Automatic Wide-Mouth Bottle Blowing Machine: Common Technical Problems & Solutions

April 17, 2026 By admin Blog 15 views

The automatic wide-mouth bottle blowing machine is widely used in the production of PET wide-mouth containers such as food jars, honey bottles, sauce bottles, cosmetic jars, and daily chemical packaging. As a key piece of equipment in the plastic packaging industry, the automatic wide-mouth bottle blowing machine requires high precision in temperature control, stretch ratio, blowing pressure, and cooling systems. Even minor parameter deviations can lead to quality defects such as uneven wall thickness, whitening, wrinkling, poor transparency, and bottom eccentricity. Mastering common technical problems and solutions of the automatic wide-mouth bottle blowing machine can greatly improve production efficiency, reduce defective rates, and ensure stable and high-quality output for manufacturers. In this article, we explain the core forming principles and detailed troubleshooting methods for the automatic wide-mouth bottle blowing machine to support stable operation and optimized production.

Automatic Wide-Mouth Bottle Blowing Machine Food Packaging Application

Forming Principle of the Automatic Wide-Mouth Bottle Blowing Machine

The working process of the automatic wide-mouth bottle blowing machine is based on the biaxial stretching orientation of PET material. During the stretch-blowing process, PET molecular chains are extended, oriented, and arranged in both axial and radial directions, which significantly improves the mechanical properties of the bottle wall, including tensile strength, impact resistance, and airtightness.

Temperature Control Range

The forming process of the automatic wide-mouth bottle blowing machine must be carried out between the glass transition temperature and crystallization temperature, generally controlled at 90–120°C. Within this temperature range, PET is in a high-elastic state, allowing fast blowing and stable cooling to form transparent bottles. In the one-step automatic wide-mouth bottle blowing machine, the temperature is mainly determined by the cooling time in the injection stage, so the coordination between injection and blowing stations is critical.

Stretch-Blow Ratio Control

To ensure uniform wall thickness and high strength, the stretch-blow ratio must be strictly controlled on the automatic wide-mouth bottle blowing machine:

•Radial stretch-blow ratio: ≤ 3.5–4.2

• Axial stretch-blow ratio: ≤ 2.8–3.1

• Preform wall thickness: ≤ 4.5 mm

Excessive stretching will cause whitening, cracking, or uneven stress distribution, while insufficient stretching will reduce bottle strength and transparency.

Three Key Actions of Blowing

The automatic wide-mouth bottle blowing machine completes forming in three consecutive actions: stretching → pre-blowing → high-pressure blowing. These three actions are completed in a very short time, but their coordination directly determines the wall thickness distribution and overall forming quality. The key parameters include stretching start time, stretching speed, pre-blow start and end time, pre-blow pressure, and pre-blow flow rate. Controlling the overall temperature distribution and temperature gradient of the preform will further improve the stability of the bottle quality.

Common Technical Problems & Solutions for Automatic Wide-Mouth Bottle Blowing Machine

In actual production, the automatic wide-mouth bottle blowing machine often encounters typical defects caused by improper parameter settings. Below are the most common problems and professional solutions for the automatic wide-mouth bottle blowing machine.

Uneven Wall Thickness: Upper Thick & Lower Thin

This defect is common on the automatic wide-mouth bottle blowing machine when pre-blow parameters are unreasonable.

• Causes: Early pre-blow start time, high pre-blow pressure, excessive pre-blow flow, uneven preform temperature.

• Solutions: Delay pre-blow time, reduce pre-blow pressure, lower air flow, and adjust heating to increase temperature at the bottom of the preform.

Uneven Wall Thickness: Lower Thick & Upper Thin

This issue usually occurs when the pre-blow action is too late on the automatic wide-mouth bottle blowing machine.

• Causes: Late pre-blow start, low pre-blow pressure, slow stretching speed.

• Solutions: Advance pre-blow time, increase pre-blow pressure, speed up the stretching rod, and optimize temperature distribution.

Wrinkles Below the Bottle Neck

Wrinkles near the neck are typical defects of the automatic wide-mouth bottle blowing machine and affect appearance and sealing performance.

•Causes: Late pre-blow, insufficient pre-blow pressure, poor cooling at the neck area.

• Solutions: Advance pre-blow time, increase pre-blow pressure, strengthen cooling for the neck area.

Whitening at the Bottle Bottom

Whitening reduces transparency and is a frequent issue on the automatic wide-mouth bottle blowing machine.

•Causes: Low preform temperature, excessive stretching, early pre-blow, high pre-blow pressure.

• Solutions: Increase bottom heating temperature, reduce stretching intensity, delay pre-blow, lower pre-blow pressure.

Magnifying Glass Phenomenon at the Bottle Bottom

This defect shows a convex bulge at the bottom and is often seen on the automatic wide-mouth bottle blowing machine.

•Causes: Excess material at the preform bottom, late pre-blow, low pre-blow pressure.

• Solutions: Use standard preforms, advance pre-blow time, increase pre-blow pressure.

Wrinkles Inside the Bottle Bottom

Internal wrinkles affect pressure resistance and are easy to appear on the automatic wide-mouth bottle blowing machine.

• Causes: High bottom temperature, poor gate cooling, late pre-blow, low flow rate.

• Solutions: Reduce bottom heating, enhance cooling at the gate, advance pre-blow, increase air flow.

Overall Haze & Poor Transparency

Whole-bottle turbidity is caused by insufficient cooling on the automatic wide-mouth bottle blowing machine.

•Causes: Short cooling time, poor cooling effect, high forming temperature.

• Solutions: Extend cooling time, strengthen cooling system, lower preform heating temperature.

Local Whitening on the Bottle Body

Local whitening is related to uneven temperature and stretching on the automatic wide-mouth bottle blowing machine.

•Causes: Local low temperature, excessive stretching, early pre-blow, stretching rod scratching.

• Solutions: Adjust local heating, delay pre-blow, check centering of the stretching rod.

Eccentric Bottle Bottom

Bottom eccentricity causes unstable standing and uneven stress on the automatic wide-mouth bottle blowing machine.

•Causes: Uneven temperature, misaligned stretching rod, unqualified preform, unreasonable blowing timing.

• Solutions: Lower preform temperature, speed up stretching, check mold centering, delay high-pressure blowing.

Production Optimization Suggestions for Automatic Wide-Mouth Bottle Blowing Machine

To maintain long-term stable operation of the automatic wide-mouth bottle blowing machine, manufacturers should establish standardized parameter settings, regular maintenance plans, and operator training systems. Key points include stabilizing temperature control, strictly controlling stretch-blow ratio, optimizing pre-blow and high-pressure blowing timing, and ensuring sufficient cooling. By implementing these measures, the automatic wide-mouth bottle blowing machine can maintain low defective rates, high output efficiency, and consistent bottle quality.

In summary, the automatic wide-mouth bottle blowing machine is highly sensitive to process parameters, and most technical problems can be solved by adjusting temperature, stretching, blowing pressure, and cooling. Understanding these rules helps manufacturers maximize the performance of the automatic wide-mouth bottle blowing machine and achieve high-efficiency PET bottle production.