Different materials of glass have different requirements for whiteness, among which the requirement for bright glass is no obvious color.

Step 2 observe bubbles

Bubbles with a certain width and length are allowed, but not too many, especially those that can be punctured with a steel needle. You'd better not buy this kind of glass.

Step 3 observe transparency

The requirements for glasses with different capacities will be different. Glass with capacity less than 142mL, and no more than one glass with length less than 1.0mm; There should be no more than one glass with a capacity of 142-284ml and a length of1.5 mm. If the transparency exceeds 1/3, it is recommended not to buy this kind of glass.

Step 4 observe miscellaneous grains

Refers to opaque granular fragments not more than 0.5mm and not more than 1 piece.

5. Look at the roundness of the cup mouth

Refers to the cup mouth is not round, and the difference between the maximum diameter and the minimum diameter is not more than 0.7- 1.0 mm.

Step 6 look at stripes

A distance of 300mm is obviously not allowed.

7. Observe the low deviation of cup height.

The height difference between the highest point and the lowest point of the cup is not more than1.0-1.5mm..

8, see the cup thickness deviation

Not more than 0.5-0.8 mm

9. Look at this print

The so-called cut marks refer to stripes or centipede-like cut marks with a length of not more than 20-25mm and a width of not more than 2.0 and not more than 1, which are beyond the bottom of the cup or are white and shiny. Don't buy anything larger than 3 mm.

10, observe the die printing.

There is a record line hidden in the cup body, so don't buy it if it is obvious in head-up.

1 1. Note that the cup is flat.

To put it bluntly, this is whether the cup is uneven or not. If it's obvious when you look up, don't buy B.

12, observe brushing and scratches.

Brushing refers to the friction between glass and glass diameter, leaving traces of loss of luster on the glass body. Don't buy it obviously. Abrasion refers to the scar left on the surface when glasses collide with each other. Don't buy shiny ones.