The requirements of the sanding belt production process for the sand belt substrate, abrasive, binder and sand density are extremely strict, and the premature end of the life of the sand belt is often caused by improper use. Below we analyze several typical problems.
1. Glue Cover:
When a layer of metal material is covered on the abrasive cutting edge, that is, sticky cap occurs. At this time, the surface of the sanding belt becomes shiny and the hand feels smooth. Sticky caps mainly occur in metal materials with high strength, especially in hard and tough materials.
- Insufficient grinding pressure is the main cause of sticky caps. For materials with high hardness, insufficient pressure makes it difficult for the abrasive particles to cut into the workpiece, and it is difficult for the abrasive particles to break and sharpen themselves.
A softer contact wheel or press plate, even if coupled with a high enough grinding pressure, will only make it collapse seriously, and the abrasive particles are difficult to press into the workpiece.
- High belt speed, so that the abrasive particles in the grinding area of insufficient time, cut into the workpiece depth thinning, and serious heating.
The causes of sticky cover are comprehensive, and the solution is also comprehensive, that is, the appropriate contact wheel or pressure plate, high enough grinding pressure, and low belt speed are the fundamental solutions to the problem. Of course, the choice of self-sharpening good abrasive is also necessary.
2. Blunt:
In the grinding process, although all the abrasive particles still exist, the sharpness is already very poor. This is due to the abrasive cutting edge due to wear blunted, this phenomenon is called dull. Normal blunting is the end of the life of the belt, and obviously the "blunting" we refer to here is mainly caused by the improper selection or use of the belt when the abrasive particles have not yet been consumed.
The softer contact wheel or press plate makes it difficult for the abrasive particles to cut into the workpiece, resulting in a flat edge.
The lack of grinding pressure is also easy to dull the abrasive belt, and the abrasive is difficult to sharpen itself.
When the workpiece is hard, the choice of sand belt is not appropriate, or the speed of the sand belt is high, and it is difficult to cut into the workpiece and dull.
The abnormal wear of the sand belt seriously affects the service life of the sand belt and greatly increases the processing cost, so it cannot be ignored.
3. Blocked:
Clogging is when the abrasive gap is quickly covered and filled with chips before the abrasive cutting edge is completely blunted, so that the abrasive belt loses its cutting ability.
There are many reasons for blockage, mostly caused by improper use, processed materials and sanding belt selection:
-- The contact wheel or press plate is too soft, causing the abrasive particles to be difficult to cut into the workpiece, the abrasive belt is mainly in the grinding state, and the temperature of the processing area is heated due to friction, so that the chips are "welded" to the abrasive belt, causing blockage. The solution should be a hard contact wheel and pressure plate, or a contact wheel and pressure plate with a peak tooth back, and a small diameter contact wheel can also be used.
- The high speed of the belt is also difficult to make the abrasive particle effectively cut into the workpiece, the same will occur blockage and workpiece burn, at this time should reduce the speed of the belt.
-- The processed material is too soft (such as aluminum, copper and other non-ferrous metals) easily cause the sand belt surface blockage, the solution should be: using sparse sand belt; Under the condition of meeting the roughness requirement, coarse grain sand belt is adopted. Silicon carbide abrasive belt with greater brittleness is adopted. The method of adding grinding additives, such as the use of lubricants, is adopted.
The processing surface of easily clogging materials is smooth, and the abrasive belt that is easy to cause scratches such as grease and coarse particle size can not be used for such materials, and the ultra-coated abrasive belt should be used, which has good chip removal and anti-clogging performance.
Second, the control of sanding belt deviation:
Deviation is the key to affect the quality and service life of the sand belt, unreasonable design of the sand belt tension and adjustment mechanism will cause the sand belt deviation and beating phenomenon is serious, so that the processing quality can not meet the specified process requirements and greatly shorten the normal service life of the sand belt, the sand belt will break and scrap in a very short time. Therefore, the choice of support frame casting, transmission and adjustment mechanism efficient and reasonable model is the key to obtain good processing results and effectively extend the service life of the sand belt.
Five, sanding belt joint fracture reasons:
1. Not enough glue; 2. Short pressure time and insufficient temperature; 3. Large tension, straight wrinkles; 4. The transmission mechanism has poor stability and unreasonable design.
Six, sand belt use common problems and solutions.
Sand belt machine running crepe, tear, run off
-- Check whether the girth of the sand belt is appropriate (the girth tolerance range is generally plus or minus 5mm);
-- Check whether the cylindricity of the sand belt (the circumference difference between the two ends) is too large (generally the circumference difference between the two ends is less than 5mm);
-- Check whether the sand belt is distorted. Simple inspection method: spread the sand belt flat on a flat ground, the end of the sand belt aligned on both sides, see whether the other end is distorted;
-- Check whether there are foreign objects on the drive wheel, the grinding plate pad and the workpiece to be machined, whether the contact wheel is parallel, whether the transmission spindle is deformed or whether the drive wheel is seriously worn.
-- Check whether the cutting amount of the workpiece meets the requirements.
