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TA I

NSTRUMENTS

TMA 2940

3–9

Cell Constant

Cell constant calibration is based on a run in

which a known sample (standard) is heated

through its transition temperature and data is

gathered for analysis. The cell constant is

calculated by dividing the actual coefficient of

expansion of the standard by the measured

coefficient of expansion. The cell constant is

then entered in the instrument control software

for calibration of the instrument.

Using the default cell constant value of 1.000 is

usually adequate; however, for greatest accu-

racy, calibration should be performed.

It is recommended that you follow the proce-

dures of ASTM Standard Test Method E831 to

perform the cell constant calibration. This

method is summarized as follows.

1. Place your reference material (normally

aluminum) on the stage (sample platform).

2. Using a 0.01 to 0.05 N force, with the

standard expansion probe, measure the

sample length.

3. Heat the sample from 20°C below the

temperature range of interest to 20°C above

the temperature range at 5°C/min heating

rate.

4. Use a data analysis program to analyze the

expansion of the aluminum over the tem-

perature range of interest.

5. Calculate the cell constant using the follow-

ing equation:

Expected (literature) expansion

Observed expansion

cell

Calibrating the TMA

Содержание TMA 2940

Страница 1: ...940 I TMA 2940 Thermomechanical Analyzer Operator s Manual PN 925615 001 Rev D Text and Binder PN 925615 002 Rev D Text Only Issued November 1999 TAInstruments Thermal Analysis Rheology A SUBSIDIARY O...

Страница 2: ...ility This publication is not a license to operate under nor a recommendation to infringe upon any process patents TA Instruments TA Operating Software and Instrument Data Analysis and Utility Softwar...

Страница 3: ...Handling Liquid Nitrogen xiii Lifting the Instrument xvi Using This Manual xvii CHAPTER 1 Introducing the TMA 2940 1 1 Introduction 1 3 Components 1 3 The 2940 Instrument 1 5 2940 Display 1 7 2940 Key...

Страница 4: ...ng the Instrument 2 9 Inspecting the System 2 9 Choosing a Location 2 10 Installing the Thermocouple 2 11 Installing the Weight Tray Door 2 13 Installing the Stage 2 14 Installing the Expansion Penetr...

Страница 5: ...31 CHAPTER 3 Running Experiments 3 1 Overview 3 3 Before You Begin 3 4 Calibrating the TMA 3 5 Force Calibration 3 5 Probe Calibration 3 6 Temperature Calibration 3 7 Cell Constant 3 9 Running a TMA E...

Страница 6: ...oning 3 15 Measuring the Sample Length 3 15 Setting Up an Experiment 3 16 Setting Up Accessories 3 17 Using Air Cool 3 17 Using a Purge Gas 3 18 Suggestions 3 18 Starting an Experiment 3 20 Stopping a...

Страница 7: ...ing the Existing Probe 4 6 Removing the Stage 4 6 Changing the Instrument Mode 4 7 Installing the Film Fiber Probe 4 7 Installing the Film Fiber Stage 4 8 Calculating the Offset 4 9 Calibration 4 11 S...

Страница 8: ...ration 4 24 Baseline Calibration 4 24 Displacement Calibration 4 25 Sample Preparation 4 26 Parallel Plate Rheometer Accessory 4 29 Description 4 29 Accessory Installation 4 29 Calibration 4 30 Sample...

Страница 9: ...A 2940 5 3 Uses of Thermomechanical Analysis 5 4 Calculating the Coefficient of Expansion 5 5 Method Considerations 5 6 Status Codes 5 7 CHAPTER 6 Maintenance and Diagnostics 6 1 Overview 6 3 Routine...

Страница 10: ...ents continued Replacements 6 8 Installing a New Thermocouple 6 8 Diagnostics 6 9 Fuses 6 9 Power Failures 6 10 TMA 2940 Test Functions 6 12 The TMA Confidence Test 6 12 Replacement Parts 6 15 APPENDI...

Страница 11: ...uctions under the guidelines de scribed below Highlights important information about equipment or procedures Emphasizes a procedure that may damage equipment or cause loss of data if not followed corr...

Страница 12: ...the stage can of the TMA 2940 indicates that a hot surface may be present Take care not to touch these areas or allow any material that may melt or burn to come in contact with these hot surfaces Plea...

Страница 13: ...y requirements of the safety standards indicated Refer to the NOTE on page 2 11 for the method of drying out the equipment before use Handling Liquid Nitrogen The TMA 2940 can use the cryogenic low te...

Страница 14: ...that closed containers have vents to relieve pressure liquid nitrogen evaporates rapidly at room temperature 4 The purity of liquid nitrogen alters as it evaporates If much of the liquid in the contai...

Страница 15: ...Do not enter confined spaces where nitrogen gas may be present unless the area is well ventilated The warning above applies to the use of liquid nitrogen Oxygen depletion sensors are sometimes utiliz...

Страница 16: ...rument The TMA 2940 is a fairly heavy instrument In order to avoid injury particularly to the back please follow this advice Use two people to lift and or carry the instrument The instrument is too he...

Страница 17: ...ng subambi ent operations CHAPTER 4 Contains the procedures used to operate the TMA with the optional accesso ries CHAPTER 5 Explains the technical aspects of the TMA and its operation CHAPTER 6 Provi...

Страница 18: ...TA INSTRUMENTS TMA 2940 XVIII...

Страница 19: ...ntroducing the TMA 2940 Introduction 1 3 Components 1 3 The 2940 Instrument 1 5 2940 Display 1 7 2940 Keypad 1 7 HEATER Switch 1 11 POWER Switch 1 11 Accessories 1 12 Standard Accessories 1 12 Optiona...

Страница 20: ...Introduction 1 2 TA INSTRUMENTS TMA 2940...

Страница 21: ...nalysis instruments Enables you to set up experiments and enter constants Stores experimental data Runs data analysis programs Components Your instrument consists of two major parts the TMA cabinet an...

Страница 22: ...monitor thermocouple The weight tray located behind the weight tray door holds the weights to exert a known force on the sample The Chromel Alumel sample thermocouple senses the temperature of the sam...

Страница 23: ...t The display provides valuable realtime information on the experiment in progress The TMA was developed by TA Instruments with the following features operates over a temperature range of 150o C to 10...

Страница 24: ...nd dilatometry with the optional accessories that can be used with the instrument The cabinet contains the keypad used to control the mechanical movements of the instrument and the display used to obs...

Страница 25: ...status display the eight character line on the top left Sample temperature display the nine characters on top right Realtime signal display the whole bottom line 2940 Keypad The instrument keypad Fig...

Страница 26: ...age is changed MEASURE Measures your sample s LENGTH length automatically use this key before beginning the run The measured length is transferred to the Experi mental Parameters window and the value...

Страница 27: ...econd time mechanical action occurs centering the LVDT coil If the probe is moving up and Probe is pushed the probe will stop and reverse its direction Raises or lowers the FURNACE furnace You can sto...

Страница 28: ...s is the same function as Stop on the controller If an experiment is not running the instrument is in a stand by or method end state the STOP key will halt any activity air cool all mechanical motion...

Страница 29: ...ivity as described for the STOP key HEATER Switch The HEATER on off switch turns the power to the instrument heater on and off see Figure 1 2 The switch should be in the ON position before you start a...

Страница 30: ...to perform various basic analyses These probes include the following The expansion probes are used to measure the thermal coefficient of expansion and glass transition The standard expansion probe is...

Страница 31: ...nts TMA These optional accesso ries will allow you to perform experiments on different types of samples Film Fiber Accessory Dilatometer Accessory Parallel Plate Rheometer Accessory Flexure Accessory...

Страница 32: ...Depth 45 5 cm 18 in Width 58 5 cm 23 in Height 66 cm 26 in Weight approx 18 kg 60 lb Power 115 V ac 50 60 Hz 10 amps Temperature 150 to 1000o C Range Sample Height 25 mm 1 inch maximum Sample Diameter...

Страница 33: ...TA INSTRUMENTS TMA 2940 1 15 Table 1 3 Temperature Control Programmed 0 01 to 200o C min heating rate Temperature 2o C reproducibility Specifications...

Страница 34: ...Introduction 1 16 TA INSTRUMENTS TMA 2940...

Страница 35: ...em 2 9 Choosing a Location 2 10 Installing the Thermocouple 2 11 Installing the Weight Tray Door 2 13 Installing the Stage 2 14 Installing the Expansion Penetration Probes 2 18 Installing a Probe 2 18...

Страница 36: ...Installation TA INSTRUMENTS TMA 2940 2 2...

Страница 37: ...wish to retain all of the shipping hardware the plywood and boxes from the instrument in the event you wish to repack and ship your instrument Unpacking the TMA Refer to Figures 2 1 to 2 3 while unpac...

Страница 38: ...one side hanging over the edge of the bench see Figure 2 2 Someone must be holding onto the unit at all times while it is in this position Figure 2 2 Removing the Plywood Board 5 While your assistant...

Страница 39: ...same manner 7 Remove the x 20 screws and mounting feet from the accessory kit Place the screw through the center of the rubber feet 8 Have your assistant lift the entire unit while you slide the plyw...

Страница 40: ...ardboard cylinder then replace the cap on the furnace post 3 Raise the furnace and rotate it clockwise to move it off to the side 4 Take the stage shield off and discard the packing foam 5 Unscrew the...

Страница 41: ...nd carefully remove the top and bottom clamp ing bars of the suspension shipping clamp 11 Using the same wrench remove the eight 8 screws from the front and rear clamping bars of the suspension shippi...

Страница 42: ...by fine tuning the positions of the weights 16 Continue with installation of the thermo couple found on page 2 11 17 Reinstall the balance enclosure and tighten the four screws 18 Plug in and turn on...

Страница 43: ...truments controller Connecting the purge gas and air line accessories and power cable If you wish to have your instrument installed by a TA Instruments Service Representative call 302 427 4000 for an...

Страница 44: ...ample working and ventilation space around the instru ment Refer to the technical speci fications in Chapter 1 for the instru ment s dimensions On a stable vibration free work surface Near a power out...

Страница 45: ...s ad equately connected to the facilities ground for safe operation Run the following method to dry out the instrument refer to Running Experiments for further infor mation 1 Ramp at 10 C min to 400 C...

Страница 46: ...ding the Thermocouple 3 Move the thermocouple off to the side of the stage platform 4 Route the thermocouple wire through the wire guide to prevent interference with the balance mechanism 5 Slide the...

Страница 47: ...tall the door 1 Locate the mounting holes on the top and bottom of the door 2 Hold the door with these mounting holes to the left 3 Put the lower hole over the small bottom post to the left of the wei...

Страница 48: ...slots counterclockwise and pull it up off the three posts 4 Remove the stage from the accessory kit 5 Slide the wave washer rippled edge washer down over the top of the stage so that it fits on the f...

Страница 49: ...s follows a Position the tip of the thermocouple so that it bends at a 90 angle and lies flat against the platform It should be close to but not touching the sample b Hold the thermocouple against the...

Страница 50: ...940 2 16 Figure 2 8 Attaching the Thermocouple to the Stage 11 Put the stage shield on the stage aligning the slot in the bottom over the thermocouple wires see Figure 2 9 12 Rotate the furnace into p...

Страница 51: ...Figure 2 9 Assembled TMA with Stage and Thermocouple 13 Install one of the probes as directed in the next section Refer to Chapter 3 for guidelines in selecting a probe Installing the Instrument Stag...

Страница 52: ...penetration flexure dilatometer and hemi spherical probes To learn how to install the film fiber probe turn to Chapter 4 Using Your Options Installing a Probe 1 Raise the furnace and rotate it clockw...

Страница 53: ...1 Raise the furnace and rotate it clockwise to move it off to the side 2 Grasp the top of the probe with one hand Using the other hand locate and hold the probe locking lever found behind the door th...

Страница 54: ...s When plugging or unplugging power cords always handle them by the plugs not by the cords Protect power and communications cable paths Do not create tripping hazards by laying them across accessways...

Страница 55: ...ss from 1 to 9 Use the binary address switches on the TMA connector panel to set the desired address see Table 2 1 Figure 2 12 shows a instru ment address of 7 If you have a multiple instruments syste...

Страница 56: ...seconds after releasing the Reset button the green Ready light should begin to glow steadily Reconfigure the instrument with the controller to bring the instrument back online Figure 2 12 Binary Addr...

Страница 57: ...he gases that can be used in the TMA see Chapter 3 Use of corrosive gases will shorten the life of the instrument 2 Make sure that the pressure of your purge source does not exceed the manufacturer s...

Страница 58: ...the PURGE fitting to a flowmeter consult your compressed gas vendor for specific requirements Then connect the flowmeter to the purge gas source 4 The recommended setting for the purge rate is 100 mL...

Страница 59: ...cabinet back marked with a maximum pressure warning label 840 kPa 120 psi as seen in the figure below Figure 2 15 TMA COOLING GAS Fitting 2 Make sure your compressed lab air source is dry filtered and...

Страница 60: ...6 is in the OFF O position Figure 2 16 Front Panel of TMA Showing POWER Switch 2 Plug the power cable into the TMA Before plugging the TMA power cable into the wall outlet make sure the instrument is...

Страница 61: ...quence will depend upon the configuration of the connectors on the back of the module All necessary cables will be provided however you may not need to use them all 1 Place the isolation transformer n...

Страница 62: ...Installation TA INSTRUMENTS TMA 2940 2 28 Figure 2 17 Isolation Transformer Cable Connections...

Страница 63: ...run an internal confidence test each time you turn on the power 3 Watch the instrument display during the confidence test for any messages that may be indicated Confidence test definitions are given i...

Страница 64: ...Installation TA INSTRUMENTS TMA 2940 2 30 TMA 2940 Thermomechanical Analyzer Standby 23 25 C DimChg 0 135 m Figure 2 18 TMA Standby Display...

Страница 65: ...instrument and wish to use the thermal analysis system for some other task leave the instrument on it will not interfere with whatever else you wish to do If your system will not be used for longer th...

Страница 66: ...Installation TA INSTRUMENTS TMA 2940 2 32...

Страница 67: ...bration 3 6 Temperature Calibration 3 7 Cell Constant 3 9 Running a TMA Experiment 3 10 Experimental Procedure 3 10 Selecting a Probe 3 11 Zeroing the Auto Measure System 3 12 Sample Preparation and L...

Страница 68: ...sories 3 17 Using Air Cool 3 17 Using a Purge Gas 3 18 Suggestions 3 18 Starting an Experiment 3 20 Stopping an Experiment 3 20 Removing Samples 3 20 Subambient Experiments 3 22 Performing a Cooling E...

Страница 69: ...the thermal method on the controller Attaching and setting up external accessories as required e g purge gas air cool gas switching accessory Zeroing the probe Preparing and loading the sample Adjusti...

Страница 70: ...roperly Make sure you have Made all necessary cable connections between the TMA and the TA controller Connected all gas lines Powered on each unit Installed all appropriate options Configured the inst...

Страница 71: ...Force Calibration Force calibration calibrates the force exerted by the probe on the sample during experiments using two weights and can be performed with any probe in place on the instrument The fir...

Страница 72: ...ely following a force calibration Probe Calibration This procedure sometimes called initializing is used to calibrate zero force the LVDT and the probe s compliance This corrects for any difference in...

Страница 73: ...ou use multiple standards the tem perature is corrected by a cubic spline fit The multiple point temperature calibration is more accurate than the one point calibration For all probe types except the...

Страница 74: ...ally approximately once a month If you are changing the temperature range of interest If the run data obtained seems to be inaccurate Regardlessofthesizeorshapeofthesamplethatyou arerunningontheTMA po...

Страница 75: ...calibration should be performed It is recommended that you follow the proce dures of ASTM Standard Test Method E831 to perform the cell constant calibration This method is summarized as follows 1 Plac...

Страница 76: ...be Selecting and preparing a sample This involves preparing a sample of the appropriate size and placing the sample in the sample stage Entering experimental information through the TA controller Crea...

Страница 77: ...TMA 2940 Probes Probe Type Contact Pressure Types Diameter Exerted by of Tests mm in 0 01 N Load Yielded Penetration 0 89 0 035 16 kPa Softening point Melting point Expansion 2 54 0 100 1 9 kPa Expan...

Страница 78: ...pter 4 to install any optional probes 3 Select the mode that is appropriate for the type of probe installed Refer the the online documentationforinformation 4 Calibrate a newly installed probe as de s...

Страница 79: ...erience temperature gradients during high heating rates Thermoplastic samples can be heated and formed into suitable specimens and then cooled however this process may change important thermal history...

Страница 80: ...tween the stage and any thermoplastic samples to prevent damage to the stage Figure 3 1 Loading a Sample 6 Adjust the sample thermocouple if needed as directed on the next page 7 Program the force on...

Страница 81: ...size or shape of the sample that you are running on the TMA position the tip of the thermocouple so that it bends at a 90 angle and lies flat against the platform It should be close to but not touchin...

Страница 82: ...nt Control func tions Refer to the online documentation to learn how to perform the following steps 1 Select the Instrument 2 Select the Instrument Mode 3 Enter Sample Information 4 Enter Instrument I...

Страница 83: ...s of all segments in the method This section describes how to use the following accessories with the TMA 2940 Air cool option Purge gas TA Instruments Gas Switching Accessory Using Air Cool Before you...

Страница 84: ...se the furnace and purge the system with nitrogen for ten minutes Then switch to helium gas for the experiment if desired To ensure an inert environment for your sample a purge rate of 100 mL min is s...

Страница 85: ...100 mL min at 100o C and above 200 mL min at 150o C and above If a denser purge gas than helium is used for subambient experiments it is recommended that the silicon washer found in the accessory kit...

Страница 86: ...e controller However the Reject function discards all of the data from the experiment the Stop function saves any data collected up to the point at which the experiment was stopped The REJECT function...

Страница 87: ...ymers as this will cause the filler to stick to the stage or probe To remove metallic materials e g indium immerse the probe and stage in an acid solution Use extreme caution when working with acid so...

Страница 88: ...eraturerange method end conditionisactivatedintheinstrumentcontrolprogram presstheSTOPkeytodeactivateitbeforetryingtocool theTMA Performing a Cooling Experiment To run a subambient experiment perform...

Страница 89: ...ents the furnace must work against the coolant in the furnace reservoir Ideally you should use the least amount of coolant necessary to keep the furnace drawing power over the entire subambi ent range...

Страница 90: ...um is used for subambient experiments it is recommended that the silicon washer found in the accessory kit be attached to the probe Raise the probe to the fully open position then place the washer so...

Страница 91: ...Probe 4 6 Removing the Stage 4 6 Changing the Instrument Mode 4 7 Installing the Film Fiber Probe 4 7 Installing the Film Fiber Stage 4 8 Calculating the Offset 4 9 Calibration 4 11 Sample Preparatio...

Страница 92: ...ration 4 24 Displacement Calibration 4 25 Sample Preparation 4 26 Parallel Plate Rheometer Accessory 4 29 Description 4 29 Accessory Installation 4 29 Calibration 4 30 Sample Preparation 4 31 Sample E...

Страница 93: ...This chapter explains the optional accessories that you can purchase to use on your TMA 2940 including the following information for each option Description Operating procedures Accessory installatio...

Страница 94: ...s as a function of force temperature or time Sample tensile stress is calculated using the following equation ST F A where ST stress at temperature T Pascals F force Newtons A cross sectional area met...

Страница 95: ...ng rate See the Thermal Solutions Advantage User Reference Guide for details When comparing run data make sure that all comparison scans are made with the thermo couple in the same position and at the...

Страница 96: ...ntly and twist slightly to aid its removal from the stage opening Removing the Stage 1 Remove the stage shield from the base of the stage by lifting it straight up This is a friction fit 2 Take off th...

Страница 97: ...configuration of the film fiber acces sory requires the installation of the probe before the stage 1 Insert the core end of the probe carefully into the opening in the top plate 2 Open the weight tra...

Страница 98: ...he flange 3 Slide the stage retainer ring carefully over the top of the stage and probe assembly so that it rests on top of the wave washer Push down and turn clockwise to tighten the retainer ring 4...

Страница 99: ...the stage assembly and put on the spring clip to hold the thermocouple in place 7 Replace the stage shield on the base of the stage 8 Move the furnace back into position and lower it See Figures 4 4 a...

Страница 100: ...eters Use a new film fiber probe and stage assembly 1 Record the value listed as Auto Measure Offset from the TA controller 2 Use calipers to measure the gap in the Auto Measure Offset Gauge and recor...

Страница 101: ...functions 7 Remove the Auto Measure Gauge and proceed with your experiment Calibration You should perform probe temperature and cell constant calibration for the film fiber accessory as you would norm...

Страница 102: ...ps Using the Aluminum Balls The aluminum balls are generally used with fiber samples as follows 1 Measure and cut the fiber sample slightly longer than desired length typically 12 to 25 mm 0 5 to 1 0...

Страница 103: ...slot in the stage with the fiber hanging down through the slot and allow the other ball to hang freely 7 Position the second ball below the slot in the film fiber probe so that the fiber is sus pended...

Страница 104: ...asure and cut the sample to the desired length typically 12 to 25 mm 0 5 to 1 0 inch Films should have a uniform width 2 Separate the jaws of one clamp Position the clamp so that the clamp relief notc...

Страница 105: ...ample see Figure 4 5 5 Move the clamp into the desired notch position for either a 9 13 or 25 mm sample 6 Tighten the screws so that the sample is flat in the block and is positioned perpendicular to...

Страница 106: ...econd clamp below the slot in the film fiber probe so that the film is suspended between the two clamps as shown in Figure 4 7 10 Measure the sample length 11 Position the thermocouple close to but no...

Страница 107: ...d a sample platform with two knife edges spaced 5 08 mm 0 2 inches apart This accessory permits the determination of deflection tempera ture under load Required loading is calculated using the follow...

Страница 108: ...rd stage if it is not already in place For instructions to install the stage refer to page 2 14 3 Install the flexure probe in the same manner as the standard expansion and penetration probes as instr...

Страница 109: ...rotate it clockwise to move it off to the side 2 Remove any previously run samples from the stage and ensure that no residue remains 3 Open the probe 4 Place the flexure platform on top of the stage 5...

Страница 110: ...Options TA INSTRUMENTS TMA 2940 4 20 Figure 4 8 Probe Setup Using Flexure Samples 8 Adjust the thermocouple position so that it is in close proximity to the sample 9 Move the furnace into position an...

Страница 111: ...ansion The cubic expansion of a sample is calculated using the following equation K S B b V where b coefficient of expansion m3 m3 o C K vial constant cm3 m S slope m o C V sample volume cm3 This volu...

Страница 112: ...m3 o C bref 3 aref Where aref is the coefficient of linear expansion of standard material m m o C measured over the same temperature range V sample volume cm3 This volume may be obtained by dividing t...

Страница 113: ...If you compare data runs make sure that all comparison scans are made with the vial filled to the same level with filling medium with the thermocouple in the same position and heated at the same rate...

Страница 114: ...brated for baseline and displacement using the procedures described as follows Baseline Calibration The dilatometer filling medium must be kept dry Store it in a desiccator when it is not being used I...

Страница 115: ...mple 2 Weigh the three aluminum balls and prepare the sample and vial as instructed on the following pages Make sure that the alumi num balls do not touch the walls of the vial and that they do not to...

Страница 116: ...htly pack the filling medium 3 Select a sample that is small enough to easily fit inside the dilatometer vial without touching the walls 4 Place the sample on the filling medium in the center of the v...

Страница 117: ...and ensure that no residue remains 9 Open the probe 10 Place the vial on the stage 11 Close the probe until the probe tip is posi tioned above the filling medium 12 Tap lightly on the upper probe asse...

Страница 118: ...hermocouple position so that it is in close proximity to the vial To avoid false thermocouple readings make sure that the thermocouple tip does not touch the sample vial 16 Move the furnace into posit...

Страница 119: ...l plates Alignment cage Accessory Installation The parallel plate rheometer accessory uses the macro expansion probe rheometer sample holder assembly and the standard stage 1 Remove the existing probe...

Страница 120: ...ple readings make sure that the thermocouple tip does not touch the alignment cages or plates Exposed portions of the two thermocouple leads must not touch each other Calibration The parallel plate rh...

Страница 121: ...e of the Sample Encap sulating Press PN 900680 902 and a special set of dies the pellet press die set To prepare samples follow the instructions found in these sections Sample Encapsulating Press__ se...

Страница 122: ...ly The plunger in the upper hermetic die assem bly is spring loaded and should be removed with care 1 Lower the Encapsulating Press handle Then rotate the die holder assembly and upper crimping die if...

Страница 123: ...either hermetic or crimping just meets the upper hermetic die 5 Loosen the setscrew in the Encapsulating Press upper die holder assembly to unlock the upper hermetic die The upper hermetic die is now...

Страница 124: ...ide and screw in the pellet press base screw until it is nearly flush with the bottom of the press 4 Place the pellet press cylinder head cavity side down on top of the pellet press base screw 5 Lower...

Страница 125: ...ccessory follow these instructions 1 Install the pellet press die set in the Encap sulating Press 2 Pour sufficient sample material 30 to 50 mg into the pellet press cylinder to produce a disc 0 25 to...

Страница 126: ...cylinder Note the position shown in Figure 4 13 Figure 4 13 Cylinder Head Positions 6 Replace the cylinder head and cylinder in the Encapsulating Press Lower the piston with the press handle This will...

Страница 127: ...TA INSTRUMENTS TMA 2940 4 37 Figure 4 14 Parallel Plate Sample Assembly 9 Load your sample according to the direc tions on page 4 41 Parallel Plate Rheometer Accessory...

Страница 128: ...head Piston 1 Assemble the pellet press cylinder and cylinder head in the sample forming posi tion for use as a mold as shown see Figure 4 15 Figure 4 15 Sample Forming Position 2 Heat up a hot plate...

Страница 129: ...piston will settle 7 Using tongs remove the weight when the piston sinks to its maximum depth 8 Remove the mold assembly from the hot plate using tongs and allow it to cool to room temperature 9 Disas...

Страница 130: ...hese instructions 1 Cut a sample from a sheet of material 0 25 to 1 00 mm in thickness using a standard 9 5 mm hole punch 2 Measure the sample thickness using cali pers to within 0 02 mm 3 Place the s...

Страница 131: ...is in close proximity to the sample To avoid false thermocouple readings make sure that the thermocouple tip does not touch the alignment cage sample or plates Exposed portions of the two thermocouple...

Страница 132: ...parallel plates together inside the cage If you want to reuse the parts follow these directions These procedures involve the use of heat or chemicals appropriate safety measures should be observed at...

Страница 133: ...rrection Calculations for Thermal Expansion of Parallel Plates 1 Calculate the apparent distance between the plates h at a given temperature or time by subtracting the decrease in distance between the...

Страница 134: ...ultiply this a by the total plate thick ness and the temperature change to obtain the thermal expansion correction factor c Subtract the correction factor from the apparent distance between the plates...

Страница 135: ...late Rheometer Accessory Table 4 1 Stainless Steel Coefficient of Expansion1 T o C Coefficient of Expansion m mo C 18 14 8 93 16 0 149 16 6 204 16 7 260 16 9 316 17 3 371 17 5 427 17 6 482 17 8 538 18...

Страница 136: ...ected for expansion of the parallel plates as previously shown on page 4 43 Then this corrected data is applied to equations developed by Dienes and Klemm J Appl Phys 17 458 1946 and Cessna and Jablon...

Страница 137: ...ndard quartz stage to obtain softening point data on substances It is in stalled operated and calibrated using the same procedures as the standard expansion and penetration probes Refer to Chapter 2 I...

Страница 138: ...Using Your Options TA INSTRUMENTS TMA 2940 4 48...

Страница 139: ...UMENTS TMA 2940 5 1 CHAPTER 5 Technical Reference Description of the TMA 2940 5 3 Uses of Thermomechanical Analysis 5 4 Calculating the Coefficient of Expansion 5 5 Method Considerations 5 6 Status Co...

Страница 140: ...5 2 TA INSTRUMENTS TMA 2940 Technical Reference...

Страница 141: ...z probe placed in contact with the sample is used to determine any linear or volumetric changes in dimension at the selected temperature and force Valuable data on melt ing points glass transition tem...

Страница 142: ...d labs It is used for quality control studies analysis of processing conditions and perfor mance characterization of samples The samples analyzed using the TMA vary widely They can include materials s...

Страница 143: ...e of a sample To calculate the coefficient of expansion a experi mental from the expansion profile you can use the Data Analysis program or the following equation L x K T x L Where measured coefficien...

Страница 144: ...ing temperatures studies of penetration temperature vs force are helpful to eliminate false values A heating rate of 5o C min or less is best for polymeric and elastomeric materials Temperature progra...

Страница 145: ...is opened to allow cooling air flow to the furnace Balance Force is being applied to balance the system at the center of the displace ment range This is used for force calibration Calib The instrument...

Страница 146: ...ib The temperature is being equilibrated to the desired set point Err xxx An error has occurred xxx will appear as a two or three digit code The local screen will give the Error Code number the contro...

Страница 147: ...ing a cooling ramp Initial The temperature is equilibrating to the desired set point When the temperature has reached equilibrium the status will change to Ready Iso The thermal program is holding the...

Страница 148: ...or a specified time Ramping The force is ramping to a specified value Ready The system has equili brated at the initial temperature and is ready to begin the next segment Press the START key to contin...

Страница 149: ...ued Code Meaning Temp The temperature calibra tion is active Unstable The Isostrain segment has been initiated but the instrument has not or cannot meet the criteria specified Zeroing The LVDT is bein...

Страница 150: ...5 12 TA INSTRUMENTS TMA 2940 Technical Reference...

Страница 151: ...tion 6 4 Cleaning 6 5 Cleaning the Keypad 6 5 Cleaning the Probe Assembly 6 5 Cleaning the Stage 6 6 Cleaning the Thermocouple 6 7 Replacements 6 8 Installing a New Thermocouple 6 8 Diagnostics 6 9 Fu...

Страница 152: ...Maintenance and Diagnostics TA INSTRUMENTS TMA 2940 6 2...

Страница 153: ...t operation of the TMA as follows Maintenance procedures needed to keep your instrument clean and in good working order Instructions on how to replace certain parts when needed Details on diagnosing f...

Страница 154: ...e performed by a representative of TA Instruments or other qualified service personnel Because there are high voltages in this instru ment untrained personnel must not attempt to test or repair any el...

Страница 155: ...are best for cleaning the keypad Wet the towel not the keypad with the glass cleaner and then wipe off the keypad and display Cleaning the Probe Assembly After each experiment check the probe assem b...

Страница 156: ...acetone on a soft cloth to wipe the top of the stage For thorough cleaning 1 Raise the furnace and rotate it clockwise to move it off to the side 2 Remove the stage shield 3 Take off the spring clip t...

Страница 157: ...r glass filler The stage may also be cleaned in a nitric acid solution Cleaning the Thermocouple Sample residue and dirt may interfere with the accuracy of the thermocouple readings To clean the therm...

Страница 158: ...g a New Thermocouple You may find that the need arises for a new thermocouple PN 944017 901 as a result of normal wear and tear accidental breakage contamination of the thermocouple etc Before removin...

Страница 159: ...urself are the external fuses located on the TMA control panel Both of these fuses are housed in safety approved fuse carriers labeled F1 and F2 see Figure 6 1 Figure 6 1 Fuse Locations Always unplug...

Страница 160: ...by a temporary drop in line voltage can result in one of two responses in the instrument If the drop is fairly large and of long duration 20 milliseconds or more the system will reset and go into its...

Страница 161: ...uires a normal line voltage of 115 V AC 50 or 60 Hz Do not operate it at less than 105 V AC or greater than 130 V AC Lower line voltage may result in poor instrument operation higher line voltage may...

Страница 162: ...designed to aid manufac turing and service in checking and repairing the instrument The TMA Confidence Test The TMA runs a confidence test every time it is started or reset The confidence test checks...

Страница 163: ...The base level system takes about 12 seconds The longest tests are the RAM tests which take about 6 seconds After the tests are completed a sign on message is displayed for three seconds The system th...

Страница 164: ...l to the operation of the TMA has failed the confidence test the instrument cannot reliably perform any further functions Table 6 1 summarizes the primary confidence tests for the TMA 2940 Table 6 1 P...

Страница 165: ...944122 901 1 Expansion Probe Assembly 944126 901 1 Penetration Probe Assembly 944123 901 1 Macro Expansion Probe Assembly 944120 901 1 Sample Stage 944017 902 1 Sample Thermocouple Type K with clip 90...

Страница 166: ...01 2 Film Clamp Assemblies 944144 001 1 Film Clamp Fixture 269789 001 1 Jeweler s Screwdriver 0 080 inch 269793 001 10 Film Clamp Screws 0 80 944202 901 Dilatometer Accessory Kit consisting of 944124...

Страница 167: ...tion 944204 901 Parallel Plate Rheometer Accessory Kit consisting of 943147 901 1 Rheometer Sample Forming Die Set 943125 000 3 Rheometer Alignment Cages 943126 000 6 Rheometer Parallel Plates 944125...

Страница 168: ...Maintenance and Diagnostics TA INSTRUMENTS TMA 2940 6 18...

Страница 169: ...000 or 302 427 4040 Fax 302 427 4001 Overseas TA Instruments Ltd Europe House Bilton Centre Cleeve Road Leatherhead Surrey KT22 7UQ England Telephone 44 1 372 360363 Fax 44 1 372 360135 TA Instruments...

Страница 170: ...ux France Telephone 33 01 30489460 Fax 33 01 30489451 TA Instruments Spain Avienda Europe 21 Planta Baja 28100 Alcobenda Madrid Spain Telephone 34 9 16618448 Fax 34 9 16610655 For technical assistance...

Страница 171: ...12 B balance enclosure 1 3 installation 2 12 removal 2 7 C cables installation 2 27 calculations parellel plate thermal expansion wall shear rate 4 43 calibration 3 7 cell constant 3 9 force 3 5 prob...

Страница 172: ...c expansion 4 21 loading 4 17 sample tensile stress 4 4 vial constant 4 22 viscosity 4 46 wall shear rate 4 46 error codes fatal 6 14 nonfatal 6 14 experiment cooling type 3 22 example 3 3 3 16 settin...

Страница 173: ...1 3 cleaning 6 5 installing 2 9 location 2 10 power requirements 2 10 repacking See TMA 2940 unpacking See TMA 2940 Instrument Control 3 16 instrument control keys 1 8 instrument keypad See TMA 2940 k...

Страница 174: ...failures 6 10 POWER on off 1 11 POWER Switch 1 11 2 26 POWER switch 2 26 2 29 probe calibration 3 6 expansion installation 2 18 film fiber installation 4 7 flexure 4 18 installation 4 7 hemispherical...

Страница 175: ...et materials 4 40 removal 3 20 temperature display 1 7 thermocouple cleaning 6 7 function 1 4 installation 6 8 removal 6 8 replacing 6 8 Sample Encapsulating Press 4 31 description 4 31 SCROLL key 1 8...

Страница 176: ...1 4 confidence test 2 29 6 13 confidence tests 6 12 description 1 3 5 3 display 1 7 features 5 3 flexure samples 4 19 installation 3 4 keypad 1 5 maintenance 6 4 part replacements 6 8 parts list 6 15...

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