What Are Format Changeover Parts?
Format changeover parts — also called change parts or format sets — are the mechanical components inside a bottling line that must be physically swapped when switching from one bottle shape or size to another. Every machine in a filling line is designed around a specific container geometry: its diameter, height, neck finish, and body profile. When production moves from a 500 ml PET bottle to a 1.5 L format, or from a round glass bottle to a square one, dozens of individual parts across multiple machines need to be replaced.
These parts are precision-engineered to handle, guide, grip, and position each specific container format through every stage of the process — from depalletising and rinsing through filling, capping, labelling, and final packaging. Without the correct change parts, the line cannot operate safely or at rated speed.
Star Wheels (Transfer Stars)
Star wheels are the most recognisable format-dependent component on any rotary bottling machine. They are rotating disc-shaped elements with precisely machined pockets that receive, transport, and release containers between machine stations. Each pocket is contoured to match the exact body diameter and profile of a specific bottle format.
- Infeed stars: receive containers from the conveyor and position them into the machine carousel
- Outfeed stars: extract containers from the carousel and transfer them to the next conveyor section
- Transfer stars: move containers between two adjacent machines (e.g. filler to capper)
- Multi-level stars: grip containers at multiple heights for improved stability during high-speed transfer
Star wheels are typically made from stainless steel (AISI 304 or 316) or high-density polyethylene (HDPE/PE-UHMW) depending on the application. For PET lines running above 20,000 bph, lightweight polymer stars with replaceable pocket inserts are common to reduce inertia and allow rapid changeover.
Feed Screws (Coclee / Worm Screws)
Feed screws — known as coclee in Italian — are helical screw-shaped components positioned at machine infeeds to space containers at precise intervals before they enter the star wheel. The screw pitch and profile are calculated to match a specific container diameter, ensuring each bottle arrives at exactly the right moment to be picked up by the star pocket.
A mismatched feed screw causes jams, missed picks, and potential container damage. For every new bottle format, a new feed screw with the correct pitch, diameter, and length must be installed. Modern systems from Krones (Contiform), Sidel (Matrix), and KHS use quick-change screw mounts with tool-free clamping to reduce downtime.
Guide Rails and Side Guides
Guide rails run along conveyors and through machine sections to keep containers aligned and upright during transport. They must be adjusted — or replaced entirely — for each bottle format to match the container width and height. Adjustable guide rail systems with handwheel or servo-driven positioning can handle a range of formats without physical part changes, but fixed guides offer more stability at very high speeds.
- Top guides: prevent bottles from tipping during acceleration/deceleration zones
- Side guides: maintain lateral alignment on straight and curved conveyor sections
- Base guides: support the bottom edge of unstable containers (e.g. lightweight PET)
- Neck guides: support PET bottles by the neck ring in air conveyor sections
Grippers, Clamps, and Neck Handling Components
In PET bottling lines, containers are frequently handled by their neck finish rather than the body. Grippers and clamps must be precisely matched to the neck diameter and ring profile. A 28 mm PCO finish requires a different gripper geometry than a 38 mm BERICAP closure. Blow moulders, rinsers, and fillers all rely on format-specific grippers.
Gripper changeover is critical for lines that run multiple neck finishes. Systems from Sidel and SIPA offer modular gripper cassettes that can be swapped in minutes. For glass lines, body clamps replace neck grippers and must match the bottle shoulder and waist profile.
Capping Heads and Chuck Sets
Capping machines require format-specific components for each closure type. Screw cappers need chuck sets matched to the cap diameter and thread pitch. Snap-on cappers, crown cappers, and ROPP cappers each have dedicated tooling per cap size. A typical format change on a rotary capper involves replacing 12–72 individual chuck inserts depending on the number of capping heads.
Labeller Change Parts
Labelling machines require bottle plates (piattelli), centring bells (campane di centraggio), and label drums or vacuum drums sized for each container format. Self-adhesive labellers may also need different label dispensing positions. For wrap-around labellers, the glue roller distance and cutting length must be adjusted per label and bottle size.
How BottlingScout Can Help
Finding the correct format changeover parts for used bottling equipment can be challenging, especially for older machines where OEM parts are no longer readily available. BottlingScout connects buyers with suppliers who stock or manufacture compatible change parts for major brands including Krones, Sidel, KHS, SIPA, Sacmi, SMI, and others. Whether you need a single feed screw, a complete star wheel set, or custom-machined grippers for a discontinued model, our network can assist.
Contact our technical team for assistance sourcing format parts, verifying compatibility, or planning a format extension for your existing line.
Frequently asked questions
What are format changeover parts in bottling?
Format changeover parts (also called change parts or format sets) are the mechanical components that must be physically replaced or adjusted when a bottling line switches from one container size or shape to another. They include star wheels, feed screws, guide rails, grippers, capping chucks, and labeller plates.
How long does a format changeover take?
A full format changeover on a complete bottling line typically takes 2–8 hours depending on the number of machines, the degree of automation, and whether quick-change systems are installed. Modern servo-driven systems can reduce this to under 1 hour for pre-configured formats.
Can I get change parts for older or discontinued machines?
Yes. Many specialised suppliers manufacture compatible change parts for older machines from Krones, KHS, Sidel, and other brands. BottlingScout can help connect you with suppliers who stock or produce these components, even when OEM support has ended.
What is a feed screw (coclea) in bottling?
A feed screw (coclea in Italian, Einlaufschnecke in German) is a helical screw positioned at the infeed of a rotary machine. It spaces containers at precise intervals to match the star wheel pocket pitch. Each bottle format requires a dedicated feed screw with the correct pitch and diameter.
Are star wheels universal or format-specific?
Star wheels are format-specific. Each pocket is machined to match a particular container diameter and profile. Some modern systems use adjustable star wheels with replaceable pocket inserts, but most high-speed applications require dedicated stars per format.