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How to cope with the component pin float and component offset after dispensing curing

On the production line of an electronics manufacturing factory, the engineers use automatic dispensing equipment to dispense and cure electronic components on circuit boards. However, they noticed that components on some boards had issues with pin floating or shifting after curing.

After analysis, it was found that the following conditions may have caused this problem. Thus, in this article, we will illustrate the phenomena about pin floating or shifting, and component offset after dispensing curing.

Table of Contents
How to dispense and pot electronic control units ECUs

What is component pin float or shift after dispensing curing?

The pin float refers to the fact that after curing, the leads of the component rise or float relative to a predetermined position. This may be caused by the shrinkage of the glue or the thermal stress during the glue curing process, which increases the gap between the pin and the surrounding environment or adjacent components. There are some bad effects it may lead to.

1.Decreased electrical connection reliability
Floating/displacement of pins may lead to poor connection between pins and pads. It affects the reliability of the electrical connection between the electronic component and the circuit board , increase resistance or cause interruption of signal transmission, thereby affecting the performance and function of the circuit.

2.Reduced mechanical stability
The floating/displacement of the pins will cause the gap between the component pins and the surrounding environment or adjacent components to become larger. It reduces the mechanical stability of the component on the board, making it susceptible to mechanical vibration or shock, which may cause the component to loosen, fall off or be damaged.

3.Reduced system reliability
Floating/displacement of pins may lead to incorrect alignment or positional shift of electronic components , which in turn affects the performance and reliability of the entire system. On complex boards, pin floating/shifting can cause spatial conflicts or signal interference among components, further reducing system reliability.

Also read: PCB signal integrity : mixing up the signals in the right way

4.Decreased product quality
Floating/displacement of pins may lead to a decrease in the quality of the produced product. Poor pin connections can cause a product to fail during testing or actual use, increasing repair and rework costs while reducing customer satisfaction and brand reputation.

What are the causes of component pin float or shift issue?

The following are some factors that may cause component pins float or shift.

01 Improper process parameters
Improper selection of dispensing process parameters can also cause pin float or shift issues. For example, applying too much pressure, applying glue in an inaccurate location, or applying it too quickly can adversely affect the pins.

02 Pin design or processing issues
Some lead design or processing issues may cause the cured lead to float or shift. For example, the shape, size, or spacing between pads of the leads may not be suitable for the dispensing process, preventing the leads from being properly positioned or secured.

03 Thermal stress
During the dispensing process, factors such as the curing temperature of the glue and heat conduction may cause thermal stress around the pins. This thermal stress may cause the pins to float or shift.

How to solve component pin float or shift issue?

How to solve component pin float or shift issue
How to solve component pin float or shift issue

There are some measures to control the floating or shifting of component pins.

01. Optimize the dispensing process parameters
Adjust the parameters of the dispensing equipment, including the location, speed and pressure of glue application, to reduce the risk of pin floating/displacement. Make sure the glue is applied evenly around the pins, avoiding too much or too little.

02. Choose the right glue
Choose the glue according to the specific application requirements, considering factors such as the shrinkage rate, adhesion performance and fluidity of the glue. Choosing glue with low shrinkage can reduce the chance of pin floating or shifting.

03. Pin supports and restraints
Use temporary supports or restraints before dispensing to keep the pins in the desired position and provide adequate support during the curing process. This reduces the pins from thermal stress and glue shrinkage.

Also read: PCB glue – a comprehensive guide for enhanced circuit board performance

04. Control the curing process
Control the temperature and time of curing to ensure that the glue is fully cured. Avoid high temperature and long curing time to reduce the impact on the pins.

05. Quality inspection and repair
Conduct quality inspection, including inspection of pin position and connection. If there is a problem of pin floating or displacement, repair it in time, such as re-dispensing or re-installing components.

06. Continuous improvement and training
Continuously improve the dispensing process, learn and apply the latest dispensing technology and solutions. Train staff to improve operational skills and awareness to ensure the stability and reliability of the dispensing process.

Component offset after dispensing curing is also one of common defects about the dispensing technology.

What is component offset in dispensing technology?

Dispensing technology is a bonding technique applied in the electronics manufacturing and assembly process by applying glue or adhesive to a specific location. Then attach components to substrates or other components. Component offset refers to the unexpected displacement or offset of components relative to their predetermined positions during the dispensing process, which may have the following effects:

1.Reliability issues
The offset of components may affect the reliability of the product. If components are not glued or secured properly, loose or unstable, there is a risk of failure or disconnection during use. This may affect the life, stability and reliability of the product.

2. Functional impact
Component deviation may lead to poor connection or failure, affecting the functional performance of the product. For example, in electronic equipment, the correct location and connection of components is a key factor in ensuring the proper operation of the circuit. If components are misaligned resulting in incorrect or poor circuit connections, it may result in non-functioning or reduced performance of the device.

3.Repair and rework costs
If component shift occurs during the dispensing process, repair or rework operations may be required to fix the shifted component . This can add cost and time, as well as lower productivity.

4.Delayed delivery time
When component offset occurs, it may be necessary to stop production and take corresponding measures to correct the offset problem. This can lead to delays in delivery times, affecting customer satisfaction and trust.

Why component offset issue appears?

Why component offset issue appears
Why component offset issue appears

The following are some factors that can cause component offset.

1.Poor Adhesion
Poor adhesion between the glue or adhesive and the component surface can cause the component to shift or shift during the curing or drying process.

2.Adhesive flow
Some adhesives have high flow during application or curing, causing components to shift before curing.

3.Mechanical Shock or Vibration
Mechanical shock or vibration during the dispensing process can cause components to move or misalign.

How to cope with the component offset phenomenon after dispensing?

Some measures to deal with component offset.

1.Glue or Adhesive Selection
Choose a suitable glue or adhesive, considering the characteristics of components and substrates. Make sure the glue has good adhesion and proper flow to reduce the risk of component misalignment.

2.Surface Finish
Appropriate surface finish of components and substrates prior to dispensing. This may include steps such as cleaning, degreasing, and sanding to improve adhesion and the geometry of the surface to reduce the potential for misalignment.

3.Precise Positioning and Fixtures
Use precise positioning tools, jigs or fixtures to ensure components remain in the correct position during the dispensing process. This can be achieved by designing suitable fixtures or employing automated equipment.

4.Control Environmental Conditions
Control environmental conditions during the dispensing process, such as temperature, humidity, and vibration. Stable environmental conditions help reduce issues such as glue flow, cure time, and material expansion, thereby reducing the risk of component misalignment.

5.Quality control and testing
Implement strict quality control measures, including real-time monitoring and testing of the dispensing process. This can be achieved through vision inspection systems, sensors or machine vision technology, as well as inspection of the finished product to ensure accurate mounting and bonding quality of components.

6.Continuous Improvement
Periodically evaluate and improve the dispensing process to identify potential misalignment issues and take appropriate action to improve. This can include optimization of process parameters, equipment update or replacement, improvements in material selection, etc.

Conclusion

No matter the component pin float or shift, and component offset after dispensing curing, both can not be ignored during the manufacturing procedure. Hope the solutions we have summarized above can give you some help and improve manufacturing efficiency.

FAQ
  • Decreased electrical connection reliability
  • Reduced mechanical stability
  • Reduced system reliability
  • Decreased product quality
  • Improper process parameters
  • Pin design or processing issues
  • Thermal stress
  • Glue or Adhesive Selection
  • Surface Finish
  • Precise Positioning and Fixtures
  • Control Environmental Conditions
  • Quality control and testing
  • Continuous Improvement

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