What you need to consider to buy a tempering furnace?

To invest a tempering furnace is one of biggest single equipment expenses for a glass deep processing company.

It directly defines your company's market value, customer base distribution, and overall profitability.

In glass process industry, we spent 20 years in the glass deep processing equipment industry, witnessed countless successful-and unsuccessful-tempering furnace investments.

That's why we've put together this guide: To help business plan to invest in tempering equipment comprehensively evaluate their operating environment and internal needs, so they can make the right purchasing decision.

1. Clarify Your Product Positioning Before Purchasing

The tempered glass market can be divided into B-end customers (place regular in large-volume orders) and C-end customers (place small in scattered orders).
B-end customers-typically engineering projects-include door/window glass and curtain wall glass, which usually have standardized specifications.
C-end customers, in the home improvement market, range from high-end system windows to ordinary residential windows.
Here's the key: B-end curtain wall glass and C-end system windows have strict requirements for imaging and glass surface quality, which means they demand higher equipment configurations.
So, you need to choose a tempering furnace with the right specifications based on your specific product positioning.

2. What Are the Criteria for Tempering Furnace Selection?

Capacity Matching: The furnace's capacity should match with your estimated annual comprehensive output.

For example, LandGlass's A2850 tempering furnace can produce 15-18 batches per hour for 5mm Low-E glass, translating to an annual output of approximately 1.5 million square meters. You can reverse-calculate the required furnace capacity based on your projected annual output to select the right model.
Workshop Space: Different furnace types-flat tempering furnaces, curved tempering furnaces, combined flat-curved tempering furnaces, double-chamber furnaces, continuous furnaces-vary significantly in length. You need to choose a model that fits your available workshop space. Additionally, don't forget to account for storage space for glass work-in-progress before and after the furnace.

Power Load: Different furnace models have different installed power. For example, when tempering 5mm clear glass, the A2850 single-chamber furnace has an installed power of about 1300kW, while the double-chamber model is around 2400kW. You should consider your factory's existing transformer capacity and the possibility of capacity expansion when making your selection.

3.Competitors' Equipment: For differentiated competition, the size of your tempering furnace should generally be larger than that of your local competitors. If nearby competitors use a 2.4m x 5m furnace, we recommend choosing a 2.4m x 6m or 2.8m x 5m model.
3. Forced Convection Furnace or Radiation Furnace?

How to Choose:
When talking about forced convection, we have to mention Low-E glass. Low-E glass is known for its low emissivity, which means it reflects most radiant heat-making it hard to heat quickly with radiation alone.

For radiation furnaces, heating Low-E glass takes too long, and the uneven heating between the upper and lower surfaces of the glass seriously affects quality. Forced convection furnaces, however, use air convection to blow heat directly onto the glass surface, overcoming the problem of Low-E glass reflecting radiant heat.
So, if coated glass accounts for more than 30% of your orders, or if you process a wide variety of glass types, a convection furnace is the way to go. Even when processing ordinary clear glass, convection furnaces outperform radiation furnaces. For most businesses, we generally recommend choosing a forced convection tempering furnace.

4.Are All Convection Technologies the Same? There's More to It Than Meets the Eye

There are three key factors to consider when evaluating convection technology:

First, the proportion and efficiency of convection heating.
Second, heating uniformity.
Third, temperature control precision.

Currently, there are three main types of convection technology in the industry: tube convection, box convection, and layered convection.

Tube convection, a basic technology, is a transitional product between radiation furnaces and convection furnaces. Box convection is an upgrade from tube convection, and layered convection is a further improvement-it effectively enhances heat transfer efficiency in the furnace, ensures uniform heating, and is more suitable for tempering double-silver and triple-silver Low-E glass.

Additionally, for true convection heating, the heating elements should be located at the air outlet of the convection system, not the return air outlet.

5. Full Top-and-Bottom Convection Furnace or Upper Half-Convection Furnace? How to Choose:

Upper half-convection furnaces use air convection to heat the upper surface of the glass and traditional radiation to heat the lower surface. They're ideal for customers with a small number of Low-E glass orders.
Full convection furnaces add a convection device to the lower part, enhancing heat transfer from below. This avoids defects like spherical bending, which occur when heating large-format glass or coated glass thinner than 4mm without lower convection-since the upper surface heats much faster than the lower surface. With full convection, both surfaces heat simultaneously, resulting in better glass quality and higher production efficiency. Full convection furnaces also handle Low-E glass with complex film layers more effectively.

6. In an Era of Quality First: The Dividing Line for Tempered Glass

Wind Marks & Flatness
Wind marks, also known as rainbow marks, are a common defect in the glass curtain wall industry. They directly affect the overall aesthetic of buildings, and some projects have even been rejected due to wind mark issues. A high-quality tempering furnace, with reasonable structural configuration and production processes, can minimize wind marks and improve the quality of building curtain walls.
Flatness is another crucial indicator for tempered glass-especially for laminated glass, which has stricter flatness requirements. Flatness is mainly measured by bow and waviness, as defined by national standards. Currently, advanced tempering furnaces can achieve batch production of 6mm clear glass with a bow ≤1‰, central waviness ≤0.05/300mm, and edge waviness ≤0.10/300mm-far exceeding national standards.
Before buying a tempering furnace, talk to existing users of the equipment or visit their facilities. Don't just rely on marketing claims.

7. How to Make Your Tempering Furnace More Profitable

Tempering furnaces typically account for a large portion of a factory's electricity costs. Good comprehensive energy-saving technology can save you a significant amount on electricity bills. For tempering glass thicker than 4mm, the main energy consumption unit is the heating section. The heat required to heat the glass is constant, so reducing heat loss during operation is key to energy control. Heat loss from the heating section mainly comes from the furnace wall and convection structure heat transfer.
LandGlass tempering furnaces use multiple insulation technologies, labyrinth seal structures, and grid-like insulation outer walls to minimize heat loss and reduce operating costs.

8. How to Avoid Wasting Money When Buying a Tempering Furnace

The quality of tempered products and the reliability of the tempering furnace directly affect your company's development and profitability over the next 5-10 years. Therefore, equipment reliability and product quality are far more important than the equipment price. High-quality tempered glass determines your company's project winning rate; reliable equipment and a complete maintenance plan can effectively reduce machine failures and downtime.
If you buy cheap equipment, the increased annual maintenance time can lead to losses of nearly one million yuan per year due to labor costs, delayed delivery compensation, and other factors. Low initial investment may seem like a bargain, but the long-term and fatal costs of poor product quality and additional operational and maintenance expenses are not worth it.

9. How to Choose Your Long-Term Partner and Win in the Future

Brand Strength: Large brand companies have their own R&D, design, and manufacturing teams. Their products have been verified by the market, ensuring quality. What's more, LandGlass has the strength and experience to provide customized design, manufacturing, and commissioning based on your actual needs, better meeting your product quality requirements. Additionally, buying from a brand manufacturer gives you brand support, which directly impacts your company's pricing power and influence.
Innovation Capability: Companies with strong innovation capabilities are highly sensitive to market changes, accurately grasping trends and continuously launching technological and product upgrades. Cooperating with such companies ensures the technical lifespan of your equipment. Businesses should focus on their future core competitiveness and stand with excellent partners to win in the future.