Rice whitening machines are vital in the rice production line. However, improper operation can damage the grain, reduce the head rice ratio, and compromise overall processing efficiency. Understanding frequent problems and their solutions helps businesses reduce costs and prolong equipment lifespan. Below are the top 5 issues most often encountered during whitening operations—along with quick and effective troubleshooting tips.
>>See more “What is rice milling? How does the rice milling process take place?”
>>See more “Export rice quality standards and the role of modern rice milling technology”
1. EXCESSIVE GRAIN BREAKAGE AFTER WHITENING
Broken grains are often caused by mismatched pressure and grain moisture levels. If the paddy is too dry or too moist, excessive force can lead to internal cracking and breakage.
- Grains that are too moist (over 17%) will make the rice grains soft and friable. When milling, the soft grain texture will make it easy to peel off the bran but also easily clog the milling blade, making the grains easily broken.
- Grains that are too dry (under 14%) have a large dispersion of the grain mass, making it easier to sift. However, the grains will be very brittle and break easily during the milling process.
The ideal humidity will range from 14 – 15.5%, convenient for milling and producing the best quality rice, limiting breakage. Therefore, it is necessary to carefully control the humidity before milling as well as pay attention to the standard storage of raw materials.
2. WHITENING CHAMBER CLOGGING
If the rice flow is unstable, clumpy or interrupted, the machine may be clogged with the milling chamber. The reason is that the input rice contains a lot of impurities, has not been hulled thoroughly or the machine is not cleaned regularly. As a result, dust, bran, husk and impurities easily accumulate, causing blockage of the milling shaft or dust extraction system.
To fix this problem, first turn off the power to avoid damage related to the motor. Then check inside the machine to see if there are any grit or foreign objects stuck. Clean the machine to remove the clogging substances. In addition, you can pay attention to the cleaning of the first rice before milling and periodically clean the mill to limit the above situation.
3. INCONSISTENT WHITENING
Dark or bright streaks on white rice after milling are signs of uneven milling. The cause is often due to unstable milling pressure distribution, weak dust extraction airflow, or unevenly worn grinding stones. This condition reduces the aesthetic value of the rice grains, directly affecting the ability to meet export standards.
To fix this, it is necessary to check and replace the screen if it is worn, readjust the dust extraction system to increase air flow, and adjust the grinding chamber and grinding wheel to ensure even force distribution across the entire grinding surface.
4. EXCESSIVE VIBRATION AND NOISE
Vibrating and making loud noises are often signs of mechanical imbalance during operation. Common causes are eccentric shafts or worn bearings after long-term use. In addition, if the bolt joints are not tightened evenly, the vibration will resonate and create loud noises. This condition not only affects the performance but can also cause sudden failure and reduce the life of the equipment.
The solution is to perform regular maintenance, check the balance of the grinding shaft, replace bearings if necessary and tighten all bolts and joints to ensure stable machine operation.
5. MACHINE OVERHEATING
When the rice milling machine overheats, it often comes with a sudden stop, which is a sign that the machine needs to rest. If this situation persists, it can cause the motor to burn out, reduce the life of the equipment and affect production progress.
To overcome this phenomenon, it is necessary to periodically maintain the engine as well as regularly check the cooling components (ventilation slots, radiator fans) to ensure that they are not clogged by dust or accumulated rice bran. In addition, it is necessary to avoid letting the machine operate continuously for a long time.
CONCLUSION
Vichem is the official distributor of Bühler equipment in Vietnam. We not only supply genuine machines but also provide full technical documentation, standard accessories and periodic maintenance services. Vichem’s technical team is always ready to support at the workshop – from installation to operation training suitable for each specific application.
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