Automated Medical Coating System Components & Benefits

All invasive medical devices and instruments are unique. Their development and manufacturing requires advanced systems and careful engineering. The coating equipment used to coat the device is one critical system. That is because most devices use surface modifying, medical coatings. These coatings ensure the safe and effective use of medical devices within the biological environment. Automated coating systems are one type of equipment that is used to reliably apply coatings to medical devices. 

Coating systems are typically classified by their level of automation. They range from manual to automated. Fully automated systems have become common, providing the highest precision and throughput for high-volume applications. These systems enable continuous, repeatable medical-grade coating deposition on devices. This is possible thanks to various components or modules installed within the systems.

In this article, we will dive deep into the different components / modules used in an automated medical coating system. We will explore the benefits of the components and how they provide tighter process control, improved manufacturing consistency, and more. If you are a Plant Manager, Operations Manager, Plant Engineering Manager, Coating Department Manager, VP Operations, Facilities Manager or Director, or COO, this article is for you. 

Want to learn more about automated systems, read our comprehensive guide on Fully Automated Coating: Performance, Compatibility, and Applications.

Modular Equipment Design Philosophy

Automated coating systems are complex. They are divided into independent modules that perform different tasks, such as coating and curing. These modules are integrated through mechanical, electrical, and software interfaces, which enhance convenience and process control.

Advanced coating systems may include numerous modules, each designed to facilitate faster validation, ensure regulatory compliance, and minimize maintenance downtime.

Companies like Hydromer®, Inc. provide both semi- and fully-automated coating systems. This allows clients to select the appropriate system that meets their specific requirements and desired automation level.

Most Common Components or Modules of an Automated Coating System

Nowadays, most advanced systems are equipped with modules based on the client’s unique requirements. Below are the most common ones you will find in a batch or inline automated coating lines.

1. Material Handling Module

In contrast to semi-automated medical coating systems, automated coating systems rely heavily on material handling modules. These transport medical device pieces from one point of the process to another. The controlled positioning, orientation, and transfer play a huge role in the adhesion and uniformity of applied coatings.

These modules incorporate electromechanical components, such as robotic arms, linear actuators, and servo motors. These ensure precise movement of parts within the system.

2. Surface Preparation Module

Coatings surface preparation is essential for removing debris, oils, dust, and other contaminants from the substrate before coating application.

A dedicated surface preparation module cleans, activates, and modifies the device surface prior to coating. A contaminant-free surface ensures strong adhesion, uniform coating, and long-term durability. For lubricious or polymeric treatments, such as hydrophilic coatings for medical devices, surface preparation directly impacts bond strength and performance in biological environments.

Common components of a surface preparation module include:

• Ultrasonic Cleaner: Uses ultrasonic waves to remove dirt and impurities from the substrate’s surface
• Solvents: Solvents such as isopropyl alcohol (IPA) and ethanol are used to remove organic residues and particulates
• Plasma Treatment Module: This module activates the device surface using ionized gas. It introduces polar functional groups, such as hydroxyl (–OH) or carbonyl (–C=O), creating nano-scale texture and improving adhesion, especially for hydrophilic coatings
• Corona Treatment Module: This method activates the substrate surface using high-voltage electrical discharge. It is a cost-effective alternative to plasma treatment, though corona treatment is generally less reliable and efficient for complex medical devices

3. Coating Application Modules

These modules apply or allow a controlled deposition of liquid medical coating onto the device surface. There are different types of coating application methods, and so the specific modules differ. However, regardless of the type of application module, their core function is the same. That is to deliver a coating in a controlled manner and ensure proper thickness or uniformity.

The right choice between different types of coating application modules depends on the specific medical device and budget. 

Below are the most common modules used by manufacturers within their automated coating systems:

• Dip Coating Module: A widely used option, this module employs electromechanical components such as linear actuators and servo motors to precisely immerse substrates in the coating solution. Accurate control of immersion and withdrawal speeds is essential for optimal results.
• Spray Coating Module: This module atomizes coatings into a fine mist, which is applied to the substrate using a spray or nozzle assembly. Options include airless, air-assisted, or ultrasonic sprays. Spray coating is suitable for implants and devices with complex geometries.
• Meniscus Coating Module: Companies like Hydromer®, Inc offer a meniscus coating application module in their fully automated coating platforms. It forms a stable liquid meniscus to apply a uniform film of coating onto the medical device surfaces. Such modules are particularly effective on micro-wires, guidewires, and similar long devices.
• Spin Coating Module: This module utilizes rotational speed, spin duration, and coating viscosity to uniformly coat medical device surfaces. In other words, the modules use a controlled high-speed rotation and the resulting centrifugal force to apply coatings.

4. Coating Management and Delivery Modules

This system is commonly referred to as a Fluid Management System. It stores and precisely delivers the coating solution during the application process.

The system includes advanced reservoirs or storage tanks, coupled with precision pumps and metering systems for effective fluid management.

In addition to storage tanks, the fluid management system includes the following modules:

• Agitation Module: Agitation or mixing is necessary to prevent sedimentation. The module is equipped with magnetic stirrers and overhead agitators to mix the coating solution properly before application.
• Pumping System: The system uses different types of pumps, including gear, peristaltic, and diaphragm pumps, to control pulsation and flow rate during coating application.
• Filtration System: Most medical-grade coatings have particulates, gels, and debris that must be removed for proper coating adhesion and thickness. As such, the manufacturers add filters of 1–10 microns to their automated coating systems.
• Degassing System: Most coating systems are equipped with the vacuum degassing chambers and inline bubble traps to prevent pinholes and cracks that are common with coatings.
• Temperature Control System: Maintaining a consistent temperature is critical, as fluctuations can affect coating thickness and viscosity. That’s why Hydromer® uses jacketed tanks and inline heat exchangers to ensure temperature stability.
• Viscosity Monitoring Module: Regular rheology testing is essential to maintain consistent coating viscosity, as even minor changes can significantly impact coating thickness and uniformity.

5. Curing Modules

The curing modules convert a coating from a liquid or semi-solid state into a solid film. The two most popular types of coating curing modules include the following:

• Thermal Curing Module: This module uses heat generated from conveyorized hot air ovens to evaporate solvents and ensure chemical crosslinking. The oven or heating elements are precisely controlled by PID temperature controllers and air circulation fans. It is the most used curing module due to its resulting adhesion and coating performance.
• UV Curing Modules: Medical device manufacturers use UV curing modules within their automated coating systems due to their fast processing times and high-volume application capabilities. These modules use UV light to activate photoinitiators and trigger rapid polymerisation. They include UV lamps, reflectors, conveyors, and irradiance sensors for very fast curing. Advanced UV curing modules can coat between 1 and over 1,000 devices/hour.

It is important to note that uneven heating or insufficient UV light leads to incomplete and non-uniform coating layers. This is why curing modules need to be precisely designed and maintained to avoid potential impacts on the coating performance, and patient safety.

6. Control Systems

This system is responsible for the smooth and consistent operation of an automated coating line. It is the central intelligence that controls mechanical motion, fluid delivery, quality parameters, and overall coating performance as well.

Below are the typical components used in a control system of a fully-automated coating system:

• PLC: The programmable logic controller (PLC) is the core of the control system, managing motors, pumps, valves, and other electromechanical components. It receives continuous feedback from sensors placed across various points in an automated coating line.
• HMI: The human-machine interface (HMI) enables operators to select process parameters, view notifications and warnings, and monitor system data. It can also automatically shut down the line in case of faults.
• Sensor Network: Various sensors, such as temperature probes, flow meters, level sensors, and viscosity monitors are installed throughout the coating line to ensure safety and efficient application. They provide feedback to the PLC for closed-loop control.
• SCADA and Data Logging Modules: These modules support historical trend analysis, process validation, and coating application reporting, assisting manufacturers with regulatory compliance and audits.

7. Quality Control Modules

A fully-automated coating system can be integrated with the inline, at-line, and offline monitoring or quality control systems. This module type  is essential for inspection and verification. It plays a crucial role in ensuring the devices meet required specifications for specificaions like thickness, adhesion, and uniformity.

Below are different modules used to verify coating parameters at different stages of the coating application:

• Inline Optical Inspection Module: Various surface defects, such as drips and streaks, are captured through high-resolution cameras and controlled lighting installation.
• Coating Thickness Measurement Module: Thickness and uniformity are important parameters when it comes to coatings. They directly affect the success of a medical device within the biological environment. There are various methods used to measure coating thickness. These include laser displacement, optical interferometry, and magnetic gauging.
• Contact Angle Measurement Module: The performance of medical coatings, such as hydrophilic types, is governed by their wettability. The wettability is high when the contact angle is low. The automated coating systems come pre-installed with advanced modules to measure the contact angle of the hydrophilic coatings.
• Adhesion Testing Module: Every coating must strongly adhere to the medical device surface. A slight delamination may lead to life-threatening situations for patients. As such, various tests, including the tape test, peel test, and cross-hatch test, are performed to ensure proper adhesion to the device post-coating application.
• Functional Testing Modules: These modules vary by the type of coating you apply to your medical devices. For example, at Hydromer®, Inc., most of our clients apply multifunctional hydrophilic coatings to their medical devices. Performance of such a lubricious coating is assessed by measuring the coefficient of friction.

8. Environment Control Modules

The performance and overall success of medical coatings heavily depend upon the atmospheric conditions during the coating application. For example, the presence of atmospheric parameters such as humidity or excessive heat drastically lowers the adhesion and leads to improper coating thickness.

The following modules are used to control key atmospheric parameters:

• Temperature control module – used to maintain the temperature in the system environment during coating application.
• Humidity control modules maintain humidity to the appropriate RH level, depending on coating chemistry.
• Airflow management systems direct natural air away from coating and curing modules.
• Solvent vapor management modules use explosion-proof ventilation and VOC monitoring to prevent fire hazards and maintain process stability.

Top 5 Benefits of a Fully-Automated Coating System

Fully automated coating systems require minimal operator involvement. All application steps are performed by machines autonomously. For example, Hydromer® systems deliver performance with only a single operator, enhancing productivity and greatly reducing labor costs.

The top five advantages of automated coating systems over manual or semi-automated systems are:

1. Repeatability: Automated coating systems can coat several thousands of parts per hour. In other words, their parts-per-hour output is extremely high, making them a reliable choice for high-volume production. All parts are coated efficiently and with excellent uniformity.
2. Automation Level: All steps, from loading to curing and packing, are optimized through mechanized processes.
3. Precision: Automated systems eliminate variations that are common in manual or semi-automated processes by maintaining tightly controlled parameters and tolerances.
4. Compliance: All processes are configured to coat medical devices as per the strict guidelines provided by worldwide regulatory bodies. For example, at Hydromer®, we optimize process parameters, operating ranges, and access levels to ensure a safe and reliable coating layer.
5. Scalability: Automated systems offer faster processing, continuous high-precision production, and reduced cycle times, allowing for easy scaling of production as needed.

Hydromer®: Hydrophilic Medical Coatings and Coating Equipment Supplier

Hydromer®, Inc. is a leading manufacturer and supplier of advanced hydrophilic coatings, with over 40 years of industry experience.

We also supply high-performance, fully automated coating systems to medical device clients and serve as a trusted partner to OEMs and contract manufacturing organizations (CMOs).

We support clients at every stage of product development, from R&D and coating formulation to contract coating and coating equipment. Our systems integrate seamlessly with various coating applications and curing methods. Hydromer also utilizes proprietary UV curing technology to process large volumes efficiently.

Automated Medical Coatings Systems by Hydromer®, Inc

Our two most popular automated coating line offerings are:

• Hydrophilic Coating System: This automated system features integrated UV curing and is designed for applying hydrophilic coatings to medical devices. It requires only one or two operators and supports an annual capacity of 200,000 to 300,000 units.
• Fully Automated Coating System: This end-to-end solution is suitable for industrial applications and compatible with various medical-grade coatings. It requires a single operator and is ideal for large-scale production of complex devices such as catheters and guidewires.

To learn more about our coating systems, please contact us.

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