21
It's an artifact of production - in particular, the construction of the conveyor belt of the machine performing the quenching process.
The pattern can be observed through a polarizing filter in the undamaged glass:
source
and it's a result of the structure of the conveyor belt through which the surface of the glass is cooled to generate the stress that ...
15
Stovetops are made of glass-ceramic which has extremely low thermal expansion, hence no cracking from temperature change. In fact, the coefficient is with $0.1 \cdot 10^{-6} \ 1/K$ even lower than that of Borosolicate glass at $3.3 \cdot 10^{-6} \ 1/K$. Since glass-ceramic can reach a negative coefficient of thermal expansion, getting even closer to zero is ...
6
A few different marking processes are available to accomplish your objective. Glass is a good choice, for reasons of durability.
Etching
One creates a mask or stencil with the desired graphic. In the case of a complex design, vinyl cutters perform the task quite well. The stencil is applied using transfer tape, after which etching chemicals are applied. ...
4
It doesn’t crack because it is the so-called Pyrex glass. It is not the same glass as common window glass which is still silica, but blended with sodium and calcium. Pyrex is silica blended with boron, making it way more thermally stable because of a smaller thermal expansion.
It also exists as pure silica glass, used mostly in high end optical applications (...
4
Borosilicate glasses (e.g. "Pyrex") have small coefficients of expansion (about $3.3\times 10^{-6}$/°C compared with $10\times 10^{-6}$/°C for steel) and can tolerate temperature differentials of about 180 °C or 330 °F.
4
TIR: Thermal infrared (longwave) transmittance of the glazing layer.
Lawrence Berkeley National Laboratory has a windows program called THERM 6.3 / WINDOW 6.3
NFRC Simulation.
In pp 55 of this manual, there is a table referencing some properties of the glazing, including this.
here is the Therm 6.3 prog dowmload.
4
the tooth-root stresses in a gear are tensile and the teeth roots have sharp corners. This means if the glass gears were carrying any sort of load, the teeth would shear off right away.
Furthermore, the teeth faces in a meshing gear set are in sliding contact, and if any grit gets into the space between the glass gear teeth, the faces will rapidly get scored ...
3
Tempered glass resists fracture because it is manufactured in such a way as to place its surfaces into a state of residual compressive stress. To cause it to experience brittle failure in tension (which is normally how glass breaks) requires overcoming those frozen-in surface stresses, which normally act to squeeze shut any surface pits or scratches at which ...
3
That's only a good idea if the gears will be rotating very slowly with almost no load.
Gear teeth undergo significant tension and compression loading, something glass is not good at handling.
Would you ever make a hammer out of glass?
3
Perhaps, depending on the materials, you could try gently heating one piece while cooling (or at least heat-sinking) the other piece, and hoping that the expansion mismatch will separate them.
You haven't identified the glass types nor their surface quality-- if the interface areas are porous, your contaminants may well have formed physical bonds which ...
2
Most weld optics have a protective glass that shields the (more expensive to replace) focusing lens from welding spatter. So there are definitely glasses that exist and can be used for this.
When designing your enclosure and/or the location of the metal parts during welding operation, try to let the laser beam propagate through the window as soon as ...
2
By definition, "tempering the glass panel all the way through" is not possible.
The interior and exterior parts of the glass must have different properties.
Tempered glass is made by cooling the exterior and interior at different times:
The glass panel is heated to a uniform temperature hot enough to soften it.
The exterior surface is cooled by air until ...
2
The value of the distributed load is trivial to determine: it is equal to the linear weight of the glass. The linear weight is itself equal to the product of the thickness, height and specific weight of the glass (depends on the type of glass, usually between 24-28 kN/m3).
How this load should be placed, however, depends on how the glass is mounted on the ...
2
Here is one way, used to drill holes through the plate glass wall of an aquarium.
Imagine a thick brass shim. we cut slots along one edge so that it looks like a saw blade with oddly square teeth.
We set this "blade" reciprocating against the glass piece we wish to cut in half and smear the "teeth" with diamond polishing paste, which ...
1
There are many factors, but intuitively the gap should be adequate to allow a decent thermal gradient for the air.
Air can establish steady convection, rising on the room side pane and descending along the colder outside pane in a much narrower plume than that of a two-inch gap, even with the damping effect of slow movement on the two sides of the pane.
That ...
1
I just noticed "mirror" was actually created by applying thin layer of
metal on top of glass.
The vast majority of modern mirrors are created by applying a thin layer of metal to the back side of the glass or transparent plastic.
With all the mirrors in my house and my car,
if I look closely at a speck of dust that recently fell through the air ...
1
Another point, that hasn't been mentioned: Over the time you will have some wear, which means scratches on the surface. These scratches can be starting points for cracks. That's why gorilla glass uses pressure stress in the surface.
1
The material has to be tested for each application as the fibre density, weave and number of layers all have effects on the stiffness.
This means even each batch may have a variation so exact values may not be easily available.
Some companies are very "expert" in this as they are using carbon fibre sheets in extreme situations and have found what ...
1
You are right that your numbers are over-estimates. They would be "correct" for a plate with no resistance to bending, which was only supported along two edges and heated across its full width between the unsupported edges.
This is a hard problem to produce a simple "formula", because in the real situation the bending will be reduced by the stiffness of the ...
1
You can cut it carefully with a hacksaw with fine tooth blade while it's held in a vise. Or cut it with a small grinder held in the vise, using a tablesaw guide.
1
Vacuum bagging is used in the creation of various items, including and especially amateur built aircraft. A suitably strong surface holds the item being bagged. Plastic film is placed over the item and taped to the surface, along with a port for the vacuum source.
Typically, a layer of dacron material is placed over the fiberglass, as it does not adhere to ...
1
Make the post go from floor to ceiling just like the one on the corner. It won't sway.
1
You may not see it but the vibration is slowly loosening the base support, compromising waterproofing, cracking the slab and causing many other damages.
As you may have seen in glass guard rails which have been engineered and permitted, they usually either have a wedge, or fin, of same thickness glass, say 6" wide perpendicular to the post bolted to the ...
1
Glasses that change color with external stimulus (smart glass) are usually laminate structures in which the glass itself is not the active component that generates the change in color or transparency, but it is used to encapsulate or to serve as a substrate for the variety of coatings, films, fluids, conductive materials, etc, that make possible the color ...
1
According to this glass manufacturer it is more about the optical properties than mechanical ones. They are looking for:
Homogeneous illumination of the touchsurface
Transparent and durable in UV and IR light radiation
Temperature-resistant to heat development in LEDs
They use borosilicate glass and aluminosilicate glass, which are by themselves scratch-...
1
Waterjet cutters work like a charm up to 5mm. I have cut 'fireproof' glass of 4mm and it came out very well.
1
Because the surface is a windshield and because you wish to have it somewhat removable, consider Solar Mike's suggestion of double sided tape, but add in a parameter for outdoor use. 3M makes a great high density foam tape that I've been using for many years to attach miscellaneous items to the windshield.
The surfaces have to be clean, of course, and the ...
1
The heater PCB is not suitable for printing on for multiple reasons.
A PCB is not as durable as the supplied glass is, nor is it as flat. The surface of a PCB held up by the corners with no other supports would droop in the middle, and no current Ultimaker has a way to compensate for that i.e. automatic mesh bed leveling. A PCB is also not as versatile as a ...
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