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Before We Start

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Lisa Eitel Motion Editor — Power Transmission and

Motion Control Design World Magazine

David R. Bickert Regional Sales Manager Nexen Group Inc.

Meet your Speakers

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What we’re going to cover in this webinar on rotary indexing

Mechanical options

Servo options Q&A

Typical applications General assembly transfer considerations

Rotary transfer uses

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Traditional option for rotary indexers — mechanical cams

• Been around in rotary-indexing tables for years • Low cost • Limited to single index the same angle • Real strength: Precision moves • Use a mechanical cam to move loads into position; curved surface engages a follower

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Rotary indexing systems abound, and the most suitable varies

Cycles on demand setups: The camshaft turns once to advance the output one position

45°

270° 360°

Index Dwell

Ou

tpu

t (β)

Input

Courtesy Cam Driven Systems

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Gearing type (worm to planetary) in index drives — serve very specific functions

Courtesy Peerless-Winsmith Inc.

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Second option … continuous operation

Continuous setups: • Motor always runs the camshaft • Cam profile dictates dwell time

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Mechanical cam indexers — include globoidal cam or barrel cam

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Mechanical cam indexers — include globoidal cam or barrel cam

Globoidal cam arrangement: • Right angle output • Oscillating output from constant input

Barrel cam arrangement: • Right angle output

• High torque • Ability to handle

horizontal loads

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Rotary indexing servo options: Traditional …

Programmable servo tables: • Can deliver flexible motion output • Can deliver fast positioning and long dwells

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Rotary indexing servo options: Traditional … and direct drive

Find the Hurley Gill article: motioncontroltips.com/2015/05/29/how-to-change-a-servomotors-inertia-ratio-to-boost-efficiency

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Rotary indexing servo option: Direct drivesCase in point …IntelLiDrives rotary table: • ACR-55UT with center aperture • 1/10 to 1,000 rpm • Velocity ripple of less than 0.1% • Very different output from traditional setups with mechanical linkages

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Some manufacturers offer both traditional setups and direct-drive indexing

Direct-drive option from Bell Everman are for precision … and accuracy of ± 12 arc-sec or to ± 6 arc-sec in special designs

Belt-driven option from Bell Everman — Compact high-torque rotary stages with openings and speed comparable to direct-drive rotary tables costing thousands more

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In summary, the mechanical and (or) electronic setup must fit the application

Direct drive options — Cost more, but are flexible • Work on lines processing multiple products

Traditional drive options — Indexers based on mechanical cams are reliable (as they have fewer components) • Mechanical-cam designs are simple and easy to maintain • They deliver accurate repetition of motion, even over high-volume production.

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Now let’s turn things over to David R. Bickert for Nexen Group …

Q&A David R. Bickert Regional Sales Manager

Nexen Group Inc.

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ThispictureiscourtesyofICONIndustries—itshowstheir6-250machine.ThedesignintegratesintoaProducAvityCenterwithuptoeightstandardmoduleswitheitherverAcalorhorizontalspindleorientaAonaswellasa12-toolATCandindexorrotarytablepermodule.Icon250machiningmodulesareflexible.CNCprogrammabilityissimple;mulA-unitsoKwareenablestransferswithoutthecomplicatedsetupofnon-CNCtechnology.

RotaryIndexingisOKenthe“Heart”oftheMachineCell

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IndexingTechnologies•  BeltDrives

•  HighSpeedApplicaAonsatLowCost•  FeedbackControlstoControlAccuracyLimitaAons

•  Cams•  DurableandLowMaintenance•  FixedIndexDisplacementLimitsFlexibility

•  DirectDriveMotor•  FlexibleProgramming•  CanHaveLimitedOutputBearingCapacity

•  RollerPinion&GearTechnology–CombinesFeatures

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MechanicalPrecision&ServoControl

NexenCRD-DDProduct

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RPS

Technology

•  Bearing-Supported Rollers Engage a Unique Tooth Profile

•  Two or More Rollers Engage Rack Teeth in Opposition at All Times

•  Virtually Eliminates Cumulative Error •  Reduced Noise Levels •  No Tooth Slap or Ball Return Noise

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Creating Theoretical Teeth Creating Initial Curve

Roller Modified Teeth Modified For Zero Backlash

RollerPinionSystem

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High Precision Gearhead

Nexen Pre-loader

ISO Mount Roller Pinion

Pinion and Gear Guards Roller Gear

High Precision Cross Roller Bearing

Mounting Plate

•  ProgrammableIndexDisplacement

•  FlexibleMounAngOrientaAons

•  LowBacklash•  HighLoadCapacity

•  PRD1500SystemAccuracyof

+/-11ArcSec•  Repeatabilityof

+/-1.2ArcSec•  HighTorqueto

InerAaRaAo

NexenPRDDesign

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NexenCRDProduct

TypicalIndexing

NexenPRDProduct

12StaAonDialPlateIndexingDesignonNexenCRD-DDProduct

ExternalDialPlate

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OutputBearingConsideraAons

(DialPlateParallelToFloor)

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Nexen Roller Pinion and Gear

ExternalForceConsideraAons

Nexen Compact Ring Drive (CRD)

f(axial)

f(axial)

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OrientaAonFlexibility•  ThingstoConsider

•  BearingCapacityforAllOrientaAons•  DoesLubricaAonDesignAllowAll

OrientaAons?

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HeadstockTypeIndexing

NexenPRDProduct

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CenterOpeningConsideraAon

NexenPRDProduct

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StaAonaryCenter-PostConsideraAon

NexenCRDProduct

BoltPa`ernforStaAonary‘Add-On’Tooling

Access‘Hole’ThroughCenterforWiring&Plumbing

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AccuracyandRepeatability

NexenCRD-DD

HighPrecisionMechanical/ServoControlEliminatestheNeedto‘Pin’DialPlate

Accuracy:•  RotaAonalError•  DeviaAonof

MeasuredValuefrom‘True’Value

Repeatability”•  ErrorBetweena

NumberofSuccessiveA`emptstoMovetotheSamePosiAon

C B A

ArcSecond=1/3600ofadegree

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Low Repeatability, Low Accuracy

High Repeatability, Low Accuracy

High Repeatability, High Accuracy

AccuracyandRepeatability

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00.050.1

0.150.2

0.250.3

0.350.4

0.450.5

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Velo

city

(m/s

)

Time (Sec)

Motion Profile

Travel (d) 2 feet 0.6096 meters

Max Speed (Vm) 2 ft/sec 0.6096 m/sec

Accel Rate (A) 2 ft/sec^2 0.6096 m/sec^2

MoAonProfile-Triangular:

Vavg = x/t

Vmax = 2 * Vavg = 2x/t

A = Vmax / ta = 4x/t^2

Area = x

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MoAonProfile-Trapezoidal:

Vavg = x/t

Vmax = 1.5 * Vavg

A = Vmax / ta = 4.5x/t^2

Area =x

t/3 t/3 t/3

Travel (d) 1.5 feet 0.4572 meters Max Speed (Vm) 1.5 ft/sec 0.4572 m/sec Accel Rate (A) 3 ft/sec^2 0.9144 m/sec^2

00.05

0.10.15

0.20.25

0.30.35

0.40.45

0.5

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Velo

city

(m/s

)

Time (Sec)

Motion Profile

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MoAonProfile–(RotaryExample)

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DialPlate

Fixture&ProductWeight

InerAaofIndexingDialPlateDialPlate

Note:InerAaofIndexingProductMustbeConsideredinAddiAontoLoadInerAa

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Example:InerAaofIndexingDialPlate

𝜌=𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑑𝑒𝑛𝑠𝑖𝑡𝑦 𝑜𝑓 𝑝𝑙𝑎𝑡𝑒 (kg/m^3)𝜋=3.1415927 (𝑢𝑛𝑖𝑡𝑙𝑒𝑠𝑠 )h = thickness of plate (m)r = radius of plate O.D. & I.D. (m)

Density = 2768 kg/m^3Thickness = 0.0254 mOuter radius = 0.610 mInner radius = 0.483 m

( 𝜋∗2768∗0.0254)/2∗(0.610↑4 − 0.483↑4 )=9.281 𝑘𝑔 𝑚^2

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DialPlate

Fixture&ProductWeightataStaAon

R

InerAaofFixture&ProductWeight

I Station = m * R2

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Torque(Friction) = Coefficient of Friction x Weight x Radius(Rollers)

AddiAonalTorqueDueToFricAon

RweightDialPlate

Rollers

Rollers

DialPlate

FricAonfromBearingDragShouldAlwaysBeConsidered

RollersUnderDialPlateADDtoOutputTorque

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•  Holding Brake or Torque Limiter Considered in “Power – Off” Conditions

•  Output Brake - Zero Backlash •  Output Brake Holds Load •  Torque Limiter Disconnects Load •  Output Brake Maintains a Small Through Hole

Output“Holding”Brake&TorqueLimiter

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RotaryIndexingApplicaAonEglishStandard(Imperial)UnitsUsedinthisExample

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RotaryIndexingApplicaAonEglishStandard(Imperial)UnitsUsedinthisExample

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RotaryIndexingApplicaAonEglishStandard(Imperial)UnitsUsedinthisExample

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RotaryIndexingApplicaAonEglishStandard(Imperial)UnitsUsedinthisExample

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Lisa Eitel

Design World @DW_LisaEitel

David R. Bickert

Nexen Group Inc. @NexenGroup

Questions?

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