The quality and cost of incoming paddy rice are two of the most important factors to understand for a modern rice mill. In most instances the price paid is directly correlated to the quality of the incoming raw material.
Factors such as kernel size, colour and chalkiness are critical parameters in the assessment of quality. Even today manual testing is the prevailing method for making such quality assessments. This manual testing relies on trained and highly experienced technicians reviewing samples kernel by kernel to make judgements that are subjective and can vary greatly between technicians. In fact, studies have demonstrated that this variation can be as high as 20%.
The Challenges: 375,000T Mill in Jiangxi Province, PRC
Data from a large, modern rice mill in Jiangxi Province in China, highlights some of the challenges faced by most if not all rice mills around the World today.
The primary issue faced in IQC is the fact that bulk rice deliveries are not typically homogenous. More often than not there are varying degrees of mixed rice varieties in any given delivery. These variations in the type and mix of rice types being delivered directly affect the quality of the final milled product due to differing levels of broken kernels, differing colours and different baseline kernel sizes. Indeed, colour is often a good indicator of the storage conditions that rice has been subjected to prior to delivery. As a result, this metric is a key determining factor in the price that is paid for bulk rice from the upstream supply chain.
When bulk deliveries arrive to a mill a sample is taken and analyzed for kernel size, color, chalkiness and damage. This process consists of a manual test in which a trained and experienced technician visually inspects a sample kernel by kernel. Each sample may contain up to 1,500 kernels and as a result typically takes in the region of 15 minutes to complete. The results from these tests will directly dictate the price which the mill pays for the bulk delivery. By definition, the manual testing method is subjective and can vary from test to test and technician to technician. As a result, the potential for error on specific tests or between testers is an ever present risk. In addition, the dependence on a small number of experienced technicians results in added risk for a mill operation. In busy periods, especially, during harvest seasons, a mill may be receiving a large number of deliveries on a daily basis and it is not unusual to see 10 or more trucks waiting for their deliveries to be sampled and tested.
If errors in the analysis occur the impact will almost certainly mean some kind of financial loss for the rice mill that goes essentially unnoticed. Every percentage point makes a difference. For example, when measuring the total chalky content in a sample, every 0.1% results in a change of 1RMB per ton paid for the incoming rice. The same factoring applies to the measurement of broken kernels and the level of heavy chalkiness in a sample. It is not unusual to see variations between even highly trained and experienced technicians of up to 2% and variations in specific measurements of chalkiness are typically even higher. Consequently, a mill could be paying 20 RMB per ton more than the real value of the shipment. When a mill is processing 375,000 tons of rice per year these losses can be very significant to the profitability of the mill.
The solution: Vibe QM3 Rice Analyser
The Vibe QM3 Rice Analyser utilises advanced machine vision technology to measure, count and classify kernel size, shape and colour. Using advanced algorithms and user friendly, real time calibration routines, the analysis results are absolute, accurate and reproducible and an analysis report can be automatically generated in as little as 10 seconds with results accurate to 0.5% compared to the manual method with tolerances greater than 2% and in some instances as high as 10%.
Using the Rice Analyser the incoming quality control (IQC) process is able to accurately and quickly determine any variations in the homogeneity of the bulk material as well as being able to identify the levels of damaged kernels and identify levels of chalkiness and yellowing.
As a result, IQC departments and rice mills are provided with an invaluable ‘expert’ inspection and analysis instrument that overcomes the limitations of subjectivity and speed that are evident in manual inspection methods. Furthermore, the superior resolution of the optical system in the QM3 provides higher levels of accuracy and reproducibility of results when compared with other instruments available in the market today.