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Hartford Technologies Blog

Cleanliness Requirements for Balls, Rollers and Pins

Posted: Apr 13, 2022 12:30:00 PM

Balls, rollers, and pins are essential components in various industries. Different cleanliness requirements for these parts are required based on international/national standards or industry practices for each application area.

The term "clean" is not a relative concept in manufacturing and production. Each industry has established standards for the cleanliness of components based on specific characteristics and requirements. For this reason, it’s important to be aware of what a clean component is and how to assess it.

What Is a Clean Component?

A clean component is one whose surface (aside from any intentional or allowable contamination) is free from foreign material that could lead to premature product failure or affect the performance of the assembly to which it will contribute.

Industries define cleanliness requirements by specifying what type, quantity, and size of foreign particles are allowable. The component's function in its assembly and other variables determine these requirements, including what temperatures they will be subjected to, how much pressure they will endure, etc.

The level of cleanliness required by your application may necessitate consultation with an expert who can assist you in determining what your needs are and how you can best meet them.

Luckily, there are standards regarding the cleanliness of components in every industry. Check the guidelines below to ensure your balls, rollers, and pins are clean enough for your application.

General Industrial Requirements for Balls Rollers and Pins

Generic industrial applications typically require parts to be simply identified as “clean and dry”. However, balls, rollers, and pins used in industrial applications are often subject to the accumulation of contaminants during their use. It is this contamination that collects over time that can be the greatest concern.

Contaminants can significantly affect the performance of the ball or roller bearing by increasing friction, reducing load carrying capacity, or inducing wear. The accumulation of foreign matter can also reduce the life of the lubricant in use.

To minimize these effects, customers should establish a regular cleaning program for their bearings and components. It will ensure that bearings and related parts perform to the most demanding operational conditions while delivering maximum service life.

Before heat treatment or plating, you can use solvents to remove oils, greases, coolants, and other contaminants from balls and other components.

In addition to removing oils and greases from the surface of balls, solvent washing will remove any residual mill scale remaining from manufacture. Typically, steel ball manufacturers stop their manufacturing processes before the final stage of removing all mill scales through mechanical grinding or tumbling. This mill scale provides rust protection during shipping and storage, but you must remove it before heat treatment or plating.

Automotive Industry Requirements for Balls Rollers and Pins

Balls, rollers, and pins are most common in automotive manufacturing. You can find them in every aspect of the industry. Whether in a roller, bearing, or something as simple as an air valve, balls, rollers, and pins play an essential role. There are strict cleanliness requirements for bearings and other components used in vehicles before entering into production or use.

All automatic transmissions and internal combustion engines use precision manufactured electro-hydraulic components with very small clearances. The presence of even small-sized debris in those systems could cause degradation of transmission function such as shift engagement quality.

That’s the reason many automotive companies have been continuously improving cleanliness of all transmission and engine components. Many Original Equipment Manufacturers (OEMs) have developed their own specifications based on the German automotive standard, VDA 19, which is what ISO 16232 requirements are based on.

Most people often overlook pre-cleaning, but it can help prevent premature bearing failure. It's a good idea to clean bearings immediately after opening their original packaging and any time they get in contact with contaminants.

Electronic Industry Requirements for Balls Rollers and Pins

In the electronic industry, ball bearings and roller bearings are used in precision instruments such as cameras, watches, and motors. These bearings are usually made of stainless steel, although they may sometimes be of a ceramic material or hardened steel. The balls and rollers used in these bearings must have a high level of precision and be extremely smooth to prevent any wobbling or rough movement. Any dust or dirt that gets into the bearing will cause friction and reduce its life. If the lubricant on the bearing becomes contaminated, it may become ineffective.

The surface of the components needs to be cleaned before assembly to ensure that they are free from all dirt, grease, or other contaminants. Cleaning should not leave any residue that could affect the performance of the bearings. For these reasons, ultrasonic cleaning and hermetic sealing in a clean room are often part of an automated production process for making ball bearings and roller bearings for the electronics industry.

Methods of Controlling Cleanliness Levels

Below we describe some ways through which you can maintain the cleanliness levels of your balls rollers and pins.

Gravimetric Method (gravimetric inspection)

The most commonly used method for controlling the cleanliness of balls, rollers, and pins is gravimetric inspection.

In this method, a sample of balls, rollers, or pins is weighed before cleaning, then cleaned and reweighed. The difference in weights between the two measurements reflects the amount of contaminant removed.

This method identifies the amount of impurity removed but not the composition of that contaminant. That means you cannot obtain information useful for determining the cause of contamination or preventing its reoccurrence. It is most effective when the contaminant is coming from a particular source or when it is possible to identify the contaminant by visual inspection following cleaning and drying.

Ultrasonic Cleaning

Ultrasonic cleaning is one of the most effective methods for maintaining cleanliness levels in the ball, roller, and pin bearings.

This cleaning method uses high-frequency sound waves to create millions of microscopic bubbles that collapse and draw contaminants away from the bearing. The process is repeated several times to ensure effective cleaning.

Another benefit of ultrasonic cleaning is that it reduces the amount of manual labor needed to clean each bearing, freeing up your time and enabling you to complete more bearings-related tasks.

It's essential to ensure that the machine you are using has enough power to remove all contaminants. To do this, you will need a process called cavitation control. During this process, an operator will adjust the flow rate and temperature of the fluid used in the ultrasonic cleaning process.

The goal is to keep each bearing free from contaminants while preventing damage or wear of the bearing.

Cleanroom Requirements

To maintain cleanliness as per the standard ISO 4406, You must carry out the entire manufacturing process in a cleanroom. The environment must be free of dust and dirt particles, and you must maintain temperature and humidity levels. In addition, filter the air through HEPA filters to remove any contaminants altogether.

As a manufacturing asset, the ability to produce, assemble, preserve and inspect a clean end product is paramount before delivery. While most cleanrooms function in much the same way, the levels of control and particulate levels vary widely. The dirtiest cleanrooms may contain 1,000,000 micron sized particles per cubic meter, while one of the cleanest cleanrooms (ISO Class 3) may contain just 1000 particles or less. The ISO class system provides an industry-wide standard for cleanliness and particles counts, therefore helping facilities measure and test their contamination levels against established benchmarks.

The impact of particles on a production process is not always predicated by volume, but instead by specific sizes of problematic particles based on the application. The increased specificity of ISO class cleanroom standards provides a more accurate and translatable picture of cleanliness, because it defines allowable particle counts in stages of 0.1 micron – 5 microns.

ISO Classes For Clean Room Contamination Levels

Summing Up

Since balls, rollers, pins and bearings are essential components in many manufacturing industries, they must be clean and free from dirt, grime, and other materials that can affect the machinery’s functioning properly.

It is essential that these components are produced with cleanliness standards required by each specific industry, and that once in place, your equipment remains free from dirt, grease, and other contaminants.

It is best to seek out the services of a ball, pin, roller and bearing manufacturer who can provide you with components that have the cleanliness levels required by your industry to get the best results. Contact us today to find out how we can help!