Glafo, PG Vejdes väg 15,
Vejdes plats 3
Tel: +46 10 516 63 50
a map at the
"about Glafo" page.
Project leader: Christina
Project status: on-going project
GLASS BY MEANS OF WATER CUTTING TECHNOLOGY – CROSS-DICIPLINARY
COLLABORATION FOR SUSTAINABLE DEVELOPMENT
The aims are:
- to develop an environmentally friendly polishing technique that produces
the same finish as an acid-polished finish; for flat surfaces, cuts
and holes both in float glass and in crystal glass
- to create a network within this field
- to appoint a person in the area of water cutting
- to produce a prototype glass polishing installation
can read the first report and the background of the
You can read
the second report here.
You can read
the third report here.
You can read
the fourth report here.
We are no longer having problems with blasting, and have started to
get really interesting results from polishing. We have started making
measurements using our optical profilometer, which therefore enables
us to investigate both the appearance and the surface smoothness parameters
of surfaces. By using narrow nozzles, we have managed to get the pressure
up to almost 50 bar.
Figure 1 shows an example of such a polished groove. It can also be
seen how we have removed material from the surface, removing almost
9 µm and leaving only faint traces of the grinding scratches.
Figure 1. Polishing using
a 0,5 mm nozzle and pressure of 43 bar, with 40 two-way passes across
the surface. The upper picture shows the general layout, with the blue
area indicating the polished surface, while the lower picture shows
the profile through the same area. Magnification 2,7 times.
Figure 2 shows
the same area, but at higher magnification. The surface has been polished
down to only small surface variations. The structure differs quite considerably
from an acid-polished surface, but working mechanisms are completely
different. The important thing is to get rid of the scratches from grinding
and to even out any high or low spots.
Figure 2. The
bottom of a polished groove, seen with 10 times magnification.
of polished holes
If we are to be able to polish a surface more effectively, we need higher
pressures and wide nozzles. This requires a larger pump, and we shall
very soon be ordering a proportioning pump. However, delivery time is
long, and so while we are waiting for the new pump we shall start trying
to polish holes. To increase the strength around holes, it is important
to round off the bottom of any cracks, as they otherwise act as stress
raisers, with high stresses over a small area and very considerable
risk of the crack propagating.
We are going to
compare the strength of drilled and water-cut holes, with and without
polishing. Testing of the unpolished holes will start in the spring.
The first question to answer is whether there is any significant difference
between a drilled hole and a water-cut hole. The first test will also
show the spread of results between the samples, and indicate how many
holes we need to test and polish in order to obtain a significant result.
Polishing cuts differs less from polishing flat surfaces than it does
from polishing holes. We have performed the first very simple tests,
which show that once we can polish flat surfaces to the desired surface
finish, not much additional development will be required in order to
be able to use the method on cuts. Polishing of cuts will therefore
not start before the autumn.