Flexible Printed Circuit Finishing And Assembly
1. Definition
The metal spring array used for membrane switches is a structure composed of multiple metal springs combined in a certain arrangement.
2. Characteristics
1. Good elasticity: able to provide stable elastic recovery.
2. Strong electrical conductivity: ensuring good electrical signal transmission.
3. High durability: can withstand multiple pressing operations.
3. Working principle
When the button on the membrane switch is pressed, the metal shrapnel is extruded and deformed, making contact with the circuit contacts, thus realizing the conduction of the circuit; after the button is released, the metal shrapnel returns to its original shape and the circuit is disconnected.
4. Application areas
It is widely used in control panels in electronic equipment, instrumentation, medical equipment, home appliances, and other fields.
5. Role in membrane switches
1. Trigger switch action: The opening and closing operation of the switch is realized through the deformation and reset of the shrapnel.
2. Ensure contact reliability: Ensure that a stable electrical connection can be maintained after long-term use and multiple operations.
3. Provide tactile feedback: users can feel obvious button feedback when operating.
Flexible Printed Circuit Board Design Advantages
Flexible circuit boards can be bent, folded, and configured into almost any shape or thickness imaginable, giving designers tremendous options when creating electronic packages. Compared to traditional designs using hardboard circuits, size, and space constraints are far less of an issue. Because the entire interconnection system can be built as one integrated component, assembly, and handling costs can be significantly reduced.
Flexible Printed Circuits The tremendous flexibility of this design choice allows electronic packages to become smaller, lighter, and more powerful.
Printed Flexible Circuits Fabrication
Surface preparation is often required to ensure that the flexible printed circuit surface is ready for subsequent bonding, such as SMT assembly, wire bonding, or pressure connector insertion. Nickel or gold, tin, silver, and solder are good metals for this purpose. Organic coatings can also be used to protect the copper until the bonding process dissolves the material away.
Flexible printed circuits have countless assembly options. In addition to electronic components and connectors, various electrical or mechanical devices can be connected to flex circuits. The circuit can also be easily bonded to curved surfaces or formed into any 3-dimensional shape. With the right construction, flexible circuits can handle dynamic bending, making them an ideal interconnect solution for electronic packages that connect moving or rotating parts.
The finishing and assembly of flexible printed circuits is an important part of the manufacturing process. Here are some common steps and techniques:
**Post-etching treatment**: After etching is completed, cleaning, film removal, and etching residue removal may be required.
**Drilling**: Drill holes on the flexible printed circuit to connect other components or conduct different layers according to the design requirements.
**Surface treatment**: such as gold plating, tin plating, etc. to improve conductivity and solderability.
**Place components**: Use an automatic placement machine to mount components (such as chips, resistors, capacitors, etc.) onto flexible printed circuits.
**Soldering**: Use appropriate soldering methods (such as reflow soldering, and wave soldering) to connect the components to the circuit.
**TESTING**: Conduct electrical testing to ensure continuity and performance of the circuit meet requirements.
**Fold and Bend**: If necessary, fold or bend the flexible printed circuit into the desired shape.
**Encapsulation and Protection**: Overlays, glue, or other encapsulation materials may be used to protect circuits.
9. **Quality Inspection**: Conduct final quality inspection, including appearance inspection, solder joint inspection, etc.
The specific implementation of these steps may vary depending on product requirements and manufacturing processes. The finishing and assembly processes require a high degree of precision and careful operation to ensure the reliability and performance of flexible printed circuits. In addition, automated equipment and strict quality control measures are often necessary in large-scale production. The true potential of flexible printed circuits may only be limited by the imagination of the designer! If you have more detailed questions about a specific finishing or assembly technique, contact a Shanyo design engineer today to learn more about the amazing possibilities that flexible circuit boards can offer.
Conclusion
Once past the prototyping stage, our customers often move to on-demand manufacturing, producing injection molded parts at Protolabs speeds. Using a steel mold, part quantities are virtually unlimited. On-demand injection molding with us allows you to meet inventory needs with no minimum order quantities, and offers supply chain flexibility through bridge tooling, just-in-time production, or dual-sourcing strategies.