One of the most heartbreaking mistakes, is when buyers are tempted to buy a toughening
plant that they can afford rather than one that is large enough to operate efficiently.
The most critical dimension is not the bed length, but the bed width. If it is
too small, then not only will many order items still have to be bought in, but the
bed loading efficiency may drop dramatically. It is often a little known fact that
empty space on a bed load has energy consumption costs roughly half as much as space
occupied by glass being toughened. Not only that, but erratic bed loading can lead
to hot and cool spots in the furnace, even on modern plants with cool air system
to try to compensate, leading to degradation in toughening quality. A plant that
is too small for the order sizes being toughened is therefore much more expensive
to run per square metre of glass being toughened.
It is not only toughening plants where the consequences of the range of order sizes,
is not fully appreciated. On a frightening number of occasions we have seen sealed
unit lines with an uncomfortable limit on the maximum size of unit that can be processed.
This often leads to the purchase of a second line with a more realistic limit.
For typical replacement glazing work, we would recommend a bed width of at least
1350mm but 1500mm is much better. We have seen three toughening plants with a bed
width of only about 1000mm. This would be adequate only if door panels were being
toughened but for anything else, this size is a huge mistake.
There is an increasing trend to purchase automatic arising lines, but these tend
to have a lower size limit which is too large for the smallest leaves, so capital
and shop floor space still needs to be found for a manual arising station.
Finally, there is usually a lower size limit on the assembled spacer frames being
sent through an automatic butyler, making it necessary still to find capital and
shop floor space for a manual butyling station.
A full Trimloss system can take account of all the above limitations and reroute
work or highlight items for manual processing where necessary.