27
Fragile knife proles
The longer and thinner protrusion of the knife, the more careful
you have to be when using it. It is not sure that all knife proles
can stand the same feeding speed. Be extra careful when
machining hardwood or wood with a lot of knots. Use common
sense, but as a rule of thumb the knife is very fragile if the depth
of the cut is twice as much as the width of it (e.g. a 10 mm wide
groove that is 20 mm deep). In this case you have to handle the
knife with care so that it does not break. A depth of cut that is
of the same measurement as the width should be handled with
a certain degree of care, and knives with a cutting depth that is
less than half of the width it cuts (e.g. a 10 mm wide groove that
is 5 mm deep) can stand rather hard treatment. If you design
your own knife proles using Logosol’s form for custom-made
moulding knives, you have to consider the vertical position of the
knife pattern in order to make the knife as strong as possible.
N.B. Dull knives increase the risk of the knives breaking and by
that also the risk of personal injuries!
Grind the knife before it becomes dull
If you grind the knife before it becomes dull the grinding gets
easier. Otherwise the edge can be damaged by, among other
things, the heat. If you notice that the knife is dull (one indication
is that the quality of the cut degrades) you must stop the work
immediately. The side cutter knives and the knives in the lower
cutter most often wear down quickest on the point where they go
over the edge of the unprocessed, often dirty surface. Generally,
the upper cutter knives are spared the longest, since the sides
of the board are already machined when the board reaches
the upper cutter.
Pattern protrusion
Maximum protrusion of the side cutter knives:
SP, 4 mm thick: 17 mm
HSS 4 mm thick: 21 mm
TCT 4 mm thick: 11 mm
SP 5.5 mm thick: 25 mm
HSS 5.5 mm thick: 25 mm
TCT 5.5 mm thick: 21 mm
TCT 1 mm thick + holder 3 mm: 11 mm
Maximum pattern protrusion in the upper cutter PH 260:
10 mm
Maximum pattern protrusion in the lower cutter PH 260:
5 alternatively 10 mm
Mounting moulding knives
Keep the knives and the cutter heads absolutely clean. The
slightest presence of wood debris or resin that get into contact
with the knife when it is being mounted can cause the knife
to break. The surfaces must be completely plane against the
knife. If a knife breaks there is a great risk that that the cutter
head is damaged. The slightest unevenness on the cutter or
the surface of the chip breaker means that this component
must be replaced.
Side cutter heads
Logosol’s planer/moulders have a 30 mm axle in the side cutter
heads. This is a standard dimension, which makes it possible
to use a great selection of cutter heads in the machines (max.
Φ 140 mm, max. height 120 mm).
The TB90 cutter is available with two or four knives. Standard
knives are available in the heights of 40, 50 or 60 mm. You can
place a second cutter head on top of the rst in order to obtain a
height of max. 120 mm. Logosol offers a wide range of standard
knives, and custom-made knives can be ordered.
A cutter head and serrated back knives in HSS or TCT are
available in optional heights. Maximum height is 120 mm.
Logosol also has solid cutter heads (in HSS or TCT), suitable
for producing different combinations of, for instance, tounged
and grooved boards using only a few cutters, or for obtaining
a deeper cut than what is possible with the TB90. Solid cutter
heads should also be used when high precision is required.
Upper and lower cutter
Logosol’s planer/moulders come with HSS planing knives in
the upper and lower cutter (410 resp. 300 mm). These are also
available in TCT.
The lower and upper cutterhead can also be equipped with
holders for replaceable thinner knives, called reversible cutters,
made of HSS or TCT.
Moulding knives can be mounted in the upper and lower cutter
together with the planing knives, which enables the machine
to plans and mould in one single operation. There are a wide
selection of 40-130 mm moulding knives that can be combined
to produce the moulding you desire. Custom-made knives can
be ordered.
Pressure marks
Sometimes light spots can appear on the machined surface.
These are pressure marks caused by wood debris around the
edge of the knife. The wood debris is then pressed between
the machined board and the back of the edge. This depends
on what sort of wood you are machining, but it can also be due
to the chip extractor of the upper cutter having too low capacity.
(Some have reached good results by mounting a nozzle blowing
compressed air along the back of the cutter.)
To Next Page
Loading...
