Forms and Dimension Allowances of Glass for Supply

Optical glass are delivered as:

• blocks and plates
• strips of rectangular and round section, tiles
• pressed blanks from molten glass
• pressed blanks from cut strips

• for glass of the types K8, K108, K208, K100, F1, F101, F8, F108, TF1, TF101, TF4, TF104, TF5, TF105 - 1000 x 1000 x 200 mm;
• for glass of the types LK3, LK5, LK6, LK7, BK6, BK8, BK10, LF5, LF7 - 1000 x 1000 x 100 mm;
• for glass of the types like TK, CTK (except CTK9), BF, OF, TBF - 600 x 500 x 70 mm;
• for glass of the type OK4 - discs up to 150 mm in diameter, 20 - 40 mm thick.

technical requirements	maximum side sizes (diameter), mm
	up to 400	400 – 600	more than 600
overall dimensions tolerances (mm)	± 2	± 2.5	± 3
thickness tolerances (mm)	± 1	± 1.5	± 3
operation surface parallelism	0.3% of length	0.2% of length

Technological bevels - 1.5 to 3 mm, as agreed.
At edges and overall size surfaces, some breaches and pop-outs up to 2% of the maximum edge (surface) length and not more than 5 mm in depth are permissible.
Plates of random form and sizes of 10 mm thick and more can be delivered according agreed specifications.

• round strips of up to 30 mm diameter made from glass of the groups LK, L, BK, F, LF, TF; the diameter tolerance is ± 0.2 mm
• rectangular strips and tiles of rectangular section of 20 x 10 mm to 100 x 15 mm sizes and maximum section area of 160 mm² made from glass of the groups K, BK, TK, CTK, F, BF

• diameter (side of rectangular): 15 to 70 mm
• minimum thickness: 3 mm for lens' blanks, 4 mm for plates' blanks
• ratio of a diameter or a diagonal of a pressed blank to its thickness: 15:1 to 1.25:1
• maximum ratio of a rectangular blank's length to its width: 3:1
• there are knurling and "swaging" prints of 0.15 mm to 0.2 mm in depth on pressed blank surfaces having been in contact with a mould