問題一覧
1
Why must the glass ribbon be annealed?
To minimize & to provide only
2
What temperature range is considered the "annealing range" of float glass?
1025°F - 905°F
3
What is meant by "Permanent Stress" in the glass?
The stress that develops as the glass is cooled through the annealing range and will remain when it reaches a uniform temperature.
4
What is meant by "Temporary Stress" in the glass?
The stress that develops at temperatures below the annealing range and is only present when a temperature gradient exist across the ribbon.
5
What happens to the glass structure as it cools through the annealing range?
The internal molecular structure is able to contract and occupy a smaller volume of space.
6
If the left and right edges of the ribbon pass through the annealing temperature range BEFORE the center portion of the ribbon which of the follow conditions is true:
The edges will be in compression and the ribbon will be more likely to split
7
What zones of the 6-1 and 6-2 lehrs are considered the "Permanent Stress Zones?"
A1, A2, and B1
8
What zones of the 6-1 and 6-2 lehrs are considered the "Temporary Stress Zones?"
B2 and C
9
What is meant by "Mu Stress"?
The stress that develops through the thickness of the glass, from top to bottom, as it cools
10
What is meant by a "positive" crossbow?
The glass ribbon is curved in such a way that the top (air-side) surface bows upward
11
What causes a positive cross bow?
The top surface of the glass passed through the annealing range before the bottom surface
12
A ribbon will tend to split under which condition?
The edges want to be shorter than the center
13
Which condition(s) will likely set up a split condition in the ribbon? (circle all that apply)
A and D
14
Which of the following is a TRUE statement?
A slower cooling rate through the annealing range will result in a lower mu stress.
15
When changing width from a narrow ribbon to a wide ribbon, which of the following changes should?
Decrease edge heat output in Zones A1 through C
16
When producing heavy glass, Edge Burners in the RETs should be positioned in which manner?
Positioned just inside the bulb edge but still outside the knurl to keep that area warm
17
The illustration below of the RET handle positions will tend to do what to the ribbon?
The ribbon is more likely to cross-break because it will make the edges hotter
18
The left and right edges of the ribbon exiting the RETs are flopping excessively. Both RET 1 and RET 2 handles are positioned as shown in question 17 above, with the following settings: L=2,LC=4,C=7,RC=4,R=2. There have been 4 cross-breaks downstream of the RETs in the last hour. Which of the following moves is most likely to help resolve the breaking issue?
Decrease the L& R handles to 1, Increase the Center to 10 (L=1,LC=4,C=10,RC=4,R=1)
19
Which of the following lehr setting changes would likely result in REDUCING mu strain values?
Decreasing the temperatures across only B1 zone equally by 5 degrees
20
There is edge hackle present at the final score while producing 6mm. Which of the following moves is likely to help reduce the hackle and improve the edge quality?
Increase the edge heater outputs in the "permanent stress" zones of the lehr