Grain Bagging Machine —Wheat, Corn, Rice & Cereals

Net Weight — Multi-Grain

The most requested system for grain facilities running multiple varieties — wheat, corn, soybeans, or rice on the same line. Each grain has a different bulk density (wheat ~780 kg/m³, corn ~720 kg/m³, soybeans ~770 kg/m³, long-grain rice ~680 kg/m³) and a volumetric system will give different actual weights for each variety unless manually recalibrated at each changeover. A net weight system with PLC recipes eliminates this entirely — recipe change at the HMI, no mechanical adjustment.

At production scale across 30 consecutive bags of mixed-grain operations, we consistently see ±0.3–0.5% accuracy — well inside the tolerances required by EU Directive 2014/31/EU on non-automatic weighing instruments and the OIML R87 standard on net quantity of products in packages.

• Bag weight:10 kg – 50 kg
• Speed:10–16 bags/min
• Accuracy:±0.3–0.5%
• Recipes:Up to 50 grain varieties stored
• Compliance:Per-bag weight log (CSV) standard

Volumetric — High Speed

For single-grain operations (e.g. a rice mill packing only one variety) where bulk density is highly consistent and speed is the priority. Gravity gate volumetric fillers have fewer moving parts than net weight systems and can run faster — up to 20 bags/min single-spout. Accuracy is ±1–2%; recalibration required when switching grain varieties or moisture content changes seasonally.

• Bag weight:10 kg – 50 kg
• Speed:Up to 20 bags/min
• Accuracy:±1–2%
• Best for:Single variety, consistent moisture

Dual Spout

Two independent net weight spouts on a shared hopper frame for operations needing 18–28 bags per minute at 25 kg. Each spout has its own load cell and fill valve — one spout can be serviced while the other continues at 50% line capacity. The dual-needle stitcher required to match this throughput is specified and costed as part of the system quote.

• Bag weight:10 kg – 50 kg
• Speed:18–28 bags/min
• Spouts:2 independent load cells
• Stitcher:Dual-needle or twin-lane

Small Pack

Vertical form-fill-seal or semi-automatic open-mouth filler for retail rice, flour, and specialty grain packs in 1 kg, 2 kg, and 5 kg sizes. VFFS for high-volume production of uniform packs; semi-auto open-mouth for lower volumes with multiple SKUs. Food-grade contact materials, printable bag options.

• Pack weight:500 g – 10 kg
• Speed (VFFS):20–80 packs/min
• Bag types:PP, laminate, kraft-PE
• Best for:Retail rice, specialty grains, export packs

With Auto Bag Placer

Bag magazine, vacuum bag presenter, fill, stitch, and conveyor integration in a single line. One operator monitors the full system; no manual bag placement. For operations running more than one shift per day, the labour saving vs a semi-automatic line typically pays back the bag placer cost within 6 months. Bag magazine capacity: 200–400 bags.

• Bag weight:10 kg – 50 kg
• Speed:8–14 bags/min (single-spout)
• Operators:1 monitoring (no manual bag placement)
• Magazine:200–400 bags per load

Semi-Automatic

Manual bag placement on fill spout, foot-pedal trigger, gravity or net weight fill. Suitable for small mills, farm stores, and cooperatives processing under 3,000 bags per month. Capital cost $4,000–$9,000 — the automation economics don’t favour automatic systems at this production volume unless labour cost is high.

• Bag weight:10 kg – 50 kg
• Speed:2–5 bags/min (operator)
• Price range:$4,000–$9,000
• Best for:Small mills, cooperatives, farm stores

Grain enters a surge hopper above the fill head from a bucket elevator, gravity bin, or conveyor. The surge hopper maintains a constant fill head pressure — consistent head pressure is what keeps fill cycle times uniform. Hoppers sized too small refill mid-cycle and cause fill-time variation that increases weight spread.

Bag is presented on the fill spout (manual or automatic placer). Pneumatic clamps close. For PP woven grain bags, clamp pressure is moderate — grain bags typically have heavier weave than feed bags and handle clamping without tearing. The bag bottom should be at least 200 mm above the floor to allow the load cell to read tare without floor-contact interference.

Coarse gate opens — grain flows at full rate. At ~88% of target weight, the fine gate takes over at ~15% of coarse flow rate. Load cell triggers cut-off when net weight is reached. In-flight correction factor (grain in freefall between valve and bag at cut-off) is calibrated per grain type and adjusts automatically via the PLC recipe.

Bag clamp releases. Bag passes to a top-folder that makes a uniform 2–3 fold closure, then to the stitcher. Stitch quality matters for grain bags that are handled roughly in transit — a broken stitch on a 50 kg wheat bag is not a minor problem. We specify the stitcher needle and thread combination for your bag material and specify a minimum stitch tension test in the commissioning checklist.

Whole, cleaned wheat and barley in 25–50 kg PP woven sacks for milling and animal feed markets. Bulk density 770–800 kg/m³, stable between harvests. High throughput is the priority at most milling facilities — dual-spout net weight systems at 20–26 bags per minute are common specifications.

Whole corn, cracked corn, and corn meal in 25–50 kg bags. Whole corn is abrasive — fill spout wear rate is 2–3× higher than soft grain. Hardened steel or ceramic-lined contact spout sections are specified as standard. Cracked corn is dustier and may require a hood extraction upgrade.

Long-grain and short-grain milled rice in 5–50 kg bags. Paddy (unhusked) is bulkier and more abrasive than milled rice. Retail rice in 1–5 kg bags is typically packed on VFFS lines with printed laminate film. Export rice in 25–50 kg PP woven sacks uses standard open-mouth net weight systems.

Whole soybeans and sunflower seeds for oil pressing input and direct feed markets. These are oilseed crops — oil coating on the seeds slightly reduces spout friction vs dry grain, which can increase fill speed but also increases slip on conveyors. Anti-static bag clamp materials are specified for high-oil-content oilseeds.

Whole and split dried legumes for food and feed markets. Chickpeas and whole lentils fill well with standard gravity gate systems. Split pulses (split red lentils, yellow peas) have irregular shapes that increase bridging risk in hopper corners — active hopper agitation is specified for high-split-fraction products.

Quinoa, amaranth, teff, farro, and specialty milling grains for premium food markets. Smaller production volumes — semi-automatic systems are often the right starting point. Packaging format (kraft paper bags, retail-ready design) matters as much as fill speed in this segment. Food-grade contact materials and allergen-separation cleanout ports are specified.

Most line speed shortfalls on grain bagging installations we diagnose are stitcher constraints, not filler limitations. Standard single-needle stitchers top out at 11–13 bags per minute in continuous operation — fine for lines targeting 10 bags per minute, a bottleneck for anything higher. We specify the stitcher for 20–25% headroom above target fill rate and include a stitcher speed test in the pre-shipment validation report. If the stitcher can’t keep pace, we resolve it before the line leaves our facility.

Grain facilities often run 3–10 different varieties on the same line across a season. Each variety has a slightly different bulk density, and seasonal moisture variation changes density further. Our PLC recipe system stores separate fill parameters for each product: coarse/fine switchpoint, in-flight correction factor, and de-aeration setting. Recipe changeover takes under 2 minutes. Buyers who are currently doing manual recalibration between varieties tell us they recover 30–60 minutes of productive time per shift after switching to recipe-based management.

We size the surge hopper to maintain consistent fill head pressure at maximum rated throughput — not to the minimum volume that fits in the available space. Undersized hoppers need to refill mid-cycle, causing fill cycle time variation that widens the fill weight distribution. For sticky or high-moisture grain, we add an active agitator to the hopper. The agitator specification is based on product moisture content and particle size at time of filling, not a generic recommendation.

Our speed and accuracy tests before shipment use a reference grain product (typically wheat or corn). If you are packing a different variety or a specialty grain with an atypical bulk density, we ask for a product sample and run the validation with your actual grain. The test report you receive reflects your product performance, not a generic published figure. This is especially relevant for oilseeds and specialty grains where bulk density can be 10–15% lower than standard cereals.

General-purpose bagging systems for grains, powders, and free-flowing materials at high speed.

Specialised systems for milled flour with fine-powder handling, de-dusting, and accurate net weight filling.

Bagging systems for grain-based feeds including de-aeration for pellets and high-void-ratio products.

Complete grain packaging lines integrating filling, sealing, checkweighing, and palletising.