Pharmaceutical Machine Change Parts: Star Wheels, Feed Worms, Grippers, Needles & Nozzles – Complete Guide

One pharmaceutical packaging machine may need to handle several bottle diameters, vial sizes, ampoule capacities or closure formats. The main machine remains the same, but the parts that directly control each container must match its geometry. These interchangeable components are commonly called change parts, format parts or size parts.

H M Pharma Machines supplies new machinery and can also develop selected pharmaceutical machine change parts for existing equipment, including machines from other manufacturers, after checking samples, dimensions and technical feasibility.

Why Precision Matters in Machine Change Parts

Change parts work in a synchronized path. The feed worm separates incoming containers, the star wheel receives them at the correct pitch, guides control their path, and downstream components position them for washing, filling, capping or labeling. A dimensional error in any one part can disturb the complete transfer sequence.

Correctly engineered parts should provide:

• Smooth container entry and exit without sudden impact.
• Accurate pitch matching between the conveyor, feed worm and star wheel.
• Stable handling without excessive pressure on glass or plastic containers.
• Repeatable positioning below filling needles, capping heads or inspection stations.
• Practical changeover and clear identification for each container size.

1. Star Wheels

A star wheel is a rotating indexing component with pockets shaped for a specific container diameter or profile. It receives bottles, vials or ampoules at a controlled pitch and transfers them to the next operation. Star wheels are used in washing, filling, capping, labeling and inspection machines.

Important star-wheel design points

• Pocket profile: must support the container without marking, tilting or excessive clearance.
• Pitch circle: must match the machine timing and adjoining transfer components.
• Height and thickness: should support the stable area of the container.
• Rotation direction: determines pocket entry and exit geometry.
• Hub and mounting: must match the shaft, key, fastener and reference position.

Black Delrin or another suitable engineering polymer is often selected for container-contact star wheels because it can be accurately machined and provides smooth, low-friction contact. Stainless-steel hubs or inserts may be used where additional mounting strength is required.

2. Feed Worms

A feed worm—also called an infeed screw—accepts containers from a conveyor and gradually separates them to the exact pitch required by the star wheel. Its helical profile is not simply a regular screw: the pitch may change along its length to accelerate and position containers smoothly.

Common feed-worm problems

• Containers hesitate or rotate at the entry.
• Bottles are pushed too tightly against the guide rail.
• The handover to the star wheel is early or late.
• Scuffing appears on the bottle body.
• Noise, vibration or repeated jamming increases at higher speed.

These symptoms may come from wear, incorrect synchronization, guide settings or a profile that does not match the container. Before replacing the part, the complete infeed arrangement should be checked. Confirm the material, profile and working range for the actual screw-and-container arrangement; a material name alone does not establish correct transfer.

3. Gripper Sets

Gripper sets are commonly used in rotary washing machines to pick, hold, invert and transfer ampoules, vials or bottles through washing stations. A typical assembly includes a stainless-steel carrier, pivots, springs, fasteners and matching Delrin or suitable engineered-polymer jaw blocks.

Each jaw pair in a gripper set should be aligned at the same working height and provide uniform contact. Unequal jaw length, weak springs, worn pivots or mismatched blocks can cause unstable holding, container drop, glass breakage or inconsistent positioning in front of the washing needles.

What to inspect in a gripper assembly

• Equal jaw-block dimensions and parallel alignment.
• Consistent spring force across all gripper stations.
• Free movement at each pivot without excessive play.
• No sharp edges or metal contact at the container holding point.
• Correct opening and closing timing during transfer.

For examples of machines that use controlled rotary handling, see our rotary gripper ampoule washing machine, rotary gripper vial washing machine and rotary gripper bottle washing machine.

4. Filling Needles and Nozzles

Needles and nozzles control the final delivery of liquid, cleaning water, compressed air or another process medium. Their bore, length, tip shape, outlet arrangement and material should match the product, container opening, flow rate and machine movement.

Common types and applications

• Filling nozzles: used for free-flowing, foaming or viscous liquids with a suitable shut-off or diving arrangement.
• Vial and ampoule filling needles: designed for small container openings and accurate positioning.
• Washing needles: deliver water and air in a defined washing sequence.
• Special outlet nozzles: may use angled, multi-hole or application-specific tips.

Product-contact parts are commonly manufactured in a suitable grade of stainless steel, selected according to process requirements. Surface finish, internal cleanability, seal compatibility and dead-volume control are especially important. The machine movement must also keep the needle centered to prevent contact with the container neck.

Related equipment includes vial liquid filling and stoppering machines, volumetric liquid filling machines and servo piston liquid filling machines.

5. Other Common Change Parts

A complete format change may require more than the four main components above. Depending on the machine and operation, it may also include:

• Infeed, center and outfeed guide rails.
• Volumetric syringe or piston-pump assemblies.
• Container neck guides and base supports.
• Cap chutes, stopper tracks and orienting-tool components for the approved capping equipment or stoppering machine.
• Timing-screw supports, spacers, bushes and mounting hubs.
• Labeling-machine wrap belts, pressing pads and guide assemblies.
• Vibratory bowl tooling for caps, plugs or rubber stoppers.

Every part should be assessed as part of the complete container path. Replacing only one worn component may not correct the problem if an adjoining guide, shaft, bearing or timing setting is also out of condition.

Material Selection for Change Parts

Can Change Parts Be Made for Other Manufacturers’ Machines?

In many cases, yes. A replacement or new-format part can be developed for an existing pharmaceutical or packaging machine, including machinery from another manufacturer, provided the required technical information is available and the design is feasible.

The safest approach is to inspect the existing part and machine interface rather than relying only on a product photograph. Machine model, shaft location, mounting method, timing, container path and sample dimensions all affect the final result. Where possible, a trial and verification plan should be agreed before regular production use.

Prepare the ordering and interface record

Start with a project reference and a list of formats. Give each drawing, sample and photograph a traceable identity. The site owner identifies the machine and intended use; the parts supplier states the measurements needed to assess feasibility and the revision proposed for manufacture.

When Should Change Parts Be Replaced?

Change parts should be inspected during preventive maintenance and every format change. Replacement or repair may be required when you observe:

• Cracks, chips, deformation or worn container-contact profiles.
• Increasing jams at the same transfer point.
• Container scratches, unstable movement or glass breakage.
• Excessive play in hubs, pivots, bushes or mounting points.
• Unequal gripper pressure or inconsistent jaw alignment.
• Leakage, dripping or damaged nozzle tips.
• Repeated timing correction after normal machine setup.

Keep a verified master sample or approved drawing for each format. Clearly label and store complete sets together so parts are not mixed between container sizes.

Care and Maintenance Tips

Before hands-on care: Trained, authorized personnel must stop and isolate hazardous energy under the machine manual and site procedure before reaching into the machine, cleaning, clearing a jam or adjusting hardware. Use only the approved manual-rotation method; do not bypass a guard or interlock. See the inspection precautions and troubleshooting guide.

• Clean parts using a method compatible with their material and process.
• Do not use metal tools on precision polymer profiles.
• Inspect mounting faces before installation and remove trapped particles.
• Use dedicated racks or trays to prevent parts from striking each other.
• Record the container size, machine name and approved setting with each set.
• Replace damaged seals, springs or fasteners with the correct specification.
• With the required isolation and approved manual-rotation method, confirm free movement before completing the machine manual’s restart checks and returning to production speed.

Frequently Asked Questions