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Fine Gobs are produced by the direct pressing of molten optical glass
into highly polished tools.The resulting glass gobs have "Fire
Polished" surfaces and are ideal as the pre-forms for precision lens
molding.The typical shape is "Convex-Oval" as shown in the drawing
below. The basic Fine Gob dimensions for various volumes are listed
below. Please advise your preferred outer diameter, thickness and
radius in your request for quote.
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Refractive Indices of the Fine Gobs are adjusted to match our catolog
values using our recommended annealing condition for each glass type.
Please
contact us if you are interested in Fine Gobs with 0.1cc or less and
0.7cc or more, and in special shapes including "Ball-Shaped" Fine Gobs
Ohara's
Fine Gobs help to extend the life of the mold pressing tools by
minimizing the reaction between the softened glass and the mold
materials. We recommend L-BAL42 as the preferred material for high
volume mold pressing production.
We
typically use our Low Softening Temperature Glasses for the production
of Fine Gobs and these materials have the same general properties as
our regular optical glasses. These glasses are environmentally safe as
they do not contain PbO and As2O3 in their composition and they allow
for a simplified waste stream disposal.
Table 2 shows the optical properties of low softening temperature Optical Glasses.
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| Type |
Code |
nd |
vd |
Tg (deg C) |
At (deg C) |
RW(P) |
RA(P) |
S.G. |
| L-BSL7 |
516641 |
1.51633 |
64.1 |
498 |
549 |
2 |
1 |
2.38 |
| L-PHL1 |
565608 |
1.56455 |
60.8 |
347 |
379 |
1 |
5 |
3.18 |
| L-PHL2 |
559625 |
1.55880 |
62.5 |
381 |
407 |
1 |
5 |
3.03 |
| L-BAL35 |
589612 |
1.58913 |
61.2 |
527 |
567 |
2 |
4 |
2.82 |
| L-BAL42 |
583594 |
1.58313 |
59.4 |
506 |
538 |
2 |
4 |
3.05 |
| L-TIM28 |
689311 |
1.68893 |
31.1 |
504 |
539 |
2 |
1 |
2.88 |
| L-LAL12 |
678549 |
1.67990 |
54.9 |
562 |
600 |
1 |
4 |
3.48 |
| L-LAL13 |
694532 |
1.69350 |
53.2 |
534 |
575 |
1 |
4 |
3.69 |
| L-LAM60 |
743493 |
1.74320 |
49.3 |
541 |
581 |
1 |
4 |
4.2 |
| L-LAM69 |
731405 |
1.73077 |
40.5 |
497 |
529 |
1 |
3 |
3.24 |
| L-LAM72 |
733489 |
1.73310 |
48.9 |
565 |
608 |
1 |
4 |
3.89 |
| L-LAH53 |
806409 |
1.80610 |
40.9 |
574 |
607 |
1 |
4 |
4.49 |
| L-LAH81 |
806404 |
1.80610 |
40.4 |
566 |
602 |
1 |
3 |
4.53 |
| L-LAH83 |
864406 |
1.86400 |
40.6 |
608 |
658 |
1 |
2 |
5.29 |
| L-NBH54 |
902251 |
1.90200 |
25.1 |
547 |
586 |
1 |
1 |
3.64 |
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