The Mechanics of Milling
Dental laboratory Milling Techniques

 
Series #1  Wax Milling

The first step of an in depth understanding of wax milling  would be to examine the dimension & configuration of the "rotary cutting tools" to be referred to as RCT.

Click:  For a download of a Bur Configuration Wall Chart

 #1               Diameter

 There are two diameters to considered, first the shanks diameter (Fig. B) which is inserted into the motor (handpiece),  generally lab handpieces accept 3/32"  and milling machines accept  3. mm or heavier diameter shanks. The diameter of the cutting part of the tool (Fig. A) can be less or greater than the diameter of the shank.

The flute length is the length of that part of the RCT that does the cutting (Fig. A). The shank length (Fig. B) should be long enough for it to be properly held by the motor however not so long that it extends excessively. Only a small portion of the shank should extend beyond the motor.

 #3         Flute Configuration

The flute is formed by removing material in such a way that it creates a spiraling outer cutting edge highlighted in red and an inner cutting edge highlighted in white, the spiral is referred to as a Helix.

 #4         Web Configuration

A front view of a two fluted  RCT shows a flute highlighted in white, notice that after two flutes are formed the cross section  of the material left resembles an hour glass. The thinnest area   of the hourglass is called the web.  RCT can have multiple flutes 2,3 and 4 are most common.

Series # 2 Metal Milling Burs