Test Coupon and Microsection
In PCB (Printed Circuit Board) production, several tests methods are used for quality control and design verification. These tests are required in order to make the circuits function perfectly and guarantee the accuracy of the manufacturing processes. “Test coupon” and “Micro section” are some of these tests.
Test coupons: It enables the detection of electrical faults and production errors in PCB production process at an early stage. It is used for electrical conductivity and road tests.
Micro section: It is a quality control process performed to examine the internal structure of the PCB in detail. Inter-layer connections, soldering quality, vias and the condition of copper paths are tested.
Both tests are used in PCB production to ensure quality, detect possible errors at early stages and improve the reliability of the product.
1.Test Coupon
A test coupon is a prototype or sample used to obtain the results of tests performed on certain areas of an electronic circuit board during the PCB production process. They are simple but effective tools used to ensure quality control in PCB production. These coupons, which are usually used at the prototype stage or any stage before mass production, are critical for detecting potential problems on the production line at an early stage.
Areas of Use and Benefits of Test Coupons
Production Error Detection: If an error occurs in the production process (copper plating errors, soldering errors etc.), it can be detected quickly with the test coupon.
Mass Production Quality Control: As production continues, the test coupons are used to show that the production is progressing smoothly and that the quality control has been carried out.
Short Circuit Testing: This is used to control unwanted electrical conductivities that occur between copper paths or the paths that are accidentally connected to each other.
Open Circuit Testing: It tests whether the paths are connected correctly. A cut or rupture of a path may cause the PCB to not function properly.
Test coupon examples
Path Test Coupon: It tests the smoothness and conductivity of copper paths.
Via Test Coupon: It checks whether the vias are opened correctly and covered properly.
2. Micro-section
Micro-section is a test method used to examine the internal structure of a PCB. In this process, a cross section is taken from the PCB and examined in detail under a microscope. It is one of the final checks aiming to improve the overall quality of PCB. Such inspections are especially critical for products that require high precision (such as medical or aircraft electronics). It is a very critical quality control stage in PCB production.
Stages of the Micro-Section Process
Taking a Section Sample: A piece of PCB (usually an area of several millimeters) is cut off.
Processing and Preparation: This section is made to be properly examined with a special cutting machine and sanding machines. When necessary, these sections can be polished and their surface smoothed for inspection.
Microscopic Examination: The prepared sections are examined in detail under a microscope. During this inspection, the quality of the layers, connections, soldering points, vias, holes and copper paths in the internal structure of the PCB is checked.
The Purpose of Micro Section Use
Soldering Quality: The robustness and adequacy of the soldering points are checked. Insufficient soldering can lead to cold soldering points, gaps around the hole, or weak connections.
Connections Between Layers: It is tested whether the inter-layer connections (such as vias) on the PCB are made correctly and the connections are covered properly.
Hole and Via Test: It is tested whether the holes made on the PCB are smooth, the vias are correctly coated and there are any connection errors.
The Quality of Copper Paths: The smoothness, thickness and wearing condition of the copper paths on the PCB are tested.
The Benefits of Micro-Section
High Reliability: Especially in critical applications, the reliability is increased by checking the structural integrity of the PCB with microscopic tests.
Fast Detection: If any errors are detected during production, they can be corrected quickly and production errors can be prevented.
Long-Term Performance: For the long-lasting and reliable operation of the PCB, the tests carried out by micro-section are critical.
