Transcript Slide 1

•
•
•
•
•
•
•
A CNC Machine that can be used not only by manufacturers but also
by small scale hobbyists at costs much less than competitors.
Three forms of communication either through serial port, Ethernet,
or USB jump drive
Controllable through a specially designed hand pendant
Multiple tool heads for different applications including milling, paste
dispensing, and air brushing
Able to move at high speeds with longer working life compared to
other relative machines
Other machines perform only one specific task
Loading different programs by current methods result in longer
machine down times and loss in revenue.
Base
X Axis
Y Axis
Z Axis
Base
Table Specifications:
•Table Work Area: 1160 in2
•Maximum Part Weight: +18 lbs
•Table Supported by Rail: 0.375 in x 1 in
Y Axis
Y-Axis Rail Design:
•Length: 38 in
•Weight Supported: 40 lbs
•Length and Weight was significant
•Guide system selected: Supported rail
Designed Considerations:
•5.5 lb cutting force
•10 lb tool head
•100 lb.in moment due to weight
•75 lb.in moment due to cutting force
X Axis
Design Specifications:
•X-Rod Diameter: 1.18 in (30mm)
•Rod Spacing: 4 in
•Supports 37.8 lbs/rod
•Maximum deflection: 0.001 in
System Loads:
•26.70 lbs, 15.63 lbs, 22.53 lbs
Alternative Design:
•4 Rods with 15.63 lbs/rod
•Rod Diameter : 1 in
•Cost increases
x
Rod 1:
26.70
Rod 2:
15.63
Rod 3:
22.53
y
Z-Axis Design Considerations:
•Minimize moment about x-axis ballscrew
•Guide system selected: Versa rails
•Moves tool head closer to center of x-axis
Alternative Design:
•2 Guide Rods
•Increases moment
Z Axis
Ballscrew Drive Specifications:
•Lead: 0.2 in/rev
•Diameter: 5/8 in
•Supports: Ball bearing & Thrust bearing
block assembly
Thrust Forces:
•Acceleration 28.9 lbs
-Static friction and acceleration force
•Constant Velocity 18.8 lbs
-Only kinetic friction
Tool Head Options:
•Spindle
•Paste dispenser
Motor Drive Assembly
• Purpose: Power Motors to drive ballscrews,
providing motion in 3 dimensions
Motor Design Requirements
• Provide a minimum 20oz.in of torque at a
speed of 4 in/sec. Required to move each
axis.
• Be cable of providing a minimum torque
safety factor of 100%.
Motor Specifications
Motor sizes:
• 276 oz.in (X-axis & Y-axis)
• 166 oz.in (Z-axis)
Motor Requirements:
• 2.8 amps/phase
• Voltage of approx. 48 volts for a torque of
80oz.in at 4in/sec.
Motor Driver Considerations
Requirements:
• step and direction inputs to move
motors
• Cable of driving motors at a
minimum of 2.8 amps.
• Surface mount chips to save
space.
Selected:
• Allegro A3986 [micro-stepping
sequencer]
Motor Driver Considerations
Other design requirements
• Low power dissipation: Mosfet H-Bridge
with very low on resistance. (.050 ohm)
• Current sense resistor: very low
resistance (.043 ohms)
•
Traces :2 oz vs. 1 oz copper.
– To Provide low trace inductance to
reduce high voltage spikes from
destroying chips. Provide low power
dissipation for motor traces.
•
Power Transformer selection: provide
power to motors that would fit into small
cabinet with minimum stray magnet
fields.
•
System monitoring and fault
identification: fuses and LEDs added to
aid trouble shooting and protect circuit
Features
•Pulse width modulation, MOSFET H-Bridge
•Motor size from 2 to 4.7 amps
•Optical Isolation for all inputs
•Full, Half, 1/4, 1/16 step resolution
•Over Current Protection
•Over temperature and under voltage protection
•Fuse Blown Indicators (3 LED’s)
•5 V supply Good LED
•Outputs to Controller
•Drive Board Ready Signal
•Drive Board Fault Signal
•Motor Power Supply Ready Signal
Block Diagram
Motor Driver Board
24 Vdc
To Controller
+-12 Vdc
+5 Vdc
Low Voltage
Power Supply
Vref
X,Y,Z axis
A+
Micro stepping
Sequencer
Step
MOSFET
H-Bridge
Direction
Optical
Isolation
Enable
PFD1, PFD2, SR
(jumper selectable
Connections to Bipolar
Stepper Motors
X,Y,Z axis
Vm+
MS1, MS2
Vm-
Logic Inputs
From Controller
Motor Power
Supply
Driver Board
Ready
-12 V
Fuse
Blown
24 V
Fuse
Blown
B+
B-
Reset
12 V
Fuse
Blown
A-
5V
GOOD
Vbb Ready
Driver Board
Fault
LED Indicators
Output Signals
System Monitoring and
Fault Identification
To
Controller
•Ethernet Microprocessor
•ENC624J600 (Microchip Technology)
•Communication Controller
•PIC24FJ256GB110 (Microchip Technology)
•Motion Controller
•PIC24HJ256GP610 (Microchip Technology)
PIC24HJ256GP610
PIC24FJ256GB110
ENC624J600
24 bit 100 pin micro-processor is used to control the communications for the CNC.
Any data that comes into the the Controller board goes thorough the Communication
micro controller.
Specific requirements:
Features
PIC24FJ256GB110
Operating
Frequency
DC - 32MHz
1 – SPI
Program Memory(Bytes)
256K
2 – UART
Program Memory(Instructions)
87,552
Data Memory(Bytes)
16,384
8 – Data Pins
Interrupt Sources
66
16 – Address Pins
I/0 Ports
A, B, C, D, E, F, G
Connections to the Com controller:
•RS232
•Serial
•USB to Go
•Ethernet
•VGA(Output)
Total I/O Pins
Remappable Pins
Timers:
Total Number (16-bit)
32-Bit (from paired 16-bit timers)
Input Capture Channels
Output Compare/PWM Channels
Input Change Notification Interrupt
Serial Communications:
UART
SPI
IC
Parallel Communications
JTAG Boundary Scan/Programming
10-Bit Analog-to-Digital Module
Analog Comparators
CTMU Interface
Resets
Instruction Set
Packages
83
44
-----------------------5
2
g
g
81
------------------------4
3
3
Yes
Yes
16
3
Yes
POR,BOR,Reset inst
76 base inst
100-pin
64 pin micro-controller specifically for Ethernet implementation.
No programming was needed for this chip. It comes pre-configured to take Ethernet
data. This micro chip connects directly to the Com Controller
Specific Requirements:
1 – SPI
External Connections:
• RJ45 Connector
Features
Pin Count
Ethernet Operating speed
Ethernet Duplex Modes
Ethernet Flow Control
Buffer Memory
Internal Interrupt Sources
Serial Host Interface(SPI)
Parallel Host Interface
Cryptographic Security Options
Receive Filter Options
Packages
ENC624J600
64
10/11 Mbps
Half and Full
Pause and Backpressure
24K
11
Yes
8
Yes
Accept or Reject packests with CRC
61-pin TQfP
24 bit micro-controller used to take the data from the communication micro chip and
distribute Data to the motor driver board.
Specific Requirements:
2 – SPI (to communication)
1 – UART (to Pendent)
8 – Data Input Pins
4 – External Interrupts
Features
PIC24HJ256GP610
Pins
100
Flash Memory
256
Ram
16
DMA Channels
8
Timer 16 bit
9
input Capture
8
Output Compare Std. PWM
8
Codec Interface
0
ADC
2ADC 32 ch
UART
2
SPI
2
IC
2
CAN
2
I/O Pins(Max)
85
PENDENT
1
2
MAIN CONTROLLER
BOARD
3
15
13
11
5
7
9
4
6
8
10
12
14
16
X_S
J4
1
J1
1
X_D
3
3
Y_S
5
5
Y_D
7
7
Z_S
9
9
Z_D
11
11
OE
13
13
OR
15
15
OM1
17
17
OM2
19
19
X_S – X-STEP
X_D – X-DIR
Y_S – Y-STEP
Y_D – Y-DIR
Z_S – Z-STEP
Z_D – Z-DIR
OE – OUTPUT ENABLE
OR – OUTPUT RESET
OM1 – OUTPUT MICROSTEPPING
OM2 – OUTPUT MICROSTEPPING
MOTOR
DRIVER
BOARD
1 – J1 SERIAL PORT: P
2 – J2 SERIAL PORT: MC
3 – TB6 PIN 3: MC
4 – J11 PIN 1: DB
5 – TB6 PIN 4: MC
6 – J11 PIN 2: DB
7 – J4 PARALELL PORT : MC
8 – J1 PARALELL PORT : DB
9 – TB7 PIN 1: MC
10 – J10 PIN 1: DB
11 – TB7 PIN 2: MC
12 – J10 PIN 2 : DB
13 – TB7 PIN 3: MC
14 – J9 PIN 1 : DB
15 – TB7 PIN 4 : MC
16 – J9 PIN 2 : DB
DB- MOTOR DRIVER BOARD
MC – MAIN CONTROLLER BOARD
P - PENDENT
Case
Screen
X:
Y:
50
-50
Z:
A:
JOG
• Requirements
– LCD Screen
– Four buttons for accessing different function
screens, accepting a command, canceling a
command, and switching the axis between y and z
on up and down directional buttons
– Four buttons to change direction on x, y, or z axes
– Feed pot dial to increase or decrease feed/speed
rates
• Casing
– Upper section will have a width of
5 inches and a length of around 2.5
inches
• Placement for LCD Screen, Function
button, Accept Button, Cancel Button,
Axis Switch Button, and Feed Pot
Override
– Lower section will have a width 3
inches and a length of 3.5 inches
• Placement for X, Y, and Z directional
buttons
• System Diagram
– LCD Screen
– PIC 24 Microcontroller
– DB9 and MAX32
• Receive and transmit information
from main controller system to
pendant system
– Voltage Regulator
• Input of 5 volts to make controlled
output of 3.3 volts
– Feed pot/Potentiometer
• Control of feed/speed rate
– Clock chip
• Steady, constant flow of
information
– Switch buttons
• PCB Layout
– Top Layer
• LCD Screen
• Top four buttons are function,
accept, cancel, and axis switch
• Bottom four buttons are four axis
direction movement
– Left and right control x axis
– Top and bottom control y or z axes
– Bottom Layer
• Remaining Components
• Tightly packed to prevent losses
• Connector at bottom to attach to
main controller system
• Screens
– Main Screen
• Upper left box contains current x, y, z,
and acceleration axes
• Lower left box contains circles for limit
switches which will either be red/green
to show on/off
• Upper right box contains current
adjustment of feed pot ranging from +50 % of the rated value
• Lower right box displays the current
state of the machine which can be jog,
idle, or run
– Other Screens
• All Sub Screens
• Offsets Screens- Home, Park, Work
Offset 1, Work Offset 2
• Soft Limits Screens- Upper and Lower
• Parameters Screens- Machine
Parameters, TCP/IP Configuration,
Communications Port
• Flash Drive Screen
X:
Y:
50
-50
Z:
A:
JOG
Mechanical Total $ 2,406.89
Electrical Total
Grand Total
$ 779.76
$
3,186.65
The Mechanical Total comprises of:
•Frame
•Bolts
•Ballscrews
•Rods
•Shafts
The Electrical Total comprises of:
•Circuit Chips
•Driver Boards
•Controller Boards
•Pendent
Step #
Step Description
Hours
1
Place parts on boards
4
2
Table Assembly
20
3
Gantry Assembly
15
4
Tapping and Drilling
13
5
Electric Box Assembly
8
6
Assemble Systems
4
7
Testing
5
Total Hours
69
Each component requires different time
frames to finish each subassembly. The
construction is simple once all subassemblies
are finished, and the machine can be fully
assembled in a 4 hour period with a three man
team. The machine is ready for operation after
testing is complete.
Dr. Haibo Wang- Faculty Technical Advisor
Mr. Mark Hopkins- Technician/ Field Engineer for Allegro Micro-devices
Mr. Howard Everton- President of Norva Plastics
Barb Saathoff- Representative from Dytronix
Tim Attig- Mechanical Shop Machinist