Custom bearings are often made from stainless steel in applications where corrosion resistance or nonmagnetic properties are needed. Many grades of stainless steel are available and it is important to select the grade which best meets the requirements of the application.
Most traditional bearings are made from 52100 alloy bearing steel. This is a chromium steel that can be heat treated and ground to achieve high load capacity and durability in bearings. 440C stainless steel is the most suitable grade when an application must meet the full load capacity of a standard bearing. It has higher levels of carbon than other grades of stainless steel, in order to achieve the hardness and strength of 52100. The higher level of carbon also means that this steel, while corrosion resistant, can rust. Passivation can help eliminate this rusting.
300 series stainless steels cannot be heat treated but have very high corrosion resistance properties. Bearings which have lighter load requirements such as thrust retainers or window roller bearings are commonly made from this type of stainless. Typically a bearing made from 300 series stainless steel has about half the capacity of a standard bearing.
For applications that require moderate load carrying capability and high corrosion resistance, precipitation hardenable stainless steels are an option. Grades such as 17-4 or 17-7 are specialty grades that can achieve strength greater than 300 series without the carbon content of the 400 series grades.
Many more grades of stainless can be used in bearing manufacturing in order to customize a bearing to precisely meet the requirements of an application.
Bearings used in medical devices are required to operate in extraordinary conditions and have special needs for reliability and cleanliness. Custom bearings can rise to the challenges of sterilization, corrosion resistance, bio-compatibility and space constraints. Beyond these engineering requirements, manufacturing bearings for the medical industry demands greater quality control and traceability.
National Bearings Company has the experience manufacturing for the medical device industry to ensure a smooth product launch. We use the IQ/OQ/PQ product development process to develop and qualify stable manufacturing processes. During manufacturing, National Bearings maintains stringent adherence to GMP to help control contaminants and manage bio-burden. To ensure the highest product quality, we are ISO 9001:2008 certified and compliant to ISO 13485.
A precision overmolded bearing is an excellent choice when you need a custom wheel, roller or pulley for a new product or when required in limited quantities. Simply put, a standard bearing is overmolded with a plastic tire. The lower cost of tooling of these designs will keep you on budget and using readily available standard bearings will keep you on schedule.
Many features can be incorporated into a custom design that can meet all of the needs of your application.
- Custom profiles
- Corrosion resistance
- Abrasion resistance
- Custom mounting configurations
The wide choice of bearings and plastic resins allow for a custom design that can meet nearly any operating requirement. Stainless steel or plated bearings for challenging environmental conditions, engineering grade resins to survive in high temperatures, resist chemicals and provide superior wear resistance.
Industries that have benefited from precision overmolded bearings include;
- Medical devices
- Food processing equipment
- Commercial interiors
- Industrial equipment
National Bearings Company provides manufacturers with high value and cost savings for projects that require a sub-assembly with a bearing or stamping at the center of it.
The broad range of our manufacturing capabilities makes sub-assemblies a core part of our business. By working with National Bearings Company, manufacturers are able to increase productivity and profits.
- Fewer SKU’s to manage and maintain in inventory
- Reduced assembly time and processes
- Just-in-time delivery to your production facility
- Customized packaging for production and service parts inventory
To manufacture and fulfill your sub-assembly requirements; National Bearings has the capability to manufacture:
- Metal stampings
- Injection molded components
- Machined parts
- Hand and robotic assembly
Your engineering and manufacturing teams can achieve cost and time savings by involving National Bearings early in the design process. Brackets, shafts and even aesthetic features can be incorporated to create a labor saving sub-assembly.
For all of your custom sub-assembly applications National Bearings is ready to assist you
For many Original Equipment Manufacturers, service and replacement parts are significant source of revenue. Large assemblies and custom parts have traditionally been supplied as service parts, but bearings are usually supplied by bearing distributors as MRO. A custom designed bearing offers the opportunity to improve the performance of an OEM’s product and create additional sales as a service part.
A custom bearing can allow equipment designers to optimize the space available and can integrate features that would have typically required additional components. A custom bearing design can improve the assembly process since fewer components are required. As a service part a custom bearing is very difficult to replace with a standard bearing.
For production volumes, custom bearings can be provided in bulk packaging or packaging that presents makes presentation to assembly machines or personnel easier. As service parts, custom bearings can be packaged individually with identification and bar coding for distribution.
Bearings used in medical device applications have unique requirements because of the extraordinary conditions in which they must perform. Biocompatibility, corrosion resistance and sterilization are just a few of the challenges the bearing must accommodate. Standard bearings are rarely able to survive in medical devices.
Custom bearings designed specifically for the application offer a solution that can meet all of the needs of a medical device. A custom design can fit into a much smaller space than a standard bearing. The number of components needed in a medical device can be reduced through the use of a custom design. Custom bearings work well in low volume durable devices or provide essential cost savings for high production disposable products.
Example: A medical implant manufacturer created a new product which requires a special installation tool. A custom needle thrust bearing made from stainless steel was designed for the tool. Initially the tool needed to be reusable and autoclavable. As the product becomes widely accepted the tool will need to be manufactured as a disposable product and the bearing can be redesigned to reduce costs.
Angular contact bearings are the most common style of bearing and are widely used because they can support both radial and axial loads. Stamped angular contact bearings are particularly well suited to custom applications.
High volume, low load or low speed applications are ideal products for this style of bearing. Complex features that add functionality and reduce overall product cost can be included in a custom design.
Case Study – Complex drill chuck bearings
Most drill chucks require a bearing to allow the release of a drill bit or tool after it has been tightened during use. A major manufacturer of chucks wanted to meet this functional need and add an aesthetic feature to alert the user when the chuck jaws were fully tightened on a drill bit.
National Bearings was able to produce a stamped angular contact that provides an audible “click,click,click” when the chuck jaws are tightened and smoothly release the tool when needed. The bearing also had to fit into the very small footprint of a chuck body and match perfectly with a plastic housing and several precision machined components.
Maintaining the high quality and consistency necessary for this demanding application is no simple task. Doing so at a cost that allows our customers to remain competitive in a global marketplace is even more important. National Bearings has been able to provide just these kinds of custom bearings to help bring value to many products.
Other industries that can benefit from stamped angular contact bearings
- Solar array OEMs
- Power tool OEMs
- Consumer goods OEMs
Purchasing managers often consider thrust washers to be nothing more than commodity washers. To clarify, a thrust washer is designed to create a surface that a bearing can roll on or a load can be applied to. To meet this requirement a thrust washer must:
- Be hardened to a hardness that matches the balls or needles
- Have a high surface finish for smooth rolling which reduces friction
- Maintain much tighter dimensional tolerances
Generally a thrust washer has more precise tolerances than a commodity washer, specifically in the thickness, id and od. This helps to ensure the proper operation of the bearing and a secure fit in an assembly. The tolerances are often plus or minus .001 to .002 of an inch.
In contrast, commodity washers are not hardened and have very rough surface finishes. Also, these washers are almost always round in shape. Whereas thrust washers can have cutouts, shapes or slugs. They can also be custom designed to fit into the application.
National Bearings has existing tooling to manufacture more than 500 sizes and shapes of thrust washers and slugs. Also, we have the ability to do the heat treating and surface finishing to produce the highest quality thrust washers.
In addition, National has expanded it’s capabilities to include custom ground thrust washers which have tolerances of .0005 of an inch or less.
Thrust washers are found in a myriad of industries and applications. Here are several areas that are prevalent:
- Power tools
- Industrial automation
- Medical devices (hospital beds, lift systems)
- Alternative energy (solar and wind)
- Wind turbine accessories and more
A thrust bearing is a bearing designed to support axial (thrust loads) in an application. Applications can include everything from point of purchase displays to crane pendants. National Bearings manufactures custom thrust bearings that are designed to meet your exact application requirement.
Thrust bearings are typically constructed of 2 or more thrust races or thrust washers and a complement of balls or rollers. In applications with heavy loads and slow speeds, a full complement thrust bearing that has the maximum number of balls/rollers moving freely in the bearing is ideal. In higher speed or lower load applications, a thrust bearing that uses a retainer is preferred.
While a standard or custom thrust bearing may provide an adequate solution, some applications do not require a complete bearing. In this case a thrust retainer or a bearing with a single washer may offer significant savings in both price and the space required.
Thrust retainers are a component of thrust bearings and are designed to hold the bearings/rollers together in the application. If another component in an assembly such as a casting or plate is acting as a race, a retainer may be a perfect fit. The advantage here is that by providing the retainer alone, the part is less expensive. Also, there are labor savings in assembly by dropping in a retainer rather than loading loose balls.
National Bearings is tooled to make more than 250 different sizes of retainer and 500 different sizes of washers and races in both plastic and metal versions.
Industries and products that feature thrust bearings include: power tools, medical devices, transportation, material handling, display/merchandising industry (spinners) and more…