Common quality defects of Glass Packgaings - Maypak

June 19, 2024

Introduction: Glass packaging is one of the most commonly used packaging materials among cosmetic packaging materials, except for plastic products and paper products. Due to the convenient molding method of glass packaging, good customer experience, and the various post-processing methods of glass packaging, It can present different features to the brand, so it is very popular in the cosmetics industry ( Mini Glass Perfume Bottle / Glass Cosmetics Set / Hand Sanitizer Glass Spray Bottle ) !  However, the bottle mouth, bottle body, bottle neck and other parts of glass packaging are prone to quality problems caused by factors such as materials, molding processes, molds, etc. This is also a major problem for brand selection. In this article, we share the common quality problems of glass packaging for the reference of customers and friends:

1. Names of Parts of Glass Bottles

01. Inner diameter, outer diameter of the mouth, sealing surface, thread, meson or ball ring, the above components are collectively called the mouth

02. The root of the bottleneck, the bottleneck, the bottle shoulder, and the bottle body. The bottle body has the initial mold seaming line and the final mold seaming line.

03. The base of the bottle, the bottom line of the mold, and the bottom of the bottle. The bottom of the bottle has a bulkhead line and most products have explosion-proof lines.

2. Common Glass Bottle Mouth Names

Crown mouth, three-turn mouth, four-turn mouth, threaded mouth, anti-theft mouth, meson mouth, pull ring mouth.

3. Quality Related Terms

01. Deep cracks: Deep cracks on the glass surface. The depth of such cracks usually exceeds 2mm. The shape can be vertical, such as an oral cleft, or the suture line can be radial. Like a crack at the bottom of a bottle.

02. Crack: A crack less than 2mm deep. Such cracks are usually reflective and appear horizontal or diagonal. Such as: headshot, neck root shot, neck shot.

03. Hairline crack: A surface crack of any length that does not penetrate deep into the glass and is not as reflective as a "deep crack". The surface of the fine cracks has small ripples. Not as straight as "deep cracks" and "cracks". For example: shallow cracks or fine cracks on the bottle that are often seen during normal inspections.

04. Crack: An unbroken gap on the glass surface that can be felt with fingernails or scratched by touch. Appears inside and outside the bottle. Unlike deep cracks and cracks, it is not reflective. Available in different lengths and widths.

4. Description of Common Quality Ddefects

01). Serious defects:

● Endangering personal safety, such as: cracking of the mouth and broken glass in the bottle. The customer cannot function normally. Such as: severe deformation, insufficient mouth.

● Sticky thread in the bottle: there is a glass thread in the bottle facing each other.

● Glass stuck to the outside of the bottle: Glass stuck to the outside of the bottle is usually quite sharp. That is, after the hot end is formed, the bottle is at a high temperature, and the two bottles come into contact with each other and stick together. Separate after reaching the cold end.

● Glass stuck in the bottle: Three defects including punch sticking and spikes in the bottle are all produced during hot end molding. Glass stuck in the bottle means that when the bottle is at high temperature, the glass block falls in and sticks to the inner surface of the bottle, but it may Appears on the bottle. There is a small sharp glass protrusion on the inner wall of the punch bottle head. A bottle spike is a sharp protrusion of glass on the inner surface of a glass bottle, usually near the bottom of the bottle.

● Cracks in the inner wall of the bottle (inner cracks): The inner surface of the bottle is cracked with cracks of any length and width, wide enough for a fingernail to enter. It has the same shape as the crack line. It is classified as a serious defect because cracks occur inside the bottle when some products require high-temperature sterilization or are filled with inflatable materials, resulting in broken glass and endangering human safety.

● Flying thorns at the mouth (double openings inside and outside), burrs on the inner edge of the bottle mouth (burrs at the bottle mouth) Flying thorns at the mouth:

● The inner diameter edge of the bottle mouth is protruding and is a piece of annular glass. When it is an outer double mouth, it is often accompanied by an increase in bottle height or unequal bottle mouth. Burrs on the inner edge of the bottle mouth: Tiny glass pieces protrude upward partially on the inner edge of the bottle mouth. These two defects affect the sealing performance of the cap and cause the crushed glass to fall into the bottle.

● Thin-skinned bubbles (broken bubbles): The bubbles inside and outside the bottle or on the sealing surface of the bottle mouth are too soft and will burst when the bottle is used normally. They can be penetrated by scraping with your fingernails.

02). Bottle mouth defects

● Bottle mouth flanging (convex mouth) and mouth mold damage: glass pieces protruding horizontally outward from the outer edge of the bottle mouth. Damage to the mouth mold: A small piece of glass protrudes from the seam line and sealing surface as well as the joint with the preliminary mold. Use a vernier caliper to align the defective part and measure it. This usually results in the outer diameter of the mouth exceeding the standard or affecting the smoothness of automatic capping. .

● Cracks at the bottle mouth (deep explosion), fine cracks on the sealing surface of the bottle (shallow explosion): Deep explosion is different from shallow explosion, it explodes deeper, and the cracks often extend from the inner edge to the outer edge, shallow explosion is Shallow cracks on top edge of bottle. The reflection of the cracks can only be seen through the refraction of light. Therefore, it is easier to miss detection. For products with high sealing requirements, such as beverage bottles, chicken essence bottles, bird's nest bottles, etc., after filling and capping bottles with shallow openings and leaving them for three to five days, you will find that the vacuum safety button bulges, air leaks, and the inside of the bottle Things will go bad.

● The depression (notch) in the bottle head is also called "through tooth"

● The inner diameter of the bottle mouth is too large. Transparent teeth: The glass on the inner wall of the bottle mouth is obviously unevenly distributed and deformed. If you touch the inside of the mouth, you will obviously feel that it is in an orphan shape and is concave inward. The inner diameter of the bottle mouth is too large: the inner diameter of the bottle mouth is larger than the design requirements. These two defects will cause leakage when some internal plugs are required.

● The drum mouth and bottle ring are too large: The drum mouth refers to the bottle mouth bulging outward. The bottle ring is too large: the bottle head size exceeds the upper limit of the standard. The drum mouth will also cause the bottle head to exceed the standard size. The cause is caused by improper operation, and the excessively large mouth ring is caused by the mold.

● The bottle mouth is cracked and the bottle mouth is damaged: the flange ring of the bottle mouth is missing and the thread of the bottle mouth is damaged, both of which collapse due to impact. Just the location where it appears is different.

● Bottle mouth cracks (exploded mouth) and thread explosion: bottle mouth cracks are cracks in the middle of the bottle head, and threads are cracks between the threads of screw-top bottles. Cracks in the convex ring of the bottle mouth (burst ball ring) and cracks under the bottle mouth ring (burst chin). The cracks on the lower edge of the bottle head below the ball ring are called burst ball rings. A chin pop is a crack at or near the seam line between the ball ring and the bottleneck.

● Rough bottle mouth (rough mouth): The surface of the bottle mouth is rough due to poor finish of the mouth mold. Some products with strict quality requirements are not allowed. Examples: Vita milk bottles, beer bottles.

● Disc-shaped mouth, uneven bottle mouth, tilted bottle mouth: The inner edge of the bottle mouth is straightly sunken due to the incomplete mouth edge, which looks like a hare lip, and is often accompanied by insufficient mouth or uneven mouth. The bottle mouth is uneven: the distance between the highest and lowest points of the bottle mouth exceeds the standard requirements. This defect must be detected with a ribbed feeler gauge. The bottle mouth is tilted: that is, the parallelism exceeds the standard, and the difference between the maximum and minimum values from the bottle mouth surface to the bottom of the bottle exceeds the standard requirements.

● Insufficient threads and too small bottleneck ring: The bottleneck thread is insufficiently formed, which in severe cases will cause the outer diameter of the thread to be too small. The bottleneck is not too small: the bottleneck dimensions are smaller than the standard lower limit.

03). Bottleneck defect

● Clamp cracks (clamp blast) and bottleneck cracks (neck blast): Cracks caused by bottle clamps are shaped like a crescent and appear at the bottom of the meson. Cracking is a crack in the neck of a bottle, usually a horizontal crack.

● Bottleneck folding, neck grabbing, bottle shoulder/neck collapse: obvious deep creases on the glass surface, usually at the bottle neck. Grabbing the neck means bottleneck deformation, and shoulder and neck collapse means insufficient air blowing into the bottleneck or shoulders.

● Crooked neck and crooked body: Crooked neck means that the bottleneck is not straight, which affects the parallelism index. Use a height ruler to measure the height of the bottle. The difference between the lowest point and the highest point can determine the degree of crooked neck. Crooked body; the deviation between the center line of the bottle mouth and the vertical line at the bottom of the bottle, the vertical axis turntable can detect the crooked body, and the height ruler cannot be used.

04). Bottle defects

● Explosion, shallow explosion: a short and deep crack, caused by the surface of the hot bottle being in contact with cold objects such as metal after molding, and the crack is reflective. Shallow cracks; shallow cracks on the surface of the glass that are of variable length, do not penetrate deep into the glass, and do not reflect light.

● Bottle crack line: An open crack on the outer surface of a bottle. It feels scratchy to the hand.

● Cold mold: Because the mold temperature is too cold, the outer surface of the glass is rough, the glass is unevenly distributed, and the hand feels uneven.

● Wrinkles: Small horizontal wrinkles on the outside of the bottle that are densely packed laterally.

● Crease: A slight crease in the surface of the glass. Usually this crease is almost horizontal.

● Blanking mark: The glass mark formed by blanking on the upper part of the bottle. There may be air bubbles around. Its shape is irregular.

● Bottle body dent: After the bottle is formed, the bottle wall is squeezed, forming an obvious or inconspicuous dent. As a result, the out-of-roundness of the bottle exceeds the standard or the diameter of the bottle is too small at some point.

● Small bottle body: The overall diameter of the bottle body is smaller than the standard lower limit, which may result in unqualified capacity or failure to label.

● Hot mold cracks: usually appear on the bottle body. Shaped like a seagull.

● Blast seams: Cracks that usually appear on the bottle body at the mold seams.

● Burst shoulder: Vertical cracks in the shoulder of a bottle.

● Deep cracks at the root of the bottle: deep cracks at the root of the bottle.

● Damage to the first mold: a sharp glass dent in the outside of the bottle.

● Mold damage: protruding glass from the outside of the bottle.

● Exploded Letters: There are shallow cracks extending outward around the lettering.

● Explosion positioning: locate surrounding cracks.

05). Defects at the bottom of the bottle

● Bottom crack: A shallow crack at the bottom of a bottle.

● Bottom burst: deep cracks in any direction on the bottom of the bottle, most of which are radial.

● Concave bottom: The center of the bottom of the bottle is abnormally concave.

● Convex bottom: The center of the bottom of the bottle protrudes outward. The bottle is placed on a flat plate and swings unevenly.

● The bottom of the bottle is uneven: The deformation of the bottom of the bottle makes it unstable on a flat surface. Rocking unevenly.

● Damage to the bottom of the mold: Damage to the bottom mold causes the glass at the bottom of the bottle to bulge.

● Mold bottom line: glass penetrates into the joint between the mold and the bottom mold or causes flying burrs due to poor cooperation between the bottom of the mold.

● The bulkhead line is incorrect: the bulkhead line is not in the center of the bottom of the bottle, but is offset to one side.

● Offset bottom: The inside of the bottom of the bottle is obliquely wavy, but the inclination exceeds the specified requirements. Usually the bottom ratio is: 1:2mm control.

● Thin bottom: The bottom glass is insufficient and cannot meet the design requirements. The bottom may also lead to a thin bottom.

06). Suture line defects

● Seam line cracks (burst seams): Vertical cracks at the seam line of the molding. Its shape is different from hot mold cracks.

● The stitching of the initial mold is poor: the iron bowl line of the bottle body is convex and sharp. After molding, the initial mold line is depressed.

● The burrs of the molding seam line are: protruding burrs at the molding seam, which are opposite in shape to the initial molding seam line.

● Wrong molding seams: The two halves of the molding die do not match well, and the joint seam line is stepped. One high and one low.

● The bulkhead wire is too deep: the glass enters the initial mold and the bulkhead seam forms an obvious zigzag seam. Visual inspection revealed that the bulkhead line was obviously dented.

● Bulkhead hairy thread (rotten bulkhead line): The bulkhead line forms a raised and jagged shape at the joint between the bulkhead and the iron bowl.

● Bottle mouth/preliminary molding seam burrs: The connection between the mouth and the iron bowl is not smooth and forms raised, stepped or jagged seams.

07). Measurement defects

● The bottle is too large: the diameter of the bottle exceeds the standard upper limit. When the bottle body is dented, it may also cause the diameter of the bottle to be too large at some point.

● Bottleneck obstruction (narrow neck): The inner diameter of the bottleneck is smaller than the specified requirements. Some products indicate the effective length of the inner plug on the design drawing according to the customer's filling tube requirements. If there is a narrow neck, it is not acceptable. Products without special requirements shall be judged by visual inspection.

● Bottleneck Inner Ring: The concentric ring of glass in the upper part of the neck or body of a bottle.

● The inner diameter of the bottle mouth is too small: the inner diameter of the bottle mouth is smaller than the specified requirements. It can be measured with a plug gauge or vernier caliper. Double openings may result in a smaller inner diameter.

● Super high: The bottle height exceeds the standard upper limit. The elongation of the bottle neck may also cause the bottle height to exceed the standard.

● Short bottle: The height of the bottle does not reach the standard lower limit, the bottle shrinks too much or the bottom of the bottle will cause the bottle to be short.

● The bottle is not round: Ovality is a deformation of the bottle cross-section from a circle to an ellipse, usually expressed by the difference between the long and short axes of the ellipse. That is: the difference between the maximum value and the minimum value of the same initial measurement surface during one rotation exceeds the standard range of bottle out-of-roundness.

● The bottle body is bulging: the bottle body is deformed and protrudes outward beyond the specified requirements.

*Maypak packaging is Glass Packaging Manufacturer and has been focusing on Glass Packagings for more than 17 years and was established in 2006,the company enjoys a good reputation at home and abroad. If you have any questions about lipstick tubes, please contact us.

Basic Information
  • Year Established
  • Business Type
  • Country / Region
  • Main Industry
  • Main Products
  • Enterprise Legal Person
  • Total Employees
  • Annual Output Value
  • Export Market
  • Cooperated Customers

Send your inquiry

Choose a different language
Current language:English