Conversion Parts

What changes with a new bottle, neck finish or preform

Not every format change needs a full set of new parts. The parts affected depend on which dimension changes: the bottle body, the neck finish or the preform.

• New bottle shape or capacity, for example from 500ml to 1.5L: star wheel pockets, transfer and outfeed guides, and other parts that touch the bottle body.
• New neck finish, for example from PCO 1810 to PCO 1881 or to a 38mm finish: neck grippers, neck guides and any part that holds the preform or bottle by the support ring or neck.
• New preform length or weight with the same neck: infeed rails and preform handling parts may need checking, and the blow mold, stretch rod and heating settings must suit the new preform.
• Same bottle on a different blowing machine: conversion parts that let one blow mold run on different blowing equipment.
• Lightweight bottles: thinner walls and lighter necks can change how bottles behave in grippers and guides, so contact parts should be checked even if nominal dimensions stay similar.

Format change parts comparison table

Measurement data to send for conversion parts

Accurate input data is the main factor in whether new parts fit the first time. Send as much of the following as possible.

• Machine make, model and serial number for every machine the parts must fit, for example SIDEL, KRONES or KHS equipment.
• Bottle drawing with body diameter, height, shoulder and base geometry, and the position of label panels.
• Neck finish drawing with thread diameter, support ring diameter and thickness, and the distance between support ring and neck top.
• Preform drawing with length, neck finish and weight.
• Existing parts or their drawings; LIHE makes conversion parts from customers' existing parts or drawings.
• Photos of the current parts installed, showing identification marks and fixing points.
• Fill type (cold fill, hot fill at about 85–95°C, or aseptic), because hot-filled bottles can be softer during handling.

Changeover steps for star wheels, guides and neck grippers

1. Step 1: Prepare the complete format kit in advance, check it against the parts list and mark each part with its position on the line.
2. Step 2: Run out the old format, stop the line and follow the lockout procedure for every machine that will be changed.
3. Step 3: Remove old star wheels, guides and neck grippers in a fixed order and store them as a kit for the next changeover.
4. Step 4: Install the new parts on their locating features and fasten them without forcing; parts that do not fit freely should be checked, not hammered.
5. Step 5: Set adjustable guides to the new bottle or neck dimensions using a sample bottle or preform as a gauge.
6. Step 6: Turn the line by hand or at slow speed and watch every transfer point for contact, scratches or misalignment.
7. Step 7: Run production samples, check for neck damage, scuffing and falls, then increase to normal speed and record the settings for the next changeover.

Reducing format change time on a PET bottle line

• Single-minute exchange of die (SMED) methods aim to complete changeovers in under 10 minutes by moving as much work as possible to the time before the line stops.
• Store each format as a complete, labelled kit so nothing is searched for during the stop.
• Use parts with fixed locating features instead of parts that must be adjusted by eye.
• Order conversion parts with the new blow mold as one complete format change package, so the mold, blowing parts and handling parts are made to the same drawings.
• Plan lead times: LIHE's stated lead time for replacement parts is 4 weeks; plan new formats so that molds and change parts arrive together.

Common fitting problems after a format change

• Bottles falling at a transfer point: pocket or guide dimensions do not match the bottle, or timing between star wheels is off.
• Scuffing on the bottle body: guides set too tight or contact surfaces worn.
• Neck finish marks or damaged support rings: neck grippers do not match the new neck finish dimensions.
• Jams at the infeed: preform length or neck dimensions differ from what the infeed rails were made for.
• Parts that fit one machine but not another of the same type: machine versions differ, so always send the model and serial number.

Frequently asked questions

Which parts must change when only the neck finish changes?

Usually the neck grippers, neck guides and blowing pins, because they touch the neck or support ring. Star wheels that handle the bottle body may stay the same if the bottle body is unchanged.

Can one blow mold run on different blowing machines?

Yes, with conversion parts that adapt the mold mounting and handling to each machine. LIHE supplies conversion parts for running one blow mold on different blowing machines.

What is the most common cause of conversion parts not fitting?

Incomplete input data, especially a missing machine model or serial number, or a bottle drawing that does not match the final bottle. Sending existing parts or their drawings reduces this risk.

Should conversion parts be ordered with the blow mold?

It is usually better, because the mold, blowing parts and handling parts are then made to the same bottle and neck drawings. LIHE supplies conversion parts with the new blow mold as a complete format change package.

How long does it take to get conversion parts?

LIHE's stated lead time for replacement parts is 4 weeks. Plan new formats so that conversion parts and molds are ready before the planned launch date.

References

1. Wikipedia — Bottling line
2. Wikipedia — Single-minute exchange of die
3. Wikipedia — Changeover
4. Wikipedia — Bottle cap
5. Wikipedia — Preform
6. KHS — official website