The tableware and container glass industry is one that never stops – churning out thousands upon thousands of glass pieces for use in the home or containing products such as bottled drinks and foods.
The glass-forming process is also one of fire and heat! These extreme conditions combined with high production levels mean all the equipment used in the glass production process must go through some pretty tough conditions and be up to the job!
This post is about some of the components used in the glass manufacturing process and how thermal sprays for the glass manufacturing industry can extend their life and keep production running smoothly, particularly on more vulnerable pieces of kit such as glass moulds and plungers.
Moulds & The Forming Process In Glass Manufacture
Many glass items such as drinking glasses and bottles are made using pressing or blowing, or a combination of the two. In the pressing method, molten glass is forced into a mould by a plunger, making the glass take the shape of the mould cavity or, compressed air forces the molten glass to take the shape of the mould.
Once the glass bottle or container has been formed into its final shape, it is usually reheated and then cooled slowly to allow even cooling. This prevents any cracking or other defects. After the glass has cooled it goes on to quality inspection where any items with damage are taken out.
The forming of glass using blowin
g or pressing methods both require the use of moulds.
Because glass moulds must withstand heat and pressure over multiple uses, stainless steel is usually used to manufacture moulds. Moulds are also usually given special surface coatings so that the glass doesn’t stick to the mould, and to preserve the longevity of the mould.
Having moulds in good condition is integral to creating good quality glass containers – the moulds need to be free from contamination and be smooth on the surfaces that come into contact with the glass. This is why in glass production moulds are frequently taken apart for cleaning and inspection. A damaged or defective mould can harm production costing manufacturers money and a loss of production time.
Surface Coatings For Glass Moulds & Other Parts Used In the Forming Process
During the moulding process temperatures of 400c – 800c are reached, so moulds need to be able to withstand heat. They must also be resistant to pressure, chemical reactions that occur when molten glass meets metal, repetitive use, and oxidisation. Moulds also need to successfully release formed glass products. That’s a lot of factors affecting moulds so you can understand why moulds need to be made of the right materials.
Because glassware moulds operate under extreme conditions of corrosion, wear and heat they are also commonly treated with surface coatings to reduce oxidisation and wear, whilst extending the component lifetime.
In glass bottle and glass container manufacturing, the mould, mould neck, and mould base funnel all benefit enormously from the application of an appropriate Flame Spray or HVOF surface coating. HVOF tungsten carbide coatings are frequently used because these types of thermal sprays have a wide range of properties.
At Alphatek, we have developed proprietary HVOF and Fluoropolymer coatings (HYPERGLAZE), especially for the glass industry that offer the ultimate protection for glass mould in even the most challenging of environments.
Because the protective properties of our finishes are so varied, they are also ideal for applying to other components in the glass manufacturing process.
Glass plungers (the parts that push the globs of molten glass into moulds) are particularly vulnerable to heat damage so can also benefit from one of our proprietary coatings. Our coatings can also be applied to glass chutes for maximum protection.
Alphatek Thermal Spraying & The Glass Industry
Alphatek specialises in surface coatings and thermal spraying in a few select areas. One of those is thermal spraying for the glass industry.
With over 25 years of experience, we serve the glass industry with a range of solutions that are designed to enhance the durability of components and extend their life. Our HYPERGLAZE treatment is particularly popular in the industry.
If we don’t already have the right solution for your problem, we can guarantee our technical team of specialists can create one.
If you are in the glass industry and want to work on a project to enhance production and preserve components such as glass moulds and plungers, please contact us.
