Docstoc

FMEA Worksheet - MAELabs UCSD

Document Sample
FMEA Worksheet - MAELabs UCSD Powered By Docstoc
					Failure modes and effects analysis (FMEA)

    Project:                               MAE 156A: Robot Competition                                                                         Date:                                           10/19/2008

  FMEA Team:       A02 - Monday Afternoon                                                                                                 Prepared by:                                              Andy Luo


SEV = How severe is effect on the customer?
OCC = How frequent is the cause likely to occur?
DET = How probable is detection of cause?
RPN = Risk priority number in order to rank concerns; calculated as SEV x OCC x DET


                                                                                   S                                      O                                                D            R                                                                                      N S   N O   N D   N R
                                                                                                                                                                                                      Actions             Responsibility (target
 Process step        Potential failure mode        Potential failure effects       E          Potential causes            C        Current process controls                E            P                                                               Actions taken          e E   e C   e E   e P
                                                                                                                                                                                                   recommended                  date)
                                                                                   V                                      C                                                T            N                                                                                      w V   w C   w T   w N

                                                                                                                                                                                               What are the actions
                                                                                                                                                                                               for reducing the
                                                                                                                                                                                               occurrence of the          Who is responsible for   What were the actions
                                                 What is the impact on the                                                     What are the existing controls that
                                                                                        What causes the step to go                                                                             cause or for improving     the recommended          implemented? Include
                   In what ways can the step     customer if the failure mode                                                  either prevent the failure mode
                                                                                   10   wrong? (i.e., How could the       10                                              10          1000     its detection? You         action? What date        completion month/year       10    10    10    1000
                   go wrong?                     is not prevented or                                                           from occurring or detect it should it
                                                                                        failure mode occur?)                                                                                   should provide actions     should it be completed   (then recalculate
                                                 corrected?                                                                    occur?
                                                                                                                                                                                               on all high RPNs and       by?                      resulting RPN).
                                                                                                                                                                                               on severity ratings of 9
                                                                                                                                                                                               or 10.




                   Causes part to be difficult   Loose parts (flanges,etc) that         Too much torque inflicted on                                                                           Take out misshapen
Screws Stripping                                                                   2                                      8    Visual image.                               1           16                                 Team                     Replaced screws              2     8     1     16
                   to make it come out.          slide around the shaft.                screw.                                                                                                 screws with pliers.




                   Motor brakes not strong       Incorrect reading when motor
                                                                                                                               What are the existing controls that
                   enough to completely stop     driver tells motor to stop but         Not enough dampeners                                                                                   More washers.
Second Robot                                                                                                                   either prevent the failure mode                                                            Team (Implemented by
                   robot arm causing it to       momentum causes arm to            8    (washers) on second robot         10                                              10          800      Implement some kind                             Increased washers.               8    10    10    800
Arm                                                                                                                            from occurring or detect it should it                                                      10/22/2008 Wed)
                   read a different value then   continute swinging for a little        arm.                                                                                                   of brake system.
                                                                                                                               occur?
                   the desired one.              bit.




                                                                                                                                                                                                                                                   Crosschecking the code.
                                                                                                                                                                                                                                                   Increasing the code
                                                 Causes the robot to behave             Wrong syntax. Incorrect usage          Complier check. Operators and
                   Cause our process to                                                                                                                                                        Crosschecking the                                   efficency. Added stopper
Coding Errors                                    "randomly" to the operator.       4    of keywords in BASIC. Incorrect   5    associates cross checking the              10          200                                 Andy Luo                                              2     3     5     30
                   activate in a incorrect order                                                                                                                                               code.                                               code to skip reading
                                                 Incorrect data attained.               logical steps.                         code.
                                                                                                                                                                                                                                                   results if a result have
                                                                                                                                                                                                                                                   already been stored.




                                                Devices blowing up. Possible                                                                                                                   Tape up leads with
                                                                                                                               Black electrical tape covering
                    Shortages. Circuits blowing destruction of microprocessor           Resistors crossing. Leads that                                                                         electrical tape. Shorten                            Clean up circuit diagram.
                                                                                                                               leads. Cutting the resistors short
Incorrect circuitry up. Incorrect values being and motor drivers. Fuses            10   are touching each other without   6                                               10          600      resistors and make       Kevin Chui                 Made sure there are no       3     5     4     60
                                                                                                                               and taping it down with electrical
                    read.                       blown. Wires being pulled               the operator realizing it.                                                                             sure circuit is clean                               loose ends.
                                                                                                                               tape.
                                                out.                                                                                                                                           and easily identifable.




                                                Incorrect values read.
                   Reads potentiometer
                                                Causes premature exit                                                                                                                          Check circuity of
Sensor Not         values too early or too late                                         Incorrect use of schematics.           Hyperterminal to locate voltage
                                                condition for first while loop     9                                      4                                                5          180      sensors. Replace           David Tasker             Replacement of sensors.      1     2     5     10
Reading            causing incorrect values to                                          Faultly device.                        anomaly.
                                                under coding. Sensors not                                                                                                                      circuits.
                   be read
                                                working and hard to detected.




           aeb55cbe-1cea-4530-b390-6cf94c8ab3fb.xls                                                                                                                    Printed 2:30 AM,1/10/2013                                                                                                        Page 1 of 3
Failure modes and effects analysis (FMEA)

    Project:                                MAE 156A: Robot Competition                                                                Date:                                           10/19/2008

  FMEA Team:       A02 - Monday Afternoon                                                                                          Prepared by:                                             Andy Luo


SEV = How severe is effect on the customer?
OCC = How frequent is the cause likely to occur?
DET = How probable is detection of cause?
RPN = Risk priority number in order to rank concerns; calculated as SEV x OCC x DET


                                                                                 S                                  O                                              D            R                                                                                 N S   N O   N D   N R
                                                                                                                                                                                              Actions           Responsibility (target
 Process step        Potential failure mode        Potential failure effects     E          Potential causes        C      Current process controls                E            P                                                             Actions taken       e E   e C   e E   e P
                                                                                                                                                                                           recommended                date)
                                                                                 V                                  C                                              T            N                                                                                 w V   w C   w T   w N




                                                                                                                                                                                       Ream the plastic
                                                                                     Too much friction between          Visual imagery of the                                          flange. Add bearings    Andy Luo (Will
Friction Drive on Potentiometer not turning      Skewed final values. Wrong
                                                                                 8   plastic flange and             5   potentiometer not moving                   1           40      to plastic flange.      implemented by            None at this moment       8     5     1    40
Potentiometers giving us invalid data            location for LED to shine on.
                                                                                     potentiometer.                     although the motor belt is moving.                             Reduce tension on       10/22/2008 Wed)
                                                                                                                                                                                       friction drive.



Gear Ratio         Slipping of the timing belt   Slow completition speed. Too    5   Given ineffective gear ratio   9   Visual imagery of the timing belt          1                   Increase the gear ratio. Erick Barrientos (Will   None as of this moment
(39:5)                                           much excess torque.                                                    slipping. Motor running but belt not                           Increase the gear        Implemented by
                                                 Reduced performability.                                                moving.                                                        located on 5VDC          10/22/2008 Wed)
                                                                                                                                                                                       motor.
                                                                                                                                                                               45                                                                                  5     9     1    45




             aeb55cbe-1cea-4530-b390-6cf94c8ab3fb.xls                                                                                                          Printed 2:30 AM,1/10/2013                                                                                                  Page 2 of 3

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:1
posted:1/10/2013
language:Unknown
pages:3