By

Asheem Kumar Palo

Centurion University of Technology and Management, INDIA

Guided By : Dr. D. Sreeramulu

Data Exchange standards

In order to transfer the data between differentSystems, a neutral file is needed

Neutral (mostly geometric) data exchange isneeded between CAD and CAM

Most widely used data exchange formats likeIGES, DXF

Problems with above data exchange standards

The existing standards will transfer only geometricinformation

Loss of information

These standards will not support the datathroughout the lifecycle of the product

CURRENT METHODOLOGY OF MAKING PARTS ON CNC CONTROL

G-Code -- Machine

Instructions

“When the designed product is produced using CNC

machine tools, the machine tool controller

needs explicit instructions describing the type

and order of individual steps required to

perform a given task. We use an instruction

language called G-Code to deliver these

instructions to the machine.”

Current NC programming using ISO 6983

%

N05 G54

N10 G00 Z10.000

N15 G91 G0 Z200

N20 T5 D1 WW

N30 G90 M5

N35 G00 X0.000 Y-150.000

N40 G00 Z5.000

N45 M08

N50 S3183.000

N55 M03

N60 F1477.000

N65 G00 X60.000 Y-150.000

N70 G00 Z5.000

N75 G00 X60.000 Y-150.000

N80 G01 Z-0.500

...

machine-specific part

program with axis

data generated by a

postprocessor

vendor-specific

extensions of the

original standard

only primitive motion

and switch

commands

no standardized data

format for spline

processing and

sophisticated NC

technology

Courtesy WZL RWTH Aachen

STEP-NC replaces this with a

rich, integrated data format

Difficulties with Current NC Programming (ISO 6983)

The existing CNC machines work using Standard

controller

CAD description has to go through a post-processor

Loss of geometric information

Programs are not interchangeable

Changes are not possible

No support of complex geometry (e.g. spline) i.e. incapable of controlling five or more axis milling

Creates large programs, difficult to handle

One way : from CAD to shop-floor. No feedback

The above difficulties can

be overcome by the new

standard called

STEP - NC

STEP (Standard for Exchange of Product Data)

- Formally known as ISO10303

Improving CAD data exchange

Replacing IGES, SET and VDAFS

More then one million CAD stations use STEP

All major CAD systems have STEP interfaces

What Is STEP?

STEP APPLICATION PROTOCOLS

Important APs for integration of CAD, CAM and CNC

AP203-Geometry

AP214-Geometry with GD&T

AP224-Manufacturing Features

AP240-process planning

AP238-STEP-NC

New Method Of Making Parts on

STEP-NC Controls

Introduction to STEP-NC

STEP-NC is the new international data input

standard for CNC systems. It is the extension of

STEP that annotates the Design information with

Manufacturing information.

It includes,

- information about the stock,

- Its manufacturing features,

- the tool requirements and

- manufacturing process sequence

Features of STEP-NC

It is Feature-based and Task-oriented

It is fully compliant with STEP

It supports bi-directional information flow

Provide an effective link between CAD/CAM and CNC

Enable interoperability of programs

High-level description of machining process -instead of

tool movement G01 x y

Object oriented and structured

A New Data Interface for NC

Programming

End user Benefits

GOAL: Reduce manufacturing costs

50% of total process plan effort is reduced

STEP-based system used to produce process plan visuals

Projected 75% reduction in man hours spent

CONCLUSIONS

With STEP-NC, all CAD, CAM and NC data can be stored in a single database.

Re-shaping of manufacturing is possible with the implementation of STEP-NC .

STEP-NC will allow CNC systems to become more intelligent.

Thus STEP-NC will emerge as a collaborative agent in the present era of e-manufacturing.

THANK YOU

An ASHEEM KUMAR PALO presentation

asheemkumarpl3@gmail.com