Electronic materials and components with high quality and reliability are in high demand. In that regard, a key test technique in the research and development stage and manufacturing process is flexural testing (Figure 1) which provides key insights into the flexural strain, flexural stress and the modulus of elasticity in bending.
Figure 1. Flexural testing provides key insights into the flexural strain, flexural stress and the modulus of elasticity in bending.
As almost all products will experience flexing a number of times during their service life, manufacturers strive to provide products that are durable and deliver superior performance in a variety of usage scenarios during their planned lifetime. Hence, it is crucial to test the performance of a product or material in order to optimize the production and quality control processes.
Flexural Strength Test Methods
Destructive and non destructive testing are the two common flexural strength testing methods (Figure 2). In destructive tests, the specimen such as PCB or final assembly is subjected to a uniform force until it breaks, followed by recording the optimum force applied and the displacement. In non-destructive tests, the sample is subjected to a uniform force of specified limit and then the displacement is recorded to ensure the capability of the sample to withstand the specified force.
Figure 2. Bend testing of final assembly.
Cyclical and fatigue testing involves specified force-displacement and force-time waveforms. Here, the sample is subjected to different strain rates over a period of time to determine force-time and force-displacement characteristics by performing analysis of cycles to failure.
The Nordson DAGE Solution
Three and four-point flexure tests can be performed on the Nordson DAGE 4000Plus tester which has fixtures to provide custom test solutions according to international standards, including ISO 14125, IEC 61189-2:TM20, IPC TM-650, and ASTM D790 and D672.
3 Point Flexure Test
The 3 point flexure fixture (Figure 3) creates stress localization by producing an optimum stress at the midpoint of the sample with less stress elsewhere. This stress localization is suitable to test specific isolation of stress on a material or component.
Figure 3. Push/pull 50kg with 3 point bend jig.
4 point flexure test
The 4 point flexure fixture exposes the largest area of the sample to stress by creating peak stresses across an extended region, highlighting the potential for flaws and defects.
A product will experience reduction in its flexural strength when it undergoes different phases of a production cycle, including heat reflow. Nordson DAGE can accurately determine the flexural strength of an end product by providing custom test solutions for specific designs and properties.
The Nordson DAGE Paragon™ Flexure Test Software
The Nordson DAGE Paragon™ flexure test software has a user-friendly interface that facilitates minimum setup time for tests. The following material properties can be determined using this innovative software:
- Flexural strength
- Stress-strain properties, such as flexural offset yield strength, tangent modulus of elasticity, and secant modulus of elasticity
- Flexural stress
- Flexural stress at break
- Flexural strain Chord modulus
- Stress at given strain
The Paragon flexure test software enables
- Custom cyclic testing for bespoke test procedures
- User selectable load range and speeds
- User defined cyclic patterns
- Destructive and non-destructive tests
With these bespoke test features, the Paragon flexure test software helps determining the break points of components or materials.
Significance of Flexural Testing
PCB and SMT technology have continuously come across new challenges in substrate design and packaging, where a final product will experience a range of mechanical strain and shock. It is therefore crucial to perform flexural testing to determine the reaction of the product when subjected to a force or changing forces such as flexing or bending, as well as its flexural properties to evaluate the endurance of products design.
Cyclical and fatigue testing quantifies the point of failure of a product under certain forces to facilitate correct product design.
Nordson DAGE offers a robust, dependable, and reproducible test for research and development, monitoring and process control through a combination of 3 point and 4 point testing capability and the cyclic and fatigue software capabilities. The Nordson DAGEe 4 point bend jig (Figure 4) quantifies midpoint deflection of a sample to 50µm using a Baumer laser displacement sensor.
Figure 4. 4 Point bend Jig.
Paragon™ Software Flexible Analysis and Reporting
Paragon is a versatile analysis suite (Figure 5) ideal for the most challenging applications:
- Force/time displacement curves
- Loop height trend analysis
- Grade pareto
- Force trend analysis (with box whisker and optional mini histogram on the same chart)
- On-board statistics and Statistical Process Control (SPC) package with histogram distribution curves (mean and current samples)
Figure 5. Flexural test results analysis.
Moreover, it provides a robust statistical results display for mean, standard deviation, maximum and minimum range.
The Paragon™ software allows data manipulation in a variety of ways:
- RS232 including a fixed field option
- ODBC compatibility (locally or via a network link)
- Copy results to the clip board to paste directly into Microsoft Excel or export directly into Excel or Word
- CSV file format availability
It is possible to configure Paragon to send results to SPC packages which are supported by, or directly available, from the manufacturer. It is also possible to store the test results directly into Microsoft Excel or Word and Adobe® Acrobat. Moreover, exporting graphs in picture formats such as .bmp, .tif, and .jpg can also be performed.
About Nordson DAGE
Dage was founded in 1961 and is a market leader in its chosen markets of Semiconductor and PCBA Manufacture. It has an award winning portfolio of Bondtester and X-ray Inspection Systems for destructive and non-destructive mechanical testing and inspection of electronic components.
Dage was acquired by the Nordson Corporation in 2006.
Nordson DAGE has a strong portfolio of award winning products for destructive and non-destructive mechanical testing and inspection of electronic components. It has an excellent, wholly owned distribution and support network of seven offices covering Europe, Japan, China, Singapore, and the USA, and maintains representative offices in other territories.
With its self-contained R&D facilities, Nordson DAGE has developed world-leading products for testing wire bonds on semiconductor packages such as BGA, Chip Scale Packages (CSP) and other electronic components. More recently Nordson DAGE has been heavily involved in the testing of the newest technology 300 mm wafer bump shear.
Nordson DAGE has developed an excellent suite of award-winning X-ray inspection equipment targeted at both the Semiconductor and PCBA markets.
Control of the patented core technology of X-ray tube manufacture ensures that the high-resolution X-ray will detect, identify and measure even the smallest of features. Nordson DAGE's high precision, state-of-the-art inspection equipment when joined with their sophisticated software offerings, ensure that the equipment is simple to use.
This information has been sourced, reviewed and adapted from materials provided by Nordson DAGE.
For more information on this source, please visit Nordson DAGE.