Bubbles Problems in Glass Lamination
1.EVA Film feel sticky (High VA content EVA Film)
The high VA content EVA Film has low melting point,the edge of EVA Film melts early,and the melting speed affects the exhaust,the bubbles are closed because the edge are sealed.
Method: It is suggest that customers keep the EVA Film in the Glass laminating machine for 20minutes in 60C,it is requested exhaust the air before the EVA film has completely melted.
It is necessary that to add more 15minutes at 50C for constant vacuum.
2.The grain in EVA film is too light and thin
The grain in the EVA film is too light or thin,it is not condusive to exhaust,and easy to appear bubbles.
Method:It is suggested customers extend the time for vacuuming,please extend the vacuum time in the first step processing 60C in glass laminating oven,or add 15mintues at 50C for contant vacuuming.
3.The exhaust performance of the equipment is not good,or the airway we put the wood strips are not placed properly.
The airway is not smooth or the pores are blocked and the air cannot be pumed out.
Method:Please check whether the airway is unobstructed,whether the pores are blocked,whther the silicone bag is damaged,whether the bite of silicone bag is jammed by foreign objects,whether the wooden strips are placed properly,
whether there is water in the vacuum pump.
4.The time for vaccum is too short or the processing for vacuum is not constant
The vacuum is too short,the 4 processes of pre-vacuum,heating vacuum,constant tempertaure vacuum and vacuum until the temperature is lower than 50C is not contstant.
The air is not exhausted out,or the air enter the laminated glass because stop the vacuum pump.
Method:From the pre-vacuum until we take out the glass until the temperature is lower than 50C,we could not stop the vacuum pump.
5.The processing temperature is too high
The processing temperature is too high,the EVA film at the edge overflows too much,the EVA film at the edge becomes thin,it would be easy to occurs bubbles all around the glass,
and the EVA lamianted glass would be easy to happened color different for Color EVA Film,such as Color Translucent EVA Film,White Translucent EVA Film,Sandblasted White EVA Film,Milky White EVA Film,Matt White EVA Film,Jade White EVA Film,Black Opaque EVA Film.The processing temperature is too high,the total quantity of EVA Film becomes thin,the quantity of EVA Film is not enough to fulfill the gap of insert material lamination and uneven of tempered glass,it would occurs bubbles.Compared with the meter temperature,the temperature of the surface of the glass is over 5C difference.it also would occurs the temperature is too high.
Method:Adjust the apporiate processing temperature according to the normal processing temperature range.Please paid more attention to the temperature difference between the surface of lamminated glass temperature and the meter shows on the Glass lamination oven.If the surface of laminated glass temperature is over 5C compared with the meter,we should reduce the temperature difference to reduce the meter on the Glass lamination Oven until the surface of the laminated glass under proper processing temperature.
6.The humidity is too big
The EVA Film and insert materials and stock surrounding is too humidity,the EVA Film and absorption absorp moisture,and the water and alcohol with water is not dry enough after wiping the glass.
Moisture happened gasification after heating,If it could not be exhausted out,it would be easy to occur bubbles.
Method:The EVA Film and insert materials should be stored in dry surrounding or air condictioning room,which could avoid the EVA Film moisture absorption,please make dehumidification before Glass Lamination,
It is necessary to sandwich the glass and EVA Film with alcohol without water,after drying the glass with Glass Drying Machine and than process the glass lamination
7.The insert material is too thick or the gap is too big,or the thickness of EVA Film is not enough
The thickness or gap for insert material is too big or the EVA we choose for lamination is too thin to fulfill the laminated glass after melting,it would occur the bubbles.
Method:The thickness of EVA film should be increased along with the increasing of thickness and gap of insert material
8.It is early to stop the vacuum pump
It is already stop vacuuming when the temperature is not less than 50C,at this time,EVA Film is still flowing,the air is easy to enter the laminated glass again to occur bubbles.
Method:Please make sure the temperature is less than 50C and than stop vacuuming.
9.The Temperature of the Silicone bag tray is still too high and the start the next processing
If the Silicone bag tray temperature is over 60C,at this time we put the next batch Laminated glass for processing,the rising temperature inside the silicone bag is too fast,the edge of EVA film would be melt very fast,and than the gas would be sealed in the glass and could not exhaust out and easy to occur bubbles.
Method:If we make the next processing,the temperature of silicone bag should reduce lower than 50C,or we make cool vacuuming for 15minutes before push the silicone bag to Glass Laminating Furnace.
10.There is no pre-vaccuming and than rise the temperature directly
There is no pre-vacuuming and than rise the temperature directly,the temperature of silicone bag rise too fast,the EVA Film during the glass edge would melt very fast,The gas is sealed in the laminated glass and could not be exhausted out and easy to occur bubbles.
Method:Please pre-vacuuming for 15minutes and than push the silicone bag into the Glass laminating oven,and start to rise the temperature.
If the bubbles appeared at the edges of laminated glass:
1.During processing,when the temperature is still over 60C,the vacuum pump stopped,and the air would enter the laminated glass along with the flowing EVA.
2.The processing temperature is too high,it would occurs the edge of the EVA film overflows too much,the EVA film becomes thin at the edge of the glass,especially laminated with the insert materials is easier to occur bubbles.
3.The Sealant erosion the EVA Film,there is also bubbles appear at the edge of glass.
Bubbles appear at the middle of glass
1.If the temperature of Glass laminated oven rise too fast,the EVA film during the glass edge would be melt fistly,it would seal the edge and result in the gas could not exhausted out and occur bubbles.
2.The EVA Film used for tempered glass is too thin,the EVA quantity is not enough to fulfill the uneven of tempered glass and occur bubbles.
3.The gap of insert materials is too big and the EVA film we used is too thin to fulfill the gap and result in bubbles.
4.When the temperature is higher,the EVA film woulld becomes thin and occurs bubbles,especially laminating with insert materials is easier to happened bubbles.