Optics11 CHIARO NANOINDENTER User Manual Download Page 40 | Manualshive

Page: 40 / 65

Optics11 CHIARO NANOINDENTER User Manual Download Page 40

40

optics11.com

5.2

The m

easurement and calculation of the Young’s modulus

The determination of the Young’s modulus relies of the measurement of

load-indentation curves,

which subsequently can be analysed by different material models. For elastoplastic materials, the
unloading part of the curve can be fitted by software with the so-called

Oliver&Pharr model

1

,

2

,

which

excludes any plasticity bias from the results. However, a more direct

Hertzian contact model

can be

used for purely (visco-) elastic materials.

Oliver and Pharr

This method derives the Young's modulus from the slope of the unloading part of the stress-strain
curve, indenter tip radius and final indentation depth using the following formula:

𝐸

∗

=

𝑆

2

⁄

√𝑅

𝑖

∙ √ℎ

𝑚𝑎𝑥

+ ℎ

𝑟

1

W.C. Oliver, G.M. Pharr, An improved technique for determining hardness and elastic modulus using load

and displacement sensing indentation J.Mater. Res. Vol. 7 No. 6 1564 (1992)

2

W.C. Oliver, G.M. Pharr, Measurement of hardness and elastic modulus by instrumented indentation:

Advances in understanding and refinements to methodology J.Mater. Res. Vol. 19 No. 1 3 (2004)

Figure 33: Schematic picture of probe (left) and picture of probe mounted in the Piuma Nanoindenter.

«
...
38
39
40
41
42
...
»

Summary of Contents for CHIARO NANOINDENTER

Page 1: ...PIUMA NANOINDENTER USER MANUAL ...

Page 2: ...ersity Campus W N Building room O 236 De Boelelaan 1081 1081 HV Amsterdam The Netherlands SHIPPING ADRESS Optics11 De Boelelaan 1081 1081 HV Amsterdam The Netherlands COMPANY INFORMATION Optics11 B V KvK CC 52469417 VAT NL850459734B01 Amsterdam NL Please see our website for more information about our products www optics11 com ...

Page 3: ...paring the setup for measurement 10 3 Using the Piuma Nanoindenter 22 4 Optimizing instrument stability and sample mounting 33 5 Working principle of the Piuma Nanoindenter instrument 38 6 Description of the Piuma software 44 7 The OP1550 interferometer 57 8 FAQ troubleshoot 61 ...

Page 4: ...17 Jakob Pyszkowski Version 2 2 Update March 21 2017 Jakob Pyszkowski Version 2 3 Update March 29 2017 Jakob Pyszkowski Version 2 4 Update May 16 2017 Jakob Pyszkowski Version 2 5 Update July 18 2017 Jakob Pyszkowski Version 2 6 Update June 20 2018 Kevin Bielawski Version 2 7 Update November 7 2018 Jakob Pyszkowski ...

Page 5: ...ber connector on the front panel and has a terminator on the back panel Do not view directly into the beam with optical instruments The OP1550 is equipped with a 220V 110V plug Disconnect the instrument before changing the fuse or before switching from 220V to 110V or vice versa Do not open the box as this might result in serious injuries ...

Page 6: ...urement is described in detail in Chapter 3 Chapter 4 describes the optimization of sample preparation and measurement conditions Chapter 5 provides a description of the Piuma Nanoindenter s working principle In Chapter 6 the Piuma Nanoindentation software suite is explained in detail Chapter 7 describes how to operate the OP1550 interferometer and finally Chapter 8 provides a FAQ and alternative ...

Page 7: ...d the actions required to start up the Piuma Nanoindenter 1 1 The Piuma Nanoindenter and its components The Piuma Nanoindenter consists of five components 1 The Piuma indenter head 2 the Optics11 OP1550 interferometer 3 the Piuma controller 4 the PC running the Piuma Nanoindenter software suite and 5 the Optics11 optical nanoindentation probes Figure 2 Picture of the Piuma Nanoindenter showing the...

Page 8: ...ts Together with the Piuma Nanoindenter the following cables are provided o 2x BNC connector cables o 1x DVI signal cable o 2x Power cable o 1x PC power cable including adapter o 2x USB B type connector cable o 50Ω Terminator When installing the system please carefully follow the scheme below Figure 3 Figure 3 Schematic drawing of the connections that are required to set up the Piuma Nano indenter...

Page 9: ...nects the USB output on the back of the OP1550 to the second HUB connector on the back of the controller box Figure 3 The optional backlight module requires 5V to operate To power this module connect the USB cable to any free USB port on the PC or the controller box The optional inverted camera module requires 5V to operate and can be connected to the Piuma through a free USB HUB port at the rear ...

Page 10: ...urn on After initialization the interferometer will show a live measurement signal on the LCD screen Starting the software Start the Piuma Nanoindenter program by double clicking the Piuma software icon on the desktop The software is loading all devices while checking the hardware connection status which should all be Idle Figure 4 As a safety check the program asks then to bring up the manual sta...

Page 11: ...ff cantilever is needed and vice versa to ensure that significant cantilever bending as well as significant sample indentation is achieved during measurements If the probe is either to stiff or too soft there will be minimal cantilever bending or indentation respectively resulting in a less optimal signal to noise ratio Advised cantilever stiffness is provided for ranges of sample Young s moduli i...

Page 12: ...o the most back right position When handling a probe take special care to avoid any contact with the cantilever as the glass cantilever at the end of the glass ferrule is extremely fragile and almost any unintended contact will cause permanently damage Therefore when handling the probe always hold it by the plastic adapter keep the optical fiber away from the cantilever and avoid touching the glas...

Page 13: ...al connector in the box by placing a piece of tape on top of the connector You can remove then the probe from the Piuma indenter head holder by compressing the plastic connector and pulling it gently out of the holder Carefully place the probe in the probe box to its designated location Caution When installing the probe always mount first the probe and then connect the fiber to the OP1550 When put...

Page 14: ...ibes the geometrical factor of the probe As this is unique for each probe leave the factor 1 000 in the configuration panel and see paragraph 2 4 Calibrating the geometrical factor in this manual on how to obtain this value through the automated calibration procedure For this procedure a value of 4000nm for the calibration depth is set by default You can can change this value in the Options menu s...

Page 15: ...t values corresponding to the preferred indenter head This can be accomplished in the XYZ stages tab of the maintenance menu by pressing Calib all Figure 8 right You can enter this menu with the password showme after clicking the Maintenance button in the main software window This procedure will take a few minutes since all XYZ values are being calibrated Figure 8 Piuma selection in advanced optio...

Page 16: ... stage to lower the probe into the solution Confirm the cantilever and a part of the glass probe is fully submersed and the liquid tension cannot affect the cantilever anymore Please note that glass is hydrophobic and that it is possible that an air bubble is trapped between the cantilever and the glass base This air bubble will affect the measurement and needs to be removed see Chapter 4 3 Automa...

Page 17: ...ternal laser will tune its wavelength rapidly from 1565nm to 1525nm to create an interference pattern on the photodiode As the photodiodes output voltage depends on the intensity of the interference pattern an automated offset and gain setting process is initiated which optimizes the photodiode output for the 0 10V range The Piuma data acquisition system operates in the 0 10V range and voltages ou...

Page 18: ...ecuted again When performing experiments with temperature control the calibration should be accomplished at the same temperature as the measurement temperature This is because the refractive index of the medium is dependent on the temperature Since the density of a liquid usually decreases with temperature it is not surprising that the speed of light in a liquid will normally increase as the tempe...

Page 19: ...facturing process of the probes which are very specific components and the distance between the tip position and the readout fiber position can slightly differ from probe to probe In the Piuma nanoindentation software the automated measurement and setting of the geometrical factor is included in the calibration procedure also referred to as calibration factor Make sure that the optical calibration...

Page 20: ...face the Piuma Nanoindenter features an automated find surface approach This approach uses a coarse fine stepping routine combining the motorized Z stage and the indentation piezo To initialize the automated find surface approach for calibrating the geometrical factor select the Calibration tab in the Piuma software and click on the Find Surface button Figure 13 For find surface adjustments e g wh...

Page 21: ...ndentation directly after the calibration After clicking on the Use new factor button click the Displacement control button at the home screen and press Indent to displace the probe again on the stiff substrate The results in the time data tab should show that the piezo displacement blue line is equal to the cantilever bending green line because the indentation starts in contact and no material de...

Page 22: ...art by bringing the probe in the field of view To do so move the manual stage all the way up to avoid damaging the probe and use the Z stage to bring down the probe into the field of view of the on board camera Put a travel value in the Travel field such as 500 µm and press the down arrow of the Z stage to move this amount down Figure 17 Figure 17 Main software window Stage controls red Piezo cont...

Page 23: ...cally will pop up you can reset the X Y and Z stages to their home position by clicking ok 3 2 Piezo controls The Piezo stack that is normally used for indenting can also be controlled manually By providing a number in the Travel field below the Piezo status bar the piezo can be commanded to make relative steps The range of the Piezo stack is 20000 nm and a manual offset can be set anywhere in thi...

Page 24: ... feels most comfortable During this process keep your eye on the probe the probe mount the clearance to the sample container and make sure the probe does not touch the sample surface by monitoring the signal voltage level on the interferometer If the probe comes into the field of view and you can assess by eye the probe is about 1 mm above the surface proceed with the automated find surface functi...

Page 25: ...eter screen during finding the surface see Chapter 7 1 3 4 Modes of operation The Piuma Nanoindenter is able to operate in three different modes Piezo displacement control D mode Load or Force control P mode Indentation depth control I mode All three modes of operation are monitoring piezo movement load cantilever bending and indentation depth The modes are differing in their controlling parameter...

Page 26: ...f cantilever and sample stiffness Since the piezo is not receiving any feedback signal from the sample cantilever bending it is working in an open loop with the sample To define such displacement profile of the probe for an experiment in D mode you need to switch first to Displacement control in the Mode Selection part of the main software window Figure 20 By clicking the Profile menu button you e...

Page 27: ...hen touching the surface The piezo starts to receive a new feedback signal from the sample which feeds the piezo in order to keep the intended load constant The P mode of operation is therefore in a closed loop with the sample In order to set a load profile you need to switch to Load control in the Mode Selection part of the main software window After that you can enter the Configure Profile windo...

Page 28: ...e By pressing the Profile button you enter the indentation profile where you now can define an exact indentation depth µm over a specific time interval s divided by default in three segments Figure 21 3 5 Dynamic mechanical analysis DMA The Piuma Nanoindenter features beside the quasi static operation a dynamic operational mode This DMA mode allows mechanical oscillations in all three modes of ope...

Page 29: ... can be defined in the Name field The Piuma software will automatically create a subfolder with this name in which the data will be saved You should avoid changing the saved file name afterwards in the Windows Explorer Figure 23 Piuma software experiment name and save location settings 3 7 Performing measurements After configuring all parameters for the experiment in the selected mode of operation...

Page 30: ...ta tab An estimate of the Young s Modulus both effective and bulk based on the chosen model is provided in the bottom of the screen Matrix indentations Instead of performing a single indentation series of indentations can be programmed to perform an automated scan over an area of the sample The indentation matrix is defined in the Scan controls of the main Piuma software window Figure 25 right The...

Page 31: ...ation as well as one file containing the effective Young s moduli per coordinate in a single grid The following points should be considered when initiating a matrix scan over an area First since a positive point to point pitch is added to the starting position it means the first point will always be displayed on the bottom left in the program s probe position field Because the stages move the samp...

Page 32: ... Modulus per coordinate This allows one to quickly recreate the Young s Modulus map in any other software program Additionally per indentation a separate text file is saved that contains all information for this indentation The header of the file contains the absolute coordinates the automatically defined surface position the probe parameters used the calibration factor applied the displacement pr...

Page 33: ...measurement error due to temperature drift sudden room or medium temperature changes should be avoided when measuring Verify the Piuma is mounted away from any air conditioning heating or ventilation vent If present the Piuma s heated stage can be used to measure samples at physiological temperatures Be aware that the heater can also introduce drift in the measurement if the sample or medium tempe...

Page 34: ...a sturdy surface and set up the peripherals outside the flow cabinet The Piuma indenter head can be wiped with ethanol or iso propyl alcohol to clean the instrument however avoid spraying any liquids or solvents directly on the Piuma indenter head In case the noise of the flow cabinet is too pronounced in the measurement consider lowering or briefly switching off the airflow during the measurement...

Page 35: ...ized correctly Figure 28 Piuma camera view of a living immersed micro tissue on a microscope slide Extra care should be taken when measuring samples that cannot be glued or weighed down 4 3 Probe stability The probe may be subject to instability if subjected to sudden temperature changes or if an air bubble is trapped near or on the cantilever upon immersion in a liquid Solution temperature When i...

Page 36: ...he surface tension is released and when immersed again the air bubble will not form Note that you should avoid directly touching the cantilever the cantilever is very fragile and can break easily when touched Holding the tissue at a safe distance will also allow you to dry the probe without touching the cantilever Figure 30 Suitable probe cantilever stiffness In order to perform successful indenta...

Page 37: ...elect a tip size several times larger than the largest pore For examining local features within one pore select a tip size that is several times smaller than the pore diameter Adhesion Adhesion between a sample and the indentation tip could interfere with the find surface procedure or affect the measurement result Three solutions for measuring adhesive samples can be provided 1 immerse the sample ...

Page 38: ...formation by detecting cantilever bending The Piuma s unique probes are at the heart of what makes the Piuma instrument so easy to operate and provide unparalleled precision at the same time The next paragraphs briefly describe the physics behind this optical probe design Interferometric displacement sensing The Piuma interferometer contains a laser source of which light is coupled into the optica...

Page 39: ...l fiber a probe holder and an indentation probe all in one piece The cantilever stiffness and tip size of the probe is calibrated at Optics11 and the values are provided on the probe s container Since the optical probe the cantilever and the tip consist of glass with resistant glue interfaces the whole probe can be immersed in any solution that does not affect glass or HT epoxy Often applications ...

Page 40: ...co elastic materials Oliver and Pharr This method derives the Young s modulus from the slope of the unloading part of the stress strain curve indenter tip radius and final indentation depth using the following formula 𝐸 𝑆 2 𝑅𝑖 ℎ𝑚𝑎𝑥 ℎ𝑟 1 W C Oliver G M Pharr An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation J Mater Res Vol 7 No 6 1564...

Page 41: ...estimate relative to the maximum load in the unloading phase default setting 60 to 80 of the maximum load on the unloading curve Hertzian contact The calculation of the effective Young s modulus by considering the Hertzian contact model follows the fit of the loading curve to the following equation 𝐸 𝑃 3 4 𝑅𝑖 ℎ𝑒 3 2 Figure 34 Typical load displacement curve of an indentation left The unloading cur...

Page 42: ... cyclic motion with frequency 𝑓 while controlling displacement or load with an amplitude of ℎ0 or 𝑃0 respectively The frequency dependent storage modulus 𝐸 and loss modulus 𝐸 are calculated with the following equations 𝐸 𝑓 1 𝜈2 𝑃0 ℎ0 cos 𝜙 1 ℎ𝑅 𝐸 𝑓 1 𝜈2 𝑃0 ℎ0 sin 𝜙 1 ℎ𝑅 If the amplitude of the input oscillation is small enough the measurements can be considered within the material linear viscoelas...

Page 43: ...terial 90 for a purely viscous material and in between 0 and 90 for a viscoelastic material After gather the frequency dependent storage and loss moduli they can be fit to lumped parameter rheological models to derive material viscoelastic constants ...

Page 44: ...esktop In case of freshly installing the Piuma software on another PC please contact Optics11 for a detailed instruction 6 1 Front panel controls The front panel contains all the controls required to operate the Piuma stages set up experiments and displays the camera feed and actual status of the system The following paragraphs will describe the features and functions of each of the areas of the f...

Page 45: ...stage next to that A stage can be moved by defining a step size in µm and clicking the arrow to the direction in which it should move Each stage is limited to 12 mm of movement Alternatively one can also use the keyboard arrow keys and the arrows keys at the numbering pad Num Lock should be off Figure 38 Arrow keys stage movement can be activated in the Advanced tab of the Options menu Figure 19 I...

Page 46: ...umber of points in X and Y direction to be scanned the dX and dY fields can be used to input the point to point pitch to be used the Start X and Start Y fields display the starting coordinates the Scans field controls the number of repetitions of the entire scan and the Indent field controls the amount of indentations per point in the matrix scan By clicking the Use XY button the current coordinat...

Page 47: ...ulk Young s Modulus using the pre configured Poisson s ratio Figure 41 To the right of the Indent results an indicator shows the suitability of the probe for the sample the indicator indicates if the probe s cantilever stiffness matches up well with the sample green suboptimal yellow or when you might need to consider using another probe red Figure 41 Indentation results after indenting a sample i...

Page 48: ...image can be magnified on the screen by clicking Magnify The LED top lighting can be switched on default or off with the LED light button Figure 42 Signal monitor and live video tab Load displacement tab The load displacement tab shows the load displacement curve of the last indentation The blue line shows the loading curve and the green line shows the unloading curve The red line indicates the po...

Page 49: ...referred Also after the point of contact the slope of the blue line should be distributed over the slope of the green and red lines as the initial displacement can only result in an approach of the sample sample deformation and cantilever bending The bottom graph shows the applied load as a function of time Figure 44 Additionally there is a possibility to activate an auxiliary graph by left mouse ...

Page 50: ...ab shows a map representation of the Young s Modulus per coordinate This map can be showed in 2D or 3D and the minimum and maximum Z axis values can be manually adjusted Figure 45 46 The Show Young s button allows to convert the effective Young s Modulus to the bulk Young s Modulus using the preconfigured Poisson s ratio ...

Page 51: ...51 Figure 45 Young s Modulus tab showing a 10x10 2D plot Figure 46 Young s Modulus plot showing a 10x10 3D plot ...

Page 52: ...us tab showing the histogram 6 3 Configuration panels The Configuration menu item provides several menus to configure the indentation profile the probe in use settings for finding the surface and advanced configuration and maintenance settings Configure indentation menu This menu allows to set a custom displacement load and indentation profile The maximum displacement or indentation depth is 20 µm...

Page 53: ...imate will be compromised The probe cantilever spring constant K in N m and the spherical tip radius µm can be found on the box the probe is shipped in These parameters are coupled to the physical probe assembly and since the probe is made of glass should not change significantly over time if properly cleaned The calibration factor describing the probe specific optical lever arm is determined by t...

Page 54: ...ce after detecting the surface using the automated find surface function the dX before scan field controls the offset in X direction of the probe tip with respect to the surface after the surface has been determined Figure 50 Options menu The Model settings section displaying the Oliver Pharr and Hertzian contact buttons allow one to select the model of choice to be applied for the indentation or ...

Page 55: ...g a standard measurement Maintenance menu The maintenance panel is protected by a password as any change in these settings may compromise the performance of the Piuma Nanoindenter Please note that changing parameters in the maintenance menu can cause unexpected behavior and potentially break the hardware on the Piuma Use caution when changing parameters It is recommended to only use the maintenanc...

Page 56: ...displacement load and indent control can be set from the General tab It is recommended to only change these settings if you have experience with tuning PID controllers Changing the parameters could result in unstable operation of the system and cause the controller to break ...

Page 57: ...ems In order to select a field or button on the OP1550 screen move the cursor over the button or field and press the center button enter In case a field is selected the field will turn blue and the up and down buttons can be used to alter the value the cursor highlights The interface is built up out of two menus The first menu Measurement Wavelength scan Demodulation and Settings can be accessed u...

Page 58: ...e Wavelength scan menu A correct wavelength scan results in a sinusoidal curve as shown in figure 53 b The Demodulation tab displays the interferometric linearization by aligning the collected datapoints to a unity circle It can be very useful for observing the cantilever bending while manually approaching the surface of a sample or a stiff surface during the calibration procedure When the tip is ...

Page 59: ...P1550 interferometer the last saved values will be loaded The Laser ADC Output Modulation and Maintenance menu The right side of the screen is reserved for the Laser ADC Output Modulation and Maintenance menu To scroll through the menus move the cursor to the section right of the graph area and press the left or right arrow Figure 55 Laser a ADC b Output c Modulation d and Maintenance menu e of th...

Page 60: ...gnal output at the Front out either as a Straight which displays the modulated signal or as a demodulated by switching to Demodul The range and sensitivity parameters can be changed in the maintenance menu in the software but it is recommended to keep them at the default settings The Modulation menu contains the controls to induce a small modulation on top of the laser output signal by quickly and...

Page 61: ...he OP1550 is ticked In case the problem persists check the probe for contamination under a stereo microscope Q3 I get more cantilever bending than displacement in the results a backward sloping load displacement curve A3 Verify the probe is calibrated in the medium the probe is used in In case this is uncertain recalibrate the probe on a stiff surface Also please ensure the tip hits the sample pri...

Page 62: ...that occur while measuring with the Piuma Nanoindenter are related to the calibration of the instrument A troubleshooting flowchart is presented on the next page to guide you through possible issues and solutions to ensure a safe calibration of the Piuma Nanoindenter and therefore a correct functionality of the instrument ...

Page 63: ...63 Flowchart Calibration ...

Page 64: ...optics11 com For troubleshooting support or questions while working with the Piuma Nanoindenter please contact Optics11 at Tel 31 20 5987917 E mail info optics11 com Office hours are between 8h and 18h CET ...

Page 65: ......

Reviews:

No comments