Powder and granule data
- Bulk-density range
- Particle distribution
- Dust and bridging
- Breakage or segregation limit
Product behaviour
How do product properties affect VFFS machine selection?
Product properties control how material is stored, fed, dosed, dropped and kept clear of the seals. A useful VFFS specification therefore describes the product as a process material, not only by its trade name or target pack weight.
Direct answer
The dosing system and the bagger must be selected as one material-handling process.
Bulk density, particle distribution, flow, aeration, dust, fragility, viscosity, temperature and inclusions can change the required hopper, feeder, dosing device, product path and cycle timing. The same recipe may not remain valid when those properties move within the production range. Representative samples and recorded conditions are needed to establish a robust configuration.
Describe powder by more than its name
For powders, record loose and settled behaviour, bulk-density variation, dust, tendency to bridge, compressibility, moisture sensitivity and the effect of agitation. Those factors influence auger geometry, hopper agitation, refill control, extraction and the relationship between screw rotation and delivered mass.
A powder that looks free-flowing in a small container may behave differently under production head pressure or after repeated agitation.
Protect granules and pieces through feed and discharge
Granules differ in size, shape, density, surface, fragility and tendency to interlock. The feeder and weigher must distribute product without excessive breakage, while chutes and forming tubes need enough opening for the largest credible piece. Mixed products also need segregation to be assessed through the complete transfer route.
The trial should inspect both pack weight and product condition after handling.
Treat liquid temperature and inclusions as design inputs
Liquid and paste flow can change with temperature, shear, air entrainment and product level. Foaming, stringing, settling and particulates affect pump, valve, nozzle and fill profile selection. Product compatibility and clean-down must be reviewed for every wetted component.
State the production temperature and largest inclusion rather than supplying only a room-temperature viscosity description.
Plan for credible variation
Production samples may vary between suppliers, batches, seasons and storage conditions. Identify which property range is allowed and which change requires a new recipe, adjustment or revalidation. A robust line is not one that runs a single ideal sample; it is one with a defined response to the variation the business accepts.
Record product condition with retained trial packs so future deviations can be compared with evidence.
Decision aid
Product properties and the decisions they influence
Use the table to identify the trial variables that belong in the machinery brief.
| Property | Possible process effect | Selection or trial response |
|---|---|---|
| Bulk density and aeration | Changes volume per unit mass and may drift after refill or agitation. | Test normal density range and refill method; select suitable dosing geometry. |
| Particle size and shape | Controls flow, bridging, breakage and product-clear time. | Trial the largest pieces and full distribution through the actual path. |
| Dust and fines | Can contaminate seals, sensors and the working area. | Define containment, extraction, cleaning and timing controls. |
| Viscosity and temperature | Changes pump load, fill profile, drip, stringing and foam. | State operating range and trial credible extremes. |
| Inclusions or mixed components | Can block valves, separate in feed or produce non-representative packs. | Define maximum inclusion and verify blend through the line. |
Quotation preparation
Information to prepare before the machinery review
Liquid and paste data
- Operating temperature
- Flow and foam behaviour
- Largest inclusion
- Clean-down and compatibility
Variation controls
- Supplier and batch range
- Storage condition
- Normal refill method
- Recipe adjustment authority
Buyer questions
Questions buyers ask about product behaviour and VFFS selection
How does bulk density affect powder dosing and hopper sizing?
Bulk density changes the volume occupied by a target mass and the amount of product held above the dosing device. Variation can alter auger delivery, refill frequency and bag headspace. Provide the credible loose and settled range and test the normal refill method so the hopper and dosing arrangement are selected around production behaviour.
Why does particle shape matter on a granule packing line?
Shape influences how pieces orient, interlock, flow through feeders and chutes, break on impact and settle in the bag. Long, flat or irregular pieces may bridge openings that pass round granules of similar weight. The largest credible pieces and the complete size distribution should be trialled through the actual feed and forming path.
How do viscosity and temperature change liquid sachet filling?
Viscosity often changes with temperature, which can alter pump load, flow rate, cutoff, drip, stringing and foaming. A room-temperature sample may not represent production. State the operating range, product preparation and any heating or cooling, then assess the fill profile and seal cleanliness at the conditions that control the process.
What does aeration do to a powder fill weight?
Aeration reduces apparent bulk density, so the same volumetric or auger movement can deliver less mass until the powder settles. Refill, agitation and transfer can add or remove air during a run. Record dose trend around those events and define whether the process needs controlled settling, deaeration or recipe adjustment.
Why should products from different suppliers be trialled separately?
Different suppliers can meet the same commercial description while varying in particle distribution, moisture, density, surface treatment or viscosity. Mixing them into one trial hides the source of behaviour. Separate evidence shows whether one recipe covers the approved range or whether supplier-specific settings and change control are needed.
Application review