as a Method for Process Control - Wichita State University€¦ · AvPro -- NCAMP May 17 2006 Tooling/Prototype Cure Cycle 1. Initial cure was set at 200F (to avoid problems with

Viscoelastic Measurement Viscoelastic Measurement as a as a

Method for Process ControlMethod for Process Control

AvPro AvPro ---- NCAMP May 17 2006NCAMP May 17 2006

Long Term GoalLong Term GoalChange From:Change From:Time and Temperature Goals with Time and Temperature Goals with

Cure State Assumed Cure State Assumed

To:To:Cure State Measured Cure State Measured with Time and with Time and

Temperature ManagedTemperature Managed


Lab Equipment Contemporary to Legacy Lab Equipment Contemporary to Legacy Specification Development ca. 1971Specification Development ca. 1971


State of the Art Test Equipment and State of the Art Test Equipment and Process ControlsProcess Controls


Why Viscoelastic Measurements?Why Viscoelastic Measurements?

Before CureBefore Cure•• Storage time & out timeStorage time & out time•• Handling and Handling and LayupLayup•• Staging timeStaging time

During CureDuring Cure•• Infusion Infusion •• Volatile ReleaseVolatile Release•• Consolidation in staged pressure curesConsolidation in staged pressure cures•• Achieve Achieve ‘‘full curefull cure’’

After CureAfter Cure•• Glass transition temperatureGlass transition temperature•• ‘‘Spring backSpring back’’ & & ‘‘FitFit--upup’’•• Fatigue Fatigue

ViscoVisco--elastic Data Used To elastic Data Used To Develop Specifications Develop Specifications

but but Requirements Not Typically Requirements Not Typically

Included In The Included In The SpecificationSpecification


Time

Tem

pTe

mp

PrePre--Production Process Production Process DevelopmentDevelopment

Testing to set limitsTesting to set limits ViscoVisco--Elastic Elastic boundariesboundaries


Tem

pTe

mp

Time

Information Conveyed in Specs, T.O.Information Conveyed in Specs, T.O.’’s s and Shop Proceduresand Shop Procedures

Experimental SetupExperimental SetupControl System and RheometerControl System and Rheometer


Method of Gathering DataMethod of Gathering Data

Production Control System modified toProduction Control System modified to::Provide setProvide set--points to analytical points to analytical instrumentsinstruments

in real time during a controlled production run in real time during a controlled production run post runpost runfrom imported data from imported data

Control of the processing equipment and Control of the processing equipment and the instrument using data from eachthe instrument using data from each


CSS300 Control SystemCSS300 Control System


Test Unit & SpecimenTest Unit & Specimen


Test CellTest CellUpper Die is a load cell and Lower Die Upper Die is a load cell and Lower Die

cycles torque on sample to a specified cycles torque on sample to a specified strain or load. Gstrain or load. G’’ & G& G”” reported. Dies are reported. Dies are heated and grooved for grippingheated and grooved for gripping


Viscosities of Common MaterialsViscosities of Common MaterialsMaterialsMaterials

CentipoiseCentipoise(cps)(cps)

Poise (Poise (psps)) PascalPascal--sec (Pa.s)sec (Pa.s)Poiseuille (PI)Poiseuille (PI)

ConsistencyConsistency

AirAir 1.00E1.00E--0303 1.00E1.00E--0505 1.00E1.00E--0606 GaseousGaseous

WaterWater 1.00E+001.00E+00 1.00E1.00E--0202 1.00E1.00E--0303 FluidFluid

Olive OilOlive Oil 1.00E+021.00E+02 1.001.00 1.00E1.00E--0101 LiquidLiquid

GlycerinGlycerin 1.00E+031.00E+03 1.00E+011.00E+01 1.001.00 LiquidLiquid

Golden Golden SyrupSyrup

1.00E+051.00E+05 1.00E+031.00E+03 1.00E+021.00E+02 Thick FluidThick Fluid

Polymer Polymer MeltsMelts

1.0E+051.0E+05--1.0E+091.0E+09

1.0E+031.0E+03--1.0E+071.0E+07

1.0E+021.0E+02--1.0E+061.0E+06

ToffeeToffee--LikeLike

PitchPitch 1.00E+121.00E+12 1.00E+101.00E+10 1.00E+091.00E+09 StiffStiff

GlassGlass 1.00E+241.00E+24 1.00E+221.00E+22 1.00E+211.00E+21 RigidRigid

1000 cps = 10 poise = 1 Pa.s = 1 PI


Typical Cure Path GTypical Cure Path G’’vsvs

Time and Temperature Time and Temperature

227.0

100200

300Temperature Profile Target[Temperature(°F)]

0

5M

10M

15M

20M

25M

G p

0100

200300

400500

Run Time[Time (mins)]

Cure Path of G'TC25 of selected Cure

Softens & Grips

Softens as HeatsCures over Time

G’ rises as cools


Typical Data from Replication of Typical Data from Replication of Shop Process in AutoclaveShop Process in Autoclave

Temperature

Elastic Modulus G’Loss Modulus G” ~ viscosity



EndEndQuestionsQuestions


Experimental GoalsExperimental Goals

Execute Cure State Feedback ScenariosExecute Cure State Feedback ScenariosManage viscosity for infusionManage viscosity for infusion

Keep viscosity constant by increasing temperature Keep viscosity constant by increasing temperature

Correlate DiCorrelate Di--Electric Analysis to ViscosityElectric Analysis to ViscosityProvide greater relevance to process Provide greater relevance to process

Manage PostManage Post--cure cure Develop heat rate data that would prevent reDevelop heat rate data that would prevent re--softening of the part or toolsoftening of the part or tool


Logic for Managed Infusion Logic for Managed Infusion ViscosityViscosity

1.1. Raise temperature until viscosity (GRaise temperature until viscosity (G””) drops to ) drops to a specified viscosity minimum a specified viscosity minimum

2.2. Stop temperature rise until cure causes Stop temperature rise until cure causes viscosity to raise to a specified maximumviscosity to raise to a specified maximum

3.3. Resume heating and repeat steps 1&2 until Resume heating and repeat steps 1&2 until maximum cure temperature is reached.maximum cure temperature is reached.

4.4. StopStopIf this were an actual part, the run would be If this were an actual part, the run would be

continued until the part were fully cured continued until the part were fully cured


Managed Viscosity CureManaged Viscosity Cure


Control Logic for DEA CalibrationControl Logic for DEA Calibration

1.1. Temperature data from a cure cycle that had Temperature data from a cure cycle that had been monitored by DEA was providedbeen monitored by DEA was provided

2.2. Data was loaded into the CSS300 Post Data was loaded into the CSS300 Post Process Analyzer Process Analyzer

3.3. The temperature cycle was duplicated on the The temperature cycle was duplicated on the rheometerrheometer

4.4. Viscosity data was plotted on graph with DEA Viscosity data was plotted on graph with DEA datadata


Temperature Replication of Cure Temperature Replication of Cure Monitored by DEA Monitored by DEA

Comparison of 977 Film between RDA-III and DEA Data

0.1

1

10

100

1000

10000

100000

0 50 100 150 200 250 300

Time (min)

RD

A-II

I η' a

nd D

EA R

eadi

ngs

0

40

80

120

160

200

Tem

pera

ture

(°C

)

Rheometer Viscosity inPa.sec

DEA

Boeing Temperature Readings

Avpro Temperature Readings


Cure Monitored by DEACure Monitored by DEARescaled to Match GraphsRescaled to Match Graphs


Tooling/Prototype Cure CycleTooling/Prototype Cure Cycle1.1. Initial cure was set at 200F Initial cure was set at 200F (to avoid problems with soft tooling and steam (to avoid problems with soft tooling and steam

outout--gassing)gassing)

2.2. Hold at 200F until GHold at 200F until G’’ near maximum value at specified near maximum value at specified temperaturetemperature

3.3. Raise temperature until a small drop in GRaise temperature until a small drop in G’’ is notedis noted4.4. Begin a hold until GBegin a hold until G’’ recovers to near maximumrecovers to near maximum5.5. Repeat steps 3 & 4 until final cure temperature is Repeat steps 3 & 4 until final cure temperature is

reachedreachedFor actual parts the cure would be continued as specified For actual parts the cure would be continued as specified

to achieve full cure.to achieve full cure.


Maintain GMaintain G’’ Modulus on Post CureModulus on Post Cure

Note Non-Linear Heat Rate


SummarySummary

Time/TemperatureTime/TemperatureUsed to control properties but there is no Used to control properties but there is no visibility on the properties controlledvisibility on the properties controlled

ViscoVisco--Elastic Monitoring & ControlElastic Monitoring & ControlTime and temperature still critical to managing Time and temperature still critical to managing material statematerial stateViscoelastic feedback provides opportunity for Viscoelastic feedback provides opportunity for process improvement and corrective actionprocess improvement and corrective actionMSM provides a basis for time and temperature MSM provides a basis for time and temperature adjustments without compromising qualityadjustments without compromising quality


ConclusionsConclusionsTools exist to measure and manage viscoelastic Tools exist to measure and manage viscoelastic propertiespropertiesTools have Immediately value for development, Tools have Immediately value for development, tooling and discrepancy dispositiontooling and discrepancy dispositionNo significant additional shop requirementsNo significant additional shop requirementsCertified structures are not harmed by MSM Certified structures are not harmed by MSM proceduresprocedures

Certification of structures based on material state Certification of structures based on material state properties desirable but will require additional properties desirable but will require additional work and substantiation work and substantiation

Documents

as a Method for Process Control - Wichita State University€¦ · AvPro -- NCAMP May 17 2006 Tooling/Prototype Cure Cycle 1. Initial cure was set at 200F (to avoid problems with