Don’t Let Bearings Fail Because Of Contaminants

Most people don’t give much thought to bearings. Without bearings, most of our modern machinery wouldn’t work. Or at least wouldn’t work as efficiently. These precision-made components enable machines to move at extremely high speeds while carrying very high loads. There are many different types of bearings but they all have one thing in common: contaminants can cause bearings to fail.

Contamination from foreign particles can get into the spindle bearings in a number of ways. Coolants can introduce foreign particles into the spindle as can vigorous cleaning with air or water hoses. To keep bearings moving freely, contaminants must be kept out of the spindles.im.SR_HoloRol

So, how can you keep the bearings contamination-free? The most effective way is with effective sealing. There are a few different types of bearing seals and we will discuss them.

A labyrinth seal consists of a series of interlocking channels that collect contaminants under high velocity and expel them. These seals do prove effective while a bearing is in rotation but it isn’t effective when the spindle is not moving. A labyrinth seal can also become overwhelmed by high volumes of coolant. Contact seals when used with labyrinth seals also add to the protection of the lubricants. Made from either rubber or metal, contact shields have a tendency to wear from seal friction and are limited to certain applications.

Instead of using just a mechanical type seal, a change to an alternative sealing solution is another option. Although these methods require a higher initial cost, they may be worth the money to extend or save spindle life.

In air-purge sealing a contact type seal or shield is used in combination with a labyrinth seal and uses low pressure air flow to expel coolant and debris out through a port. This air-purge system should also be used during cleaning.

The AirShields™ or air-seals system combines a labyrinth seal, a floating seal, and the air-purge system. In this system it is the floating seal that helps reduce friction when the spindle is moving and when the spindle is stopped it forms a barrier against contaminants.

We have just touched on the available sealing options but it is important to find the right sealing solution in each application to prevent bearings from being damaged by contamination. Taking steps to improve sealing will lead to more efficient and productive machinery.

 

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Introducing Our New Website

Change is good.  As the season will soon change to winter and 2013 will shortly become 2014, we are excited to announce our own change: Our new website.

Why the change? We had a goal to create a new website that would attract and serve new customers while benefiting, without confusing or alienating, our existing clients. A new machinery division URL was formed, which ties together the old URLs, creating one universal website.

While still maintaining our identity of EDAC Technologies, we wanted to simultaneously set the focus on our Machinery division and the information we provide on it. In this way, we can highlight the division as a whole, emphasizing our recognized and trusted engineering approach to solving our customers’ manufacturing challenges—through our spindles, centerless grinding, and grinding machines.

Our new and improved website features our highlighted parts grinding services, which we plan on developing even further on the site. While this is a significant aspect of Smith-Renaud’s business, now it is being promoted and offered as part of a process solution, where EDAC Machinery grinds the parts and develops machines for that grinding application, and then easily provides the customer the capability to make the parts on their own.

Our new website also features a highlight of our in-stock machines and spindles, making the site an invaluable resource and solution to any immediate and/or urgent emergency situations or rapidly forming opportunities.

We welcome you to visit the new online home of EDAC Machinery, and please feel free to share your thoughts with us on this change, which we believe is for the better.

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The Importance of Preventive Maintenance

In manufacturing, as important as it is to create quality products, it is crucial that products being used are properly maintained. In fact, preventative maintenance is a significant aspect of working with machinery and components. Downtime associated with machinery failure accounts for major losses in efficiency and money.

Some components may be more in plain view than others, and it’s important to remember to perform maintenance on everything, large and small. While it’s impossible for anyone to predict problems to come, what one can do to combat issues is prevention. Set up parameters to follow—indicators of how a machine should be functioning and ways of establishing when there is a problem. Furthermore, set up a routine, a maintenance schedule which you adhere to stringently; set tasks on a daily, weekly, and monthly basis.

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Also important is to know common reasons for equipment failure. For instance, did you know the number one cause of machinery malfunctioning is contamination? When you’re aware of this, you can prevent it. Then make sure everyone in your company who is exposed to these parts is aware of failure causes, failure signs, and failure solutions.

Yet another thing to always consider is proper safety precautions—even more crucial than care of equipment is the safety of those operating it. Some of the many safety considerations include: keeping a clean, well-lit area; only allowing authorized personnel to operate machinery, electrical boxes that are labeled and easy to find; have everyone know how to stop the machine(s) in an emergency; keep hands away from moving parts, and never wear loose-hanging clothing, neckties, accessories while machines are in operation; and much more.

PREVENTIVE MAINTENANCE SCHEDULE

SYSTEM AND TYPE OF CHECK

D

A

I

L

Y

W

E

E

K

L

Y

M

O

N

T

H

L

Y

6

 M

O

N

T

H

S

O

T

H

E

R

HYDRAULIC SYSTEM

Check Tank Oil Level

X

Check For Leaks

X

Check Oil Pressure

X

Check Oil Filter Element

X

X

As Required

Change Oil & Clean Tank

X

Change Tank Suction Strainer

X

Clean Filler Breather Cap

X

Clean Magnet in Hydraulic Tank

X

 

COOLANT SYSTEM

Check Coolant Level, If Applicable

X

Wash Down Machine With Coolant

X

Check Coolant Flow

X

Change Coolant and Clean Tank

X

As Required

Each system within a machine has many parts that require different maintenance. For your reference, below is our preventive maintenance schedule. And remember, while no one can 100% avoid failures, adhering to proper prevention can go a long way.

 

 

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Made in the USA: Yesterday, Today, and Tomorrow

It used to be that saying Made in the USA went a long way. Consumers were proud to purchase goods made here in America, and it was almost a given. Then outsourcing came along, and many companies were forced to send their business overseas in order to stay competitive; cheaper foreign labor meant keeping production costs down.

Thankfully, American manufacturing is now making a major comeback, as reshoring is bringing business back to American soil. Along with it, Made in the USA is also making a comeback, with small and large businesses—as well as consumers—again realizing the true value in U.S. manufacturing.Flag_of_the_United_States_(Pantone).svg

According to a recent article in Time magazine, “American workers are busy making things that customers around the world want to buy — and defying the narrative of the nation’s supposedly inevitable manufacturing decline.” Large companies such as Apple and Airbus, along with small businesses, are bringing business home. Accordingly, Americans are once again taking pride in—and making a special effort to—buy American. Thankfully the trend seems to be continuing, as it’s crucial to the country’s economy.

As much as it is now a trend, for us, it’s always been this way. We are and , and we realize that Made in the USA isn’t just words. They speak, without having to define it. Dealing with spindles, it’s a great advantage for our customers that we are Made in the USA. When they work with us, as opposed to our foreign competitors, when it comes time for service or support, they don’t have to go overseas to get it. By dealing with us, on-shore, our clients save time and money.

We also have the ability to provide support for foreign-made machines. While the U.S. used to be the primary machine building country in the world, it’s now virtually non-existent. We can repair these machines, eliminating the need to send them back to Asia or buy an entirely new spindle. We can do it here, saving money and aggravation.

While we’re thrilled that American manufacturing is a growing trend, we’re also proud to have consistently remained a true American manufacturer—trendy or not.

 

 

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Hydrostatic and Hydrodynamic Spindles Part 2.

The hydrodynamic bearing is dependent on rotation and a low pressure oil supply to build up a wedge of oil between two surfaces – the shaft and bearing – to create the oil film producing the load support.  The geometry of the bearing surfaces aid in forming the wedge.  A low pressure oil source is required.  Spindles built with hydrodynamic bearings feature extreme accuracy, and very good vibration dampening.  High loads at start-up should be avoided.

The advantages of the fluid fed bearings, as outlined, outweigh the increased costs.  Spindles built with fluid fed bearings are more expensive to build.  This is mainly due to low volume, the unique geometry of the bearings and the additional processing necessary to ensure the precision.

Either style of fluid bearing dictates the need for an auxiliary temperature controlled oil supply system.  High pressure oil supply systems are needed for the hydrostatic bearing while low pressure oil systems are used for hydrodynamic bearings.

Because both types of fluid fed bearings are utilized in precise applications, temperature control for the oil supply system is a necessity.  Oil filtration, generally in the range of 1-micron is also required.  An accumulator in the oil supply system is recommended so that oil pressure can be maintained during shutdown in the event of a power failure.

When maintained as directed, spindles with fluid fed bearings can provide infinite (in theory) bearing life since there is no metal to metal contact.  Failures are usually due to human error such as poor maintenance of the oil filtration, use of improper fluid viscosity, temperature control system failures, and machine crashes.

 

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Hydrostatic and Hydrodynamic Spindles Part 1.

In the small world of precision spindles, there exist two types of bearings; rolling element bearings and non-contact type bearings.  Rolling element bearings, as the term indicates, rotate due to integral components that roll such as balls and rollers.  Non-contact type bearings would be defined as those that support rotation, but have no contact between the rotating and non-rotating components.  Air bearings, magnetic bearings and fluid fed bearings are included.  Fluid fed bearings, either hydrostatic or hydrodynamic, are integrated in high-precision spindles.

Throughout this discussion we will focus on the spindles designed to incorporate the oil fed hydrostatic or hydrodynamic bearings.  Each style relies on a fluid, usually oil, to create a clearance between the moving and stationary elements.  However, that is where the similarity ends.  Hydrostatic bearings support a load by means of high pressure oil.  Hydrodynamic bearings support a load by a lubricant film.

Journal bearings support the radial loads and thrust bearings support the axial loads.  The fluid fed bearings are usually radial or axial in design.  Some designs have been developed to incorporate both radial and axial functions in an opposing pair of angular or spherical bearings.  Basically, the bearings float the load on a renewing film of lubricant.  The hydrostatic and hydrodynamic bearing designs are substantially different from each other and are almost always application dependent.

Hydrostatic bearings require an external high pressure oil source along with a restrictor integrated into the design to provide a controlled oil film and generate load support.  Generally, the oil is distributed to multiple cavities through metering devices called restrictors.  Spindles built with hydrostatic bearings characteristically have high stiffness, extreme accuracy, and excellent vibration dampening features.  The extreme accuracy is a result of the averaging of form errors of the surfaces that make up the bearing elements.  Because a hydrostatic bearing is not dependent upon rotation to generate the oil film, it can accommodate heavy loads at zero speed.  The low random motion error and vibration dampening makes the hydrostatic bearing ideal for ultra-precision machining such as those required for precision optics including mirrors.

Stay tuned for next month when we dive into Hydrodynamic spindles!

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Precision Spindle Bearings: Storage Guidelines for a Long Shelf Life

Gros-Ite Precision spindle bearings—used by many industries, for many applications—are known for their extremely high degree of accuracy.  As such, a high quality precision bearing will provide precise accuracy for a long time, and come with a tested, proven shelf and storage life (shelf life is up to five years).

In order to preserve the shelf, storage, and service life, and get the most out of your precision spindle bearings and their performance, it’s important to follow the guidelines for proper storage:

  • Store bearings in original packaging until time of service
  • Do not alter the original package markings
  • Be sure to store them in an environment where relative humidity is below 60% and temperature is maintained between 32°F and 104°F
  • Keep storage area free of dust, dirt, harmful vapors, liquids, and other contaminants
  • Keep storage area free of vibrations from railroads, construction equipment, vibratory feeders, etc.
  • Avoid storage in areas with extreme conditions
  • Be sure to keep packaging from being pierced, crushed, or damaged in any way
  • Remove bearing from packaging in a clean environment and put into service right away
  • When removing a bearing from a bulk packed container, reseal container immediately
  • Storage conditions and bearing lubricant will temper 5-year shelf life.  If conditions are ideal and manufacturer’s rust inhibiting oil is protected, this shelf life is practical. If bearings are grease lubricated, oil can weep out and shelf life could be reduced by 50%.  If storage conditions are less than ideal, consult the manufacturer for revised shelf life recommendations
  • Bearings stored for time periods longer than recommended should be returned to manufacturer for inspection and relube

Follow these storage guidelines, and you’ll get the most out of your precision spindle bearings, and quality will be assured.

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