Welcome to our comprehensive guide on corona treatment systems! Here, we’ll explore the essentials, benefits, and applications of this vital surface treatment technique. Join us as we unravel the intricacies of corona treatment systems and help you make informed decisions for your business needs.
Introduction
Ever tried to print on plastic and found the ink smearing? That’s a surface energy problem, and there’s a solution: corona treatment. In this guide, I’ll leverage my 20+ years of experience to explain how this high-frequency electrical discharge technique can enhance adhesion and improve your products. Ready to increase the wettability of polymer surfaces by up to 40% or more? [1] Let’s dive in.
Corona Treatment Basics
What is corona treatment?
Corona treatment is a surface modification technique that uses a high-frequency electrical discharge to increase the adhesion properties of various materials, such as plastic films,paper, and foils. By altering the surface energy, corona treatment ensures better bonding with inks, coatings, and adhesives, which is crucial in industries like printing, packaging, and manufacturing.
How does corona treatment work?
Corona treatment operates by exposing a material’s surface to a high voltage, generating a corona discharge or plasma of ionized air. This plasma interacts with the material’s surface, disrupting molecular bonds and forming new functional groups that are more inclined to bond with other substances. The outcome is an increase in surface energy, leading to enhanced adhesion. This high-frequency corona discharge occurs between electrodes and a grounded metal roll, with the material to be treated placed in the gap.
Benefits of corona treatment
- ●Improved adhesion: Enhancing the bonding properties of materials, ensuring better quality and durability of the final product.
- ●Increased wettability: Enhances the wettability of materials, which is crucial for processes like pritning and coating.
- ●Versatility: It can be applied to a wide range of materials and products, making it a valuable technique across numerous industries.
- ●Cost-effectiveness: Corona treatment is an energy-efficient solution that can help reduce material waste and overall production costs.
- ●Environmentally friendly: Offers a greener alternative to other surface treatment methods that involve hazardous chemicals or produce harmful waste.
Applications (More in pics below)
- ●Film blowing: Enhancing the adhesion properties of plastic films for packaging and other applications.
- ●Printing: Ensuring high-quality printing on materials like paper, plastic (PP/PE/PET/BOPP/PVC, etc.), metal, and foil.
- ●Extrusion coating and laminating: Improving the bond strength between layers in multilayer films and laminates.
- ●Textile processing: Increases the wettability of fabrics, enhancing their dyeability and printability.
- ●Automotive manufacturing: Improving the adhesion of paint or coatings on various parts, leading to better quality finishes.
The importance of pre-treatment and understanding corona treatment decay
This is where the significance of pre-treatment comes into play. Materials that have not been treated immediately after production can be challenging to treat afterwards. As such, it’s recommended to apply corona treatment shortly after the production process. For prolonged effects, a refresher treatment just before the application of liquid or other media to the surface may be necessary.
Understanding these nuances is crucial for maximizing the benefits of corona treatment and maintaining the quality of your products. As every material and application can be unique, it’s important to tailor the treatment process to suit your specific needs.
Components of a Corona Treatment System
Corona generators are the heart of any corona treatment system. They are responsible for generating high-frequency electricity to create the corona effect.
Output Power Ranges: Corona generators come in various power output ranges, typically classified as low (2-4 KW), medium (6-15 KW), and high (20 KW and above). The power output range required depends on the specific application and material being treated.
- Types of Generators: There are different types of corona generators, such as oil-immersed and air-cooled generators. Oil-immersed generators use a transformer immersed in oil for better cooling and higher power output, while air-cooled generators rely on air circulation for cooling and are more suitable for smaller power outputs.
- Generator Features: Modern corona generators often come with advanced features such as automatic power control, adjustable frequency, and remote monitoring capabilities. These features help improve the efficiency and reliability of the corona treatment process.
Discharge racks, also known as corona stations, are the components that apply the corona effect directly onto the material being treated. They consist of various elements such as electrodes, treatment rollers, and silicone sleeves.
- Function and Purpose: Discharge racks are designed to hold and position the electrodes and treatment rollers, ensuring proper corona treatment and even distribution of the electrical discharge.
- Structure of Discharge Racks:
Based on Mounting Style: Discharge racks can be fixed or adjustable, depending on the application and the need for flexibility in positioning the electrodes and treatment rollers.
Frame Materials:The frames of discharge racks can be made from materials like aluminum and stainless steel. The choice of material depends on factors such as cost, weight, and durability.
Electrodes play a crucial role in the corona treatment process, as they generate the high-frequency electrical discharge that creates the corona effect. There are various types of electrodes made from different materials:
- Ceramic Electrodes: The durability and high-temperature resistance of ceramic electrodes make them a preferred choice in corona treatment systems. These electrodes are designed for treating a diverse range of substrates, from conductive materials such as aluminum foil and metallized films to non-conductive ones like PE and PP.
They can handle widths varying from 0.1m to 3m. Each individual ceramic rod can accommodate a load of about 1.25 kW/m, and an electrode box can house up to 6 rods, thereby achieving a total output of up to 7.5 kW/m.
At Hongchang, we collaborate with German manufacturers to create a patented square cross-section ceramic tube with a metallic inner conductor. These electrodes are housed in specialized insulators, and each rod can be individually replaced.
Aluminum Electrodes: Aluminum electrodes are another popular choice. They come in various tooth configurations and can be segmented to accommodate different power outputs and material treatments.
- The use of Aluminum Rollers: In our corona treatment systems for sheet materials, we utilize pairs of aluminum and rubber rollers. Each pair forms an efficient discharge electrode group, creating an effective corona treatment field.
The aluminum roller in each pair serves as the discharge electrode. It generates a high-frequency electrical discharge, producing the corona effect required for surface treatment. The rubber roller, meanwhile, maintains the necessary tension and alignment of the material during the treatment process. This pairing of rollers is an integral part of our system design, enhancing adaptability to various materials and improving the overall treatment quality.
Stainless Steel Electrodes: Stainless steel electrodes are less common but still used in some corona treatment systems. They offer the advantage of durability and resistance to corrosion.
Copper Electrodes, Tungsten Electrodes, and Graphite Electrodes: These materials are less commonly used for electrodes in corona treatment systems but can be found in some specific applications.
Treatment rollers and silicone sleeves are essential components of discharge racks, as they help ensure proper corona treatment and protect the material from damage.
- Function and Purpose: Treatment rollers provide support for the material being treated, while silicone sleeves act as a protective barrier between the rollers and the material, preventing damage from the high-frequency electrical discharge.
- Types of Treatment Rollers: Treatment rollers can be made from various materials and come in different diameters, depending on the application and material being treated.
- Silicone Sleeve Characteristics: Silicone sleeves are available in various hardness levels and thicknesses to suit different applications and material types.
Ancillary equipment and accessories
Choosing the Right System for Your Needs
When selecting the appropriate corona treatment system, there are several factors to consider. Understanding these factors will help you make well-informed decisions to enhance the adhesion properties of materials in your production processes.
Factors to consider
Different materials have varying responses to corona treatment. For instance, polyethylene and polypropylene often require a higher treatment level than materials like PVC or PET. See the table and formula at 6.1 part for common materials and required dyne levels.
Your specific application dictates the required treatment level. For printing, a dyne level of 38-40 is typically sufficient. But for laminating applications, a higher treatment level (over 42 dynes) might be needed due to the increased demand for adhesion.
The speed of your production line is another vital factor. A faster line speed requires a more potent corona treater to ensure the material spends enough time in the corona field for effective treatment. For instance, if your production line operates at 200m/min, a corona treater with an output of around 2-3kW might be necessary to achieve a treatment level suitable for printing (38-40 dynes).
The cost of a corona treatment system varies significantly based on its capabilities, with prices ranging anywhere from $800 to $50,000. However, keep in mind that a more expensive system may provide better results, especially for more demanding applications or higher line speeds.
Finally, consider the available installation space. A corona treater for a 1.5m wide web, for example, might need a clear space of about 2.5m wide for proper installation and operation.
Common challenges and how to overcome them
This could be due to irregular line speed, uneven material thickness, or improper electrode alignment. The key to overcoming this challenge is regular system checks and maintenance. Always ensure the equipment is correctly calibrated and the materials are of consistent quality and thickness.
The electrodes and sleeves, particularly in high-speed production lines, can wear out over time, affecting the quality of the corona treatment. This issue can be managed by scheduling regular equipment checks and timely replacements, ensuring optimal system performance.
High-voltage corona treatment demand rigorous safety protocols and regular equipment checks. Proper ozone management is necessary due to ozone generation during the process. Ambient conditions like temperature and humidity can also impact the effectiveness of corona treatment.
Hongchang's corona treatment systems
Discover Hongchang’s high-power, reliable corona treatment units, designed with advanced protection features and intelligent auto-adjusting power levels to seamlessly match your production line speed.
0-4KW, small and portable, dry type for easy transportation, with all kinds of protections
0-20/30KW large power, alarm light, the updates are made to its circuits and transformers
Small and portable design
Could match with single or double heads
Max treatment width 5CM per head
220V input voltage, 0-500/1000W
Best treatment distance is 8-10CM
Note: well insulation is required
We offers both standard and customizable corona treatment frames, meticulously tailored to your material specifications and treatment requirements, ensuring optimal performance and value in your production process.
Installation, Maintenance, and After-sales Support
Guide to proper installation and setup
Correct installation is critical to harnessing the full potential of a corona treatment system. Each system comes with its unique installation manual, but some general steps apply:
Treater Station Placement
Should be in a dry, dust-free space with ample ventilation, and away from any flammable materials.
Power Generator Positioning
Should be placed at an optimal distance from the treater station, as specified in the manual.
High-Voltage Cable
Needs to be properly insulated, kept short to minimize power loss, and securely connected to the generator and station.
Control Panel Settings
Adjusted based on material and application. Thicker materials might need a higher power setting.
Tips for preventive maintenance and troubleshooting
Just like your car needs its regular oil changes, your corona treatment system also benefits from preventive maintenance. This not only extends its lifespan but also ensures a consistent quality of treatment. Regular checks for any signs of wear and tear and prompt part replacements can make a world of difference.
Cleaning the electrodes and dielectric rolls can prevent contaminants from accumulating and affecting effective cooling. This can cause machine stoppage, and the defective ceramic bars will need to be replaced before production can resume. Dirty electrodes can also result in uneven corona treatment of the film.
Use spirits or alcohol for cleaning, ensuring that the bars and insulators are thoroughly dry before reinserting them into the system.
If you run into issues like sudden power loss or uneven treatment, your first port of call should be the troubleshooting guide in the manual. It’s a treasure trove of solutions for common issues.
Hongchang's commitment to ongoing customer support
HW3006+AFS frame
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HW3020+HFS frame
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HW3016+rotatory structure frame
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HW2003E+SF frame
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HW3010+AFS frame
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1 of 1Advanced Techniques
Surface energy measurement and over-treatment concerns
Surface energy, measured in dynes/cm, influences the adhesion properties of materials. A higher dyne level signifies better adhesion. Different materials have varying surface energy levels, and thus, require different treatment intensities to achieve optimal adhesion. Techniques like using dyne pens or liquids can help you measure surface energy, ensuring the treatment system is working effectively.
Here’s a table with the typical required dyne levels for some common materials in different applications:
| Materials | Printing (dynes/cm) | Coating/Converting (dynes/cm) | Laminating (dynes/cm) | Bonding/Gluing (dynes/cm) |
|---|---|---|---|---|
| Polyvinyl Chloride (PVC) | 38 - 40 | 38 - 42 | 42 - 46 | 42 - 46 |
| Low-Density Polyethylene (LDPE) | 38 - 42 | 38 - 40 | 42 - 44 | 42 - 44 |
| High-Density Polyethylene (HDPE) | 38 - 42 | 38 - 40 | 42 - 44 | 42 - 44 |
| Oriented Polypropylene (OPP) | 38 - 42 | 40 - 44 | 44 - 48 | 44 - 48 |
| Biaxially Oriented Polypropylene (BOPP) | 38 - 42 | 40 - 44 | 44 - 48 | 44 - 48 |
| Polypropylene (PP) | 38 - 42 | 40 - 44 | 44 - 48 | 44 - 48 |
| Polystyrene (PS) | 38 - 42 | 38 - 42 | 42 - 46 | 42 - 46 |
| Acrylonitrile Butadiene Styrene (ABS) | 38 - 42 | 40 - 44 | 42 - 46 | 44 - 48 |
| Nylon | 40 - 44 | 40 - 44 | 42 - 46 | 44 - 48 |
| Polyurethane (PU) | 40 - 44 | 40 - 44 | 42 - 46 | 44 - 48 |
| Copper Foil | 42 - 44 | 42 - 46 | N/A | 44 - 48 |
| Polyethylene Terephthalate (PET) | 42 - 44 | 42 - 46 | 44 - 48 | 46 - 50 |
| Polyamide (PA) | 42 - 46 | 42 - 46 | 44 - 48 | 44 - 48 |
| Polycarbonate (PC) | 42 - 46 | 42 - 46 | 44 - 48 | 44 - 48 |
| Glass | 42 - 46 | 40 - 44 | N/A | 44 - 48 |
| Aluminum Foil | 46 - 50 | 44 - 48 | 48 - 54 | 48 - 52 |
Automated systems
Automated corona treatment systems are akin to a diligent assistant, taking care of repetitive tasks, and allowing you to focus on larger goals. With automatic power adjustments based on line speed, these systems enhance the efficiency and consistency of the treatment process.
Automation not only saves time and energy but also minimizes the risk of human error. In the realm of corona treatment, automation is a common feature that significantly enhances operational efficiency.
Customized solutions offered by Hongchang
Whether your challenge is a specific material, a unique shape, or a specific application, we listen, we understand, and we design a system that’s just right for you. Our goal is to provide a corona treatment solution that truly fits your needs, like a custom-made key. We’re not just selling products; we’re creating solutions that help you achieve your goals.
Corona vs. Plasma Treatments
Mechanism of operation
Corona treatment, predominantly utilized in plastic film processing, relies on the ionization of ambient air to produce high-energy discharges that modify the surface properties. Its advantages lie in cost-effectiveness, straightforward operation, and easy incorporation into existing production lines. But if the discharge is too strong, it could potentially cause damage in the substrate.
Plasma treatment, conversely, offers greater flexibility. It uses an array of gases such as argon or nitrogen, creating a spectrum of plasma effects suitable for treating a broader range of materials, including plastics, metals, ceramics, and glass. Though more intense than corona treatment, when managed correctly, plasma treatment can result in superior, long-lasting effects without damaging the material.
Applicability and effects
Corona treatments shine in their ability to treat larger surfaces efficiently and are a go-to solution for improving adhesion of inks, coatings, and adhesives to films and fabrics.
Plasma treatments, however, push the boundaries of surface treatment by offering superior adhesion levels and additional functionalities like cleaning, etching, and activating surfaces. These make plasma treatment a preferred choice for more diverse and demanding applications, such as preparing surfaces for painting or bonding in the automotive industry.
Cost implications
Corona treatment systems are typically less expensive, with entry-level models starting in the low thousands of dollars (e.g., USD 800-5,000) for basic, benchtop units suitable for smaller-scale operations. Larger or more advanced units designed for industrial-scale operations can range from the tens of thousands to over a hundred thousand dollars.
Plasma treatment systems, on the other hand, generally come at a higher cost due to their increased complexity, flexibility, and capabilities. Basic benchtop plasma cleaners might start around USD 5,000-10,000, but prices can escalate rapidly for larger units or systems offering more sophisticated features, often costing several tens of thousands to over a hundred thousand dollars.
Environmental considerations
Both corona and plasma treatments score high on the environmental friendliness scale, as they eliminate the need for hazardous chemicals. However, their environmental impact can differ based on operational variables like the type of gas used in plasma treatments.
In conclusion, the choice between corona and plasma treatment should hinge on a balanced consideration of your specific material, application, quality requirements, production speed, and budget. For an in-depth understanding of plasma treatments, explore our comprehensive guide.
Conclusion
Recap of corona treatment systems and their benefits
Corona treatment systems are a groundbreaking technological solution that aids businesses across diverse sectors in enhancing the adhesion properties of their materials. This translates into superior quality in printing, coating, and laminating processes. From packaging and automotive manufacturers to textile mills, the versatility, cost-effectiveness, and environmental friendliness of corona treatment systems have proven beneficial.
Contact us for more information and consultation
Whether you’re a material manufacturer interested in enhancing your product quality, a machinery manufacturer looking to integrate corona treatment into your systems, a wholesaler seeking competitive edge, or a trader exploring promising products to represent, we’re here to help. At Hongchang, our knowledgeable team is always prepared to answer your questions, provide guidance, and assist you in choosing the ideal solution tailored to your specific needs.
In conclusion, grasping and utilizing corona treatment can be transformative, regardless of the industry you’re operating in. The secret to harnessing this technology’s full potential lies not only in selecting the right equipment but also in understanding the science behind it.
As we wrap up this discussion, we leave you with a question to ponder: How could corona treatment redefine the possibilities for your products or services? Don’t hesitate to get in touch with us to explore this potential further.
Frequently Asked
What can we help with today?
Our team of experts can help you choose the right treatment system based on your specific application requirements. We consider factors such as material type, thickness, surface properties, speed, usage, and required dyne level to recommend the most suitable solution for your needs.
Yes, we offer customized solutions tailored to meet the specific needs of our customers. Our team will work closely with you to understand your requirements and develop a solution that meets your needs.
Yes, we have a CE certification and have also applied for multiple patents.
You can contact us through our website or by phone to request a quote for your specific needs. Our team will work with you to provide a customized solution and pricing estimate.
We offer comprehensive technical support and after-sales service to ensure your system performs optimally. Our team of experienced engineers is available to assist with installation, maintenance, and troubleshooting.
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