Depending on the raw materials used in the manufacture of glass, glass bottles can be split into three main types that include the following.
● Borosilicate Glass: This is a heat-resistant glass that is used to make glass appliances that are used for high-temperature processes like lab beakers and tubings that are exposed to high temperatures every day.
● Treated Soda Lime Glass: Soda-lime glass is made when crushed glass is added to the main raw materials or cullet. The amount of cullet that’s added is what influences the final structure of the glass. Overall, cullets melt at low temperatures, and this makes glass through this method faster. However, the final products cannot withstand high temperatures either.
● Treated Soda Lime: This is the same version of soda-lime glass, but one which has some chemicals added to further fortify the structure or change the color of the glass. It is a little stronger than regular soda-lime but weaker than borosilicate glass.
Bottle Glass Making Processes
Blown Glass Process
Also known as the molded glass process, this is where the air is blown into heated gobs of aqueous glass to create cavities that eventually cool down to form bottles. The process begins with the heated and melted forms of glass being removed from the furnace quickly and placed on molding machines where hot air is quickly blown into them to produce a neck and a rough container shape before any cooling is allowed to take place.
Once the container is shaped, the process requires another round of extra methods that are necessary to give it the final shape. These two processes are briefly discussed below.
● Blow and Blow Process: In this step, hot and compressed air is used to fashion the hot gob into a parison that now becomes the neck and the body of what will become the final bottle. The parison is then flipped quickly to the other side of the molding machine, where more hot air is blown through it to give it the final desired shape.
● Press and Blow Process: In this process, the plunger is inserted first into the gob and then air directed into the created cavity to quickly transform the gob into a parison. This is the best method used when it comes to controlling the shape of the bottle mouth. With the addition of other refined techniques like the vacuum assist process, this method can be used to create super narrow necks and mouth openings.
Tubular Glass Forming Processes
This is a process of glass bottle making that involves the continuous draw of hot air into the melting gob to create a tubular shaped cavity. This is the process you go for when you want to achieve uniform diameters and thickness. There are two processes that are used in this method, and they include the following.
● Danner Process: Here, the glass flows straight from the furnace in the form of a ribbon towards the forehearth. The tubing sizes here range from 1.6mm to 66.5mm in diameter, with a drawing rate of up to to 400m per minute for smaller sizes. The ribbons then fall on the upper end of a refractory sleeve that’s carried by a hollow shaft that continuously forms the bottle.
● Vello Process: In this, the glass is allowed to flow into a bowl, where the shaping process begins. A hollow vertical mandrel is directly mounted into the bowl, and the glass flows through an annular space that’s found between the ring and the bell. The process continues weaving itself in this manner, producing bottles along the way.
Once the shape of the bottle has formed, the still hot bottle is passed on to the final section of the glass bottle manufacturing process. This final phase comes in the form of four main processes that are briefly discussed below.
● Conditioning: Also called the annealing process, the finished bottles are loaded into a machine called the Annealing Lehr, where they are heated up again until their temperature reaches over 800 degrees. This is to eliminate all the stress that may have built up in the structure. Without conditioning, the glass would shatter at the slightest of touches once allowed to cool.
● Surface Treatment: This is the external treatment that the bottle undergoes with the aim of reducing and preventing abrading, a condition that makes the glass prone to breakages and cracks. Usually, a fine film made of polyethylene is sprayed across the surface of the glass bottle to form a tin oxide coating which prevents the bottles from sticking to each other when they come into contact.
● Internal Treatment: This is a process that involves the addition of an Internal Fliurnation Treatment (IFT) to reinforce the glass further and turn it from Type III to Type II to prevent another defective process called blooming. Here the tin oxide treatment is also applied. Before it begins, the temperatures are reduced to 135 degrees for it to work. Once that’s done, the coating can then be washed off, leaving the glass bottle stronger.
● Quality Inspection: After all is done and the glass bottles have attained the shape and size desired, the final part is to conduct a quality check to ensure that everything has come out ecstasy as required. This process involves things like measuring their weight, checking the dimensions, the transparency, and any other necessary checks for any cracks or discoloration. The process also involves checking wall thickness, damage detection, sealing abilities, base and sidewall scanning, and dimensional analysis.
● Branding: Once the glasses have passed the quality inspection, they can now be branded and packaged or, depending on the request of the client, they can be shipped as they are.
Making glass bottles is not that hard, and this is the reason why they are mass-produced all over the world. There are many new innovative ways of making bottles that most glass manufacturers are turning to in a bid to find renewable raw materials. If you have been thinking of starting out in the glass bottle manufacturing industry, then make sure you have done your due diligence beforehand. For more information on glass-making processes, check out our website and have any questions you may have answered by our team of experts.