Static electricity: What is it?
Static electricity is a natural phenomenon where electrical charges build up on the surface of materials until they can discharge. Atoms usually aim for a balance between protons and electrons, keeping a neutral charge, but sometimes imbalances happen:
- Positive charge: When an atom loses an electron, it forms positive ions, resulting in a positive charge.
- Negative charge: When an atom gains an electron, it forms negative ions, resulting in a negative charge.
These imbalances create electrostatic charges, which can negatively impact industrial processes.
How is static electricity produced in industrial environments?
Static electricity naturally happens in all industrial activities when electrons are transferred or gained between materials, resulting in the formation of an electrostatic charge.
Charge creation through contact and separation:
For example, when a cylinder repeatedly strikes a material, it can generate a positive charge on one component and a negative charge on the other.
Charging induced by friction:
Industrial processes like conveyor belts or materials moving over rollers are common examples of how friction can generate static electricity.
When a charged object induces charge in another body just by being nearby, without direct contact, it causes an imbalance of charges within that body. This is especially crucial in the electronics industry because electronic components are highly sensitive to even very low potential discharges.
Charging via electrostatic blowing:
In cleaning tasks that involve blowing, it is essential to preprocess the compressed air by filtering out contaminating particles and drying it to avoid condensation on the cleaned surface. Inadequate humidity causes the air to become more insulating, which can result in the generation of an electrostatic charge on the surfaces subjected to blowing.
What dangers does static electricity present in industrial environments?
Static electricity poses significant risks to the overall efficiency of industrial machinery and processes, as assessed by OEE (Overall Equipment Effectiveness).
OEE evaluates machine availability, process performance, and product quality, with static-related issues impacting each parameter in varying ways:
Electrostatic charges generate forces of attraction or repulsion between materials, leading to line jams and unplanned stops, consequently impacting machine uptime.
At times, it is necessary to reduce machine speed to minimise static charge generation, which in turn affects cycle times.
Static charge causes dust to adhere, contaminants to be attracted, and electronic components to be damaged, affecting the quality of the end product and increasing rejection rates.
Machine uptime and performance are linked to macroscopic statics, mainly observed in industrial processes involving the handling and transportation of plastics and polymers.
Some problems associated with macroscopic statics include:
- Defective welding and cutting
- Winding machine jams
- Part feeder blockages
- Defects in shrink wrapping
- Mishandling
Conversely, product quality is related to microscopic statics, which are connected to industrial processes involving electronic parts, semiconductors, and automotive components, where surface cleanliness is paramount.
Some occurrences linked with microscopic statics include:
- Formation of paint process pores
- Contamination of plastic items
- Defects in injection molding
- Fracturing of fragile materials
- Electrostatic discharge (ESD), causing irreparable harm to electronic components or latent harm that shortens their lifespan.
Both macroscopic and microscopic statics can negatively impact industrial processes across diverse sectors, as well as product quality and workplace safety. Operators may face risks from electrostatic discharges (ESD), and an abundance of charge could potentially cause fires or severe accidents, compromising workplace safety.
How can static electricity be managed and reduced in industrial processes?
Methods for managing static electricity can be classified as follows:
The first step in pinpointing crucial areas and alleviating electrostatic charges is measurement. Employing sensors, like SMC's static electricity sensors, is the primary method for addressing this hidden threat.
To prevent electrostatic discharges that endanger workers, it is essential to implement proper grounding. Ensuring effective grounding of all conductive materials helps disperse generated electrostatic charges and prevents the flow of electric current from devices to users.
Systems for controlling and eliminating static:
A variety of ionizers or static electricity eliminators are accessible:
These static eliminators are commonly used on large surfaces and over long distances.
Ionizing nozzles are usually efficient in neutralising static energy on specific surfaces.
Ionizer fans are often used to cover larger work areas or spaces where compressed air is unavailable.
Ionizing air guns are used for manually cleaning insulating materials to prevent static charges from causing particles to adhere to the surface.
Static-resistant components:
Choosing appropriate auxiliary component materials is vital for controlling static electricity in industrial processes. For example, anti-static pneumatic connections for blowers or anti-static suction cups in vacuum applications are engineered to minimise and disperse the generated charge.
Technical cleaning for industrial purposes:
When statically adhered particles compromise product quality, it is advisable to conduct an industrial technical cleaning of surfaces. SMC offers desktop duster boxes that can neutralise static electricity, remove, and collect dust in a single unit. These are suitable for use in clean rooms.
SMC's range of anti-static solutions is guided by simplicity and effectiveness.
By using our anti-static solutions, you can improve the efficiency and quality of your industrial processes. Our static electricity meters and eliminators are engineered for straightforward installation and maintenance.
Find the suitable ionizer to prevent unplanned shutdowns, resolve quality concerns with your final product, and safeguard operators from discharges.
Need help selecting static electricity sensors or eliminators? Contact our experts in electrostatic charge control and neutralization for expert guidance in either Finnish or English.
