2007 project lead the way computer integrated manufacturing spring final part c

Computer Integrated Manufacturing

Final Examination

Part C College Credit Performance

Spring 2007 Student Name: ___________________________________ Date: _____________________ Class Period: _____________

Total Points: ____________/50

Project Lead The Way, Inc. Copyright 2007

Section 1A: CNC Programming [25 Points Total] Directions: No simulation software may be used. Study the narrative and the

drawing below, and fill in the missing information in the CNC program. Narrative: Linear Bearing Company has asked you to create the NC code to machine

features into existing aluminum castings. Side 1 has a ¾” diameter thru hole that is formed in the casting when it is produced. The program you write will be for the counter bored area on side 1 and the slot on side 2. All milling is done in single passes to the finished depth. A robot is used to load the casting into a pneumatic vise for the first milling operation on side 1. When side 1 has been machined, the robot reorients the work piece so that side 2 can be machined. The casting is always oriented in the vise so that the lower left-hand corner on the top-facing surface is the PRZ as indicated in the drawing.


[18 points – 1 point each]

NOTE: Symbol ( ) substituted for rapid traverse code on lines N16, N20, N24, N32, N35 and N37 as per duplicate answer from line N8. ( ) substituted for linear interpolation code on line N34 as per duplicate answer from line N18. (♣) substituted for spindle off code in line N36 as per duplication in line N21. ( ) substituted for tool change code in line N23 as per duplicate answer in line N7. ( ) substituted for spindle on code in line N31 as per duplication in line N15.

N1 ; CNC Programming Spring 2007 N2 ; Tool library: Tool 1 - 1/4" 2 flute center cutting end mill, Tool 2 - 3/8" 4 flute end mill, Tool

3 - 4 flute 1/2" non center-cutting end mill N3 ; Recommended cutting speed for 6061 aluminum = 90 FPM, feed rate = .006 IPT N4 _________ ; Absolute Coordinates N5 _________ ; Inch Increments N6 ; Side 1 Machining Sequence N7 _________ _________ ; Tool change to ½” end mill tool for SIDE 1 N8 _________ X10.000 Y4.000 ; Rapid traverse to robot loading location N9 M26 H1 ; Turn output 1 OFF to open pneumatic vise N10 M25 H2 ; Turn output 2 ON to signal robot to begin loading N11 G04 F4 ; Wait 4 seconds for robot to receive signal N12 M26 H2 ; Turn output 2 OFF N13 G25 H1 ; Wait for robot signal to continue milling sequence N14 M25 H1 ; Turn output 1 ON to close pneumatic vise N15 _________ _________ ; Spindle ON clockwise at calculated speed N16 X1.500 Y1.500 Z.125 ; Rapid traverse above point A N17 _________ ; Rapid traverse to appropriate counter bore depth N18 _________ X1.250 _________ ; Cut to point B at appropriate feed rate N19 _________ X1.250 Y1.500 _________ _________ ; Climb milling, circular interpolation

around point A N20 Z3.000 ; Rapid traverse, retract 3" above Z-axis zero plane N21 _________ ; Spindle off N22 ; Side 2 Machining Sequence N23 _________ ; Tool change to 3/8” end mill N24 X10.000 Y4.000 ; Rapid traverse to safe position for loading N25 M26 H1 ; Turn output 1 OFF to open pneumatic vise N26 M25 H2 ; Turn output 2 ON to signal robot to rotate casting to side 2 N27 G04 F4 ; Wait 4 seconds for robot to receive signal N28 M26 H2 ; Turn output 2 OFF N29 G25 H1 ; Wait for robot signal to continue milling sequence N30 M25 H1 ; Turn output 1 ON to close pneumatic vise N31 _________ ; Spindle ON clockwise at calculated speed N32 X.594 Y.380 Z.125 ; Rapid traverse above point C N33 _________ ; Rapid traverse to the finished slot depth N34 X2.140 Y.944 _________ ; Cut to D at calculated feed rate N35 Z2.000 ; Rapid traverse, retract 2" above Z-axis zero plane N36 ♣ ; Spindle OFF N37 X10.000 Y4.000 ; Rapid traverse to safe position N38 M26 H1 ; Turn output 1 OFF to open pneumatic vise N39 M25 H2 ; Turn output 2 ON to send signal to robot to rotate casting N40 G04 F4 ; Wait 4 seconds for robot to receive signal N41 M26 H2 ; Turn output 2 OFF Lines N42 - N80 are similar codes to machine identical features on two remaining sides N81 M47 ; Rewind program to the beginning (Line N1) to start an entirely new casting


Section 1B: Short Answer Written Response [5 Points – 1 point each] Directions: Answer the following questions about the CNC program. Use complete

sentences to fully convey your answers to the questions. 1.1 What does the semicolon do in the code?

1.2 On line N13, why is it important for the robot to send a signal to the milling

machine?

1.3 On line N81, what miscellaneous code could be substituted for M47 if you wanted

to end the program instead of milling another casting?

1.4 Why are no G-codes specified before the coordinates on lines N17 and N33?

1.5 What would need to be done to all of the coordinates in this program if a G21 or G71 code were used?


Section 1C: Calculations [2 Points] Directions: Refer to the technical drawing from the CNC programming section to solve

this problem. You must show your math work to obtain full credit. One point is awarded for showing a formula and substitutions. The second point is awarded for identifying the correct answer with the correct unit of measure. Measurement tools, such as a protractor, may not be used to determine the angle. Degree of accuracy = 0.000.

1.7 What is the measurement of angle E?


Section 2: Robot Programming [10 Points Total] Directions: No simulation software may be used. Study the program narrative, the

movement order, and the graphic below. Fill in the missing information in the robot program using the options contained in the answer bank on the following page. The answer blank items may be used once, more than once, or not on all.

Narrative: In the following program, the robot picks up a cylinder and places it on the

conveyor. The conveyor starts to run moving the cylinder to the other end. When the cylinder passes in front of the sensor at position 3, the conveyor stops. The robot picks up the cylinder and places it onto the pallet. The robot then picks up the pallet and places the pallet on top of the platform. The sides of the pallet in the cell setup are parallel to the sides of the platform. They should remain parallel to the sides of the platform after the robot places the pallet on the platform.

The sensor is connected to input 1 and is wired so that a block passing in front of it creates an “On” signal.


Robot Program [8 Points – 1 point each] 1 Go to Position 99 Speed 5 2 Open Gripper 3 Go to Position 11 Speed 5 4 Go to Position 1 Speed 5 5 ______ Gripper 6 Go to Position 11 Speed 5 7 Go to Position 12 Speed 5 8 Go to Position 2 Speed 5 9 Open Gripper 10 Go to Position 12 Speed 5 11 START_CONVEYOR: 12 ______ 13 If Input 1 On Jump to STOP_CONVEYOR 14 ______ 15 STOP_CONVEYOR: 16 ______ 17 Go to Position _____ Speed 5 18 Go to Position _____ Speed 5 19 Close Gripper 20 Go to Position 13 Speed 5 21 Go to Position 14 Speed 5 22 Go to Position _____ Speed 5 23 Open Gripper 24 Go to Position 14 Speed 5 25 Go to Position 15 Speed 5 26 Go to Position ____ Speed 5 27 Close Gripper 28 Go to Position 15 Speed 5 29 Go to Position 16 Speed 5 30 Go to Position 6 Speed 5 31 Open Gripper 32 Go to Position 99 Speed 5

Point # X (mm) Y (mm) Z (mm) Pitch (deg) Roll (deg) Type

1 0.00 -302.00 10.00 -90.00 0.00 Abs 2 250.00 -200.00 100.00 -90.00 0.00 Abs 3 250.00 305.00 95.00 -90.00 0.00 Abs 4 0.00 265.00 32.50 -90.00 5.00 Abs 5 0.00 205.00 45.00 -90.00 0.00 Abs 6 195.00 86.00 187.00 -90.00 ? Abs

11 0.00 0.00 200.00 0.00 0.00 Rel 1 12 250.00 -200.00 210.00 -90.00 0.00 Abs 13 250.00 305.00 210.00 -90.00 0.00 Abs 14 0.00 265.00 210.00 -90.00 5.00 Abs 15 0.00 205.00 210.00 -90.00 0.00 Abs 16 195.00 86.00 210.00 -90.00 ? Abs 99 xxxx xxxx xxxx xxxx xxxx Abs

Roll Angle Calculation [2 points] Calculate the roll angle for position 6, so that when the robot places the pallet on topof the platform, the sides of the pallet arparallel to the sides of the platform. One point is awarded for showing a correct method of determining the roll angle and one point for a correct answer.

e

_________________ ANS.

Answer Bank STOP Conveyor Axis 7 START_CONVEYOR: Jump to START_CONVEYOR Start Conveyor Axis 7 at Speed 5 in Plus Direction

1 11 4 14 2 12 5 15 3 13 6 16


Section 3: Factory Simulation [15 Points Total] Directions: No simulation software may be used. Study the narrative, model

illustration, and flowchart program. Then, answer the questions that follow. Narrative: A vertical drilling operation has been modeled using Fischertechnik parts.

The model is connected to a Fischertechnik controller that can vary output port intensity. The transport system moves a shuttle between two stations referred to as Bottom and Top. Upon start-up, the transport system turns on a warning light (M1), waits and then moves the shuttle to the Bottom position. The warning light remains on while the system is on. A robot loads and unloads the parts at the Bottom position. Switch I1 detects if the shuttle is at the Bottom position. Light M2 is across from phototransistor I2. Photo transistor I2 detects that a part has been loaded and outputs a 0 (low) when the light is blocked. After a part is loaded and a time delay has elapsed, the shuttle at M3 conveys the part up while the drill spindle M4 is simultaneously turned on. M3 is wired such that CCW is down. Switch I3 is used to detect that the part has been drilled to the proper depth.


Fischertechniks Program Flow Chart


Refer to the letters next to the flowchart symbols for questions 3.1–3.9. [9 points – 1 point each] 3.1 Which output must be turned on at A (M1, M2, M3 or M4)? 3.2 Which output must be turned on at B in order to allow the

phototransistor to function properly (M1, M2, M3 or M4)?

3.3 What action must M3 take at C (CW, CCW or Stop)? 3.4 Is switch I1 wired normally open or normally closed at D (NO or

NC)?

3.5 What action must M3 take at E (CCW, CW or Stop)? 3.6 Which number goes on the right branch of I2 at F (0 or 1)? 3.7 What action must M3 take at G (CCW, CW or Stop)? 3.8 What action must M4 take at H (CCW, CW or Stop)? 3.9 What action must M3 take at I (CCW, CW or Stop)? Questions 3.10–3.15 relate to the overall program, and not to individual flowchart symbols. [6 points – 1 point each] 3.10 How many seconds does the robot have to get out of the way

while removing a part?

3.11 Rather than a time delay, what term describes the

communication between the robot and drilling station that would be more effective at avoiding a ‘crash’?

3.12 If the transport system stops functioning between the Top and

Bottom positions, and the program is restarted, what action will the shuttle take first? (Write the letter of the best response.)

A. Wait for input B. Move to the bottom

C. Move to the top

3.13 Is the phototransistor connected to an (input or an output) on

the interface box?

3.14 In which direction does the shuttle move faster (up or down)? 3.15 If the system is waiting for a part to be loaded and the light

bulb M2 burns out, what motion will change next?


2007 project lead the way computer integrated manufacturing spring final part c

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