Vacuum glass processing technology classification

In the past 20 years, the development of vacuum glass have got glorious success and China now has been the leading VIG research and production base in the world.

From vacuum glass theory, laboratory preparation to industrial production, and the application in various category,to development of tempered vacuum glass and laminated vacuum glass .

Till 2022, there’re over 20 vacuum glass manufacturers around the world,most of them are located in China.While as there’s high technology barriers ,each factory has their unique equipment ,technology to seal the glass, here HaanGlas classify VIG processing technology based on below points.

  1. Tempered VIG VS anneal VIG.

Anneal vacuum glass,typically Fineo glass and Spacia,process VIG with anneal glass,which make it cannot be applied in high rise buildings.Impact resistance,and easy to hurt people once glass is broken,so the anneal VIG are used in low rise buildings and historical building renovation.

Compared with anneal glass, the strength and impact resistance of physical tempered glass are greatly improved, so “tempered vacuum glass” also greatly improves the overall impact strength, wind pressure resistance, bending resistance, Thermal shock resistance and safety after breakage.

Tempered vacuum glass- glass will break into small particles and won't hurt people

Tempered vacuum glass- glass will break into small particles and won’t hurt people

While because of vacuum glass structure, the stress concentration at the micro support pillars is unavoidable.

The disadvantage is that its mechanical strength is not as good as same thickness toughened glass and laminated glass,but tempered Vaccum glass application in large scale facade projects proved that its safety performance.

  1. Metal edge sealing VS Glass solder edge sealing.

Glass solder edge sealing technology is used by most VIG manufacturers,compared with other materials, glass solder materials is easy to seal with permanently ,but there’re also some disadvantages.

As glass solder and glass panels must be heated to over 400 ℃ for better and faster,while the high temperature will cause glass anneal and overall strength decrease,more importantly,the glass anneal in glass center and glass edge are different,so glass strength is uneven, potential breakage ratio is increased significantly.

The cooling process from over 400℃ to room temperature also affect glass strength and glass flatness.The glass solder materials usually contain lead,this harmful materials is not eco friendly.

During edge sealing process,glass solder parameters should be strictly controled,or there’ll be micro bubbles and cracks occurs and affect the bonding and sealing effect.

Glass solder edge sealing VIG & metal edge sealed Vacuum glass,both are tempered vacuum glass

Glass solder edge sealing VIG & metal edge sealed Vacuum glass,both are tempered vacuum glass

Land glass is the world 1st manufacturer that seal VIG with low temperature metal materials,edge sealing is finished between 200-300℃,which is far lower than glass anneal temperature, the evenly strength ensures low breakage ratio and high finished product ratio.

  1. Evacuation holes & Flat VIG.

Vacuum glass evacuation holes, with holes or without holes, this is decided by the production process.

If the glass edge is sealed in high vacuum degree condition,then no need to drill holes on glass panels,while if the glass is sealed first,and then evacuate the air inside and create high vacuum degree ,then manufacturers must drill holes on glass and cover it after production.

Of course VIG without holes will have better visual effect,the defects of evacuation holes are:

  • The existing of holes will affect overall appearance.
  • The hole would become potential point of VIG failure.
  • Bring difficulty to handling and installation.
  • Whether the air is evacuated by hand or by machine,there’ll always some air back into the glass before covering it,which will affect the glass U value.
Evacuation holes from and back side in vacuum glass

Evacuation holes from and back side in vacuum glass

Of course there’re other small difference,such as:

4.Micro support pillars.

Different material supporting pillars are used,whether its material metal one or glass ceramics, and shapes can be divided into C shape,cylinder shape,round balls, color can be transparent, black, translucent etc.Now with the development of micro pillars,spacing are typically 40-50mm ,it’s hard to note the existing of the pillars in 1 meter distance.

Translucent ceramic glass supporting pillars in vacuum glass

Translucent ceramic glass supporting pillars in vacuum glass

According to the research,the pillar plays the most important role in deciding the VIG U value,affected factors include Pillar shape,size,height,placement,conductivity etc.The pillar also decide the soundproof performance.

Micplacement will also cause nearby compression increased and become potential breakage reasons.

Generally for glass solder edge sealing,manufacturers silk screen ceramic glass on glass surface and fix it through tempering process.

Metal edge manufacturers usually use stainless balls as the pillars.

  1. Air absorption materials.

All the air absorption materials inside glass aims to absorb potential air or moisture penetrate into the glass in the next decades,some in stripe shapes along glass edge and some are round circles inside glass.

The function of air absorption is to absorb the air or other gas inside the VIG and keep high vacuum degree in the following 20 and even longer time.


Tempered VIG with metal edge sealing technology, and no evacuation hole designs are the best vacuum glass products in the world, HaanGlass VIG meet all above feature and we’re proud to work with potential partners to explore the new big market.

Extend: 6 factors  affect  the  vacuum  insulating  glass  quality