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Advanced CAD/CAM
Citation preview
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
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