Organizational Efficiency depends upon Improvement in P-ProductivityQ-QualityC-CostD-DeliveryS-Safety, Health & EnvironmentM-MoraleWhat is Productivity

Productivity = OutputInputFor fix or constant Output, to Improve Productivity What is in Our hand is to reduce InputHow it can be Done?No of VehiclesOr DeliverableManpower OrResource consumed

Deployment of Manpower is done on the basis of Work contentWork content is defined by usingWork Measurement

Work Measurement

What Is a Work measurement?A work measurement is a specification for performing a unit of work (operation).A work measurement addresses:How an operation should be performed (method)How long an operation should take (time)

Uses of Work Measurement Determine labor costsPlan and schedule workers and machinesDetermine feasibility of producing a new productPlan overall production scheduleSet production goalsReview achievement of goalsGauge individual or departmental efficiencyDetermine the actual costs of production

Work Measurement Systems History1 Time Study : F W Taylor1900s2 Motion Study: Gilbreth1920s3 PMTS (Predetermined Motion Time Systems): > MTM I (Methods Time Measurement)1940s> Work Factors 1950s> MTM II1950s> MOST (Maynard Operation Sequence Technique)1970s

What Is Time Study?Time Study is a work measurement technique that:Uses a stopwatch to time operationsAdjusts the time by applying a performance rating that reflects performance of an average worker

Average Trained WorkerA representative average of those employees who are trained and able to satisfactorily perform any and all phases of the work involved, in accordance with the requirements of the job under consideration.

Average Trained WorkerWorks with average skill and effortIs not a super-performer, not an under-achieverIs sufficiently trained

Normal Pace Consistent, continuous pacePace that can be maintained throughout the work period without causing undue fatigue

Performance RatingThe analyst observes the worker to determine if he/she is performing the work at an average level.If the worker is performing at an above average level, the performance rating increases the time.If the worker is performing at a below average level, the performance rating decreases the time.

What is a Predetermined Motion Time System (PMTS)?A work measurement technique that utilizes catalogs (tables) of standard times which are assigned to fundamental motions that make up an activity.The times for the fundamental motions are totaled to determine the normal time for performing the activity.

Features of PMTSEliminates the need for subjective performance ratingsAllows for simulation/forecastingFacilitates methods improvement

The History of PMTSPioneered by the micro motion studies of Frank and Lillian GilbrethManual activities are combinations of basic elements.Reduced motion = reduced time = higher productivityNumerous work measurement systems followed.

Methods Time Measurement (MTM)Developed by H. B. Maynard, in 1948Based on micro motions established by the GilbrethsIdentifies the variables which affect the time to perform each motion

Basic ElementsReachMoveTurnApply PressureGraspPositionRelease DisengageEye Travel Eye FocusLeg - Foot MotionSide StepTurn BodyWalkBendStoopKneel on One KneeKneel on Both KneesSit and Stand from a Sitting Position

Maynard Operation Sequence Technique (MOST)Considered a revolutionary PMTSDeveloped by Kjell Zandin and H. B. Maynard and Company, Inc. in 1974Based on MTM:The movement of objects follows consistently repeating patterns.Repeated patterns in the sequence of MTM have been consolidated.

Features of MOSTReduces application timeIs accurateIs easy to learn and useRequires a minimum of paperworkGenerates consistent resultsEncourages method improvementCan be used in a wide variety of industries100% performance levelactivity timings can be obtained in advance

MOST Work Measurement SystemsBasicMOSTThe most commonly used version of MOSTTypically used for :Activities that are medium cycle (a few seconds to approximately 10 minutes)Repetitive and non-repetitive activitiesAdminMOSTVersion of BasicMOST that focuses on analyzing administrative and clerical activities

MOST Work Measurement SystemsMiniMOSTProduces a very detailed and precise analysisTypically used for activities that:Are short cycle (approximately 20 seconds or less)Are highly repetitive; occur frequentlyFeature very little variationMaxiMOSTTypically used for setups, heavy assembly, maintenance or utilitiesLonger cycle activities (2 minutes to more than several hours)Activities that are non-repetitive or vary widely from cycle to cycle variations

MOST Analysis Components

Method DescriptionDocuments the action performedClear, concise and easily understoodComprised of recommended wordsExample:Pick up a marker that is three steps away on the floor and lay the marker aside on the flip chart.Method Description: Move 3 steps, bend & arise, grasp marker from floor, Move 3 steps, put on flip chart

Sequence ModelsSequence models represent the sequence of events that occurs when an object is moved or a tool is used.Predefined sequence models represent different types of activities.General Move (moved freely through space)Controlled Move (movement restricted; attached or in contact)Tool Use (using common hand tools)

MOST AnalysisExample:Pick up a marker that is three steps away on the floor and lay the marker aside on the flip chart.

A0 = No return necessaryHow did I PUT the object?RETURN?How did I GET the object? Get Put Return

Time CalculationTo arrive at the time for the step:Sum the index values.6 + 6 + 1 + 6 + 0 + 1 + 0 = 20Multiply by a factor of 10 to get time value (in BasicMOST).20 x 10 = 200 TMU

Time Measurement Units

MOSTMaynard Operations

Sequence

Technique

A MOST analysis is a complete study of an operation consisting of one or several method steps and corresponding sequence models,as well as appropriate parameter time values and total normal time for the operation. MOST concentrates on the movements of objects

Concept of MOSTIn Work, you move an objectGET and PUTFor example, you can lift a box and place it down three feet away.This is the foundation of BasicMOST and the sequence models that make up MOST.

Sequence ModelsThere are three types of sequence models:General MoveABG ABP AControlled MoveABG MXI ATool UseABG ABP _ ABP A

MOST AnalysisBreak down the task in method stepsEach method step involves the movement of an object:Freely Through Space GENERAL MOVEOver a Restricted Path CONTROLLED MOVEUsing a Tool TOOL USEApply the appropriate time values to each parameter in the sequence model.Total the time for the sub-operation

General Move

General MoveSpatial displacement of an object. The object follows an unrestricted path through the air.

Examples of General MovesGrasp an object and put it on a shelf.While holding a part, walk to a bin and drop part in.Take a washer from your pocket and put it on a bolt.

General Move PhasesParametersA = Action DistanceB = Body MotionG = Gain ControlP = Placement

Data Card

Action Distance

A0 - Any displacement of the fingers, hands, and/or feet, either loaded or unloaded. Eg. Reaching between the keys on a pocket calculator or placing nuts,washers on bolts located

The last parameter used to allocate time for an operator to return by walking to his or her workplace (starting position) Time for returning hand without steps is normally not allowed on the last A parameter, since moving hands to another object or objects is a part of the initial A parameter of the subsequent sequence model.A3- The trunk of the body is shifted or displaced by walking, stepping to the side, or turning the body around using one or two steps. Steps refer to the total number of times each foot hits the floor. (One step = 0.75 meter or 2 & feet)

Body Motion (B)Refers to either vertical (up and down) motions of the body or the actions necessary to overcome an obstruction or impairment to body movement.

B3 - bend and arise, 50% Occurrence. And Sit or stand without moving chair.

B6 - Bend and 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 and subsequently return to an upright position. Bending from waist with the knees stiff, stooping down by bending at the knees, or kneeling down on one knee.

B10 - Sit or Stand, When the act of sitting down or standing up requires a series several hand, foot, and body motions to move a chair or stool into a position that allows the body either Sit or Stand

B16 Stand and bend , Bend and Sit ,Climb On or Off

Gain Control (G)Gain Control covers all manual motions(mainly finger, hand, and foot employed to obtain complete manual control of an object and subsequently to relinquish that control.

G1 Light Object- GRASP Any type of grasp can be used as long as no difficulty is encountered. Pick up hammer from work bench, Obtain one washer from a parts bin full of washers.Grasp lever, crank, knob toggle switch, foot pedal. Light objects Simo, Picking Hammer and nail, pick up a pencil and a straight-edge, using both the hands.

G3 Light Object(s) Non Simo.- GET Because of the nature of job or the conditions under which the job is performed, the operator is unable to gain control of two objects or of two suitable grasping points of one object simultaneously.While one hand is grasping an object, the other hand must wait before it can grasp the other object.

G3 Heavy or Bulky - GETControl of heavy or bulky objects is achieved only after the muscles are tensed to a point at which the effects of the difficulty created by the weight, shape, or size are overcome.The hesitation or pause needed for the attainment of sufficient muscular force required to move the object.Eg Get hold of automobile battery located on the floor. Take hold of a loaded hand cart before pulling. Get hold of briefcase by reaching over other baggage. Pickup empty television packing box.

G3 Blind or Obstructed- GET,FREE The operator must feel around for the object before it can be grasped. The fingers or hand must be worked around the obstacle before reaching the object.

G3 DISENGAGE is characterized by the application of pressure (to overcome resistance) followed by the sudden movement and recoil of the object. The recoil of the object must follow an unrestricted path through air. Eg. Disengage tightly fitting socket from a ratchet tool. Remove knife stuck in wood. Disengage the cork from a wine bottle.G3 Interlocked The object is intermingled or tangled with other objects and must be separated or worked free before complete control is achieved. Eg. Remove hammer from crowded toolbox. From a box of springs, gain control of one spring that is tangled with another.

G3:COLLECT Gaining control of several objects is accomplished. The objects may be jumbled together in a pile or spread over a surface.

COLLECT WILL COVER gaining control of up to two objects ( two grasps) per hand I.e. a total of four if two hands are used simultaneously. E.g.. Grasp handful of nails from a bin. Collect several sheets of paper lying on the table. Get handful of change from your pocket.

Placement (P) Placement refers to actions occurring at the final stage of an objects displacement to align, orient or engage the object with another before control of the object is relinquished. Placement includes limited amount of insertion( up to 2, 5 cm.) as a part of placement. P0 Pickup object(s) PICKUP, CARRY. HOLD.Placement does not occur. The object is picked up and held. PICKUP should be used within reach and CARRY for a pickup followed by steps.P0 Toss object(s)-TOSS, THROW,The objects released during preceding move (action distance parameter) without placing motions or pause to point the object toward the target. Eg. Toss a finished part into a bin.Throw balled-up paper into a trash can.P1 Lay Aside - MOVEThe object is placed in an approximate location with apparent aligning or adjusting motions. This placement requires low control by mental, visual or muscular senses.

P1 Loose FitThe object is placed in more specific location, but tolerances are such that only modest amount of mental a,visual, or muscular control is necessary to place it.The clearance between engaging parts is loose enough so that a single adjusting motion, without application of pressure, is required to seat or position the object. Eg. Place washer on bolt. Put coat hanger on rack. Place dull pencil into a sharpener.

P3 Adjustments PLACE,REPLACEAdjustments are defined as the corrective actions occurring at the point of placement caused by difficulty in handling the object, closeness to fit uncomfortable working conditions.Eg. Place key in lock. Align center punch to scribe a mark.

P3 Light PressureDue to close tolerances or the nature of placement, application of force is needed to seat the object . e.g. Place moist stamp on a envelope Insert electric plug into a socket.

P3 Double PlacementsTwo distinct placements occur during the total placing activity. e.g. to assemble two parts held by fixture. Place an original on a photocopy machine

Parameter IndexingFollow sequence model and look up index values according to application rulesSum the index values1 + 0 + 3 + 1 + 0 + 1 + 0 = 6Multiply by 106 X 10 = 60 TMUGetPutReturnA B GA B PA1 0 31 0 10

Examples - Grasp a bolt & washer simultaneously from different bins, put washer on bolt.Get hand tray from 2-3 steps & return to keep it in vehicle.Get the cap of marker from table& Put the cap on the marker with light pressurePick up a large box within reach and stack it neatly in place on a pallet 2 steps awayTake a spring from bin & fit it on assembly which is below knee.After removal of plastic cover from subassembly, move 3 steps to dust bin, throw it and return to workplace.

FrequenciesOne or more of the parameters in the General Move Sequence can occur more than once.

Examples - FrequenciesPick up a book and put it within reach on a shelf. (repeat action for a second book) (A1B0G1 A1B0P1 A0) 2 Collect 4 pins from a bin and put them individually into 4 loose fitting slots (distances are within reach) A1B0G3 (A1B0P1) A0 (4)

Examples - FrequenciesCollect a handful of washers from a bin within reach and put on six bolts located 5 inches apart. A1B0G3 (A1B0P1) A0 (6)1+ 0 + 3 + ((1+0+1) X 6 )+ 0 = 1616 X 10 = 160 TMU

Controlled Move

Controlled MoveThe movement of objects along a controlled or restricted pathExamples of Controlled Moves:Push a button.Pull a lever 8 inches.Flip a switch.Press a clutch pedal.

Controlled Move PhasesParametersA=B=G=M=Move ControlledX=Process TimeI=Alignment

Data Card

M Move ControlledPush/Pull/PivotM0No Action

M1 Push/Pull/Pivot < 12 inches (30 cm.)Push ButtonPush or Pull SwitchRotate Knob

M Move ControlledPush/Pull/PivotM3 Push/Pull/Pivot > 12 inches (30cm.)Push/Pull with ResistanceSeatUnseatPush/Pull with High ControlPush/Pull with 2 Stages < 12 in. (30cm.) eachPush/Pull with 2 Stages < 24 in. Total

M Move ControlledPush/Pull/PivotM6Push/Pull with 2 Stages > 12 in. (30cm.)Push/Pull with 2 Stages > 24 in. Total Push with 1 - 2 Steps

M10 Push/Pull 3 - 4 Stages Push/Pull with 3-5 Steps

M16 Push with 6 - 9 Steps

M Move ControlledCrankCranking actions are performed by moving the fingers, hand, wrist, and/or forearm in a circular path more than half a revolution.M3 1 RevolutionM6 3 RevolutionsM10 6 RevolutionsM16 11 RevolutionsM24 16 Revolutions

M Move ControlledPush-Pull CrankingBack and forth movement of the elbow instead of pivoting at the wrist and/or elbow. This type of cranking is analyzed by using the number of pushes plus pulls as a frequency for the M1 parameter. (M3 if there is substantial resistance). Where possible, push-pull cranking should be replaced with pivotal cranking.

X Process TimeThe portion of work controlled by electronic or mechanical devices or machines, not by manual actions. Used for machine controlled activities having a fixed, short duration.

X Process TimeX0No Process TimeX1.5 Sec., .01 min., .0001 hr.X31.5 Sec., .02 min., .0004 hr.X62.5 sec., .04 min., .0007 hr.X104.5 sec., .07 min., .0012 hr.Note: Values are read up to and including.

I AlignmentManual actions following the Move Controlled or at the conclusion of process time to achieve an alignment or specific orientation of objectsEye Times are considered in the Alignment process.Area of normal vision requires no additional eye timeCircle 4 inch (10cm) in diameter at 16 inches (40cm) distanceIf one of the two points lies outside the area of normal vision, two separate alignments are required.Three CategoriesAlignment of Typical ObjectsAlignment of Machine ToolsAlignment of Non-Typical Objects

I AlignmentTypical ObjectsI0No AlignmentI1 Align to 1 PointI3 Align to 2 Points < 4 in. (10cm.)I6 Align to 2 Points > 4 in. (10cm.)I16 Align with Precision

I AlignmentMachining Tools

I3Align to Workpiece

I6Align to Scale Mark

I10Align Indicator Dial

I AlignmentNon-typical Objects (Flat, Large Flimsy, Sharp, Difficult to Handle)

I0Against Stop(s)I31 Adjustment to StopI62 Adjustments to Stop(s)1 Adjustment to 2 StopsI103 Adjustments to Stop(s)2-3 Adjustments to Linemark

Index the Sequence Model

A press operator grasps the handle of a safety gate within reach and pulls it open 15 inches.A punch press operator pushes two buttons simultaneously within reach to actuate the press. Press cycles for 2.5 seconds.Reach 2 grasping points on a box (non simo and within reach)and push the box along a conveyor walking 4 steps.Operator moves to trolley which 6 steps away & rotate trolley for other side of trolley to in front, with 8 steps.An operator gains control of a section of glass within reach and carefully slides into a fixture

Tool Use

Tool UseCombination of General Moves and Controlled Moves Covers the handling and use of toolsGet ToolPut ToolTool ActionAside ToolReturn

Tool UseExamples of Tool Use activities:Secure a cap on a bottle with 5 finger spins.Fasten a screw with a screwdriver 8 wrist turns.Loosen a nut with a wrench using 3 wrist strokes.Cut open a box with a knife.Read 3 words from purchase order.Wipe a surface with a cloth.

Tool Use PhasesF FastenL LoosenC CutS Surface TreatM MeasureR RecordT ThinkTool Use ParametersA B G Get ToolA B P PutToolTool ActionA B P AsideToolA Return

Tool Use AnalysisPick up a screwdriver from the table within reach and place it on the head of a screw, turn down the screw 9 wrist turns and set aside the tool.A1B0G1 A1B0P3 F16 A1B0P1 A0 = 240 TMU

Fasten / Loosen & Tool Placement

Cut, Surface Treat, Measure, Record and Think

F/L Fasten or LoosenIncludes manually or mechanically assembling or disassembling one object to or from another using the fingers, hand or a hand toolFinger ActionsWrist ActionsArm Actions

Index the Sequence ModelObtain a nut from a parts bin located within reach, place it on a bolt and fasten with 12 finger actions.A1 B0 G1A1 B0 P3F16 A0 B0 P0 A0=220 TMU

C CutManual actions employed to separate, divide or remove part of an object using a sharp-edged hand toolPliersScissorsKnife

S - Surface TreatActivities aimed at cleaning material or particles from or applying a substance, coating or finish to the surface of an objectAir-cleanBrush-cleanWipe

M MeasureActions employed to determine a certain physical characteristic of an object by comparison with a standard measuring device Identify Measurement DeviceProfile GaugeFixed ScaleCaliperFeeler GaugeSteel TapeDepth MicrometerOD-MicrometerID-Micrometer

R RecordManual actions performed with a writing instrument or marking tool for the purpose of recording informationWriteMark

T ThinkRefers to the use of sensory mental processes, particularly those involving visual perceptionInspectRead

Olny srmat poelpe can raed tihs. cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoatnt tihng is taht the frist and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deosnot raed ervey lteter by istlef, but the wrod as a wlohe. Amzanig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt!

Index the Sequence ModelAn operator picks up a job card (located within reach), reads the instructions (45 words), and asides the card 3 steps away.A1 B0 G1 A1 B0 P0 T24 A6 B0 P1 A0 = 340 TMU

Grasp bolt which is within reach, place it on assembly & fasten with 12 finger spins2. Take open end spanner from tool board, tighten a nut with 8 wrist strokes, put spanner again on board.3. Grasp a T wrench & fasten a bolt with 10 arm turns & put T wrench aside within reach4. Grasp pen from pocket & write 5 digits on Traveler card, keep pen back to pocket.5. Move to vehicle with 2 steps & read 6 words for model details.

Abhay S LomteExt. 8503M 9422404207Lomte.abhay@mahindra.com

Transition to ES: If standards are used for these things, need to be accurate. For this reason, ESThis slide appears in Edition 2. It follows slide PMTS-37.

Read definition of sequence models

Read definition of phase.

Read phase model.Work is the movements of objects following a tactical production outline. Efficient, smooth, productive work is performed when the basic motion patterns are tactically arranged and smoothly choreographed (methods engineering).

In work you move an object. There are two steps in moving an object: Get the object and Put the object (demonstrate). In work you have a get and a put. This is the foundation of the BasicMOST models.Text book, p. 8Objects can be moved in only one to two ways: either they are picked up and moved freely through space, or they are moved and maintain contact with another surface. For each type of move, a different sequence of events occurs; therefore, a separate MOST activity sequence model applies. The use of tools is analyzed through a separate activity sequence model that allows the analyst the opportunity to follow the movement of a hand tool through a standard sequence of events, where, in fact, is a combination of the tow basic sequence models.

Consequently, only three BasicMOST activity sequences are needed for describing manual work, plus a fourth for measuring the movements of objects with manual cranes.Build SlideM3, One Stage > 12 inches (30 cm) p. 56Object displacement is achieved by a movement of the hands, arms, or feet exceeding 12 inches (30 cm). The maximum displacement covered by this parameter occurs with the extension of the arm plus body assistance.Example: Push a carton across conveyor rollers. Pull a chain hoist full length. Close a cabinet door by pulling it shut. Open a file drawer full length.M3, Resistance, Seat/Unseat p.56Conditions surrounding the object or device require that resistance be overcome prior to, during, or following the Controlled Move. This parameter variant covers the muscular force applied to seat or unseat an object or, if necessary, the short manual actions employed to latch or unlatch the object. Also, the object is moved and resistance is present throughout the move.Includes up to 12 inches of movement in addition to unseat/unseat, resistance criteria.Example: Engage the emergency brake on an automobile. Twist on a radiator cap securely. Push a heavy box across a table.M3, High Control p. 56Care is needed to maintain or establish a specific orientation or alignment of the object during the Controlled Move. Characterized by a higher degree of visual concentration, this parameter variant is sometimes recognized by noticeably slower movements to keep within tolerance requirements or to prevent injury or damage.Example: Turn the dial on a combination lock to a specific number. Slide a fragile item carefully across a workbench. Carefully slide a plank toward a running table saw blade. Set a cup full of hot water on a table within reach.M3, Two Stages < 12 (30 cm) p. 56An object is displaced in two directions or increments a distance not exceeding 12 inches (30 cm) per stage without relinquishing control.Example: Engage and subsequently disengage the feed on a cutting machine with a short hand lever. Open and subsequently close a small tool box. Shift from first to the third gear with a manual transmission.Stages may occur in uneven increments providing they do not total more than 24 inches for both stages.This category refers to the manual actions employed to rotate such objects as cranks, handwheels and reels. These cranking actions are performed by moving the fingers, hand wrist and or forearm in a circular path more than half a revolution using 1 rotate wrist, 2 pivot at elbow, 3 Push pullAny motion less than half a revolution is not considered a crank and must be treated as a Push/Pull/Pivot.In addition to the actual cranking time, index values for Crank also include a factor that covers the actions that sometimes occur before or after the cranking motion. These actions may involve the application of muscular force to seat or unseat the crank or the short manual actions employed to engage or disengage the device undergoing the cranking motion. Index values for cranking are based on t he number of revolutions completed (rounded to the nearest whole number).Example: Move an engine lathe carriage by cranking a handwheel. Drill a hole in a wooden block by cranking the handle on a manual hand drill.Push - Pull Cranking p. 60Push-Pull cranking is analyzed by using the number of pushes plus pulls as a frequency for the M1 parameter. The M3 parameter is used if there is substantial resistance during cranking. Whenever possible, push-pull (reciprocal) cranking should be replaced by the more efficient pivotal cranking method.

Process time occurs as that portion of work controlled by electronic or mechanical devices or machines, not by manual actions. The X parameter of the Controlled Move sequence is intended to cover predominantly fixed process times of relatively short duration (up to the upper limit of the time range for index value 330).

As a rule of thumb, the process time expressed as an index number should not exceed 2 minutes for cycle times over 10 minutes or 20% of the cycle time for cycle times less than 10 minutes in order to maintain a consistent level of accuracy. If the process time exceeds these limits, the discrete value should be allowed on a separate line as Process Time (PT);Note: The actual clock time is never placed on the X parameter of the sequence model. Only the index value that statistically represents the actual time should be placed in the sequence model.Example: There is a process time of 6 seconds between the time a button is pushed and the time a photocopy machine produces a copy. After a switch is thrown, there is a warm-up period in a cathode ray tube. A punch press cycles in 1.5 seconds after the palm buttons are hit.Textbook, p.62Alignment refers to manual actions following the Move Controlled or at the conclusion of process time (I.e., adjust instrument setting) to achieve an alignment or specific orientation of objects.Normally, any adjusting motions required during a Controlled Move are covered in the M3 parameter variant for High Control. That index value, however, is not sufficient to cover the activity to line up an object to one or more points following the Move Controlled. This type of alignment is influenced by the ability (or inability) of the eyes to focus on the point(s) in more than one area at a time.The average covered by a single eye focus is described by a circle 4 inches (10 cm) in diameter at a normal reading distance of about 16 inches (40 cm) from the eyes. Within this area of normal vision, the alignment of an object to those points can be performed without any additional eye times. If one of the two points lies outside this area, tow separate alignments are required, owing to the inability of the eyes to focus on both points simultaneously. In fact, an object would first be aligned to one point, and then the object would be finally adjusted to correct for the minor shifting from the first point. The area of normal vision is therefore the basis for defining most of the Alignment parameter variants.