63×3 White Rice Grader — How a Vietnamese Rice Exporter Met Broken Rice Percentage Specifications with the 63×3 White Rice Grader

A Vietnamese rice-exporting company had been supplying Asian and Middle Eastern buyers with milled white rice from its Mekong Delta processing facility. Export contracts specified a broken rice percentage cap of 5% — a standard requirement for premium-grade rice in those markets. Without a mechanical grading stage, the operation relied on manual inspection and selective selling to manage the broken-rice content, which was inconsistent and commercially limiting. The addition of the Starlight 63×3 White Rice Grader resolved the grading gap and provided the company with a reliable, documented broken-rice percentage for every export lot.

Operation Background

A rice-exporting company operating a processing facility in Vietnam's Mekong Delta had built a strong paddy procurement network across local farming communities and a milling line that produced approximately 1,100 kg/h of milled white rice. The operation supplied buyers in Southeast Asia and the Middle East under contracts specifying a maximum broken-rice percentage of 5% for the primary grade, with a secondary market for the 5–25% broken grade at a lower price.

The problem was verification. Without a mechanical grading stage, the operation could not reliably determine the broken-rice percentage for any given production lot. Whitening and polishing produced rice with a variable broken content — typically ranging from 3–8% depending on paddy moisture, batch origin, and whitener setting. When the broken percentage was naturally within specification, the operation sold it as premium grade. When it was not — which happened on roughly 30% of production lots — it was downgraded and sold at the secondary price, or blended with lower-broken lots in the hope of averaging within specification.

Blending to manage broken percentages was commercially inefficient and logistically complicated. It required holding output from multiple production runs before shipping, accurately estimating the percentage broken in each batch via manual sampling, and calculating blend ratios to stay within specification — all without a reliable measurement method. On several occasions, blended lots shipped to buyers tested outside specification upon arrival, resulting in claims and reputational damage with buyers who were otherwise satisfied with the operation's service.

The Challenge

The core problem was the absence of a mechanical separation stage that could reliably divide the milled white rice output into a head-rice fraction and a broken fraction, providing the operation with guaranteed broken-rice percentage control on every lot rather than variable natural output.

Rice grading by length works on the principle that head rice (whole or near-whole grains) is longer than broken rice (grain fragments). A grading machine with cylindrical or flat screen apertures sized to pass broken grains while retaining head rice separates the two fractions with high consistency and repeatability. Once separated, the head-rice fraction has a known maximum broken percentage, and the broken fraction can be sold as a secondary grade or processed separately.

For the Vietnamese operation, a mechanical grader would eliminate the need for blending, provide a documented broken-rice percentage for each lot, and allow the operation to commit to a consistent supply at the premium-grade specification rather than managing probabilistic output.

The throughput requirement was approximately 1,100 kg/h of milled white rice — matching the whitener and polisher output rate, so no bottleneck was introduced at the grading stage.

Equipment Selected

63×3 White Rice Grader — Output 1.0–1.2 t/h

The Starlight 63×3 White Rice Grader was selected for its throughput matching the operation's milled output and its screen configuration for the long-grain Indica varieties the operation processes.

The 63×3 designation refers to the grader's screen drum dimensions and configuration. The machine uses cylindrical screen drums with apertures sized to pass broken rice fragments while retaining head rice grains. The "×3" refers to the triple-drum configuration — three grading cylinders in sequence, which provides progressive, high-efficiency separation across the head-rice, medium-broken, and fine-broken fractions.

At 1.0–1.2 t/h output capacity, the 63×3 White Rice Grader matched the operation's 1,100 kg/h milled white rice output rate. No buffer accumulation would develop at the grader inlet under normal operating conditions.

Screen aperture size was specified for the long-grain Indica varieties, the operation processed — the screen opening that passes broken grain fragments of the specific grain length being processed, while retaining whole and near-whole grains. Aperture specification is grain-specific; the same aperture size that correctly grades a long-grain Indica variety may pass whole grains of a shorter variety, so correct specification at the ordering stage is important.

Configuration and Deployment

The 63×3 White Rice Grader was installed as the final stage of the milling sequence, between the polisher outlet and the bagging station. The grader's three discharge outlets — head rice, medium brokens, and fines — were directed to separate collection bins feeding separate bagging stations.

A fourth outlet for dust and very fine particles was connected to the operation's existing dust collection system.

Screen calibration during commissioning involved running the grader at the operation's standard throughput and sampling the head-rice discharge and brokens discharge at intervals to verify that the separation was performing to specification. The commissioning technician confirmed that the head-rice fraction contained less than 5% broken content — within the export contract specification — and that the medium-brokens fraction contained minimal whole grains (whole grain carry-over into the brokens fraction represents a yield loss that raises the cost of the separation process).

The operation's quality protocol was updated to include a grader output sample check at the start of each production run — a simple sieve test using the operation's existing equipment to confirm the broken percentage of the head-rice fraction before bagging commenced.

Results

In the first export season following the grader installation, the Vietnamese operation shipped every primary-grade lot with a broken rice percentage within the 5% contract specification. The need to blend lots to manage broken content was eliminated — every production run's head-rice fraction discharged from the grader was confirmed within specification before bagging.

Buyer claims related to out-of-specification broken percentage ceased entirely. The two buyers who had previously raised specification claims both continued as customers and extended their supply agreements for the following season.

The medium-brokens fraction — previously an imprecisely estimated by-product blended back into primary-grade lots — became a cleanly separated secondary product sold consistently to a domestic buyer at the established broken rice market price. The separation of this fraction added a predictable secondary revenue stream that had previously been obscured within blended primary-grade lots.

The operation's export capacity effectively increased: with every primary-grade lot reliably within specification, the operation could commit to larger forward supply volumes with confidence — which it had previously been unable to do without blending risk.

Who This Machine Suits

The Starlight 63×3 White Rice Grader is the right solution for:

Rice exporters supplying buyers with broken rice percentage specifications who cannot reliably meet those specifications without a mechanical grading stage separating head rice from brokens on every production lot.

Commercial processors selling into multiple grade markets — premium head rice grade and secondary brokens grade — who need a clean mechanical separation to allocate output to the correct price tier rather than blending or manually sorting.

Operations where blending to manage broken percentage is a current practice, where the commercial cost of blending (inventory holding, labour, shipping delay, occasional specification miss) can be offset by the efficiency of mechanical grading.

New production line builds where the output grade specification requires a broken rice percentage cap and mechanical grading is the appropriate final stage to guarantee that specification on every lot.

For operations processing both long-grain and short-grain varieties, note that screen aperture is grain-specific. Discuss multi-variety grading requirements with Starlight's engineering team to confirm whether a single screen set or interchangeable screens are appropriate. See the Rice Grading & Length Selection collection for the full range of grading equipment.

Frequently Asked Questions

How does a cylindrical screen grader separate head rice from broken rice?

The cylindrical screen grader uses rotating drum screens with apertures sized to pass grain fragments shorter than whole grains while retaining whole and near-whole grains. As milled rice enters the rotating drum, shorter broken fragments pass through the screen apertures and are collected below, while longer head rice grains are retained inside the drum and conveyed to the head-rice discharge. The triple-drum (×3) configuration provides three sequential separation stages, improving the precision of separation — particularly in the intermediate fraction between clearly whole and clearly broken grain.

What screen aperture size do I need for my grain variety?

Screen aperture size is determined by the grain length profile of the variety being graded — specifically the length that distinguishes a "broken" grain fragment from an acceptably short whole grain in your buyers' specification. For standard long-grain Indica varieties (grain length 6–7 mm), the appropriate aperture is different from a short-grain Japonica (grain length 4–5 mm). Starlight provides aperture specification guidance as part of the order process — confirm your grain variety and the broken rice definition in your buyer's specification when placing the order.

Can I use the grader to separate multiple broken fractions for different markets?

Yes. The 63×3 White Rice Grader produces three discharge fractions: head rice (whole and near-whole), medium brokens (broken fragments above the fines threshold), and fines. Each fraction can be directed to a separate collection and bagging point for different buyers or markets. This is particularly useful for operations that have identified a market for 5–25% broken rice (a common secondary grade in many domestic markets) as well as a primary head-rice buyer. The three-fraction output avoids the need to re-grade or blend the secondary fraction before sale.

Discuss Your Grading Requirements with Starlight's Engineering Team

If your export contracts specify a broken rice percentage cap and you do not have a mechanical grading stage, Starlight's engineering team can advise on the right grader configuration for your grain variety and throughput.

Request a Custom Rice Milling Solution View the 63×3 White Rice Grader Browse Rice Grading Equipment Explore Custom Rice Milling Lines (30–200 TPD)