Flexural test plays a vital role in the research and manufacture of reliable electric components and materials. It is used to study the ability of the material to refrain from deformation under stress. The test also analyzes the parameters such as flexural strain, flexural stress and elastic modulus in bending.
With the growing demand for human interface devices like touch screen displays, mobile phones, etc, the devices undergo a number of flexing cycles during manufacture. This ensures guaranteed performance and prolonged service life of the products. However, to meet these criteria, it is necessary to optimize the manufacturing and quality control processes by analyzing the material’s performance.
This article describes the use of Nordson DAGE 4000Plus tester that performs 3 and 4 point flexure tests of a wide range of samples.
Overview of Existing Flexural Test Methods
Flexural testing involves simulation of tensile and compression stress on samples like final assembly or PCB so as to monitor the physical characteristics of the material. It is of two types - destructive and non destructive testing.
In destructive tests, a uniform force is continuously applied on the assembly or PCB to analyze the maximum force and displacement. Non-destructive tests, however, involves the application of uniform force to a certain limit followed by recording the displacement and tolerance limit of the PCB and the assembly.
Cyclical and fatigue testing involves analyzing the specified force-displacement and force-time waveforms. It also induces various strain rates onto a sample for a time period, which allows failure analysis of cycles and determination of force-displacement and force-time characteristics.
Flexural Testing Using Nordson DAGE Solution
Nordson DAGE 4000Plus tester offers the ability to carry out 3 and 4 point flexure tests. The device complies with a range of international standards such as ISO 14125, TM20, IEC 61189-2, IPC TM-650, ASTM D790 and D672.
The 3 point flexure fixture of the tester provides peak stress at the middle of the specimen with reduced stress. The localization of stress is suitable for analyzing the specific isolation of stress applied on the material. Figure 1 shows the 3 point flexure fixture of Nordson DAGE 4000Plus tester.
Figure 1. Push/pull 50 kg with 3 point bend jig.
The 4 point flexure fixtureprovides peak stresses of the sample’s extended region, exposing large length of specimen to identify flaws and defects. Figure 2 shows the Nordson DAGE 4 point bend jig.
Figure 2. 4 point bend jig.
Nordson DAGE also provides bespoke test solutions that offer unique design and properties to help end product testing. The bespoke test solution involves testing one of the key aspects of flexural strength properties of the sample. In general, materials are subjected to different test conditions such as heat reflow prior to the fabrication of the product. These steps can have a significant impact on the product’s flexural strength.
Nordson DAGE Software
Nordson DAGE Paragon™ flexure test software offers a convenient interface for minimum test setup time. This enables the following characteristics to be determined:
- Stress-strain properties including secant modulus of elasticity, tangent modulus of elasticity and flexural offset yield strength, which are represented graphically
- Flexural stress and strain
- Chord modulus
- Stress at given strain
- Flexural stress at break
- Flexural strength measured during rupture where the material experience high stress
Apart from the above, the software can be employed for bespoke cyclic testing which involves selectable load range and speeds, user-defined cyclic patterns and custom test procedures to determine the fail points of the material.
The software is flexible for most of the demanding applications such as grade pareto, force trend analysis (with box whisker and optional mini histogram on the same chart), loop height trend analysis, force/time displacement curves, and on-board statistics and statistical process control (SPC) package. The statistical results provide a combination of mean, maximum and minimum range, standard deviation, mean – 3s, Cpk and Cp.
Data manipulation is carried out in a number of ways such as CSV file format, RS232, ODBC compatibility and via Microsoft Excel, Word or Adobe® Acrobat. Figure 3 shows the flexural test analysis results using Paragon™ software.
Figure 3. Flexural test analysis results.
The packaging and substrate design of PCB and SMT technology remains challenging for the manufacturers as the products tend to undergo a number of mechanical shock and strain. Flexural testing can be performed to determine the response of the product with respect to forces such as flexing or bending. Flexural properties also ensure that the design is within the desired tolerance limit. By contrast, cyclical and fatigue testing can determine the ability of the product to sustain forces before failure, providing appropriate design of the product.
Nordson DAGE combined with the cyclic and fatigue software offers a complete solution for 3 point and 4 point testing. It offers strong, reliable and repeatable testing procedures for process control, test and inspection, and research and development.
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 DAGEhas 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.
Our core strategy:
- To support our customers wherever they do business,
- To continually develop new products that provide its customers with enhanced competitive advantages,
- To develop products which bring new advantages to its customer base
- To control the core technologies that underpin its products.
This information has been sourced, reviewed and adapted from materials provided by Nordson DAGE.
For more information on this source, please visit Nordson DAGE.