For many manufacturers of glass bottles, receiving a myriad of quality issues from customers each year can lead to complaints and losses for both parties. The root cause often lies in inadequate quality control during the manufacturing process. Let's delve into some essential quality control measures:
Mold Inspection:
Most glass bottle manufacturers rely on molds provided by customers or newly developed molds based on drawings or sample bottles. Key dimensions affecting molding must be communicated and negotiated with customers immediately upon mold opening to ensure consensus on modification suggestions, which significantly impacts the yield and molding effect of subsequent products.
All molds must be inspected for mouth molds, initial molds, and final molds upon arrival, in accordance with drawings or customer requirements.
Piece Inspection:
Before entering the annealing line after mold installation, the first 10-30 products produced per mold should be inspected for dimensional specifications, including mouth size, inner and outer diameters of the neck, correct and clear engraving on the bottom, and accuracy of the bottle body pattern.
Immediately after the bottles come out of the annealing line, 2-3 products per mold are selected by the quality inspection team leader for comprehensive inspection according to the drawings. Additionally, volume measurement, weight measurement, inner and outer diameters of the neck, and, if necessary, filling the bottle with water to test the sealing with the supplied cap and leakage are conducted. Furthermore, internal pressure, internal stress, and acid-alkali resistance tests are performed.
Process Inspection:
Without changing molds, every 2 hours, 2 products per mold are sampled for volume and weight inspection during the process. Additionally, inner and outer diameters of the neck are checked, as oil residue tends to accumulate on the neck mold during use, causing loose sealing of the cap and wine leakage.
During the process, new molds may be installed due to mold-related reasons. Therefore, the quality inspection department must immediately notify the production department. The quality inspection department must conduct piece and process inspections of bottles produced with new molds to prevent quality issues caused by unnoticed inspection after mold change.
Full Inspection:
After coming off the annealing line, quality control personnel conduct a full visual inspection of all products. This includes:
Checking for bubbles on the bottle surface, neck misalignment, uneven bottoms, seam thickness, color consistency, neck dimensions, and any defects affecting appearance or functionality.
Incoming Inspection:
Quality management personnel sample finished products awaiting storage according to an AQL counting sampling plan. Samples are taken from various parts (top, middle, bottom) to conduct rigorous inspections according to standards or customer requirements. Qualified batches are immediately stored, while non-conforming batches are marked, isolated, and returned for rework until they pass inspection.
Frosting Process Bottle Inspection:
Reddish coloration may occur due to excessive temperature or slow conveyor speed, causing a reduction reaction in the decolorizing agent.
Poor adhesion of frosting paper may result from low temperature. Adjustments should be made based on different frosting paper materials and required temperatures.
Blisters on the frosting paper may occur if air bubbles inside the paper are not removed or if the surface is not completely dry before frosting. Non-conforming products can be scraped off with dilute hydrochloric acid and re-frosted.
Mixing bottles with different degrees due to identical bottle shapes but different frosting degrees can lead to customer complaints and quality incidents during labeling, frosting, inspection, and packaging.
For comprehensive quality control in glass bottle manufacturing, meticulous attention to detail and adherence to standards at every stage of production are crucial. With these measures in place, manufacturers can minimize quality issues, enhance customer satisfaction, and maintain their reputation in the industry.
For more insights into glass bottle manufacturing and quality control, visit De varo Packaging.
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