Inseto

Month: April 2020

WIN-PLASMA Creating A Sequence

27th April 2020

This document advises on how create a sequence in the Plasma Etch Win-Plasma Application (IKB-048).

This document presumes the user is familiar with the Low Pressure Plasma process and the Plasma Etch Inc. Equipment.

WARNING: Only qualified and competent personnel should create a new sequence; incorrect parameters may cause damage to the system.

Note: Use the onscreen shortcut to bring up the onscreen keyboard when needing to enter text into a text field.

  1. Check and release the EMO if engaged.
  2. Set the power circuit breaker to the On (Up) position.
  3. Press the ‘Start’ button on the front panel to power up the system.
  4. Open the ‘Win-Plasma’ Application on your Windows PC.
  5. Navigate to the ‘Technician’ tab.
  6. Open the ‘Sequence’ menu within the ‘Technician’ tab. Within this menu you can create, save, edit, delete and modify Sequences to be used on your system.
    1. Time (Minutes) – Time that Plasma is present in the Sequence.
    2. RF (Watts) – Unit of power demanded from the RF Generator.
    3. Gas 1 – Selection of process gas; refer to rear panel of machine to check which process gas inputs in to which gas line.
    4. Flow 1 (sccm) – Flow demand of Gas 1 selection.
  7. Create and save a new sequence and save accordingly into the Windows directory.
  8. Close all windows and tabs and Navigate back to the main Win-Plasma Screen.
  9. Open the ‘Sequence’ tab from the main screen; this will allow you to open the load in any sequence made within the main directory.
  10. Press ‘Load’ to accept the sequence.
  11. You will see that the ‘Process Sequence’ box within the main screen will update with the Sequence name and details its parameter variables.
  12. The system is ready to run the newly loaded sequence.

For more information on Plasma Etch, plasma cleaning and etching equipment, please click HERE.

Author

Date

Version

Author

Adam Marshall

Date

27 March 2020

Version

IKB048 Rev. 1

Download

WIN-PLASMA Running A Sequence

27th April 2020

This document advises on how to run a sequence in the Plasma Etch Win-Plasma Application (IKB-049).

This document presumes the user is familiar with the Low Pressure Plasma process and the Plasma Etch Inc. Equipment.

WARNING: Only qualified and competent personnel should create a new sequence; incorrect parameters may cause damage to the system.

Note: Use the onscreen shortcut to bring up the onscreen keyboard when needing to enter text into a text field.

  1. Check and release the EMO if engaged.
  2. Set the power circuit breaker to the On (Up) position.
  3. Press the ‘Start’ button on the front panel to power up the system.
  4. Open the ‘Win-Plasma’ Application on your Windows PC.
  5. Open the ‘Sequence’ tab from the main screen; this will allow you to open the load in any sequence made within the main directory.
  6. Press ‘Load’ to accept the sequence.
  7. The ‘Process Sequence’ box within the main screen will update with the Sequence name and details of its parameter variables.
  8. Double-check that the loaded sequence variables (as below) are correct:
    1. Time (Minutes) – Time that Plasma is present in the Sequence.
    2. RF (Watts) – Unit of power demanded from the RF Generator.
    3. Gas 1 – Selection of process gas; refer to rear panel of machine to check which process gas inputs in to which gas line.
    4. Flow 1 (sccm) – Flow demand of Gas 1 selection.
  9. From the main screen open the ‘Power’ tab.
  10. Using the on screen switches, enable power to all of the switches available.
  11. Exit and close back to the main screen.
  12. The system is now ready to start the loaded Plasma Cycle.
  13. There are a few main commands in the ‘Commands’ tab from the main screen. These are:
    1. Plasma – The Plasma process will run from start to finish automatically following the sequence loaded into the main screen. Upon completion of the plasma cycle the user will be informed through the screen, light tower and/or buzzer.
    2. Cycle Off – The Cycle Off command brings the chamber back to atmosphere for the process of loading/unloading.
    3. Standby – When the system is not immediately in use it should be placed in standby mode. Depending on the type of vacuum pump installed, the N2 gas purge lines to a ‘wet’ pump will be enabled to ‘clean’ the vacuum pump oil.
    4. Shutdown – This command will begin the shutdown procedure for the system. The pump, temp control and RF isolators will be disabled in a safe sequence.
    5. Plasma Time – If the Plasma process is running it can be changed mid-cycle with this command. It can be shortened or extended. It is the only sequence variable that can be edited in process.
    6. Silence Alarm – If an Alarm state is present on the machine and the buzzer is wished to be turned off, this feature will silence the audible alarm. The last alarm state is displayed on the main screen.
    7. Quick Stop – When the plasma cycle is running this command will stop the plasma counter immediately. The chamber will then continue through the rest of the cycle such as purge and cycle off.
  14. To begin a cycle, make sure the chamber door is closed and that all gas lines are present at the correct pressures to the rear of the machine.
  15. From the ‘Commands’ tab, confirm the start of a sequence with the ‘Plasma’ command.
  16. The Plasma process will run from start to finish automatically following the sequence loaded into the main screen. Upon completion of the plasma cycle the user will be informed through the screen, light tower and/or buzzer.
    1. The Vacuum Pump engages and begins to evacuate the chamber.
    2. Once the ‘Vacuum set-point’ has been reached the system will go into ‘Gas Stabilisation’.
    3. The ‘Gas Stabilisation’ allows the gases to stabilize for a period.
    4. After the process gasses are stabilised, the RF power is enabled. The Wattage is determined by the loaded sequence.
    5. Inside the Chamber a Plasma Glow will be seen and the Plasma process timer will start. This is determined by time in the loaded sequence.
    6. Once the ‘Plasma time’ is completed, the RF power is removed and the plasma glow will disappear from the chamber as the process gas valves are closed. The vacuum pump will be isolated from the chamber.
    7. Chamber Vent Valve is opened for the period. This time dilutes any contaminants or harmful elements in the chamber before being evacuated by the vacuum pump again.
    8. After completion of the ‘Purge Vent’ the chamber is evacuated by the pump until the ‘Vacuum set-point’ is reached again.
    9. The process is complete
    10. The next step depends on whether the ‘Auto Cycle Off’ cue is enabled or disabled. If it is ‘On’ the chamber will vent to Atmospheric pressure using the ‘Atmospheric Vent’ period determined in the setup menu. If it is ‘Off’ the ‘Cycle Off’ cue will need to be initiated using the commands menu.
  17. The process is complete. You will be back at the main screen of Win-Plasma with options to begin a new sequence cycle or shutdown the machine.
  18. To shut down the system, use the ‘Shutdown’ command from the ‘Commands’ tab.
  19. Wait for all timers to finish, you will notice the machine remove power from the RF, Pump & Temp controller.
  20. To close the Win-Plasma Application, click on the PE icon on the bottom of the main screen.
  21. You will be prompted to confirm to close Application.
  22. Power down the Windows PC.
  23. Turn off the chamber with the main power isolator on the rear of the machine and isolate gas lines.

For more information on Plasma Etch, plasma cleaning and etching equipment, please click HERE.

Author

Date

Version

Author

Adam Marshall

Date

31 March 2020

Version

IKB049 Rev. 1

Download

Explanation of Low Pressure Plasma Cleaning

25th April 2020

Explanation of the process and use of low pressure plasma cleaning (IKB-014).

Low Pressure Plasma Treatment uses controlled vacuum plasma for plasma cleaning and etching, in order to alter the surface of a material and to improve bonding, printing, painting, coating, or wet-ability. The process is performed in a plasma chamber under vacuum pressure. It is commonly used in the manufacturing of electronic devices. Almost any dry material can be treated in a plasma chamber.

Low Pressure Plasma Cleaning involves the removal of impurities and contaminants from surfaces through the use of energised plasma created from gaseous species. Gases such as Argon and Oxygen are used, as well as mixtures such as air and Hydrogen / Nitrogen. The plasma is created by using high frequency (RF) voltages (typically >10MHz) or Microwave frequency voltages to ionize the low-pressure gas (typically around 150mTorr-400mTorr), although atmospheric pressure plasmas are now also common.

In plasma, gas atoms are excited to higher energy states and also ionised. As the atoms and molecules ‘relax’ to their normal lower energy states, they release a photon of light which this results in the glow or light associated with plasma. Different mixtures of process gases give different colours. For example, oxygen plasma emits a light blue colour where as an oxygen / argon mixture is pink.

Plasma’s activated species include atoms, ions, electrons, free radicals, metastables and photons in the short-wave ultraviolet range (vacuum UV, or VUV for short). This ‘mixture’, which incidentally is around room temperature, then interacts with any surface placed in the plasma chamber.

Depending on the power of the RF energy supplied, a side effect of the Plasma process is that the part being treated can rise in temperature. Although temperature controlled chambers can be used to control and increase the cleaning/etch rate (60-90 degrees Celsius can increase the etch rate by up to four times), temperature sensitive components can be processed at >15 degrees Celsius.

If the gas used is oxygen, the plasma is an effective, economical, environmentally safe method for critical cleaning. The VUV energy is very effective in the breaking of most organic bonds (i.e., C–H, C–C, C=C, C–O, and C–N) of surface contaminants. This helps to break apart high molecular weight contaminants. A second cleaning action is carried out by the oxygen species created in the plasma (O2+, O2-, O3, O, O+, O-, ionised ozone, metastable excited oxygen, and free electrons). These species react with organic contaminants to form H2O, CO, CO2, and lower molecular weight hydrocarbons. These compounds have relatively high vapour pressures and are evacuated from the chamber during processing. The resulting surface is ultra-clean.

PE-100-Benchtop Plasma Cleaner
Example Low Pressure Plasma Cleaning / Etching Equipment

Low Pressure Plasma Chamber View

If the part to be treated consists of easily oxidised materials such as silver or copper, inert gases such as argon or helium are used instead. The plasma activated atoms and ions behave like a molecular sandblast and can break down organic contaminants. These contaminants are again vaporized and evacuated from the chamber during processing.

Low Pressure Plasma Treatment systems are able to remove 100% of these organic contaminants. This increases the bond strength of a solder or glue, increases or decreases wettability, and ensures any type of printing, painting, or coating remains on the object’s surface.

Typically, Low Pressure Plasma Cleaning process can last between 2-20 minutes, upon completion of the plasma cycle, the process chamber is evacuated under vacuum finally to remove any contamination from the Plasma process.

For more information on Plasma Etch, plasma cleaning and etching equipment, please click HERE.

Author

Date

Version

Author

Adam Marshall

Date

23 April 2020

Version

IKB014 Rev. 5

Download

Probe Station Basics

22nd April 2020

What is a Probe Station and how does it work? (IKB-051)

The semiconductor probe station is a well-established tool for testing circuits and devices on silicon wafers, dies and open microchips – but what is it and how does it work?

Probe stations allow a user to position electrical, optical or RF probes onto a device and to then test the response of that device to an external stimulus (electrical, optical or RF). These tests can be simple such as continuity or isolation checks, or more sophisticated involving full functional tests of complex microcircuits.

A probe station can run tests on a full wafer or after it has been sawn up into individual die. Testing at a whole wafer level allows the manufacturer to test a device multiple times at different stages throughout the production process, and closely monitor fabrication to see if any defects are present. Testing on individual die prior to final packaging allows defective devices to be removed from circulation ensuring only functioning devices are packaged. Probe stations have much use throughout R&D, product development and failure analysis where engineers need a flexible yet precise tool to conduct a range of tests on different areas of a device.

What sets a good probe station apart and adds value to your testing, is its ability to precisely control where those probes are positioned on the device, how that external stimulus is applied and the environmental conditions that surround the device as the test takes place.

Basic Components

A probe station is comprised of six basic components:

  • Chuck – a device for holding the wafer or die without damaging it.
  • Stage – for positioning the chuck in X, Y, Z and Theta (θ).
  • Manipulators – for positioning the probes on the device under test (DUT).
  • Platen – for holding the manipulators and bringing the probes into contact with the device.
  • Probe tips & arms – mounted onto the manipulator, they directly contact the device.
  • Optics – for viewing and magnifying the device under test and probe tips.
Wafer probe station key components.

How does it work?

Probe stations hold a wafer or a die on a chuck mounted on a stage which allows the positioning of the DUT in the centre of the field of view of the microscope.

Manipulators are placed on the planar surface of the platen, and into the manipulators are inserted probe arms & tips. The probe tips must be suitable for the test programme to be carried out. The user then precisely positions the probe tips on the correct locations within the device by adjusting the corresponding manipulator. The probes are then brought into contact with the wafer by lowering the platen; the device is now able to be tested.

For wafers with multiple devices, after the first device is tested the platen can be raised and the stage holding the wafer moved to the next device. The process of positioning the probe tips is repeated until all required devices have been tested. This process can all be done manually by an operator but if the stages and manipulators are motorised and the microscope connected to a computer vision system then the process can become semi-automatic or fully automatic. This can increase the productivity and throughput of the probe station and reduce the labour needed to run multiple tests.

Configuring your probe station
Moving on from these probe station basics there are a number of questions you should ask about your testing requirements that will allow you to specify the options you need for your probe station:

  • What level of automation do you need?
  • How will your test affect the probe tips selected?
  • Do you need to control the temperature and local environment around your device?
  • Will you need to stimulate optically or magnetically?
  • What size features are you probing?
  • How will you contact the device under test?

For more information on SemiProbe Probe Stations – Wafer Probing Equipment, please click HERE.

Author

Date

Version

Author

Chris Valentine

Date

22 April 2020

Version

IKB051 Rev. 1

Download

Laser Trimming Basics

22nd April 2020

What is laser trimming and how does it work? (IKB-052)

Laser trimming is the manufacturing process of using a laser to adjust the operating parameters of an electronic component or circuit by incrementally reducing the amount of component material.

Laser Trimming Equipment
LS Laser Trim Equipment

The most common use of laser trimming is to change the resistance of a thick-film or thin-film resistor by burning away a small proportion of the resistive material. This cut, or trim, increases the resistance of the component by narrowing or increasing the current path through the resistive material.

Actively measuring the resistance value of this resistor as the trim is in progress means that this is a very accurate way of determining the final result.

Certain types of capacitors can also be accurately laser trimmed to the correct capacitance. Removing the top layer of a multilayer capacitor decreases the capacitance by reducing the area of the top electrode.

There are two main types of trimming process: Passive and Active. Passive trim is the adjustment of a single component, for example a resistor or capacitor, to a given value. If the trimming alters the whole circuit output such as voltage, frequency or attenuation, then this is called an Active trim. During the trim process the circuit output is monitored continuously, shutting off the laser automatically when the desired output is achieved.

Process variability stems from the laser spot size, laser power at the component level, and wavelength / pulse duration of the laser source.

Both passive and active trim require electrical contact to the component circuit for feedback measurement. This is usually achieved via a dedicated probe card utilising spring blades or pressure pins.

Laser Trim Examples of Trimmed Thick and Thin Film Devices
Example Laser Trim Cuts

For further information on our range of laser trimming equipment, please click HERE.

Author

Date

Version

Author

Adam Marshall

Date

22 April 2020

Version

IKB052 Rev. 1

Download

Understanding Wire Pull Testing

22nd April 2020

Explanation of non-destructive and destructive testing of ultrasonically welded interconnects in microelectronics (IKB-003).

  • Wire Pull testing is an established methodology for verifying ultrasonic wire bonding interconnects in microelectronics.
  • Pull testing involves a precision tooltip applying an upward (pulling) load on the wire under test, while work-piece or product assembly is held stationary.
  • As the tool moves upwards, the force (load) being applied to the work sample is accurately measured and recorded as the test result.
  • Standard pull tests involves a suitable pull hook being placed underneath the wire loop being tested.
  • Load applied perpendicular (at 90°) to the work-piece under test.
  • Destructive testing tests ultimate strength of the wire bonding until failure occurs.
  • Non – destructive testing applies a pre-defined load to the wire under test for a pre-defined duration to test wire integrity on high value assemblies without compromising the interconnect itself.
  • Pull test can be used for ball bond, wedge bond and ribbon bond interconnects.
Wire bond pull test method and failure modes.

Further information:

Wire Pull Test Method, please click HERE.

Nordson-DAGE bond and materials testing equipment, please click HERE

Or to visit the Nordson website, click HERE

Author

Date

Version

Author

Jim Rhodes

Date

22 May 2017

Version

IKB003 Rev. 3

Download

MIL STD 883 Shear Testing

21st April 2020

Explanation of the MIL STD 883 shear testing; describing the type of failure resulting from this application of force (if failure occurs); and the visual appearance of the residual die attach media and substrate/header metallization (IKB-026).

Shear Strength:

A force sufficient to shear the die from its mounting or equal to twice the minimum specified shear strength (figure 2019-4), whichever occurs first, shall be applied to the die.

Testing Methods:

See IKB018 UNDERSTANDING BALL BOND AND DIE SHEAR TESTING for an explanation of how shear testing works, and the main points to take note of when shear testing.

Failure Criteria:

A device which fails any of the following criteria shall constitute a failure:

  1. Fails die strength requirements (1.0X) of figure 2019-4.
  2. Separation with less than 1.25 times the minimum strength (1.0X) specified in figure 2019-4 and evidence of less than 50 percent adhesion of the die attach medium.
  3. Separation with less than 2.0 times the minimum strength (1.0X) specified in figure 2019-4 and evidence of less than 10 percent of adhesion of the die attach medium.

NOTE: For eutectic die attach, residual silicon attached in discrete areas of the die attach medium shall be considered as evidence of such adhesion. For metalised glass die attach, die attach material on the die and on the package base shall be considered as evidence of acceptable adhesion.

Separation Categories:

When specified, the force required to achieve separation and the category of the separation shall be recorded:

  • a. Shearing of die with residual silicon remaining.
  • b. Separation of die from die attach medium.
  • c. Separation of die and die attach medium from package.

SUMMARY:

The following details shall be specified:

  • a. Minimum die attach strength if other than shown on figure 2019-4.
  • b. Number of devices to be tested and the acceptance criteria.
  • c. Requirement for data recording, when applicable (see 3.2.1).
Figure 2019-4. Die Shear Strength Criteria (minimum force verses die attach area)

NOTES:

  1. All die area larger than 64 x 10-4 (IN)2 shall withstand a minimum force of 2.5 kg or a multiple thereof (see Failure Criteria section above).
  2. All die area smaller than 5 x 10-4 (IN)2 shall withstand a minimum force (1.0X) of 0.04 kg/10-4 (IN)2 or a minimum force (2X) of 0.08 kg/10-4 (IN)2. FIGURE 2019-4. Die shear strength criteria (minimum force versus die attach area).

Ref: MIL-STD-883E METHOD 2019.5 29 May 1987 1 METHOD 2019.5 DIE SHEAR STRENGTH

For more information on Nordson-DAGE bond and materials testing equipment, please click HERE.

Author

Date

Version

Author

Matt Houston

Date

03 July 2017

Version

IKB026 Rev. 1

Download

Understanding Shear Test: Ball & Die Shear

21st April 2020

Explanation of different types of common shear testing methods used in microelectronic assembly (IKB-018).

There are two typical types of shear test which are commonly used; these are ball shear and die/component shear.

A shear test involves a precision chisel-shaped tool tip being placed behind the bond or device to be tested. The sample is then moved against the tool, effectively pushing against the bond or device until it shears from its pad, or the substrate.

As the testing progresses, the applied shearing force (load) is accurately measured and recorded as the test result.

The following illustrates two typical types of shear test:

Ball Shear:

This test involves shearing solder balls or wire bonds, as shown right.

Bond Shear Testing Process
Bond Shear Testing Process

Die Shear:

This test involves shearing complete device dies/components from the substrate, as shown:

Die shear testing may involve the application of very high shear loads and can currently be tested up to 200KG.

When shear testing, it is very important that you follow a few simple rules:

  1. Make sure the tool you are using covers 80% or more of the component/ball which you are testing.
  2. If the shear tool is >100%, make sure when testing that this does not touch any surrounding devices/balls.
  3. Make sure the part you are testing is central to the tool being tested against.
  4. The die contact tool shall load against an edge of the die/ball which most closely approximates a 90° angle with the base of the header or substrate to which it is bonded
Die Shear Testing Process
Die Shear Testing Process

Theory of Shear Testing

The basic parameters and their order during the shear test movement are explained below:

Land Speed (LS): Sets the speed at which the tool is lowered, measured in millimetres per second. A fast speed gives the best test throughput. A slower speed is the most gentle on fragile or delicate parts. The shear test proceeds from a manually set tool height.

Shear Height (SH): Sets the tool height required above the substrate prior to shearing. The tool will first move downwards (at the rate set in Land Speed parameter) and touchdown on the surface, the Z axis will then move to set Shear Height distance upwards and lock in position.

Test Speed (TS): Sets the test speed, measured in microns (micrometres) or millimetres per second. This is the horizontal speed of the XY table during the test. A fast speed gives the best test throughput. A slower speed may allow such effects as sample material creep to take place which may uncover other failure modes.

Test Load (TL): Sets the test load, measured in grams or kilograms. In destructive testing this parameter can set a simple Pass/Fail condition. Bonds above this setting are deemed to have passed, those below are failures.

Max Test Load (MTL): Sets the maximum test load to be applied, measured in grams or kilograms. This parameter is used in destructive tests to set a test ‘window’. With Max Test Load set higher than Test Load, bonds between the two limits will be deemed to have passed; bonds below Test Load or above Max Test Load will be failures.

Overtravel (OT): Sets the overtravel distance. Once a test has been detected as finished, the tool can be set to continue a further distance, clearing the test site and allowing inspection.

Max Shear Distance: Sets the distance the shear tool will travel after the start of the test. This can prevent the tool continuing further than necessary and colliding with other bonds or objects on the work sample substrate.

Diagram 1 – shows the point at which different parameters take place during shear testing.

Further information:

Wire Bond Shear Test Method, please click HERE.

Passivation Shear Test Method, please click HERE.

Die Shear Test Method, please click HERE.

Nordson-DAGE bond and materials testing equipment, please click HERE.

Author

Date

Version

Author

Matt Houston

Date

04 July 2017

Version

IKB018 Rev. 2

Download

Dage Hot Bump Pull Testing

21st April 2020

What is Hot Bump Pull Testing (HBP) and how does it work? (IKB-031)

HBP Test Process

The HBP (Hot Bump Pull) test process involves the following phases:

  • Applying a test pin to the solder ball or bump under test
  • Heating the pin to melt and re-flow the solder onto the pin-tip
  • Cooling the pin and test site in a controlled manner to solidify the solder
  • Applying a vertical pull load (of up to 10kg) until the joint fails

HBP Test Applications

Typically, the HBP test method is used by substrate manufacturers during research and development in order to:

  • Remove the maximum amount of material possible from a bonding pad
  • Evaluate the strength of the various interconnecting materials
  • Test low profile or irregular shape samples where standard gripping techniques do not work

HBP testing is applicable to both traditional solder ball and flip chip bumps either bonded or formed by the deposition process and is also used to identify pad crater failures on the substrate side (IPC 9708). Generally, HBP testing is destructive. However, you can configure the test to be non-destructive if required.

Temperature / Time Profiles

Dage Paragon software provides accurate HBP test temperature control using a series of user-definable Temperature / Time Profiles.

A profile consists of six individually configured temperature/time points, defined as follows:

  1. T1 Warm-up 1 Initial temperature to ramp to in the specified duration
  2. T2 Hold 1 Duration to hold at the temperature defined in T1
  3. T3 Warm-up 2 Final temperature to ramp to in the specified duration
  4. T4 Hold 2 Duration to hold at the final temperature defined by T3
  5. T5 Cool 1 Initial temperature to cool to in the specified duration
  6. T6 Cool 2 Final temperature to cool to and the duration of the cooling period

Details

  • Patented industry unique test solution
  • Up to 10kg tensile pull
  • Pneumatic clamping for rapid pin load and unload
  • Built in extraction to remove fumes from any flux used
  • Rugged design for reliable and reproducible load measurement
  • The HBP cartridge can apply the following range of pull loads:
    • Range 1 – 10kg
    • Range 2 – 5kg
    • Range 3 – 2.5kg
    • Range 4 – 1kg

Temperature / Time Profiles

Hot Bump Pull Test Process
Performing a HBP Test Cycle


Further information:

Hot Bump Pull Test Method, please click HERE.

Nordson-DAGE bond and materials testing equipment, please click HERE.

Author

Date

Version

Author

Matt Houston

Date

20 November 2017

Version

IKB031 Rev. 1

Download

3 and 4 Point Flex Bend Testing

21st April 2020

What is 3 or 4 point bend testing and how does it work? in materials test? (IKB-030)

4 Point Bend Testing:

All bend testing is based on beam theory, which relates the stresses, strains and deflection of the sample to its dimensions and the applied load. The simplest form of bend is known as pure bend and this is what we aim to achieve in a four point bend test. Typically this form of the bend test is used to determine failure strain of interconnect on circuit boards. Four point bending can also be used to determine material parameters, such as flexural modulus, and for composites such as those used for circuit boards.

3 Point Bend Testing:

Three point bending is best understood by looking at the strains in a simple cantilever, where one end is fixed and the other end deflects with the applied load. In the three point bend the maximum stress occurs in the centre of the beam, under the loading anvil. The stress at this point is the same as that experienced at the fixed end of a cantilever, equal in length to the distance between the support and centre anvils. Increasing the span of the support anvils increases the maximum stress for a given applied load, and in this way large stresses can be developed for moderate applied loads.

Fatigue Test: Flex Bend

Under load, the yellow square distorts such that the bottom is stretched (in tension) and the top contracts (in compression). The centre line of the square remains unchanged; this is the neutral surface and is at the mid thickness for a simple rectangular beam.

Fatigue Test: Wire Pull

Further information:

Flex-Bend Test Method, please click HERE.

Nordson-DAGE bond and materials testing equipment, please click HERE.

Author

Date

Version

Author

Alex Forster

Date

06 May 2020

Version

IKB030 Rev. 1

Download