2009 Project Lead The Way Computer Integrated Manufacturing Spring Final Part C

Computer Integrated Manufacturing

Final Examination

Part CCollege Credit

Spring 2009PRACTICE EXAM

Student Name: ___________________________________

Date: _____________________

Class Period: _____________

Total Points: ____________/50

Project Lead The Way®

Copyright 2006 - Page 1 of 8

1. CNC Programming [25 Points Total]Directions: No simulation software may be used. The cam shown in the technical drawing below is to be machined from a piece of mild steel. The Machinery’s Handbook recommends a cutting speed of 90 FPM, and a feed rate of 0.006 IPT. An end mill plunge rate and a drill rate of ½ the calculated feed rate will also be used. The holes in the Cam are machined using both linear interpolation moves and canned drilling cycles. The counterbore in the center hole is machined using a profiling cut. Use your knowledge of CNC milling, cutting speeds, feed rates and G&M code to complete the NC program on Page 3.

Formulas:



N = Spindle Speed (RPM)CS = Recommended Cutting SpeedD = Tool Diameter (inches)Fm = Milling Feed Rate (IPM)ft = Recommended Feed Rate (IPT)nt = # of Teeth on the Cutter

Note:

Symbol () substituted for tool change code on line N18,N26 and N32 as per duplicate answer from line N12 Symbol () substituted for spindle on CW code on line N19 and N27 as per duplicate answer from line N13. () substituted for rapid traverse code on lines N16,N20, N28 ,N34 and N40 as per duplicate answer from line N14. () substituted for linear interpolation code on lines N37 and N39 as per duplicate answer from line N35.

N1 ((((Programmed By PLTW Spring 2006 CIM)))))N2 __________ ; Absolute CoordinatesN3 __________ ; Inch UnitsN4 ((((((((((((((((Tooling Information)))))))))))))))))))))))))N5 ; Tool 1 1/8" 4 flute center cutting end mill N6 ; Tool 2 1/8" DrillN7 ; Tool 3 1/4" DrillN8 ; Tool 4 1/4" 2 flute center cutting end mill N9 ; Tool 5 1/2" 2 flute center cutting end mill N10 ; Cutting Speed 90 fpm N11 ; Feed rate .006 ipt for mild steelN12 __________ _________ ; Tool change to 1/4" drillN13 __________ __________ ; Spindle on CW at 1440 RPMN14 ________ ___________ __________ ___________ ; Rapid traverse 1/4" above PRZN15 G01 Z-.315 __________ ; Drill 5/16" Deep at 8.64 IPMN16 Z.25 ; Rapid retract drill 1/4"N17 (((((((((((Canned Drilling Cycle))))))))))))))))N18 T2 ; Tool change to 1/8" drillN19 S2880N20 X0.000 Y.375 Z.250 ; Rapid traverse 1/4" above point E N21 G81Z-.315 R.25 F17.28 ; Canned drilling cycle 5/16" deep at feed of 17.28 ipmN22 X-.375 Y.166 ; Drill at point DN23 X__________ Y_________ ; Drill at point C, Calculate coordinates of point CN24 G80 ; Cancel canned drilling CycleN25 ((((((((((((((((Profile Cut Center Hole Counter Bore)))))))))))))))))))))N26 __________ ;Tool change to 1/8" end millN27 __________ ; Spindle on CW at calculated speedN28 X.125 Y0.000 Z.25 ; Rapid traverse 1/4" above point BN29 __________ Z-.125 F34.56 ; Plunge cut 1/8" deep at 34.56 ipmN30 __________ X.125 Y0.000 I0.000 J0.000 _______; Circular interpolation Climb milling at calculated ;feed rateN31 ((((((((((((((((Profile Cut Perimeter of Cam)))))))))))))))))))))N32 T5 ; Tool change to 1/2" End millN33 M03 S720 ; Spindle on CW at 720 RPMN34 X.980 Y.200 Z.25 ; Rapid traverse to 1/4" above HN35 ________ Z-.250 __________ ; Plunge cut at calculated feedN36 __________ X-.980 Y.200 I0.000 J0.000 F8.64 ; CW circular interpolation to point IN37 X-.735 Y1.400 ; Cut to JN38 G02 X.735 Y1.400 __________ __________ ; CW circular interpolation to point center at FN39 X.980 Y.200 ; Cut to HN40 Z1 ; Rapid retract tooling to Z1N41 __________ ; Spindle offN42 __________ ; End of program



2. Robot Programming [10 Points Total]

Directions: No simulation software may be used. Use the answer bank and robot program below to complete the missing program information. The answer blank items may be used once, more than once, or not at all.

Narrative: The following robot program is used to transfer cubes from a pneumatic feeder to a pallet. The robot will palletize 8 cubes, two rows high, with four cubes in each row. The robot will first place all four cubes in the bottom row 1 and then stack four more cubes on the top row 2.

Variables: The following variables will be used to define the positions of the robot in the program:

ABDROP Designates staging position above the drop-off point. The following positions are used for this variable: 30, 31, 32, 33

DROP Designates the drop-off point for the cube on the pallet (rows 1 and 2). The following positions are used for this variable: 20, 21, 22, 23, 24, 25, 26, 27

Movement Order: 99 → 200 → 100 → 200 → 300 → ABDROP → DROP → ABDROP → 300 (repeat as needed back to 200)



30

24

20

31

25

21

32

26

22

33

27

23

200

100

300

Row 1

Row 2

Directions: Fill in the blanks with the correct term from the answer bank provided. (1 Point each)

1: ________ Gripper2: Set Variable ABDROP = 30 3: Set Variable __________ = _________4: Set Variable CYCLE = 15: Go to Position 99 Speed 106: LOOP:7: Turn On Output 18: Turn Off Output 19: Go to Position 200 Fast10: Go linear to Position 100 Fast11: ________ Gripper12: Go to Position ________ Fast13: Go to Position 300 Fast14: Go to Position ABDROP Fast15: Go linear to Position DROP Fast16: Open Gripper17: Go linear to Position ABDROP Fast18: Go to Position 300 Fast19: Set Variable __________ = __________ + 120: Set Variable DROP = DROP + 1

21: Set Variable CYCLE = CYCLE + 122: If CYCLE == 5 Jump to RESET23: RETURN:24: If CYCLE >= 9 Jump to END25: Jump to LOOP26: RESET:27: Set Variable ABDROP = 3028: Jump to RETURN29: END:30: Go to Position 99 Fast

QUESTION 1 (1 Point)What is the purpose of the CYCLE variable?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

QUESTION 2 (1 Point)Why is the ABDROP variable reset to 30 in line 27?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________

QUESTION 3 (1 Point)Why must the variable numbers be in sequential order?

_________________________________________________________________________

_________________________________________________________________________

_________________________________________________________________________



Answer Bank

ABDROPCloseCYCLEDROPENDLoopOpenSet Variable10203040100200300

3. Fischertechnik [15 Points Total]

Directions: No simulation software may be used. Use the accompanying narrative and the program flow chart to answer the following questions.

Narrative: A simulation of a one axis overhead gantry is built with Fischertechnik parts.

The gantry moves steel castings from a conveyor belt on the left to one on the right. An electromagnet is mounted on the gantry and is used to lift and hold the steel castings while the shuttle transfers them. Note: An electromagnet produces a magnetic field when it is powered. At startup, the lamp across from the phototransistor is turned on and remains on. A switch is used to initiate movement of the gantry by a worker. The shuttle motor turns counterclockwise when moving to the left and clockwise when moving to the right. A warning lamp turns on and the shuttle waits 15 seconds before movement occurs to position the electromagnet over the steel casting on the left conveyor. When the electromagnet is in the correct position as indicated by the phototransistor, the electromagnet is energized and picks up the casting. The system waits for 3 seconds before the casting is moved to the right where a position sensor indicates that the gantry is above the right conveyor; the system waits 4 seconds to allow the casting to stop swinging, before turning off the electromagnet. When the magnet is turned off, the part releases and a 3 second delay is used to allow the magnetic field to diminish before the cycle starts over again.



The letters to the left of the flow-chart icons correspond to the questions below.

A. At this point in the program, output (M1, M2, M3, M4) ____________ must be turned (OFF, ON). _________________________

B. How many seconds is the delay? ________

C. Which number must be on the bottom branch of the phototransistor decision block (0 or 1)? ___________________________________

D. What action must motor M3 take (CW, CCW, Stop)? _____________________________

E. At this point in the program, output (M1, M2, M3, M4) ______ must take what action (CW, CCW, Stop)? ____________________

F. How many seconds is the delay? ________

G. At this point in the program, output (M1, M2, M3, M4) ________ must be turned (OFF, ON). ______________________________



A.

B.

C.

Questions below relate to the overall program, and not to individual flowchart symbols.

1. If the warning light (M1) were not functioning properly when the program was running, what software troubleshooting method could be used to force the M1 output to turn on and off to check its function?

__________

_____________________________________

2. A Fischertechnik system (hardware and program) was previously set up and worked correctly. It is later setup again and one of the motors runs the wrong direction, even though the program has not changed. What needs to be done to the hardware to correct the problem?

______

3. If switch I1 is pushed 3 times within 2 seconds, how many castings will be moved?

_________________________

4. If the simulated gantry is 8 inches long, approximately how long does it take to complete one program cycle? (Circle the best answer.)

A. 7 sec B. 10 secC. 22 secD. 25 secE. over 25 sec

5. Is motor M3 connected to an input or an output on the interface box?



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2009 Project Lead The Way Computer Integrated Manufacturing Spring Final Part C