Dental Handpiece Bearing Failure - Highspeeds

In Dental Handpieces, The Bearings Are Directly Responsible for about 90% of all Failures. The Frequency in which Failure occurs Depends Highly upon the type of Bearings being used in your Handpiece.

There are 3 Main Components of Dental Ball bearings that affect their Life Span. They are:

1. The Retainers (“Cages”)
2. The Contact (Radial or Angular)
3. The ABEC Rating

The Cages are Round in Shape with 8 holes, each Holding 1 Steel Ball. The Purpose of this Cage is to Keep the Balls in place while Allowing them to Spin. This is the Part of the Bearing that Most Commonly Fails. Failure is normally due to Degradation caused by the Sterilization Process. The 2 most Common Types of Cages used are:

1. Phenolic: A Plastic Formed by the Reaction of Phenol and Formaldehyde. Originally used as Bakelite” (as in - for those of us Old enough to remember, the old Bakelite Radio Cabinets). The Disadvantages of Phenolic Cages in Dental Handpieces are:

• Have a Tendency to Become Brittle and Break
• Heat Tolerance (300 F degrees (149 C)

2. Torlon: A Plastic Formed by the Reaction of Polyamide and Imide. Its Main Advantages over the Phenolic cages are:

• Higher Heat tolerance (450 F degrees (260 C))
• Exceptional Chemical Resistance
• Outstanding Mechanical Strength & Excellent Thermal Stability

The Contact Design of the Bearings Describes the Way the Bearings Inner And Outer Races Maintain a Relationship with Each Other:

• Radial: The Races on a Radial Contact Bearing maintain a Radial Load that takes an Oblique Path that tends to Separate the Races Axially:
• Angular: An Angular Contact Bearing uses Axially Asymmetric Races. An Angular Load passes in a Straight Line Through the Bearing. Angular Contact Bearings allow “Combined Loads” (Loading in Both the Radial and Axial directions). In High Speed Applications, the Centrifugal Forces Generated by the Balls will Change the Contact Angle at the Inner and Outer race. This is the Better Choice for Dental Handpieces.

The ABEC Bearing Rating System was Developed by the Annular Bearing Engineering Council of the American Bearing Manufacturers Association (ABMA) as a way to Rate “Precision Bearings”. The Ratings are a Numerical System from 1 to 9, with the Highest Number assigned Representing a Higher Standard of Precision:

• The Higher the Number
• The Tighter the Tolerance
• The More Expensive the Bearing

The Handpiece Repair Industry Standard is ABEC 7 Rated Bearings, Including the Rebuild Kits for the EZ- Press and Other Do-it-Yourself Systems. What Your Handpiece Repair Facility Should Be Using:

• Angular Contact Bearings
• Constructed with A Torlon Retainer and
• An ABEC 7 or Higher Rating

“Never Allow the Replacement of only One Bearing In Your Dental Handpiece. This is Not an Acceptable Practice and You Are Throwing Your Money Away”

At WeKnowTheDrill.com, our Standard Rebuild includes ABEC 7 Bearings. Our Premium Rebuild Includes ABEC 9 Bearings & 6-Month Warranty

Source: www.articletrader.com