Dressing of grinding wheels

Dressing the wheel refers to removing the current layer of abrasive, so that a fresh and sharp surface is exposed to the work surface. Trueing the wheel makes the grinding surface parallel to the grinding table or other reference plane, so that the entire grinding wheel is even and produces an accurate surface.

Dressing of Diamond and CBN vitrified bonded wheels.

 

         One of the possible tools which may be applied for dressing of diamond and CBN vitrified bonded grinding wheels are rotated tools. It is connected with specific work of such kind of tools, namely rotated dressing tools do not interact on the grain, but mostly on the bond as it is more brittle. During dressing rotated wheel break off the bond and tear the more overhanging superabrasive grains.

 

Attention!!! Dressing diamond/CBN wheels by single point dresser or stationary diamond tools with fine grits leads to dulling of CBN/diamond grains and degradation of wheels working ability.

 

Portable machines with abrasive wheel made of silicon carbide for dressing diamond/CBN wheels are distributed widely as they allow to make dressing of diamond/CBN wheels on different bonds vitrify, resin and metal as well. They are produced in 2 types: power-driven (Picture 1, a) and with centrifugal brake (Picture 1, b)

     

   

a)      AR.jpg                            b)AR1.jpg

 

. 1

 

This tool has been developed for truing various types of resin and vitrified bonds.

 

Diamond and CBN wheels:

1.     1A1 (Straight Wheels);

2.     1A1R (Cut off wheels);

3.     Mounted and un-mounted internal grinding wheels;

4.     1V1 Angle Wheels;

5.     11V9 Cup Wheels;

6.     Core drill outer diameters.

 

Truing Procedure

After the truing tool is been properly set up bring the Diamond or CBN wheel in the truing wheel together to just avoid making contact. Run the Diamond or CBN wheel at operating speed then start the truing wheel spinning in the direction of rotation of the Diamond or CBN  wheel at point of contact, in other words in the same direction it will rotate when driven by the Diamond or CBN  wheel

 

Instructions

The truing device should be mounted so that its wheel spindle is parallel to that of a Peripheral type wheel or perpendicular to that of a cylinder or cup type wheel. At the end of each pass the truing wheel should run off the Diamond or CBN  wheel otherwise it may chip at the edges.

Use either hand or machine cross feed. Internal grinders a rotary table type surface greatest require that the table on which the tool is clamp remain stationary during the truing operation.

 

Truing wheel speed

For average truing operations the most effective truing wheel speed is between 5 and 8 surface meter per second. Excessive wear of the dressing wheel will result if too low of a speed is employed. Too high of a speed will result in the lack of truing wheel wear which is essential for effective truing.  The truing will speed is controlled by adjusting the brake shoes the speeds are obtained by making the following adjustments

1. screws turned in again spindle for maximum speed 8 S.M.P.S.

2. screws turned out from again spindle two revolutions for minimum speed 5 S.M.P.S.

3. screws turned out from against spindle one revolution for present setting  

 

While the truing wheel is still spinning bring the two wheels together until they make contact. Pass one wheel back-and-forth across the face of the other at a rate of 1 to 1,5 meter per minute, with the down feed of 0,01 to 0,02 millimeter at the end of each stroke. Completion of the trimming operation is indicated by even continuous contact of wheels.

Cross feeding it reads faster than 1,5 meter per minute or with down feeds and excessive 0,02 millimeter per pass may result in a slightly crown face on the Diamond or CBN  wheel. On the final pass reduced the down feed to 0,01 millimeter per pass. Resin bond diamond and CBN wheels offer less resistance to truing the vitrified bonded wheels and should be checked for truth with an indicator after 0,1 to 0,2 millimeter total truing fee to avoid unnecessary loss of Diamond and CBN wheel.