determined protective front, and
removing all segments between the segment of minimal order and the segment of maximal order.

5. A CAM system for simulating machining of a workpiece comprising:
a processor coupled with memory to simulate machining of a subject workpiece with a cutting tool having a cutting part and a non-cutting part, the non-cutting part having a non-cutting front, the processor configured to:
provide a modeled volume representing (i) the subject workpiece and (ii) a trajectory of the cutting tool;
determine a colliding sweep of the cutting tool, wherein the colliding sweep represents volume swept by the non-cutting front of the cutting tool when the cutting tool follows the trajectory, and wherein determining the colliding sweep comprises dissociating motion of the cutting part and motion of the non-cutting part, the dissociating motion includes determining volume swept by the non-cutting front when the cutting tool is moving to follow the trajectory at a given time t, wherein the non-cutting front comprises a set of points with instantaneous speed vectors at the given time t that are oriented towards an exterior of the moving cutting tool, wherein at the given time t, the non-cutting front Front(t) is a subset of S outer defined by:
Front(t)={xϵS outer ;<Rot(t)n(x),∂/∂tTraj(t)x>≥0},

Front
⁡

(
t
)

=

{

x
∈

S
outer

;

〈

Rot
(
t
)

⁢

n
(
x
)

,

∂

∂
t

Assignees

• Dassault Systemes

Inventors

• Montana Nicolas
• Monteil Marc
• Nosenzo Romain
• Lieutier Andre

Classifications

• Y02P90/02

  Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS] · CPC title

• G05B19/4069 Primary

  Simulating machining process on screen (G05B19/4068 takes precedence) · CPC title

• G06T2210/04

  Architectural design, interior design · CPC title

• G05B17/02

  electric · CPC title

• G06T19/00 Primary

  Manipulating three-dimensional [3D] models or images for computer graphics · CPC title