The glass is removed from the tempering furnace once the process is complete, and everything appears to be in perfect condition. However, upon closer inspection, you realise that something is amiss: distorted reflections and undulations affecting the flatness of the surface. In short, the result is nothing like what was expected, and the sheet has to be discarded.

In many cases, the culprit is roller wave, a defect that originates inside the furnace during tempering and which unfortunately becomes apparent due to suboptimal handling.

Have you ever experienced this nightmare? If so, you certainly wouldn’t want it to happen again: having to discard sheets, wasting material and time on unexpected rework, and losing customers’ confidence in your work while they wait.

However, you can avoid all these problems by using specialised technologies to minimise the risk of tempering defects on glass sheets. Such technologies are found in Mazzaroppi furnaces.

What is a roller wave?

It is a surface undulation that forms on glass during the tempering process. It is not a random or unpredictable defect; rather, it is the direct result of the way the glass behaves when it is in a plastic state, i.e. at a high temperature, as it flows over the furnace’s transport rollers.

At this stage, the glass is extremely malleable. Local differences in pressure, temperature and speed between the rollers and the sheet of glass cause micro-bends to form, which repeat along the direction of travel. In the most severe cases, the result is visible to the naked eye: optical distortions, loss of flatness and altered reflections.

However, roller wave is not merely an aesthetic defect. It has tangible consequences for product quality and regulatory compliance. The European standard EN 12150-1, which governs toughened glass for the construction industry, includes a section dedicated to measuring roller wave and establishes maximum permissible values. Glass exceeding these limits is not considered compliant.

Roller wave is particularly critical in applications where optical quality is under constant scrutiny, such as curtain walls and structural glazing. In these contexts, the distorted reflection is visible to anyone passing by the building. Similarly, in high-end windows and interior glass features, aesthetic appeal is an integral part of the product, so such an imperfection would be unacceptable to the end customer. Finally, in automotive and display glass, optical tolerances are even more stringent. In all these contexts, glass with visible roller wave is not just imperfect; it is unsaleable.

So, how is roller wave detected?

This is not always straightforward: at first glance, the sheet may appear intact, and the defect only becomes apparent when the surface is observed at the correct angle or using specialised instruments.

This is why Mazzaroppi systems are equipped with a zebra-striped optical panel at the furnace exit. This high-contrast striped pattern reflects on the surface of the sheet and reveals optical distortions and geometric deformations that would be invisible to the naked eye. This is a non-destructive, practical and particularly useful method of monitoring continuous production.

For those looking to go beyond visual inspection, Mazzaroppi systems can be integrated with automatic end-of-line scanners that can measure flatness, deformation and optical distortion in real time. This data can then be linked to systems that monitor the furnace’s operating parameters, thereby transforming quality control into a continuous, automated and traceable process. This ensures process repeatability and consistent quality standards.

Mazzaroppi’s technological solution to the roller wave problem comes into play at the most critical moment of the process

Mazzaroppi furnaces feature an intelligent, integrated glass handling control system based on continuously variable kinematics, which is capable of self-adjusting throughout the entire process cycle. The system does not use fixed parameters set in advance; it adapts in real time to the specific characteristics of each sheet of glass, such as type and thickness, by dynamically modifying accelerations, speeds and movement profiles.

All of this is made possible by high-precision servo motors, which enable precise control of each stage of the handling process. This control is particularly important during stages when the glass is at a high temperature and the risk of viscous deformation is greatest, as the sheet is most vulnerable at this point as it passes over the transport rollers.

The principle is simple: if micro-deflections causing roller wave arise from variations in pressure, speed and temperature between the roller and the glass, the solution is to ensure smooth, continuous, adaptive movement. By applying real-time control cycle by cycle and sheet by sheet, the mechanical and thermal stresses responsible for the defect are significantly reduced, resulting in a tangible and measurable improvement in the flatness and optical quality of the toughened glass. The proprietary Mazzaroppi technology that achieves this is called M No Roll – Roller Wave Intelligent Setting and was designed and tested by the Mazzaroppi technical team. Reducing defects is the most effective way to add value to glass, avoid waste and complaints, and ensure the consistent excellent quality of the finished product.

To ensure you’re getting the best results from your tempering process and that your system is truly energy-efficient, contact the Mazzaroppi team for a free Energy Saving Check.

This analysis of your furnace’s energy performance will tell you how much you could save on your energy bills by choosing a Mazzaroppi solution. If you don’t yet have a furnace, the check will show you how quickly you can recoup your investment with a Mazzaroppi system thanks to its low energy consumption and excellent hardening results.

Call us to find out more.

Regular maintenance is essential to keep any equipment in perfect working order. For a glass tempering furnace, which is subjected to high thermal stress daily, regular checks are vital for ensuring optimal performance and a long lifespan.

If you have invested in a high-quality, long-lasting furnace, regular maintenance is what will enable it to support you in your work for decades.

Why is maintenance so important?

Good maintenance ensures:

• uniform heating,
• consistent quality of tempered glass,
• safety for operators,
• longer system life.

To achieve this, it is useful to plan daily, weekly and monthly checks, as well as more thorough inspections at regular intervals. Many of these activities can be carried out directly by operators and performing them consistently minimises the risk of machine downtime.

Daily checks:

Every day, it is important to:

• Keep the furnace clean by removing dust and residues.
• Check the ceramic rollers and internal surfaces.
• Check operating parameters (temperature, pressure and ventilation).
• Pay attention to any warning lights or alarms. Often, the manufacturer can intervene remotely to quickly resolve minor problems.

Weekly checks:

At longer intervals, it is necessary to:

• Keep electrical panels clean and ventilated.
• Check and replace air filters if necessary.

Monthly checks:

Every month (or every few months), it is recommended to:

• Thoroughly clean the ceramic rollers.
• Check the cooling section and remove any residues.
• Check that the heating chamber is clean and, if necessary, remove any remaining glass residue.

Annual checks:

• Lubricate gearboxes, motors and bearings according to the manufacturer’s instructions.

Additional tips for maintaining the efficiency of your oven

• Document every intervention, including the date, operators and activities carried out, as well as any anomalies found.
• Assign clear responsibilities for each check: if it is not clear who is responsible for what, checks are likely to be skipped.
• Raise awareness among operators during the installation phase.
• Increase the frequency of inspections in dusty or particularly harsh environments.
• Seal the furnace in case of prolonged downtime, and perform a complete check before restarting.

In order to require low maintenance, what should a glass tempering furnace be like?

A furnace designed to require little maintenance must:

• be constructed of high-quality materials,
• ensure uniform and accurate temperature control,
• have robust mechanical, electrical and electronic components,
• use efficient and adjustable cooling systems,
• integrate intelligent remote control and monitoring systems.

The Mazzaroppi approach

At Mazzaroppi, we design and manufacture energy-efficient, long-lasting glass tempering furnaces. We use only the highest quality European materials and provide continuous assistance, both remotely and on site.

During installation:

• we train operators on how to use the machinery and on maintenance procedures;
• we set up production recipes;
• we demonstrate all the necessary operations for smooth and safe use;
• we remain in constant contact, both remotely and in person, to assist with any requirements.

We also carry out regular and ad hoc maintenance, as well as upgrading and revamping our systems for those who wish to improve performance after decades of operation.

Would you like a long-lasting tempering furnace?

Contact us today for more information — we’re always happy to help!

Purchasing a glass tempering furnace is a strategic decision that represents a significant milestone for any glassworks or company.

It not only raises your technological level, but also allows you to enter a more competitive market and offer new processes to customers.

For many businesses, it is a significant investment that requires careful consideration to avoid unpleasant surprises and ensure a quick and lasting return on investment. This is why it is important to carry out the necessary assessments before making a purchase.

So, what questions should you ask yourself before buying a glass tempering furnace? Here are the main aspects to consider.

Is building work required?

Many people think that installing a tempering oven inevitably involves invasive structural work, such as adapting the premises or changing the layout of production areas. While this may have been true of older generation ovens, today’s technology has advanced significantly.

A compact and carefully designed furnace, such as Mazzaroppi’s TP Compact, for example, can be installed in confined spaces without the need for building work or a supporting wall. This results in faster installation times, lower costs, and above all, fewer interruptions to ongoing production.

Do I need to rebuild the electrical cabinet?

The installed power is one of the most important factors to consider when purchasing a glass tempering furnace. Many traditional systems, particularly larger ones, require dedicated electrical cabinets and significant upgrades to the internal network. This can result in unexpected expenses and system downtime.

It can take up to a year before your furnace is operational, and this will require considerable additional expenditure.

The solution is to choose a furnace that operates at a low power level without compromising the quality of the tempering process. Thanks to specific, optimised software, it is now possible to limit power consumption peaks.

Mazzaroppi’s patented M Efficiency 5.0 software ensures that glass from 4 to 19 mm can be tempered with only 180 kW installed. This means the system can operate without requiring dedicated electrical cabinets, resulting in significant time and cost savings.

How much does it consume?

Consumption is a variable that directly affects the profitability of the investment. It is not enough to know how much the furnace consumes when it is ‘up and running’; you also need to assess its consumption when it is not producing.

For example, a furnace with a Start&Stop function can be turned off at the end of a shift and back on again in just half an hour. This avoids hidden costs associated with maintaining the temperature during periods of inactivity.

Additionally, an advanced convection management system adapts power consumption to the type of glass and percentage of oven filling, significantly reducing consumption. Meanwhile, rapid thickness change systems enable switching from 4 mm to 19 mm glass without lengthy downtime.

Is it user-friendly?

Unfortunately, the shortage of skilled labour is a widespread problem that cannot be ignored when deciding to purchase new machinery.

Although a tempering furnace is a complex machine, it can be designed to be user-friendly. This involves intuitive interfaces, preset cycles, rapid assistance and the ability to monitor parameters remotely.

A user-friendly furnace reduces operator errors, shortens staff training times, and ensures consistent product quality.

Do you think it’s impossible to find energy efficiency, ease of use and high performance in a single furnace? Fortunately, this is not the case.

Mazzaroppi’s glass tempering solutions are the most energy-efficient on the market. They guarantee energy savings of up to 70% compared to competing furnaces while offering excellent performance and guaranteed ease of use.

We are committed to making tempering accessible and straightforward for glassworks and companies of all sizes, helping even the smallest businesses to grow and optimise their investment.

Would you like to find out more about our furnaces?

Call us with no obligation to ask your questions.

An inefficient transition between different glass formats can cause real problems during the tempering process. It’s not just a matter of wasting time; unfortunately, there are real risks to the success of the process, which could be irreparably compromised.

So, how can these problems be avoided? The answer lies in choosing a glass tempering furnace that is optimised for smooth and fast format changes.

Here are the main risks that can be avoided with this type of furnace.

The management problems of a format change that is too slow…

First, let’s address the critical issues related to your production rates. As you are aware, if a cog jams, it can disrupt all the programmes in your production ‘machine’.

If this problem is not an unexpected event, but rather a recurring risk — as is the case with a format change that is too slow — you will lose time and money with every hardening cycle.

Increased downtime

A slow format change reduces productivity, causing unnecessary machine downtime and slowing down overall production.

Need to temper only in series

If the format change takes too long, you cannot switch from one type of glass to another as and when required, but must schedule long series of identical glass tempering.

This reduces your flexibility.

Energy waste

While waiting to switch from one format to another, furnaces often remain on but are not producing, resulting in increased energy costs. If you find yourself in this situation all the time, it will certainly be noticeable on your bill.

Risk of operational errors

Working times that are too long can lead to carelessness or errors in parameter adjustment, which can result in defects in the tempered glass.

… and technical problems

The speed at which the format changes also has a direct impact on the quality of glass tempering.

Thermal unevenness

A slowdown in format change can result in the glass being heated unevenly. This increases the risk of spontaneous breakage or fragmentation defects.

Glass deformation

If the furnace is left inactive or on standby for too long between formats, and the glass is not heated or cooled evenly, it can become deformed, for example by warping or undulating. These imperfections affect the appearance, flatness and functionality of the final product, for example softening or optical distortion (e.g. distorted reflections on the glass).

Increase in surface defects

Inefficient format change management can introduce surface defects, such as scratches or inclusions, which act as trigger points for breakage during or after tempering.

Risk of accidents

If the glass has not been tempered correctly, it is more likely to break and endanger the safety of operators. Accidental breakage of a glass sheet can pose a serious danger to nearby workers.

A fast and safe changeover is essential to guarantee you a smooth and flexible production of your tempered glass, as well as to contain the consumption of your furnace.

Mazzaroppi’s ovens are the most energy-efficient on the market because they can assure you excellent tempering with consumption up to 70 percent lower than competing solutions – thanks to proprietary technologies designed and manufactured to optimize tempering yield and efficiency.

The M Adapt – Thickness Change Responsive System, for example, is a technology that ensures responsive thickness changes, eliminating unproductive waiting times. Mazzaroppi furnaces adapt quickly and flexibly to the production needs of glassworks and companies, enabling consecutive changes to the thickness of the batch or the type of glass without any waiting time.

The principle behind Mazzaroppi technology is simple: the furnace should adapt to the production needs of the moment by automatically changing the process parameters, rather than the company having to adapt to the furnace’s functionality.

This eliminates waiting times for format changes and reduces unproductive energy costs.

Would you like to know how much you could save with a truly energy-efficient glass tempering furnace?

Request Mazzaroppi’s free Energy Saving Check and we will show you how to guarantee up to 70% lower energy consumption than competing solutions, while avoiding material and time wastage and always achieving the best possible results.

Call us to find out more.

Cameo Glass is an important British company specialising in the production of customised glass solutions. For its site in Swindon, about an hour and a half from London, it chose a Mazzaroppi TP Compact furnace. A choice that makes us proud and that guarantees Cameo Glass UK several advantages.

Who is Cameo Glass?

Cameo Glass has two important things in common with Mazzaroppi: its specialisation in the glass sector and the fact that it is a family business. Since 1994 it has been producing tempered glass, lacquered glass and high-precision custom-made glass products.

For the sale and installation of the furnace, the Mazzaroppi team worked with the company’s official UK distributor, Stone and Glass Group.

Why did Cameo Glass choose the TP Compact?

The company chose a 1.9 m x 3.6 m TP Compact oven with convection.

This allowed Cameo Glass to:

• Replace its old tempering furnace with a larger model: The TP Compact is more compact, so although it is larger than the previous machine, it can be installed in the same space without requiring any adaptations or brickwork.
• Using the same electrical cabinets as the old furnace: TP Compact uses the same power as the previous machine, so there was no need to adapt the equipment. The new Mazzaroppi kiln was commissioned with a total installed power of only 315 KW.
• Record energy savings: compared to its predecessor, TP Compact has drastically reduced the company’s consumption and therefore its operating costs.
• Optimising production: TP Compact’s ease of use has made it easier for the company to set new quality standards.
• Having a furnace up and running in just 10 days: the installation was carried out over the Christmas period, allowing Cameo Glass to resume operations at the beginning of January. Even before the installation was complete, the furnace could be used for tempering and it worked perfectly.

The Mazzaroppi solution

The TP Compact furnace chosen by Cameo Glass is equipped with a new patented Mazzaroppi technology.

Thanks to this patent, the furnace guarantees an exceptional reduction in consumption peaks, thus significantly reducing energy consumption and, like all Mazzaroppi solutions, guaranteeing perfect tempering results.

This new technology joins others that have made Mazzaroppi furnaces the ideal choice for glassworks and companies of all sizes, such as:

• M Start&Stop function, which allows the furnace to be switched off every evening and restarted in just half an hour, reducing production consumption.
• M OptiConvection, the latest generation convection system.
• M Adapt, which ensures a responsive thickness change system with no waiting time.

Cameo Glass is delighted with their choice and we at Mazzaroppi are proud to have contributed to increasing their productivity while reducing their energy consumption.

What is the furnace that can revolutionise your work?

Give us a call to find out more.

What size companies choose TP Compact, the compact oven from Mazzaroppi? There is no single answer to this question: TP Compact is so versatile and high-performance that it adapts to the needs of glassworks and also to those of large companies.

An example of this is the European group Vandaglas, with offices throughout Europe, which chose TP Compact for its Austrian headquarters.

Who is Vandaglas?

The group produces high quality insulating glass and interior glass in all possible shapes and sizes and is active in its locations in the Netherlands, Germany, Switzerland, England and, indeed, Austria, although its products are used worldwide for architectural façades and design projects. With more than 900 employees, it has to date realised more than 10,000 façade projects in over 50 countries worldwide.

‘We put all our efforts into our future,’ says Managing Director Nicolas Alexander Lahodny, ‘and that is why we are very pleased with the investment made in our Heidenreichstein site with the purchase of the new TP Compact. We are looking forward to delivering our first in-house tempered glass to our customers!’.

Why did Vandaglas choose TP Compact?

A globally established company needs an oven capable of ensuring a level of performance excellence. But it is not only this that determines the choice of the right tempering furnace for its needs.

In particular, Vandaglass needed:

• reduced electrical installation: this was their fundamental problem, as they needed to avoid having to redo the entire electrical installation. This would not only have required a particularly large financial investment, but also a good three years to complete.
• limited production consumption: to keep labour costs at an appropriate level.
• limited floor space occupied: they wanted to make the best use of the available company space.
• quality of tempering: they were not willing to compromise on the yield of their final product.
• ease of use of the furnace: for every company today it is essential to have equipment that can be operated even by non-highly specialised personnel and always give excellent results.

Thanks to discussions with the Head of Group Process Engineering at Vandaglas, Guillaume Kaminski, we finalised the choice of the best oven to meet all these needs, after an analysis and testing phase that also took place in part at Mazzaroppi’s Aprilia site, near Rome.

The Mazzaroppi solution

TP Compact meets all the requirements expressed by the company. The model chosen for Vandaglas is 1.9×3.6 metres in size, with convection for low-e, i.e. low-emissivity glass.

In addition, installation and testing took place on schedule, thanks to the valuable collaboration of Site Manager Mario Müllauer and Head of Group Process Engineering Guillaume Kaminski.

The compact, high-performance furnace from Mazzaroppi meets all the quality requirements imposed by Vandaglas, to the full satisfaction of the company, which can now:

• Temper glass in-house with up to 70% lower consumption than other tempering furnaces.
• Have an oven that is always ready, because TP Compact goes from 0 to 680° C in one hour.
• Eliminate unproductive costs, because TP Compact can be switched off every night and the day after the first start-up it can reach temperature in half an hour.

Would you also like to know if there is a tempering furnace that can revolutionise your work too?

We’ll tell you: ask for a free Mazzaroppi Energy Saving Check and discover the solution for you, perfectly adaptable to your space and in line with the consumption you do not want to exceed.