Why can't finished laminated glass be cut?
Risk of structural damage
Laminated glass is made by bonding two (or more) layers of glass with an interlayer film (PVB/EVA/SGP) under high temperature and high pressure. When cutting:
The glass layer may shatter instantly due to uneven stress (especially if it contains a tempered layer).
The interlayer film may be pulled and torn by the cutting tool, resulting in delamination and bubbling at the edges.
Loss of security
Cutting can disrupt the integrity of the glass and the interlayer film, causing laminated glass to lose the following core functions:
Impact resistance (decreased fragmentation adhesion ability);
Waterproof/airtight (The cut is prone to water seepage, causing corrosion of the film layer);
Structural strength (sudden drop in edge strength, prone to cracking from the cut).
Professional certification has expired.
If the glass has already passed safety certifications (such as bulletproof and hurricane-resistant standards), the certifications will be immediately invalidated after cutting.
Under what circumstances can cutting be done?
The cutting stage in the ✅ production process
Single-layer glass substrate stage
Before the interlayer synthesis, the single-layer ordinary glass (untempered) is cut/edge-ground, and the operation at this time is no different from that of ordinary glass.
Tempered glass substrates cannot be cut (any processing after tempering will cause cracking).
Intermediate film cutting (Special process)
The interlayer film can be cut separately with a knife mold or laser, but it must be precisely matched with the contour of the glass; otherwise, moisture is likely to seep into the edges after lamination.
✅ water jet cutting (for non-tempered laminated glass only)
Applicable conditions
The glass layer is ordinary float glass (non-tempered).
Professional equipment (ultra-high pressure water jet + abrasive) is required;
The edges must be resealed after cutting.
Limitations
Slow speed and high cost (≈￥300- ￥800 per meter);
The strength at the incision site decreases by approximately 40%, making it unsuitable for load-bearing areas.
Long-term moisture resistance cannot be guaranteed (edge banding may fail).
If the size is incorrect, how can it be remedied?
Return to the factory for remaking (Recommended
Re-produce single-pane laminated glass according to the correct size and replace the wrong glass.
Cost: ￥400- ￥2000 per square meter (depending on thickness/film layer).
Adjust the installation plan
Modify the frame structure or fill the sealant to adapt to the existing glass size (only for minor adjustments with an error of less than 5mm).
Replace with other types of glass
If there is no urgent need for safety, single-layer tempered glass (which can be cut but loses the safety of the interlayer) can be used instead.
Key points to note
Self-cutting is strictly prohibited.
Using tools such as Angle grinders and glass knives to cut can cause the glass to shatter and the interlayer to curl, resulting in personal injury.
Beware of false advertising
Some merchants claim to be able to "cut laminated glass without damage", but in fact, it is fraud (there is no mature technology to achieve this at present).
Reserve a margin in the design stage
When placing an order for laminated glass, the dimensions must be accurate to within ±0.5mm (it is recommended to recheck the dimensions on site three times).
