Combiblock for Still Water and Mineral Water (0.2–2 L)

1. Why still water is the natural fit for a combiblock

Of all beverage products, small-format still water is where a blow-fill-cap block makes the clearest case. The reasoning is not about the machine being advanced; it is about what water production is economically sensitive to.

1. Resin is the dominant cost. Water sells on thin margins and the bottle is a large share of the cost of goods. Anything that reduces grams per bottle goes straight to the bottom line.
2. Volumes are high and formats are stable. A water plant typically runs a small number of sizes continuously, which suits a block optimised around a few moulds.
3. The product is simple. No carbonation, no pulp, no heat. The filling task itself is undemanding, so the value is in bottle production and handling.
4. Labour per bottle matters. At high output, operator count per shift is a visible line in the cost model.

Those four conditions align exactly with what a combiblock changes: lighter bottles, fewer machines, fewer operators, less floor area.

2. Bottle weight — where the real saving sits

On a conventional line an empty bottle is blown, then floated across the plant on an air conveyor. To survive that journey without deforming, the bottle needs a degree of stiffness it does not otherwise require. That stiffness is paid for in grams of PET on every bottle.

Inside a combiblock the bottle is gripped by the neck ring from the moment it leaves the mould until it is capped. It never rides on its base and never rubs a rail, so the structural allowance for conveyor handling can be reduced.

The achievable weight is set together with the preform supplier and the mould designer. Bottle height, neck finish, top load requirement and your distribution conditions all constrain it. Any supplier who quotes a bottle weight before seeing your bottle drawing is guessing.

3. Capacity bands for still water

Output falls as bottle volume rises for two reasons: the mould cavity needs longer to cool a larger bottle, and each bottle takes longer to fill. A line rated at a small format will not hold that rate on a large one, so state the size mix you actually intend to run. Capacity is confirmed after preform and bottle drawings are reviewed. Selection method across the full range is in combiblock capacity selection.

4. Valve choice for water

Water is the one product family where the cheapest valve is frequently the right answer.

The decision framework, including how to calculate whether accuracy pays for itself, is in load cell vs volumetric vs mechanical filling valve.

5. What surrounds the block

A block is not a line. For a water plant the complete scope normally includes:

• Water treatment — specified from an analysis of your source water; a separate scope in nearly every contract
• Preform and cap handling — unscrambler, hopper, elevator and chute
• The combiblock — blow, fill, cap
• Labelling — OPP hot-melt, sleeve or self-adhesive depending on your pack design
• Coding — date and batch printing
• Shrink packing — film wrapping into retail packs
• Palletising — manual, semi-automatic or robotic
• Utilities — compressed air generation with drying and filtration, plus power distribution

6. Floor space and manpower

Two practical effects follow from deleting the air conveyor, and both show up in the plant layout rather than in the machine specification.

6.1 Floor area

A separate blower and filler need the two machines plus the conveyor run between them, and that run is not short — air conveyors need length to buffer and to route around obstacles. A block occupies one footprint. For plants in leased industrial space, or retrofitting into an existing building, this is often the deciding factor rather than a secondary benefit.

6.2 Operators

Separate machines are separately tended. One block with one control system needs one operator. Over three shifts and a full year that difference is a real payroll line, and it grows in markets where wages are rising. The comparison with figures is in combiblock vs separate blowing and filling line.

7. Preforms and caps decide more than the machine does

Two plants with identical blocks can run at noticeably different efficiencies, and the difference is usually not the machine. It is the consistency of what feeds it.

7.1 Preforms

Preform weight consistency, neck finish quality and material clarity all affect the blowing process. Variation between batches shows up as wall thickness scatter and, at the extreme, as blow-outs. A plant that buys preforms on price alone and changes supplier frequently will spend its life re-tuning the heating profile. Qualify two suppliers, keep both, and test a new batch before committing a production run to it.

7.2 Caps

Closures are the most common source of post-commissioning trouble on water lines. Liner material, thread tolerance and tamper band consistency all influence capping torque and seal integrity. If you change cap supplier after commissioning, expect to re-tune the capping heads — and plan the change during a maintenance window rather than mid-season.

7.3 Bring both to the factory test

Send your real preforms and real caps in production quantity for the Factory Acceptance Test. Testing on generic materials and then discovering your own behave differently defeats the purpose of testing at all. The protocol and what to send is set out in quality control and the FAT process.

8. When a combiblock is the wrong answer

Three situations where separate machines remain the better purchase, stated plainly because buying the wrong configuration is expensive in both directions:

1. You also sell empty bottles. A block fills what it blows. If bottles are a product line in their own right, you need a blow moulder that can deliver them.
2. Very low output. Below roughly 8,000 BPH the economics thin out. The saved operators and floor area are smaller in absolute terms, while the block still carries its integrated cost.
3. You already own a serviceable blow moulder. Replacing working equipment to gain integration benefits rarely returns the capital.

There is also a resilience argument worth acknowledging: integrated machines fail as a unit. With separate machines a filler fault leaves the blower producing bottles into a buffer. With a block, a stop is a stop. Plants that run continuously should weigh that against the operating savings rather than treating integration as free.

Frequently asked questions