Glass containers are a type of container for food storage and usually made from glass. They are often seen as an eco-friendlier alternative to plastic containers and be better for the environment.
Glass containers are also often used in the restaurant industry because they can be washed and reused. It helps reduce waste and increase sustainability.
Glass food containers are inspected for manufacturing defects, physical damage, and chemical contamination.
The QC inspects the containers to make sure that they are safe for use and are not contaminated by any kind of chemicals. The inspection process is very detailed and includes looking at the quality of the container, its design, labeling, testing, etc.
When looking at the external inspection of a glass food storage container, there are many aspects to check for quality standards. We have summarized thirteen points to ensure that you have fully inspected any glass container in professional way.
- If there are any damages present on any part of the surface of the glass container, it should be avoided as this can cause injury if someone handles it too roughly. If there are tears, bursts, chips, and scratches on glassware, it is unacceptable.
- The mouth of the container is a common problem with glass food containers. The mouth is the opening in the top of the container, where you can pour food into it or drink out of it. The bottom of a glass container is also important because this is where you will find any unevenness or skewing.
If there are any problems with these two parts, then it could affect how well your product will be able to be used as well as how safe it will be for consumers.
- The colored glass must not be mixed with recycled materials. The heart of the product must be transparent and white, without other miscellaneous colors. The hue of the colored glass must be stable and pure, uniform and consistent.
- You should always keep the even thickness of the glassware, rather than thin on one side but thick on the other. That is the basic rule during the glassware molding process, either being blown by hand or pressed by machine.
- The glass material should be in a very liquid state, free of any stones (unmelted slag), streaks, vapor bubbles, or other defects that may cause the molten glass to solidify unevenly.
- Glassware that is more than 1cm in diameter should not have any vapor bubbles (except for a special effect glass), and the number of bubbles below the mouth should not be more than 2 bubbles with 2mm or bigger in diameters, or 3 bubbles with diameters of at least 1mm.
Meanwhile, it is not acceptable that any formation of small vapor-filled bubbles are gathered together in the glassware.
- After the glass is finished and de-molded, it should be annealed twice within two hours to ensure more stable quality and prevent the product from bursting.
High borosilicate glass, with a certain degree of thermal stability, can ensure that it won’t break in the time range that is between 600 ° and -20 °. The material must never be heated to a high degree or chilled too low.
- The glass should have no waterlines on the inside and outside of the container and touching it should feel smooth all over without any noticeable textures, e.g., wrinkles, abrasion marks, and shear marks. You should also make sure there are no cracks present or unsaturated defects on the surface.
- The glass must be clean on the inside and outside, with no debris, dust, water stains, glass debris or other imperfections to be found. The glass container must also be clear and without any discoloration or distortion.
Every aspect of the appearance and hygiene of a product impacts the final purchase that is made by a consumer. If there is anything that may make a customer wary, such as dirt or smells, they are less likely to buy it.
Note: (Rust stains on glass products are usually caused by the rusting of the clamp and mold that the glass is clamped in while being heated during annealing. The rust cannot be removed afterward, so it is important to remove rust from the jaws and molds before production to avoid this problem.
It is also important to avoid dust when dissolving the material. (Impurities may fall into the material and cause the product to contain impurities after forming)
- When you’re sticking paper or logo on your glass products, the sticker paper should be flat and in a perfect rectangle shape. It is not acceptable for there to be any uneven lines or wrinkles. If there are any bubbles from the adhesive, they need to be carefully smoothed out and pressed firmly against the glass.
After paper sticking, it should naturally dry for 10 hours before baking, as the flower paper in the immersion will remain wet and small drops of water. Baking will cause small droplets of water to break on top of the flower paper and lead to pinholes.
- Glass product dimensions should conform to the size requirements. The error can not be too large, usually, the maximum error is ±1mm
If you want to assemble the lid or other accessories, more attention should be paid to the internal diameter of the product. This will make it easier to meet the assembly requirements.
- Glass is fragile and one of the most delicate substances on earth, so it needs to be handled with extreme care. The product should be stood upright during transportation from the production line to the packaging workshop.
Every product should be spanned with pearl cotton, and the products should be separated by egg grids so that they cannot collide with one another to produce damage.
- During the inspection process, it is important to check whether the packaging method of the product, the label and content used and if any, the content of manual(s), box mark information are correct. If all information is complete and accurate, you should go further to examine its cleanliness and measure its size.
Glass Container Accessory Inspection
One of the most common problems with glass containers is that they are difficult to open or close securely, especially if you have arthritis or other hand issues.
It is important to inspect the lid of a glass container before buying it to ensure that it will fit properly with the container and it will be easy enough to open and close.
- Each cover inside, whether there is a silicone ring or not, silicone rings must not appear broken. It is important to check the position of the silicone ring before going any further and make sure it is placed correctly.
- The glass container’s cover and silicone sleeve should be clean and free from any type of scratch, damage, or other imperfection. There is no detectable odor coming from the materials.
Our lid has no BPA component in the polymerization production process and will not release BPA in the use process. It meets the environmental requirements.
- To ensure that the color of silicone is correct, it should be tested on a carton color card. It is specially designed for checking the colors of silicone.
Glass Container Quality Test and Inspection
The quality of glass containers is determined by their filling capacity, thermal shock resistance, and adhesion. The filling capacity is the measurement of how much liquid the container can hold. Thermal shock resistance is the ability of a glass container to withstand sudden temperature changes. Adhesion is how well a seal forms between the glass container and its lid.
- Filling capacity: Fill the sample container with water and pour it on the cup, then record this as the maximum volume. Repeat this process 30 times, pouring water repeatedly and recording it each time.
- A matching lid and glassware set should have a tight fit, but there is a limit to how tight the lid can be. It can help protect the glassware but if it’s too tight it will be difficult to pry open and could cause breakage.
Glassware should also be checked for durability and leaks, especially if they’re packaged together. The most important thing is whether the functionality of the lid still works as intended.
- Adhesion test: If glassware has a coating and printing on the lid, use 3M adhesive tape to stick it to the coating. After one minute, quickly tear off the tape. If the coating does not peel off with the tape, then it is safe for use.
- Thermal shock resistance testing.
Thermal shock testing is a process where you test the adaptability of something to sudden changes in temperature. In this test, glass is usually subjected to a high and low-temperature shock tester.
Carton Box Inspection
Look for any signs of wear or tear. Check the corners and edges of the box for any damage or dirt. Also, check for any tape on the outside of the box. It would indicate that someone has tried to fix a tear or broken seal.
The size of the carton box should be measured to make sure that it is the same as mentioned in the carton mark. If you don’t measure it, you will not know whether it meets your requirements or not.
The weight of the carton box should be the same as mentioned in the carton mark. The box weight can be measured by using a scale or by using weights.
An inspection of the box label can be made to ensure that it matches the PO. This is done by checking the box label information.
The paper quality is a good indicator of the quality of the carton box. If the paper is damp or too soft, it might be stored in an area with high humidity and can’t be used anymore.
To inspect the tape that seals the box, you should check if it is properly sealed and if there are any signs of damage on the surface of the tape. If there are any cracks in the seal, it might not be closed properly and may have been tampered with.
The drop box test is used to determine the durability of a carton box. The test consists of dropping the box from a height of 30 feet onto two faces and one corner. A pass is considered if the box can withstand 2 drops on two faces and one corner without any damage.
Color box Inspection / Individual Packaging Inspection (if applicable)
The color box or individual packaging size should be in accordance with the product, and it should also have a bar code. The color and printing of the packaging should be clear, and if it is an individual packing, there should not be any traces of glue on the surface.
The inspection of the color box or individual package is an important part of the PO process to verify that the product ordered matches what was ordered and to ensure that it meets all safety standards.
The color box or individual packaging is sealed with tape that has the company’s name, address, and other information. The seal should be placed on the front of the package and should not be tampered with.
The inspection is the process of checking for defects and flaws in a product. Visual inspection is one of the most used methods for inspecting glass containers.
Visual inspection can be used for different purposes, such as quality control, production line monitoring, and quality assurance. The main purpose of visual inspection is to find any defects or flaws in the product that may have been missed during previous steps in production.
The glass containers are made from different materials, leading to different colors. The glass container’s color can change as it ages or is exposed to different environmental conditions.
The person doing the inspection should look at the logo and pattern on the container and compare them with what was on a sample container. If there are any discrepancies, then it may be possible that something has been spilled or leaked onto the container during production which could lead to contamination of the food inside.
The glass container is a fragile and sensitive product. It is not just about the quality of the glassware, but also the spraying quality.
Spraying quality refers to how well the content is sprayed on the surface of the container. The joints on top and bottom of the glassware should also be smooth and free from any defects.
Vacuum noise is an important indicator of the quality of the glassware. It is a good warning signal that there may be some problems in the manufacturing process or with the glassware itself.
To make sure that your glassware is safe and secure, it is important to check its lid for any defects or damages. If the silicone rubber ring is easy to move or loose, this indicates that there may be a leak in the container. It could result in contamination of your food product.
The main purpose of this visual inspection is to make sure that the container does not have any chips or cracks in it. It is clean and has all of the necessary stickers and texts on it.
Glass Container Inspection Standards
The inspection standards for glass containers are determined by the AQL (Acceptable Quality Limit) sampling. The sampling is done in a manner to ensure that the probability of accepting all items in a lot or batch is equal to or greater than a specified level.
The AQL (Acceptable Quality Limit) sampling is done by picking samples at random and then examining them to see if they meet the clients’ standards. If they meet the standards, then the entire lot or batch is accepted. If it fails, it must be reworked until it meets the standards.
CR: 0 / Major:2.5 / Minor:4.0 / General Level 2 / MIL STD 105E
Glass Container Inspection Procedure
The inspection procedure for glass containers is a process where the quality of the glass container is inspected to meet the standards set by regulatory bodies.
- It is important to make sure all the necessary tools are present before arriving at the factory and contact the person in charge, Quality Control should check with the factory whether there are any issues with the number of goods available and go to the warehouse to verify there is enough stock.
- Once you have determined the desired quantity, Quality Control can then draw the box. The principle behind sampling is to draw the boxes evenly and that carton boxes should be drawn from different parties on average and pay attention to whether or not the factory has any empty boxes.
The number of drawn carton boxes is the square root of the total. For example, if the total number of boxes is 100, the number of drawn boxes should be 10 boxes; if the total number of boxes is 80 boxes, then 9 should be drawn.
- Another important step in production is to make sure that the stamp is placed on the carton box before it goes to inspection. This will ensure that there are no changes made to the following process of putting it on the shelf.
- After picking the carton boxes and sending them to the inspection station, you need to verify that they were picked by the Quality Control department before release. To do this, you need to check the chop mark on each box.
- The inspection is usually carried out in the factory’s inspection room with a bright lamp and a color difference determined in a standard light box, using a standard indoor light source.
The sample is held at eye level for roughly half a hand’s length (roughly 8 inches) and each fitting is inspected for around three to four seconds.
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