What is static electricity?
Static electricity is a natural phenomenon where electrical charges accumulate on the surface of materials until they find a way to discharge. Atoms generally seek a balance between protons and electrons, maintaining a neutral charge, but sometimes imbalances occur:
- Positive charge: This occurs when an atom loses an electron, resulting in positive ions and creating a positive charge.
- Negative charge: This occurs when an atom gains an electron, resulting in negative ions and creating a negative charge.
These imbalances generate electrostatic charges, which can adversely affect industrial processes.
How is static electricity generated in industrial environments?
Static electricity naturally occurs in all industrial processes when there is a transfer or gain of electrons between materials, leading to create an electrostatic charge.
Charge generation through contact and separation:
For instance, when a cylinder continually impacts a material, it can create a positive charge on one element and a negative charge on the other.
Friction-induced charging:
Industrial processes such as conveyor belts or material movement over rollers are common examples of how friction can produce static electricity.
In cases where a charged object induces charge in another body solely through proximity, even without direct contact, it results in an imbalance of charges within the element itself. This is particularly critical in the electronics industry due to electronic components' sensitivity to very low potential discharges.
Electrostatic charging through blowing:
In cleaning applications involving blowing, it is crucial to pretreat the compressed air by filtering it to remove contaminating particles and drying it to prevent condensation on the cleaned part. Insufficient humidity causes the air to become more insulating, potentially leading to the generation of an electrostatic charge on the surfaces where blowing occurs.
What risks does static electricity pose in industrial settings?
Static electricity presents substantial risks to the overall efficiency of industrial machinery and processes, as measured by OEE (Overall Equipment Effectiveness).
OEE assesses machine availability, process performance, and product quality, with static-related issues affecting each parameter differently:
Electrostatic charges create forces of attraction or repulsion between materials, causing line jams and unplanned stops, thereby affecting machine availability.
Occasionally, it is required to decrease machine speed to minimise the generation of static charge, which compromises cycle times.
Static charge leads to the adherence of dust, attraction of contaminants, and damage to electronic components, impacting the quality of the final product and raising rejection rates.
Availability and performance are connected to macroscopic statics, primarily observed in industrial processes that entail the transportation and manipulation of plastics and polymers.
Some issues linked with macroscopic statics include:
- Faulty welding and cutting
- Jams in winding machines
- Blockages in part feeders
- Flaws in shrink wrapping
- Improper handling
On the contrary, quality is associated with microscopic statics, which are linked to industrial processes involving electronic parts, semiconductors, and automotive components, where surface cleanliness plays a crucial role.
Some incidents associated with microscopic statics include:
- Formation of pores in painting processes
- Contamination of plastic products
- Flaws in injection molds
- Fracturing of brittle materials
- Electrostatic discharge (ESD), resulting in irreparable damage to electronic components or latent damage that reduces their lifespan.
Both macroscopic and microscopic statics can adversely affect industrial processes across various sectors, as well as product quality and industrial safety. Operators may be affected by electrostatic discharges (ESD), and an excess of charge could potentially lead to fires or serious accidents, impacting workplace safety.
How to manage and mitigate static electricity in industrial processes?
Strategies for controlling static electricity can be categorised as follows:
The initial step in identifying critical points and mitigating electrostatic charges involves measurement. Using sensors, such as SMC's static electricity sensors, is the primary approach to combatting this unseen adversary.
Preventing electrostatic discharges that pose risks to workers necessitates proper grounding. Ensuring that all conductive materials are grounded effectively helps dissipate generated electrostatic charges and prevents the flow of electric current from devices to users.
Static control and elimination systems:
Various types of ionizers or static electricity eliminators are available:
These static eliminators are typically employed on extensive surfaces and for extended distances.
Ionizing nozzles are generally effective for neutralising static energy on more targeted surfaces.
Ionizer fans are frequently used to cover larger working areas or spaces where compressed air is not accessible.
Ionizing air guns are employed for manually cleaning insulating materials to prevent static charges from causing particles to adhere to the surface.
The selection of auxiliary component materials is crucial for managing static electricity in industrial processes. For instance, anti-static pneumatic connections for blowers or, in vacuum applications, anti-static suction cups are designed to reduce and disperse the generated charge.
Industrial technical cleaning:
In cases where statically adhered particles detrimentally affect product quality, conducting an industrial technical cleaning of surfaces is recommended. SMC provides desktop duster boxes capable of neutralising static electricity, eliminating, and collecting dust in a single unit. These can be used in clean rooms.
Simplicity and effectiveness are the guiding principles behind SMC's lineup of anti-static solutions.
With our anti-static solutions, you can enhance the efficiency and quality of your industrial processes. Our static electricity meters and eliminators are designed for easy installation and maintenance.
Discover the appropriate ionizer to prevent unexpected shutdowns, address quality issues in your end product, and protect operators from discharges.
Require assistance in choosing static electricity sensors or eliminators? Reach out to our specialists in electrostatic charge control and neutralisation for expert guidance in either Danish or English.
