MOST - PowerPoint PPT Presentation

About This Presentation
Title:

MOST

Description:

MOST Maynard Operation Sequence Technique Work Measurement System Methods - Time Measurement H. B. Maynard was one of three persons instrumental in the creation of MTM. – PowerPoint PPT presentation

Number of Views:1304
Avg rating:3.0/5.0
Slides: 159
Provided by: LRA8
Category:
Tags: most | technique

less

Transcript and Presenter's Notes

Title: MOST


1
MOST
  • Maynard Operation Sequence Technique
  • Work Measurement System

2
Methods - Time Measurement
  • H. B. Maynard was one of three persons
    instrumental in the creation of MTM.

3
Kjell Zandin, while working in the Swedish
Division of H. B. Maynard in the late 1960s,
detected striking similarities in the sequence of
MTM defined motions whenever an object was
handled.
4
Under MOST, the primary work units are no longer
basic motions as in MTM, but collections of these
basic motions dealing with moving object.
5
MOST makes the assumption that to move an object,
a standard sequence of events occurs.
6
Under MOST, objects can be moved in only one of
two ways
  • They are picked up and moved freely through space
    -- the GENERAL MOVE.
  • They are moved and maintain contact with another
    surface -- the CONTROLLED MOVE.

7
The MOST Family
  • Basic MOST -- General Operations
  • Mini MOST -- Repetitive Operations
  • Maxi MOST -- Non-repetitive Operations
  • Clerical MOST -- Clerical Operations

8
Maxi MOST is used to analyze operations that are
likely to be performed less than 150 times per
week.
9
Basic MOST is used for operations that are likely
to be performed more than 150 times but less than
1500 times per week.
10
Mini MOST is used to analyze operations likely to
be repeated more than 1500 times per week.
11
The Decision Diagram provides a simple procedure
for selecting the most appropriate MOST Work
Measurement System to use.
12
The MOST Decision Diagram is based on /- 5
accuracy and a 95 confidence level.
13
System Selection Charts may be used in lieu of
the Decision Diagram for choosing the best MOST
Work Measurement System to use.
14
The MOST Standard Form provides the analyst with
a simple, consistent format for analyzing work
using the method.
15
It should be possible to complete a MOST analysis
by observing two complete cycles of work in slow
motion.
16
If the method is well established and the analyst
knows the operation and conditions, the Basic
MOST calculations can be made from the office and
used to predict the times for a new procedure.
17
General Rules for Using MOST
  • Each sequence model is fixed.
  • No letter may be added or omitted for the General
    or Controlled Move Sequence.
  • In general, no letter may be added or omitted for
    the Tool Use Sequence, with a few exceptions.

18
General Move Sequence
19
Four subactivities constitute the General Move
Sequence
  • A Action Distance (mainly horizontal)
  • B Body Motion (mainly vertical)
  • G Gain Control
  • P Placement

20
Roughly 50 of all manual work occurs as a
General Move.The percentage runs higher for
assembly and material handling and lower for
machine shop operations.
21
The General Move follows a fixed sequence of
steps
  • Reach, either directly or in conjunction with
    body motions or steps.
  • Gain control of the object.
  • Move the object, as in reach.
  • Place the object in temporary or final position.
  • Return to the workplace.

22
The General Move Sequence Model
  • A B G A B P A

23
Action Distance (A)
  • This parameter is used to analyze all spatial
    movement or actions of the fingers, hands, and/or
    feet.

24
A0 lt 2 Inches
  • This is any displacement of the fingers, hands,
    and/or feet a distance of 2 inches or less.

25
A1 Within Reach
  • Actions that are confined to an area described by
    the arc of the outstretched arm pivoted about the
    shoulder.

26
A3 One to Two Steps
  • The trunk of the body is shifted or displaced by
    walking, stepping to the side, or turning the
    body around using 1 or 2 steps.

27
More Than 2 Steps
  • Used with Action Distance data table to cover
    longer movements.

28
Body Motion (B)
  • This parameter is used to analyze either vertical
    motions of the body or the actions necessary to
    overcome an obstruction or impairment to body
    movement.

29
B6 -- Bend Arise
  • From an erect standing position, the trunk of the
    body is lowered by bending from the waist and/or
    knees to allow the hands to reach below the knees.

30
B3 -- Bend Arise, 50 Occurrence
  • Bend Arise is required only 50 of the time
    during a repetitive activity.

31
B10 -- Sit or Stand
  • A series of several hand, foot, and body motions
    to move a stool / chair into position followed by
    the body sitting or standing.

32
B16 -- Stand and Bend
  • This is a case where a sitting person must stand
    up and walk to a location to gain control of an
    object placed below knee level, where a Bend
    Arise is required.

33
B16 -- Bend Sit
  • This applies when gaining control of an object
    requires a Bend Arise followed by a Sit prior
    to placing the object.

34
B16 -- Climb On or Off
  • This parameter variant covers climbing on or off
    a work platform on any raised surface (3 ft)
    using a series of hand and body motions to lift
    or lower the body.

35
B16 -- Passing Through Door
  • Passing through a door consists of reaching for
    and turning the handle, opening the door, walking
    through the door, and subsequently closing the
    door.

36
Gain Control (G)
  • This parameter is used to analyze all manual
    motions employed to obtain complete manual
    control of an object(s) and to subsequently
    relinquish that control.

37
G1 -- Light Object
  • Gain control of an object by grasping it as long
    as no difficulty is encountered.

38
G1 -- Light Objects Simo
  • One hand gains control of a light object while
    the other hand obtains another light object.

39
G3 -- Light Object(s) Non-Simo
  • While one hand is grasping an object, the other
    hand must wait before it can grasp the other
    object.

40
G3 -- Heavy or Bulky
  • In grasping a heavy or bulky object there is a
    delay between when the object is grasped and when
    it begins to move due to weight, bulk, etc.

41
G3 -- Blind or Obstructed
  • Access to the object is restricted because an
    obstacle prevents the operator from seeing the
    object or creates an obstruction to the
    hand/fingers in attempting to gain control.

42
G3 -- Disengage
  • An application of muscular force to free an
    object from its surroundings typified by a need
    to overcome resistance followed by sudden
    movement and recoil of the object.

43
G3 -- Interlocked
  • Interlocked means the object is intermingled or
    tangled with other objects and must be separated
    or worked free before reaching control.

44
G3 -- Collect
  • Gain control of several objects jumbled together
    in a pile or spread out on a surface.

45
Placement (P)
  • This parameter is used to analyze actions at the
    final stage of an objects displacement to align,
    orient, and/or engage the object with other
    object(s) before control of the object is
    relinquished.

46
P0 -- Pickup Objects
  • This is placement in which no placement occurs.
    The object is picked up and held.

47
P0 -- Toss Object(s)
  • Another placement where placement does not
    occur. The object is released during the action
    distance (A) parameter without placing motions
    or pause to point the object toward the target.

48
P1 -- Lay Aside
  • The object is placed in an appropriate locations
    with no apparent aligning or adjusting motions.

49
P1 -- Loose Fit
  • The object is placed in a more specific location
    than described by the Lay Aside parameter, but
    with tolerances so loose that only a modest
    amount of control is needed for placement.

50
P3 -- Adjustments
  • Adjustments are defined as the corrective actions
    occurring at the point of placement, and
    recognized by obvious efforts, hesitations, or
    correcting motions to align, orient, and/or
    engage the object.

51
P3 -- Light Pressure
  • Because of close tolerances or the nature of the
    placement, the application of muscular force is
    needed to seat the object.

52
P3 -- Double
  • With double, two distinct phases occur during
    the total placing activity.

53
P6 -- Care or Precision
  • Extreme care is needed to place an object within
    a closely defined relationship with another
    object, and characterized by the obvious slow
    motion of the placement due to the high degree of
    concentration required.

54
P6 -- Heavy Pressure
  • As a result of very tight tolerances, a high
    degree of muscular force is needed to engage the
    object.

55
P6 -- Blind or Obstructed
  • Accessibility to the point of placement is
    restricted because an obstacle prevents the
    operator from seeing the point of placement, or
    creates an obstruction to the hand/fingers when
    attempting to place the object.

56
P6 -- Intermediate Moves
  • Several intermediate moves of the object are
    required prior to placing.

57
General Move Example
  • From a stack located 10 feet away, a heavy object
    must be picked up and moved 5 feet and placed on
    top of a workbench with some adjustments.

58
General Move Example
  • An assembly worker gets a handful of washers (6)
    from a bin located within reach and puts one on
    each of six bolts located within reach, which are
    four inches apart.

59
General Move Example
  • A worker gains control of two fittings that are
    within reach and located more than two inches
    apart, one at a time, and places them on separate
    trays that are within reach and located less than
    2 inches apart.

60
B3 -- Sit or Stand without Moving Chair
  • When the body is simply lowered into a chair from
    an erect position, without hand/foot motions
    required to manipulate the chair.

61
P3 -- Loose Fit Blind
  • In this case the operator must feel around for
    the placement location before a loose placement
    can occur.

62
Controlled Move Sequence
63
Three new subactivities are found in the
Controlled Move Sequence
M Move Controlled X Process
Times I Align
64
The Controlled Move Sequence describes the manual
displacement of an object over a controlled
path.
65
The Controlled Move follows a fixed sequence of
steps
Reach, either directly or in conjunction with
body motions or steps. Gain control of the
object. Move the object over a controlled
path. Allow time for the process to occur. Align
the object after the move/process. Return to the
workplace.
66
A Controlled Move is performed under the
following conditions
  • The object or device is restrained by its
    attachment to another object
  • Its controlled during the move by the contact it
    makes with the surface of another object.
  • It must be moved on a controlled path to
    accomplish the activity.

67
Move Controlled (M)
  • This parameter is used to analyze all manually
    guided movements or actions of an object over a
    controlled path.

68
M1 -- One Stage lt 12
  • Object displacement is achieved by a movement of
    the fingers/hands/feet not exceeding 12 inches.

69
M1 -- Button/Switch/Knob
  • The device is actuated by a short pressing,
    moving, or rotating action of the
    fingers/hands/wrist/feet.

70
M3 -- One Stage gt 12
  • Object displacement is achieved by a movement of
    the hands, arms, or feet, plus body motion,
    exceeding 12 inches.

71
M3 -- Resistance, Seat/Unseat
  • Conditions surrounding the object or device
    require that resistance be overcome prior to,
    during, or after the Controlled Move.

72
M3 -- High Control
  • This parameter reflects the need to align an
    object using a high degree of visual
    concentration.

73
M3 -- Two Stages lt 12
  • An object is displaced in two directions or
    increments a distance not exceeding 12 inches per
    stage without relinquishing control.

74
M6 -- Two Stages gt 12 -- OR-- With One - Two
Steps
  • An object is displaced in two directions or
    increments a distance exceeding 12 inches per
    stage without relinquishing control.

75
M10 -- Three to Four Stages --- OR --- 3 -
5 Steps
  • An object is displaced three or four directions
    or increments without relinquishing control or
    pushed/pulled on a conveyor belt.

76
M16 -- Move Controlled with 6 - 9 Steps
  • Push or pull an object(s) using 6 - 9 steps.

77
Cranking action is performed by moving the
fingers, hand, wrist, and/or forearm in a
circular path more than half a revolution. Less
than this is considered a Push/Pull/Pivot.
78
Push - Pull Cranking
  • If cranking results in a back - and - forth
    movement of the elbow instead of pivoting at the
    wrist and / or elbow, it is considered push -
    pull cranking.

79
Pivotal cranking is more efficient than push -
pull cranking, and should be used whenever
possible.
80
Process Time
  • Process time is that portion of work controlled
    by electronic or mechanical devices / machines,
    not by manual actions.

81
As a rule of thumb, the process time expressed as
an index number should not exceed 20 of the
cycle time.
82
Alignment refers to manual actions following the
Move Controlled or at the conclusion of process
time to achieve an alignment or specific
orientation of objects.
83
Within the area of normal vision (a 4 diameter
circle), the alignment of an object to two points
can be performed without any additional eye
times.
84
I1 -- To One Point
  • Following a controlled move, an object is aligned
    to one point.

85
I3 -- To Two Points lt 4 Apart
  • The object is aligned to points not more than 4
    inches apart following a Controlled Move.

86
I6 -- To Two Points gt 4 Apart
  • The object is aligned to points more than 4
    inches apart following a Controlled Move.

87
I16 -- Precision
  • The object is aligned to several points with
    extreme care or precision following a Controlled
    Move.

88
I3 -- To Workpiece
  • A Machining Operations parameter where the
    machine tool is aligned to the workpiece prior to
    making a cut.

89
I6 -- To Scale Mark
  • Another Machining Operations parameter, the
    machine tool is aligned to a scale mark prior to
    making a cut.

90
I10 -- To Indicator Dial
  • The third Machining Operations parameter, the
    machine tool is aligned to the correct indicator
    dial setting prior to making a cut.

91
Alignment of Nontypical Objects
  • Nontypical objects are those that are especially
    large, flimsy, sharp, or require special handling.

92
Alignment of a nontypical object normally takes
place as a series of short correcting motions (lt
2) following the Controlled Move, usually with
the assistance of stops, guides, or marks.
93
Controlled Move Example
  • From a position in front of a lathe, the operator
    takes two steps to the side, turns the handwheel
    two rotations, and sets the cutting tool by
    aligning the handwheel dial to a scale mark.

94
Controlled Move Example
  • A milling machine operator walks four steps to
    the quick-feeding cross lever and engages the
    feed. The machine time following the 4 lever
    action is 2.5 seconds.

95
Controlled Move Example
  • A material handler takes hold of a heavy carton
    with both hands and pushes it 18 across conveyor
    rollers.

96
Controlled Move Example
  • Using the foot pedal to activate the machine, a
    sewing machine operator makes a stitch requiring
    3.5 seconds process time. The operator must
    reach the pedal with the foot.

97
The Tool Use Sequence is a combination of the
General Move and Controlled Move activities.
98
Tools not listed in the tables that are similar
to a tool in the table can use their time values
for analysis.
99
Tool Use Phases
  • Get Tool (Object)
  • Put Tool (Object) in Place
  • Use Tool
  • Put Tool (Object) Aside
  • Return

100
The Tool Use Sequence model makes use of the A,
B, G, and P parameters, which are all
familiar to us, plus the new Tool Use parameters.
101
The Tool Use Sequence Model
  • A B G A B P A B P A
  • consists of the tool use parameters F, L, C,
    S, M, R, T.

102
Tool Use Sequence Parameters
  • F -- Fasten
  • L -- Loosen
  • C -- Cut
  • S -- Surface Treat
  • M -- Measure
  • R -- Record
  • T -- Think

103
Fasten / Loosen
  • Manually or mechanically assembling or
    disassembling one object to or from another using
    the fingers, a hand, or hand tools.

104
Index values for F and L are determined by
the body member performing the action.
105
Finger Spins are the movement of the fingers and
thumb to run a threaded fastener down or out, and
include a light application of pressure for
seating / unseating the fastener.
106
Wrist Actions
  • Wrist Turn
  • Wrist Stroke (with reposition)
  • Wrist Crank
  • Tap

107
Wrist Turn
  • During a wrist turn, the tool is not removed from
    the fastener during use and not repositioned on
    the fastener after an action.

108
Wrist Stroke (with reposition)
  • In this tool use, after each stroke with the tool
    and before making each subsequent stroke, the
    tool must be removed from the fastener and
    repositioned.

109
Wrist Crank
  • Wrist crank applies to tools that are spun or
    rotated around a fastener while remaining affixed
    to it.

110
Tap
  • This parameter covers the use of a hammer (or
    similar device) to exert short tapping motions by
    pivoting the hand at the wrist.

111
Arm Actions
  • Arm Turn
  • Arm Stroke (with reposition)
  • Arm Crank
  • Strike
  • T-Wrench (two hands)

112
Arm Turn(s)
  • Arm Turn(s), applying to ratchets, occur when the
    tool is held near the end of the handle,
    resulting in a pulling action on the tool.

113
Arm Stroke (with reposition)
  • Following each stroke or pull with the tool, it
    must be removed and repositioned again on the
    fastener before making a subsequent pull.

114
Arm Crank
  • The tool is used with a circular movement of the
    forearm as it is pivoted at the elbow or the
    shoulder to push or crank the tool around the
    fastener.

115
Strike
  • Strike is the use of a hammer with an up - and -
    down motion performed with the hand as it is
    pivoted from the elbow.

116
T-Wrench (two hands)
  • A two - handed arm action, including the reach
    for each hand to the opposite handle before
    making the next turn, and involving a 180 degree
    turn of the T-wrench with each action.

117
Power Tools
  • The use of electric and pneumatic power wrenches
    to run a standard threaded fastener down or out a
    length 1 1/2 times the bolt diameter.

118
The time values generated by the data card for
power tool use must be compared to the times
generated by the tools used in the shop, and
adjusted if necessary.
119
Torque Wrenches
  • F6 -- Torque wrench handle length to 10.
  • F10 -- Handle length from 10 - 15.
  • F16 -- Handle length from 15 - 40.
  • In all cases, the value is for one arm action and
    includes the time either to align the dial or to
    await the click.

120
Tool Placement
  • As a general rule, the P parameter for the
    Fasten / Loosen tools will carry the index values
    indicated in the Tool Placement table.

121
Tool Use Frequencies Example
  • An operator picks up a screwdriver within reach
    and tightens two screws with six wrist turns each
    and then sets aside the screwdriver.

122
Multiple Tool Actions Example
  • A screw is fastened with a screwdriver. A total
    of 18 spins and 4 wrist turns are necessary.

123
Multiple Tool Actions Example
  • A nut is fastened with a ratchet wrench.
    Following 3 wrist cranks, 6 wrist turns are
    applied.

124
Tool Use Example -- F / L
  • Obtain a nut from a parts bin located within
    reach, place it on a bolt, and run it down with 7
    finger actions.

125
Tool Use Example - F / L
  • Pick up a small screwdriver that lies within
    reach and fasten a screw with 6 finger actions,
    and set aside the tool.

126
Tool Use Example -- F / L
  • Obtain a power wrench that lies within reach, run
    down four 3/8 bolts located 6 apart, and set
    aside wrench.

127
Tool Use Example -- F / L
  • From a position in front of an engine lathe,
    obtain a large T-wrench located 5 steps away and
    loosen one bolt on a chuck on the engine lathe
    with both hands using five arm actions. Set
    aside the T-wrench from the machine, but within
    reach.

128
Cut
  • Pliers
  • Scissors
  • Knife

129
Pliers
  • C3 -- Soft Using pliers with one hand and
    making one cut.
  • C6 -- Medium Using pliers with one hand and
    making two cuts.
  • C10 -- Hard Using the pliers with two
    hands and making two cuts.

130
Pliers
  • C1 -- Grip Using pliers to hold an item and
    subsequently release the pressure on the item.
  • C6 -- Twist Close pliers jaws on two wires and
    use two twisting actions to join the wires
    together.
  • C6 -- Form Loop Close pliers jaws on wire and
    using two actions, bend loop in end of wire.
  • C16 -- Secure Cotter Pin Use pliers to bend both
    legs on cotter pin to hold it in position.

131
Index values using scissors are selected
according to the number of cuts used.
132
Tool Use Example -- Cut
  • An operator picks up a knife from a workbench two
    steps away, makes one cut across the top of a
    cardboard box, and sets aside the knife on the
    workbench.

133
Tool Use Example -- Cut
  • During a sewing operation, a tailor cuts the
    thread from the machine before setting aside the
    finished garment. The scissors are held in the
    palm during the sewing operation.

134
Tool Use Example -- Cut
  • Following a soldering operation, an electronic
    component assembler must cut off the excess small
    - gauge wire from a terminal connection. The
    pliers are located within reach.

135
Tool Use Example -- Cut
  • An electrician working on transmission lines
    takes a pair of pliers from the tool belt and
    cuts off a piece of line. The line is heavy,
    such that 2 hands are needed to cut through the
    wire.

136
Surface Treat
  • Surface Treat covers the activities aimed at
    cleaning material or particles from or applying a
    substance, coating, or finish to the surface of
    an object.

137
Index values for cleaning tools are based
primarily on the amount of surface area (sq. ft.)
cleaned.
138
Tool Use Example Surface Treat
  • Before marking off a piece of sheet metal (4 ft
    sq) for a cutting operation, the operator takes a
    rag from his or her back pocket and wipes an oily
    film from the surface.

139
Tool Use Example Surface Treat
  • Following a sanding operation, an operator
    standing at a workbench picks up a brush located
    within reach and brushes the dust and chips from
    the working are (6 ft sq), and then sets aside
    the brush on the workbench.

140
Tool Use Example Surface Treat
  • Before assembling three components to a casting,
    the operator obtains an air hose (within reach)
    and blows the small metal filings left from the
    previous machining operation out of 3 cavities.
    The distance between cavities is gt 2.

141
M10 -- Profile Gauge
  • Used to compare the profile of an object to that
    of the gauge.

142
M16 -- Fixed Scale
  • Covers the use of a linear (yardstick) or angular
    (protractor) measuring device.

143
M16 -- Calipers lt 12
  • Covers the use of vernier calipers with a
    capacity to 12 inches.

144
M24 -- Feeler Gauge
  • Covers the use of a gauge to measure the gap
    between two points.

145
M32 -- Steel Tape lt 6 Ft.
  • This parameter covers the use of a steel tape to
    measure, from a fixed position, between two
    points.

146
Micrometers lt 4
  • M32 -- Depth measurement
  • M42 -- Outside diameter measurement
  • M54 -- Inside diameter measurement

147
Tool Use Example -- Measure
  • Before welding two steel plates, a welder obtains
    a square and checks the angle between the plates
    to see that it is correct. The square (a profile
    gauge) is located three steps away on a workbench.

148
Tool Use Example -- Measure
  • Following a turning operation, a machinist checks
    the diameter of a small shaft with a micrometer.
    The micrometer is located on and returned to the
    workbench 2 steps away.

149
Measure Supplemental Values
  • M6 -- Snap gauge OD to 2
  • M10 -- Snap gauge OD to 4
  • M16 -- Plug gauge go/no-go to 1
  • M24 -- Thread gauge go/no-go int/ext to 1
  • M24 -- Vernier Depth Gauge to 6
  • M42 -- Thread gauge go/no-go int/ext 1-2

150
Record
  • Write covers routine clerical activities.
  • Index value based on number of digits or words
  • Mark covers marking object
  • Each mark is considered a digit

151
Tool Use Example -- Record
  • After finishing an assigned job, the operator
    picks up a clipboard and pencil (simo) from the
    workbench, fills out the completion date on the
    job card, and signs his name. He then returns
    the board and pencil to the workbench.

152
Tool Use Example -- Record
  • To order a part, a clerk takes a pencil from her
    shirt pocket and writes a six-digit part number
    on the requisition form on her desk. She then
    clips the pencil back in her pocket.

153
Tool Use Example -- Record
  • Part of a packing operation involves identifying
    the components in the carton. This involves
    picking up a felt marker (within reach) and
    marking a 6-digit number on the container.

154
Think
  • Most of the time think occurs internal to the
    manual work, but there are times it must be
    considered as a separate activity.

155
Think -- Inspect
  • The type of inspection work were looking at here
    is that where only simple yes / no decisions
    are quickly made on the existence of a particular
    defect in a part.

156
Inspect -- Read
  • The column Digits or Single Words is to be used
    for reading technical data (part numbers, codes,
    quantities, etc.)
  • The column Text of Words is used when analyzing
    situations in which the operator reads words
    arranged into sentences or paragraphs.
  • Other, specialized, values exist for reading
    gauges, scales, date/time, tables.

157
Tool Use Example -- Think
  • During a testing operation, an electronics
    technician picks up a meter lead, places it on a
    terminal, and reads voltage off the meter scale.
    The lead is then put aside.

158
Tool Use Example -- Think
  • Prior to starting a turning operation, an
    operator picks up a work order set and reads a
    paragraph that describes the method to be
    followed. It contains an average of 30 words.
    The operator then places the set aside on the
    workbench.
Write a Comment
User Comments (0)
About PowerShow.com