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Multi-head Weigher Guide: Weighing Heads, Dosing Accuracy, and Making the Right Choice

The multihead weigher is the heart of high-speed packaging lines: 10 to 14 heads, ±0.5 g accuracy, up to 80 weighings per minute. This guide explains how the system works and walks you through the selection process.

Why the multi-head scale sets the pace

A packaging line is only as fast and as accurate as its dosing system. When it comes to bulk materials, the Multi-head scale The standard is over 30 cycles per minute—no other dosing method combines 80 weighings per minute with ±0.5 g accuracy. This guide explains the principle, walks you through the selection process in five steps, and highlights what matters during operation.

The Combination Principle: Calculating Instead of Weighing

The basic principle is what distinguishes a multi-head scale from any simple scale: It is not a single pan that must reach the target weight—the control system selects the best total from among many partial weights.

The process in each cycle: The distribution plate places the product into the heads; each weighing pan is suspended on its own load cell. The control system reads all weights simultaneously and calculates which combination of three to five pans comes closest to the target fill weight. Exactly those pans open into the collection hopper; the rest wait for the next cycle. With 10 heads, the control system has over 100 combinations to choose from; with 14 heads, over 1,000—which is why accuracy increases with the number of heads.

Layout: From the Inlet to the Collection Hopper

Feed conveyor: A bucket elevator or vibrating conveyor feeds the product—slowly and with gentle transitions for fragile goods (Details in the Snacks article).
Linear bowls: Pre-distributors roughly portion the product among the heads so that no bowl overflows.
Scale heads: 10 to 14 heads, each tray equipped with its own load cell, flap or flap-tray system for soft opening.
Collection hopper: It picks up the combined load and releases it into the filling chute of the packaging machine.
Controls: Recipe management for target weight, combination rules, and cycle time specifications, synchronized with the vertical filling and capping machine.

Head Count: What Having More People Really Brings

Heads	Combinations	Typical Applications
10	over 100	Standard bulk material, 30 to 60 cycles per minute.
12	over 400	Higher accuracy requirements, mixed products
14	over 1,000	High cycle rates of up to 80 per minute, tight tolerances

More heads mean greater accuracy and higher cycle rates—but also more cleaning effort and more load cells to service. The rule: Choose the number of heads based on fill weight and target accuracy, not on maximum capacity. Small fill weights under 100 g benefit from many small pans; large fill weights of 2 kg or more require pan volume rather than the number of heads.

Selection in Five Steps

Classify product: Particle size, susceptibility to breakage, fat and dust content. Fragile products dictate drop heights and pan coatings; products prone to shredding require nonstick coatings or heated transfer points.
Set the fill weight range: The range between the smallest and largest recipes determines the tray size and combination logic. Very wide ranges work better with two sets of trays.
Defining accuracy: ±0.5 g for weights between 100 and 300 g is standard; anyone who needs ±0.3 g accuracy for 50-g portions (as required by retail regulations) must use batch counting and gravimetric readjustment via the reweighing station.
Select the hygienic version: SS304 for product contact, open design, tool-free shell removal for cleaning; CIP-compatible versions for daily product changeovers.
Clarify integration: Synchronization with the bagging machine, opening angle relative to the filling chute, metal detector, and in-line reweighing check—the scale is a team player, not a standalone device.

Operations: Three Things That Compromise Accuracy

Variations in refill levels: If the scale runs out of material (the hopper is too small), accuracy and cycle time will suffer. The hopper should hold enough material to sustain at least five minutes of production.
Dust and Caking: Dust can cause the pans to be weighed incorrectly, and baked goods residue can skew the empty weight. Regular zeroing and cleaning intervals tailored to the product keep the display accurate.
Temperature drift: Load cells drift with changes in ambient temperature. Scales in buildings exposed to sunlight require a warm-up period in the morning and regular zero-calibration cycles.

Wear parts relevant to planning: flap seals on the housings, vibration springs for the linear housings, and flap stops. Keeping these parts in stock reduces downtime from days to hours—the same principle as with Predictive Maintenance for Packaging Machines.

When a multi-head scale is not the right choice

At rates below 20 to 30 cycles per minute, the investment isn't worth it—a linear scale or volumetric dosing is sufficient in this case. For powders with varying bulk density, the Screw Feeder with Gravimetric Control More precisely. And for general cargo with a specific arrangement (cookies in rows), no scale is used for portioning; instead, a conveyor line leads to the destination.

Frequently Asked Questions

How many weighings per minute can a multihead weigher perform?

Up to 80 weighings per minute with 14 heads and a free-flowing product; with 10 heads, 50 to 70 is a realistic figure. Synchronization with the packaging machine further limits the line cycle rate.

When is it worth upgrading from 10 to 14 heads?

For tight tolerances (±0.5 g or better), high cycle rates, or mixed products whose components are weighed separately. For standard bulk materials with a tolerance of ±1 g, the additional cost is difficult to justify.

How do you clean the scale?

Trays that can be disassembled with tools and linear trays can be cleaned in minutes; CIP-compatible versions require no disassembly. The effort required depends on the product: spices and crunchy snacks require daily cleaning, while grains and granules require weekly cleaning.

Can a multi-head scale mix two product components?

Yes—with a split dispensing system and separate dispensing heads, the control system weighs both components separately and dispenses them together. Typical applications include muesli blends and snack mixes with a defined mixing ratio.

Request technical specifications and a quote for your production line. Please specify the product, bag size, and target output (bags/min.) – Request Technical Specifications and a Quote.

Evelyn

As an expert with 16 years of experience and over 300 completed projects, my goal is to provide you with the most suitable packaging solution right from the start.

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