A cup filling machine rated at 6,000 cups/hour may deliver a very different result when the dairy switches from 150 g to 500 g cups, increases yogurt viscosity or changes the lidding film. The dosing stroke, heat-seal dwell time and supporting stations all influence the final number of sealed cups.
For set yogurt, the filler sits between starter addition and incubation. For stirred yogurt, it handles an already fermented, shear-sensitive product. Fruit pieces add another constraint: the pump, valve and nozzle must move them consistently without leaving product on the sealing rim.
This guide covers the equipment decisions behind those production requirements—line capacity, linear versus rotary layouts, filling methods, temperature, cup tooling, cleaning and factory acceptance testing.
Start With the Yogurt Process: Set or Stirred?
The first equipment question is what enters the cups. Set yogurt and stirred yogurt use different production sequences, even when the finished packages look similar.
| Product | Process around filling | Main equipment concern |
|---|---|---|
| Set yogurt (cup-fermented) | Heat-treated yogurt milk is inoculated, filled into cups and then incubated in the packages | Control the temperature and elapsed time from inoculation through filling; move cups gently before the gel forms |
| Stirred yogurt | Milk ferments in a tank; the coagulum is stirred, cooled and then filled | Maintain feed consistency, limit unnecessary shear and control filling temperature |
| Fruit-piece stirred yogurt | Fermented yogurt receives fruit preparation before or during filling | Meter yogurt and fruit consistently, protect pieces and keep the seal area clean |
| Drinking yogurt in cups | A lower-viscosity finished product is filled after the specified fermentation and cooling steps | Control splashing, foam, net contents and sealing |
Set yogurt: plan the inoculation-to-filling window
In a typical warm-fill set-yogurt process, the heat-treated milk is cooled to around 42–45°C, inoculated and filled into cups before incubation. That temperature range suits many thermophilic yogurt cultures. Some larger lines instead prepare and inoculate milk at a lower temperature, then heat the mix inline to the selected incubation temperature immediately before filling.
The filling plan needs the starter-addition point, milk temperature at the filler, batch size and the elapsed time from the first to the last cup. During this period, temperature and culture activity influence the condition of the milk delivered to each cup. Align the filler with the incubation-room schedule and move filled cups gently as the gel develops.
For the process background, see Teagasc's yogurt production guidance and the FAO yogurt manufacturing outline.
Stirred yogurt: protect texture after fermentation
Stirred yogurt completes fermentation in a tank. A common industrial arrangement cools the fermented gel to approximately 15–22°C, gently smooths it and passes it through a buffer to filling. Final cooling takes place after packing. Other production lines fill at colder temperatures, using their own cooling and holding arrangement.
Record the actual temperature at the filling inlet, viscosity, pump speed and transfer distance. These settings affect flow, nozzle cut-off and recovery of the yogurt's texture in the cup. For fruit yogurt, include the fruit dosing point and the longest product-transfer path in the same review.
Commercial technical guidance describes filling around 20°C for some stirred products because product structure can recover during subsequent in-pack cooling. The plant's hygiene controls and cooling capacity must support the chosen process.
Calculate Cups per Batch, Then Size the Line
Begin with the quantity available for filling and the declared net content of each cup. For weight-labeled yogurt, use kilograms and grams consistently.
Cups to fill = Available product (kg) × 1,000 ÷ Net fill (g/cup)
Consider 600 kg of yogurt to be packed in 150 g cups:
- Required acceptable cups: 600 × 1,000 ÷ 150 = 4,000 cups.
- If the approved filling window is 90 minutes, the line needs to deliver about 2,667 acceptable cups/hour during that period.
- If the planning estimate for the whole line is 85% effective output, the corresponding nominal capacity is 2,667 ÷ 0.85 ≈ 3,138 cups/hour.
Here, 90 minutes and 85% are the assumptions in the calculation. In the equipment proposal, replace them with the batch schedule and the effective output recorded for the intended cup and recipe.
Calculate Output From Indexing Cycles
An indexing cup filler may process several cups with each cycle:
Nominal cups/hour = Cups per cycle × Cycles per minute × 60
For a four-cup machine operating at 16 cycles/minute, nominal output is 3,840 cups/hour. At the assumed 85% effective-output level, it would produce about 3,264 acceptable cups/hour, completing the 4,000-cup batch in approximately 74 minutes.
For this four-cup configuration, the sealing station, dosing stroke and film movement must all complete within each indexing cycle. Larger cups or a different lid can change the achievable cycles per minute.
Calculate Saleable Cup Output
A machine's real output is affected by stops, running speed and rejected packages. Cup-magazine replenishment, missing cups, film-roll changes, cleaning and seal adjustments can all reduce the number of saleable packs.
A useful factory-test report records the duration, cups fed, acceptable sealed cups, rejects by cause and downtime. It can also separate mechanical stops from product-quality losses, making it easier to compare the proposed configurations.
Linear or Rotary Cup Filling Machine?
Both formats can combine cup feeding, dosing, lidding, sealing and discharge. The better choice depends on available floor space, required output, product range and how the machine is serviced.
| Selection factor | Linear indexing line | Rotary indexing machine |
|---|---|---|
| Physical arrangement | Stations along a straight path, with one or more parallel lanes | Stations arranged around an indexing turntable |
| Capacity approach | Additional lanes or heads may increase output | Number of pockets and cycles determines output |
| Layout | Longer footprint, convenient for some in-line connections | Compact arrangement for many configurations |
| Cup-size change | Check lane tooling, guides, transport nests and sealing dies | Check pocket plates, guides and sealing tooling |
| Maintenance access | Access along the transport path | Access around the rotary table and stations |
| Best way to compare | Actual good cups/hour at the proposed format | Actual good cups/hour at the proposed format |
NexAgri supplies linear and rotary yogurt cup fillers, from semi-automatic units to fully automatic lines. Standard cup-filling configurations include equipment rated around 1,200–6,000 cups/hour, with compact lower-output models and larger-capacity lines available for specific projects. The final model is chosen around the number of cups per index, cup formats, dosing method and sealing arrangement.
For a processor starting with a few cup sizes and limited daily output, compare the cleaning and changeover time as carefully as the machine price. For a plant expecting large volumes of one established format, sustained output and downstream synchronization may carry more weight.
Choose the Dosing System for the Actual Yogurt
Servo-driven piston filling is a strong option for thick stirred yogurt and many fruit-containing recipes because the measured piston stroke can be adjusted and repeated through the control system. Ordinary piston fillers, suitable pump-assisted systems, gravity filling and flowmeter-based filling also have applications. The right arrangement depends on the product and the machine design.
| Dosing approach | Where to evaluate it | Main point to verify |
|---|---|---|
| Servo piston | Thick stirred yogurt and selected fruit-containing products | Fill-weight repeatability, product shear, valve passage and nozzle shutoff |
| Conventional piston | Viscous products or lower-output lines | Adjustment method, dosing repeatability and format changeover |
| Gravity or controlled-pressure | Relatively free-flowing products | Stable head pressure, foam, dripping and net contents |
| Flowmeter-based | Pumpable products compatible with the meter | Meter suitability for viscosity, aeration and any inclusions |
With two-stage servo filling, the piston starts with a higher flow rate and slows toward the target weight or volume. The slower finishing stage reduces splashing and helps the shutoff valve cut the yogurt cleanly. The HMI recipe can store the filling curve for each product and cup size; the supplier sets the transition point during commissioning using the real material.
Size the Passage for Fruit Pieces
For strawberry or peach yogurt, the biggest particle often determines the valve and nozzle design. Specify the maximum length, width and thickness of the pieces, their firmness, fruit percentage and viscosity at filling temperature.
For example, with 10 × 10 mm peach dice, the engineer should check the narrowest passage through the feed pump, piston valve seat and filling nozzle. A 25 mm unobstructed passage is one practical trial configuration to discuss for this size of fruit. It is the actual clear opening, including the valve in its operating position, that matters. Soft berries, high fruit concentration or irregular pieces may need a different arrangement.
During the sample run, compare fruit entering the machine with fruit recovered from finished cups. Record particle breakage, blocked valves, fruit distribution, dripping and yogurt on the cup rim. Keep pipe runs short where practical and use gentle agitation in the feed tank to limit settling during production.
Compare Filling Accuracy at the Ordered Cup Sizes
Servo-piston filler proposals commonly quote accuracy targets such as ±0.5% to ±1% under defined test conditions. On a 150 g cup, these percentages correspond to ±0.75 g to ±1.5 g. At 500 g, they correspond to ±2.5 g to ±5 g. The quoted tolerance should state whether it describes individual fills, repeatability or another measurement.
A practical acceptance test weighs cups from every filling head at the planned running speed, after startup and following a restart. Record the mean, spread and any underweight units against the product's applicable net-content rules. A steady 2 g overfill across 10,000 cups uses 20 kg of additional yogurt, so dosing accuracy affects both compliance and yield.
For a NexAgri quotation, the actual fill-weight tolerance and test method are specified against the selected machine, cup size and yogurt recipe.
Cup, Lid and Sealing Compatibility Come Before Purchase
Send physical cup and lid samples before the final tooling design. “150 g cup” does not identify its mouth diameter, rim shape, height, wall stiffness or sealable surface.
| Packaging item | What to check |
|---|---|
| PP, PS or PET cup | Rim flatness, heat resistance, dimensional tolerance and compatibility with the intended lidding material |
| Paper cup | Rim construction, stiffness, moisture resistance and sealable coating |
| Pre-cut foil lid | Positioning, pickup, compatible heat-seal coating and peel strength |
| Roll-fed lidding film | Printed registration, web tracking, sealing and cutting, and waste-film removal |
| Overcap / plastic lid | Cup-rim fit, lid feeding and whether it supplements a primary sealed membrane |
Changing cup diameter typically requires adjusted or replacement cup nests, locating guides, sealing dies and film-cutting components. Changing cup height can also affect the nozzle and discharge system. Include a tooling list and changeover demonstration for each ordered cup format.
Seal quality is an operating result
During trials, inspect for yogurt on the sealing rim, wrinkled film, incomplete bonds, lid displacement and leaks after normal handling. Sealing performance depends on the particular cup/lid material pair, tool condition, pressure, time and temperature. The settings that work on one cup or film may require adjustment for another.
The inspection package can combine cup presence detection, film tracking, sealing-temperature monitoring, date coding and reject handling. Where leak testing is specified, include the actual finished-pack test and reject mechanism in the acceptance plan.
Check Hygienic Design and the Actual Cleaning Circuit
Yogurt left in dosing cylinders, valve cavities and nozzles can create a hygiene risk, especially on lines that frequently switch between plain and fruit recipes. The equipment schedule should identify which product-contact sections can be cleaned in place and which components need inspection or dismantling.
Review the hopper, feed pipes, pump, dosing cylinders, valve manifolds, nozzles and any product return line as one cleaning circuit. Confirm chemical compatibility of seals, drainage, cleaning flow and return connections. Product-contact stainless steel grades such as 304 and 316L can be specified for individual components according to the product and cleaning environment.
PLC/HMI controls can manage filling quantity, indexing speed, sealing settings, cup detection and saved product recipes. Depending on the chosen configuration, the line can also include servo dosing, CIP, advanced inspection, UV treatment and protected filling-air systems. Higher-hygiene or aseptic processes require their own process and equipment design.
For cleaning acceptance, document the flow through the feed tank, lines, dosing cylinders, valves and nozzles, including flow, contact time, drainage and any parts requiring dismantling. Inspect the first production cups after the line returns to service.
Balance the Filler With the Processing and Packing Line
An 8,000-cup/hour dosing station connected to a 5,000-cup/hour lid-handling or sealing section delivers, at best, a line constrained by the slower station. The same applies to cup feeding and downstream accumulation.
Map the complete packaging sequence:
- Product feed and controlled holding.
- Cup denesting and positioning.
- Filling, including any separate fruit or topping dose.
- Lid or film feeding and registration.
- Heat sealing and cutting or lid application.
- Date coding, weight or seal checks and rejection.
- Cup discharge, tray packing and transfer to incubation or refrigerated handling.
For set yogurt, coordinate filling and sealed-cup handling with incubation-room capacity and the agreed inoculation-to-filling schedule. For stirred yogurt, coordinate fermented-product cooling and buffer-tank discharge with the cup line. Long waits and aggressive recirculation can undermine good upstream processing.
When a line later adds fruit dosing, a second cup size or automatic cartoning, the equipment schedule should show the expected output at each station and the available accumulation space between them.
What Should a Yogurt Filling Machine FAT Include?
A factory acceptance test is the opportunity to turn the quotation into a measurable result. Agree on the test materials, accepted cup formats, running speeds and inspection methods before the test date.
| FAT item | Evidence to record |
|---|---|
| Cup and lidding compatibility | Actual supplied samples, tooling, lid alignment and seal checks |
| Product dosing | Fill weights by head at each ordered package size and agreed speed |
| Stable output | Accepted cups per hour, interruptions, rejected cups and causes |
| Viscous or fruit product | Feed temperature, viscosity or product description, blockages and fruit condition |
| Startup / stop / restart | First acceptable cups, dosing response and seal recovery |
| Changeover | Parts replaced, adjustment steps and time recorded |
| Hygienic functions | Product-contact inspection, cleaning path and agreed cleaning demonstration |
| Controls | Cup detection, alarms, recipes, language, electrical requirements and protective functions |
| Handover | Manuals, drawings, spare parts, maintenance access and test report |
A 30–60-minute representative run is useful for investigating immediate dosing, cup-feeding and sealing problems. For production contracts, agree on a longer continuous test when needed to demonstrate output stability. Run each ordered cup format—for example, 100 g, 150 g, 200 g and 500 g—with the correct change parts installed.
Where the buyer's yogurt recipe is available, use it during the factory test. If the run uses a substitute product, the site acceptance plan should include the actual recipe. Record saleable output, fill-weight distribution, seal integrity, changeover time and cleaning performance in the test report.
What to Send NexAgri for Equipment Selection
To compare a semi-automatic filler with a fully automatic linear or rotary line, provide:
- Product type: set, stirred, fruit-piece, concentrated or drinking yogurt.
- Product data: filling temperature, viscosity or representative sample, largest fruit size and fruit percentage.
- Production: batch size, daily volume, filling shifts and planned production window.
- Cups: sample or drawing, cup material, rim diameter, height and net content for each format.
- Closure: pre-cut foil, roll film, plastic overcap, coding and tamper-evidence requirements.
- Automation: manual or automatic cup feeding, inspection, checkweighing, reject handling and end-of-line packing.
- Utilities and layout: voltage/frequency, compressed air, water, drainage, available space and integration points.
- Documentation and testing: drawings, material specifications, FAT items, installation and spare-parts requirements.
NexAgri supplies semi-automatic and automatic linear or rotary cup filling and sealing machines, together with configurable dosing, cup handling, lidding, coding and inspection equipment. A project may also include milk preparation, homogenization, heat treatment, fermentation, cooling, fruit dosing, CIP and secondary packaging. Equipment specifications, layouts, tooling information, factory testing, installation guidance and spare-parts support can be organized for the agreed scope.
Explore NexAgri dairy packaging equipment and dairy production lines. For a quotation, contact NexAgri with your yogurt type, cup samples, target output and available plant utilities.
For related processing problems, see our guide to stirred yogurt separation after fruit addition.
Frequently Asked Questions
How many cups per hour should a yogurt filling machine produce?
Calculate the number of acceptable cups from batch quantity and net contents, then divide by the actual available filling hours. Compare that result with the line's demonstrated good-cup output after stops and rejects. The required capacity depends on the product and packaging arrangement.
Do set yogurt and stirred yogurt need the same filling schedule?
Set yogurt commonly enters cups around 42–45°C in a warm-fill process before incubation. Stirred yogurt is fermented in a tank, and some lines cool it to around 15–22°C before filling. The operating schedule and downstream cooling are developed for each product.
Which filling system is suitable for yogurt with strawberry or peach pieces?
Servo-piston dosing with a fruit-compatible valve is a practical starting option. For 10 mm fruit dice, assess the smallest clear passage through the feed pump, valve and nozzle; a 25 mm passage can be included in a sample trial. Check fruit breakage, distribution and seal-rim cleanliness at the intended speed.
Can the same machine fill 150 g and 500 g cups?
Yes, where the dosing stroke covers both fill weights and the machine has the right cup nests, nozzle height and sealing tooling. The 500 g format often requires a longer filling stroke, so its cups/hour rating may be lower. Request changeover details and a speed test for both cup formats.
Is a cup filler with a CIP connection fully CIP-cleanable?
The equipment specification should map the cleaning route through the hopper, product pipes, pumps, cylinders and valves. The FAT can then check flow, drainage, components requiring dismantling and cleaning results for the intended yogurt and fruit recipes.
Conclusion
The right yogurt cup filler brings together the product's filling temperature and texture, the required cup count, the dosing valve, cup tooling and the sealing station. For set yogurt, the equipment plan follows the inoculation and incubation schedule. For stirred and fruit yogurt, product transfer and gentle dosing are central to stable output.
Use the proposed cups, lids and recipe during the equipment trial. A test showing accepted cups per hour, fill weights by head, seal results and cleaning performance provides a sound basis for comparing machines and moving to production.
