Wheel Dressing
The key to maximizing the grinding performance of a wheel is a good dressing tool and good dressing skills. An operator with a high quality dressing tool and a good knowledge of dressing techniques is able to maintain a high grinding performance of the grinding wheel. Instead of just relying on buying a good grinding wheel.
Dressing of grinding wheels is the process of shaping or removing the dull surface of a grinding wheel with a dressing tool in order to restore the grinding performance and correct geometry of the working surface. Timely and correct dressing of the grinding wheel, the correct use of diamond dressing tools, is to improve grinding efficiency and ensure the quality of grinding the most indispensable and important links.
sharpshooter
Sharpening is the process of sharpening the grits of a superabrasive wheel. In this process, the bond between the grits and the dulled grits are removed, so that the grits of the wheel, which have very strong grinding properties, protrude beyond the bond and form a sharp cutting edge. Sharpening also removes minute material from the pores on the surface of the wheel to prevent an increase in the grinding forces acting on the wheel, which can cause vibrations and burns on the surface of the part.
Without proper dressing, even the best grinding wheels are unlikely to achieve the high quality and dimensional consistency of machined parts. In fact, when you invest in a high-quality grinding wheel, it is important to dress it well in order to achieve high grinding performance.
Reconstructive
Shaping is part of the preparation of the grinding wheel and is carried out at the same time as sharpening of the normal grinding wheel. In the case of superabrasives, the two processes are carried out separately, with the wheel being shaped first. In the case of grinding with superabrasives, shaping is carried out using a shaping tool or roller, and sharpening is often carried out using a ceramic bonded dressing rod, which is sharpened after shaping.
The right way to trim
1.Adoption of microtrimming
There always seems to be a temptation to choose a greater depth of trimming in order to minimize trimming time. This is an extremely wrong idea. The grinding wheel must be dressed at the optimum depth of removal. Selecting too large a depth of removal generates high cutting temperatures, reduces dresser life, and removes useful wheel layers. The end result is damage to both the dresser and the grinding wheel, which is counterproductive.
The optimum amount of dressing is the amount that restores the geometry of the grinding wheel after several passes and just enough to produce a good grinding edge.
With a single-point dressing tool, the grinding wheel should be touched in the direction of the diameter of the grinding wheel at an inclination of 10-15 degrees to the centerline of the shaft. This will create a sharpening action when the single point dressing tool is periodically rotated. A dressing tool with multiple points of contact does not need to be tilted at this angle. Change to use the entire end face of the dressing tool to contact the surface of the grinding wheel.
2.Oscillation is the enemy of repair.
Reduces oscillations during wheel dressing and prevents dressing marks on the wheel surface, knocks, and damage to the dressing tool. This means that it is also necessary to maintain the balance of the wheel, which is determined by the construction characteristics of the wheel itself. Uneven density and wheel geometry can affect the inherent balance of a wheel. Therefore, it is also important to select a high quality grinding wheel.
In the case of a high quality grinding wheel, proper installation is all that is required to keep the wheel well balanced. According to the wheel manufacturer’s instructions, the wheel is marked with an upward arrow, which indicates the position of the light end of the wheel after rough balancing. The user can then follow the arrow instructions and keep an eye on the grinding wheel to make it dynamically balanced. An even filling of the coolant can sometimes help to maintain the balance of the grinding wheel.
To further prevent oscillation, ensure that the dressing tool is securely clamped to the holder and maintain minimum overhang to ensure adequate rigidity of the dressing tool. If a diamond tool is not clamped securely, it can cause oscillation, noise, rippling on the part’s exterior, straining the part’s exterior, and damage to the dressing tool.
3.Insist on cooling off
Proper use of coolant can accelerate dressing speed and increase dressing power. As a rule of thumb, a 3/8-inch diameter stream of coolant can remove a lot of heat from the dresser and extend the life of the dresser. As the diamond dressing tool passes over the wheel, a coolant nozzle is installed to fill the entire surface of the wheel or to continually refill the diamond dressing tool with coolant. Never allow the dressing tool to be withdrawn from the coolant after it has made contact with the wheel and started dressing. Failure to do so will result in cracking or fracturing of the diamond dressing tool when exposed to changes in the polar temperatures of cold and he
High-precision filtration of the cooling fluid by means of a filter prevents repeated circulation of dirt or chips in the cooling fluid. Contaminated coolant can cause the wheel to wear out quickly, increasing the number of times the wheel has to be dressed. Dry dressing of the grinding wheel is only done during dry grinding (as long as the cooling of the diamond dressing tool can be discontinued under these conditions). At the end of the day, turn off the coolant and let the wheel run for a few minutes. This prevents the wheel from cracking.
How to protect your grinding wheel?
It is important to ensure that the spindle bearings are at a certain temperature (e.g. in the normal grinding condition of the wheel) before the grinding wheel is dressed including shaping and sharpening. This prevents damage to the part geometry and abnormal wear of grinding wheels and dressing tools. Dressing tools must be handled with care as they are generally made of hard, abrasion-resistant, yet brittle diamond material and are very sensitive to small cracks and breakage caused by minor impacts and stresses.
Because the diamond shaper itself is a knife, it needs to be kept very sharp. Using a dull dressing tool to dress the surface of the grinding wheel will dull the wheel. In order to maintain a high quality and sharp diamond dressing tool, it is necessary to rotate the single-point or tapered dressing tool in 1/8 turn every so often. The number of rotations can be determined according to the trimming conditions and, based on experience, at least one rotation per day. For chisel heads and molded dressing tools, it is generally necessary to rotate them 180° before blunting them.
Most cylindrical grinding machines place the part and grinding wheel on a horizontal line. The highest point of the outer circle of the part and the highest point of the outer circle of the wheel are referred to as the part/wheel contact points, and the diamond dressing tool should dress the wheel as close to the part/wheel contact points as possible. For internal grinding wheels, it is even more important to dress the diamond dressing tool close to the highest point of the wheel’s outer diameter (i.e., the point of contact between the part and the wheel during hole grinding).
