Computer Aided Engineering
Applications
3. Advanced Manufacturing 3.5 NC programming
3.6 Automated Manufacturing systems
Engi 6928 - Fall 2014
3.6 Automated Manufacturing systems
3.7 Rapid prototyping
3.5 Part programming3.5 Part programming
Structure of an Automated manufacturing system
Product
descriptionCAM software MCU
Machine
Hardware
Data IO
SCADA
descriptionCAM software MCU
HardwarePDE NC
CODEControl
Commands
3.5 Part programming3.5 Part programming
• A Part program is a sequence of instructions which
describe the manufacturing operations to be
performed on a work piece, in the form required by a
computer controlled manufacturing machine.
• Upon receiving of the part program (NC code), the
automated machine executes the instructions in the automated machine executes the instructions in the
code line by line.
A typical NC Code
•The main program
•N specifies the sequence number
•Comments can be given in brackets or
after;
3.5 Part programming3.5 Part programming
Some of the main NC codes
• Setup commands
– G90/91 Absolute programming/ Incremental programming
– G70/G71 Inch / Metric format
– G54..G59 Work Coordinate system (set by probe)
– G28 Return to Home
• Linear interpolation vs Rapid traverse• Linear interpolation vs Rapid traverse
– G00 X5 Y6 Rapid traverse to point (5,6) (typically 5-20 m/min speeds)
– G01 X5 Y6 Linear interpolation to point (5, 6). (@ feed rate)
3.5 Part programming3.5 Part programming
• Miscellaneous commands
– M03/M04/ M05 spindle on CW/CCW/ off
– M07/M08/ M09 coolant on mist/flood/ off
– M02 program end
– M06 tool change
• Spindle, Feed and tools• Spindle, Feed and tools
– S 1000 set spindle 1000 rpm
– F 1 set feed rate 1 mm/min
– T01 select tool 01
3.5 Part programming3.5 Part programming
• Circular interpolation
– G02 X5 Y5 R5
(move to x5 y5 with radius 5
clockwise)
• Cutter compensation
– G 40/41/42 Cutter radius compensation
Cancel/ Left/ Right
– G 43/49 Cutter height compensation/ cancel
3.5 Part programming3.5 Part programming
• Job setup – Work offset
G54 Setup
• Job setup – Tool offset
– tool diameter/ height compensation
– Tool wear
3.5 Part programming3.5 Part programming
Tool offset setup
3.5 Part programming3.5 Part programming
Exercise 1– Write part programs for the following tool
paths.
Thickness =20mm
Tool Info
Tool # 1
Drill ∅5
S=1200
F=70
Tool #2
Drill the 4 holes and perform the finishing profile cut
Dimensions are Metric
Tool #2
End Mill ∅20
S=2000
F=400
Assume G54 set at
the top face
Tool Table
T1 L15 D5
T2 L15 D20
3.5 Part programming3.5 Part programming
• Path verification using NC corrector-
– Limitations (tool setup), work offset setup
– Cutter length offset
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Structure of an Automated manufacturing system
Product
descriptionCAM software MCU
Machine
Hardware
Data IO
SCADA
descriptionCAM software MCU
HardwarePDE NC
CODEControl
Commands
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Main components
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Mechanical Components
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Mechanical Components
Belt Drives
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Axis configurations
Z
X
2 Axis CNC Lathe
3 Axis CNC Mill5 Axis CNC Mill Configurations
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Stepper motor drives
•Open loop
•Low load applications
•Initialization with Limit switches
•Step sequences are used to control the motors
•Basic Length Unit (BLU) = Pitch of ball screw
Steps per revolution
Example: 400 half steps per rev, 4mm
Pitch implies a 10 um BLU
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Servo motor drives Relays
•Closed loop PID using quadrature encoders
•More precise than stepper drives
•Initialization with Limit switches/ absolute encoders
•Direction step commands given to PID as reference
•Basic Length Unit (BLU) = Pitch of ball screw
Resolution of encoder
ON/OFF relay drivers
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Machine Control unit
NC CODE•Read G code Line by Line
•Interpolate points from current
to target
•Generate Individual axis
To A
ctua
tor d
rivers
•Generate Individual axis
reference commands (inverse
kinematics)
To A
ctua
tor d
rivers
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Summary
Machine Control Unit
Decode NC code
Interpolation
Axis command
NC Code
file
Servo DrivesPower
Module
Stepper Drives
USB/LAN
24V
5VQuadrature decoders
Axis command
generation
file
Relay DrivesUSER I/O
Job setup
Manual controls
Code Edits
RS232
3.6 Automated Manufacturing systems3.6 Automated Manufacturing systems
Exercise: Identify the axis reference commands and the motor
voltage commands for the following lines of GCode. Assume a
24 V relay and stepper with 400 half steps per revolution
connected to a 4mm lead ball screw.
Exercise: Identify the main system components involved in
designing a 3 axis PCB drilling machine.
G01 X0.05 F100
G01 X0.03 F50
M07
designing a 3 axis PCB drilling machine.
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3.7 Rapid prototyping3.7 Rapid prototyping
• Rapid prototyping is a group of techniques used to
quickly fabricate a scale model of a physical part or
assembly using three-dimensional computer aided
design (CAD) data.
There are many methods used in RP. The methods • There are many methods used in RP. The methods
are also referred to as additive manufacturing
3.7 Rapid prototyping3.7 Rapid prototyping
1. SLA – Stereo Lithography apparatus
Materials : Resins
Ά
3.7 Rapid prototyping3.7 Rapid prototyping
2. SLS – Selective laser sintering
Materials : Metallic powders
Polymer powders
3.7 Rapid prototyping3.7 Rapid prototyping
3. FDM- Fused deposition modelling
Materials : ABS – (M30)
MUN: Fortus 400mc
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3.7 Rapid prototyping3.7 Rapid prototyping
4. Zcorp printers
Multi-Jet modelling
Polyjet modelling
Investment casting