Electronic components are an integral part of electronic devices. They serve as the building block of electronic devices. Just like all other products, electronic components have shelf life. You might be wondering what shelf life really means. Understanding the shelf life of an electronic component is very crucial when designing electronic devices.
Some manufacturers store electronic components longer than their recommended shelf lives. In this article, we will discuss the shelf life, handling, and storage conditions of some electronic components.
What is Shelf Life?
Shelf life is a term often used in the electronics industry. It describes the time during which you can store a material. Therefore, the shelf life of an electronic component is the length of time a component can be stored and remain suitable for use. Electronic components can experience damage after a certain period of time. Therefore, after that period of time, these components may not function as expected.
Also, an electronic component that exceeds its shelf life may be unsuitable for use. Shelf life can also mean the time limit of how long you can store an electronic component. However, shelf life may not indicate the safety of a particular product. A product may exceed its shelf life and still remain functional.
Basically, shelf life is the time during which a product remains safe under defined storage conditions. The assessment of electronic component shelf life is a challenge in the electronics industry. However, it is the basic process for electronic companies to maintain their reputation. Also, shelf life is a popular term in the electronics industry. This term is well understood in the industry.
Several factors contribute to the shelf life of a product. Also, these factors include moisture, mechanical stress, and heat. A product stored under good conditions may have a longer shelf life. Therefore, the storage atmosphere of a product contributes to the length of its shelf life.
Also, the manufacture date of a component is very important. For instance, integrated circuits have a good shelf life when stored properly.
Storage of Electronic Components
Long term storage means storing components beyond their guaranteed lifetime while retaining their functional integrity. Also, it is crucial to retain the integrity of components to ensure safe processing when using appropriate assembly. There are several storage methods for electronic components. However, the intended storage period determines the storage method to use.
You can create special storage conditions which reduce aging processes while retaining processing performance. It is impossible to extend the maximum shelf life of some components regardless of any further measures. For instance, no further measures can extend the shelf life of batteries.
Packaging can impact the capabilities of long term storage. Also, long-term packaging may be costlier than standard packaging. Packaging should be carefully selected to ensure items are properly handled.
Furthermore, environmental legislation may cause changes to the processing and production of subassemblies and components. For example, there will be storage-related aging effects if legislation replaces lead-based surface coating with modified coating systems. Old components may not function as expected.
Factors Impacting Storage and Error Patterns
There are several factors and error patterns impacting many subassemblies and components. It is important to address these factors to ensure proper storage.
Corrosion describes how a component reacts with its environment. Most corrosive products have a destructive impact. However, some corrosive products like nickel oxide and tin dioxide are ideal for passivation. Corrosion may result in reduced conductivity of plug-in contacts and switches.
Also, corrosion increases contact resistance. Temperature and humidity are factors that can impact corrosive mechanisms.
Gas emissions from materials surrounding a component can result in contamination. Also, the type of material used can result in failures despite complying with the ideal storage conditions.
Embrittlement occurs when a material losses ductility. Also, brittle materials can make components mechanically damaged during assembly. Gases and radiation enhance irreversible embrittlement.
Solid-state diffusion occurs where particles form a substance mixes with that from another. Also, the presence of diffusion particles and environmental conditions affect diffusion. Diffusion can have negative impacts like change in contact layers and change in solderability.
Popcorn effect results from improper storage of components. For instance, if you store moisture-sensitive components outside moisture-proof packaging for a longer time, water can accumulate in the potting compound of the housing. Also, the moisture will vaporize when it is inside reflow oven as a result of the rise in temperature. Therefore, this results in a sudden increase in volume. This can thereby cause delamination to the substrate interfaces.
Non-wetting, dewetting, and wetting are three major soldering mechanisms. Also, non-wetting describes the inability of molten solder to create a metallic bond. Wetting is the ability of a molten solder to create an intermetallic relationship with the base metal. Dewetting is a defect that occurs after actual wetting.
FR4 PCBs age with time. Although this substrate can retain moisture over time, it will demand for a pre-bake before soldering. Also, the major concern here is reduced solderability. The surface treatment determines the effect of aging on the usability of circuit boards. Also, common finishes seen for prototype PCBs are lead-free HASL and leaded HASL.
Tin-lead HASL features great shelf life that exceeds 12 months. However, ENIG and lead-free HASL are listed as 12 months. Also, the gold coating in ENIG can be porous. Therefore, this allows oxygen to come in contact with the nickel layer, which results in oxidation. Also, it is quite surprising that tin-lead HASL features a longer shelf life than lead-free HASL. However, this depends on the storage conditions.
Vacuum sealing is the recommended method for long-term PCB storage. Also, you can try this if you have a vacuum sealer in your kitchen. You may not worry about your PCB aging if you are etching it yourself. Component leads and sheet metal require proper storage.
Solderability and Long-term Storage
Components solderability after long-term storage like replacement of parts inventory is a concern for some customers. Also, manufacturers supply electronic parts in moisture-barrier bags (MBB). These bags protect the units from environmental factors. Experts recommend MBB for parts that will go through reflow soldering to prevent delamination.
Minor levels of oxidation from temperature and humidity can affect tin-plated parts. Also, the oxidation accumulated from this exposure doesn’t impact the parts’ solderability quality. Long-term storage doesn’t affect solderability if done at ambient conditions. Therefore, storing parts in a sealed bag is enough.
Handling of Electronic Components
Most electronic components are susceptible to electrostatic discharge. Also, components can get easily damaged due to electrostatic discharge ESD. For instance, ESD can affect capacitors. Some manufacturers ship components in sealed bags. These bags comprise tape-and-reel products.
Also, these shipping materials can be conductive and antistatic depending on the configuration. The customer must implement the electrostatic discharge precautions in JEDEC JESD625. Some of the precautions include the use of ESD protected table surfaces and ESD gloves.
You must remove the cover tape at a rate of 10mm per second when using tape-and-reel packaged devices. Also, you should integrate other environmental precautions. The use of shipping bags to protect the product is ideal. Also, this protection should prevent contaminants like corrosive materials, chemicals, and dust.
Furthermore, it is wrong to handle electronic devices with bare hands. Unmasked personnel should never handle electronic devices. It is crucial to ensure the proper use of finger cots. Also, replace finger cots immediately if contaminated. Gloves can effectively prevent contamination.
Use face masks when handling components. Also, face masks prevent spittle from getting to the surface of the components. Ensure you use gowns or smocks. In addition, use protective footwear as it helps to maintain a clean environment. Personnel should wear protective clothing and footwear from head to foot. This includes full head covering, gloves, and booties.
It is acceptable to wear full suit and face masks in a clean environment. Also, ensure you don’t subject components to unmasked personnel.
Recommended Procedure for Storing Components
These guidelines provide the processing and storage preparations for electronic components. Also, these guidelines offer procedures for long-term storage of components.
Determine the type of storage
When storing components for long-term, ensure you check their form throughout the whole time. It is crucial to consider if the storage of subcomponents, components, or end products offer the best option for maintaining capability. Also, you will need to assess the storage process for any risk. For instance, you can assess the suitability of the packaging for long term storage.
Select suitable packaging
Ensure you pack the packed goods in an MBB, especially if the manufacturer didn’t give any recommendations to extend shelf life. Also, ensure you can clearly see the moisture indicators through the bag. The MBB bag should contain moisture and desiccant indicators for the intended storage period.
Define extended storage conditions
You can define extended storage conditions by determining if the standard storage conditions are sufficient. Also, there are measures you can take to prevent the occurrence of harmful effects. These measures include storing in inert condition and minimizing air humidity.
Plan measures to maintain processing performance and capability
Ensure you inspect the condition of stored goods at regular intervals. This will prevent any negative impacts of long-term storage. Also, you can perform a random inspection if you plan regular production based on the stocks of stored goods. If this inspection isn’t enough, there are additional measures. Also, these measures can help to identify any changes to processing performance and capability.
Implement inspection and action plan
It is important to comply with product-specific conditions when taking off goods from storage. Visual anomalies like damp or warped outer packaging need immediate inspection of the packaged components.
More Information on the Shelf Life of Components
- Active components like oscillators and semiconductors are acceptable if they are less than 2 years old. However, they must pass a solderability test if they are older than 2 years and less than 5 years old.
- Passive components like capacitors and resistors have a shelf life of about 5 years if there is no proof of corrosion.
- Mechanical hardware such as sheet metal have a shelf life of about 5 years if there is no proof of corrosion
- Aluminum electrolytic capacitors have a shelf life less than a year old. If older than a year, you need to seek recommendations from the component manufacturer.
- Finish circuit board assemblies have shelf life of about 5 years if there is no proof of corrosion.
- Miscellaneous like transformers and connectors have a shelf life of about 5 years if there is no corrosion.
Frequently Asked Questions
What is the Shelf Life of Transistors?
Transistors don’t easily wear out. Due to the diffusion of atoms, there is a slow change. Transistor devices become obsolete in less than 10 years. However, there are certain factors that affect their shelf life. These factors include operating conditions and size. Also, the degradation of the gate dielectric makes the performance of transistors degrade with time.
What is the Shelf Life of a Resistor?
Resistors are widely used in several applications. These components have their shelf life. You can store resistors in the compartment. They may rust overtime, but they won’t become defective. The resistor will not produce heat if there is no flow of current to it.
What is the Shelf Life of SMD Components?
SMDs can become sensitive to retaining moisture within a package’s molding compound. Also, during board solder reflow, surface-mount devices can retain moisture. Therefore, delamination can occur between the lead frame and molding compound. The shelf life of SMD is above 5 years for moisture sensitivity level (MSL) 3. However, the shelf life might be limitless for MSL 2 and MSL 1.
Electrolytic capacitors can expire. Once the dielectric compound dries out, it kills the capacitance. Sometimes, the expiration condition of electrolytic capacitors isn’t a date.
Do electronic devices have an expiration date?
Yes, electronic devices have an expiration date. The manufacturer might indicate the expiration date depending upon the device. Metals in electronic components can corrode. Also, moisture and ESD can damage these components. Therefore, it is important to indicate the shelf life of electronic devices.
Electronic components have shelf life. It is important to raise awareness of storage problems when developing components. The use of the right material can help to extend storage capabilities of components. Also, electronic manufacturers should adhere to guidelines as regards the storage and handling of components.