06 Step NC

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STEP NCTool path programming in an intelligent Step NC Manufacturing Context

Adopted and edited from a presentation made by:

Raphal LAGUIONIE - Matthieu RAUCH Jean-Yves HASCOET

Institut Recherche Communications Cybernetique Nantes (IRCCyN) France.

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Scope

Introduction & Applications

Step_NC: A new approach

Lacks of curent G-code

A new vision: Step_NC

Machining strategies in a Step_NC file

The Korean Step_NC prototype

Pattern strategies

A new method to build toolpaths

Proposition of integration in Step_NC standard

Validation of the proposition

Implementation in PosSFP (Shop Floor Programming System) Development of a Step_NC numerical chain

From the CAD model to the machined part

Conclusion

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Introduction

The STEP-NC AP238 Standard

The STEP-NC AP238 standard is the result of a ten yearinternational effort to replace the RS274D (ISO 6983) M and G codestandard with a modern associative language that connects the CADdesign data used to determine the machining requirements for anoperation with the CAM process data that solves thoserequirements.

Enabling e-Manufacturing for Mechanical PartsSTEP-NC allows manufacturing organizations to seamlessly sharemachining and measurement information between machines andover the Internet. The emerging STEP-NC technology is yieldingprocess improvements including a 15% reduction in machining

time. The automated measurement and compensation enabled bySTEP-NC promises to yield parts that meet higher accuracyrequirements for less cost. The integrated simulation andverification enabled by STEP-NC promises to guarantee that everypart will be made correctly and that production will stop whenevercuts are about to be made that do not meets design requirements.

Resources: Step Tools, Inc. http://www.steptools.com/library/stepnc/

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Working Steps & Advanctages

Working Steps

STEP-NC changes the way that manufacturing is done by defining data as"working steps": a library of specific operations that might be performed ona CNC machine tool. In other words, it breaks down every machiningoperation into the steps required to perform the operation. In the past, CNCmachine tools had to be programmed using G and M codes (from ISO 6983),which were instructions that only told the machine what moves to make,without any semantic content that referred to the part being processed.

STEP-NC will make G and M codes obsolete.

AdvantagesWith the concept of "working steps" in place, the manufacturing processbecomes streamlined. Now, a machine tool can receive a file with STEP-NCdata, "know" what it means, and proceed milling the piece without any moreinstructions. There will be no more programming the machine tool for each

individual piece. Moreover, the benefit of the standard goes further. With aset of standard "working steps" in place, all manufacturers will be able toshare information reliably and instantaneously. A STEP-NC converted CADfile that is completed on the east coast can be sent over the internet to amachine shop on the west coast and they can immediately start milling thepart.

Resources: Step Tools, Inc. http://www.steptools.com/library/stepnc/

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Applications

Step NC will enable:-

Smart Process Control

Smart Process Monitoring

Smart Manufacturing

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The current programming standard : G-code

CAM Post-processor

M216

G0 Z25

G0 X50

Y60 G1

X95 M02

G-Code

Based on principles of the 60s

Ambiguous semantics in some cases

Vendor-specific extensions Difficulty of changes on the machine tool

Impossible Feed back

Use of post-processors

As many configurations

as CAM softwares /

machine tools

more than 4500 today

Step_NC: a new approach

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Benefits of Step_NCA new vision of the numerical chain

Total integration of

CAD-CAM-CNC

Total integration of

CAD-CAM-CNC

No information

lost

No information

lost

Implementation of a

single file

Implementation of a

single file

Bidirectional

data flow


No more post-processors, no G & M codes

Machine-unspecific program

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Comparison G code Step_NC


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CNC in Step_NC numerical chain


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Structure of a Step_NC file


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Korean prototype of Step_NC numerical chain

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PosSFP :

Featurerecognition

Choice of machining

strategies attributesStep_NC file

generationMachining entities


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Study situation in Step_NC development

First step :

Goal :

Interpreted

programming

Evolution with

:

Integrated

programming

Advanced

programming


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First step : Contribution to standard development

Enrichment of strategies proposed in Step_NC :

Pattern strategies : GUIDE CURVE + PATTERN

Exemples of strategies built on pattern curves :

Trochodal

milling :

Plunge

milling :

Pattern strategies : a new method to build toolpaths

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Validation of this proposition of integration

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CAD

partMachining

PosSFPReading

tools

Toolpath

generation Adaptation

Step 1 :

Implementation oftrochoidal milling in :- Step_NC Standard

- PosSFP

Step 2 :

Building of readingtools and toolpaths

generators

Step 3 :

Machiningtest parts

Step_NC

Strategy

parametersToolpaths

Step_NC

File

Integration of pattern strategies in Step_NC

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Conclusion & More Benefits of Step NC

Creation of an interpreted Step NC numerical chain

First Step through advanced programming

possibility to work with Step NC on conventional means

Interest of pattern strategies

Generation simplicity

Few attributes needed to generate a complete toolpath

Easy portability

Compatibility with Step NC standard and high level programming

Enrichment of Step NC possibilities

Pattern strategies

Step NC

Conclusion

- G-code programming is no more the solution

- Bidirectional data flow

- 1 single file (no lost of data, no redundancy, etc.)

- Less correction time

- Step_NC file portability

- Total integration of CNC feed-back to design and NC planning

- Capitalization of shop floor feedbacks and experiences

- New possibilities for toolpath generation and machining strategies

- Ability ofreal-time adaptation and optimization of toolpaths and machining parameters

Advanced Step NC

06 Step NC

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