STEEL + TECHNOLOGY 04/2019 EXTRACT

76 | STEEL PROCESSING
Sawing instead of groove turning
Ring cutting machine evolves into
machining centre
Dango & Dienenthal has developed a unique machine that separates huge sleeves into individual rings by
sawing. Operation is faster and cheaper than grooving. The basic machine can be upgraded to a machining
centre by attachments for turning, milling and drilling, and for ultrasonic testing.
Dango & Dienenthal has developed its
new RTM 30-8 ring cutting machine
in cooperation with the German
mechanical engineering company Klaaßen
Maschinenbau GmbH. Compared to the
conventional method, the sawing of ring
sleeves has a number of benefits. So far,
the sleeves used to be cut into rings by
grooving on carrousel-type turning lathes.
Due to the low cutting speed, the high tool
wear and the necessity to repeatedly
retract the chisel for the removal of chips,
this was a rather time-consuming process.
Additionally, the radial depth of cut – i.e.
the maximum wall thickness of the sleeves
– was limited to about 80 mm.
Now, Dango & Dienenthal und Klaaßen
have developed a new machine concept
based on experience with a prototype
machine. Fundamentally new about the
system is that the individual rings are no
longer cut by groove turning but by a sawing.
The first full-scale machine is now in
operation at Klaaßen.
Sawing saves on material and
enhances precision
Sawing instead of turning provides material
savings between 30 and 50 percent –
especially when producing thin rings.
Thanks to the extremely precisely operating
circular saw, the thin blade and the
excellent plane-parallelism of the cut pieces,
machining allowances can be drastically
reduced.
Additionally, sawing reduces the cutting
time dramatically – by up to 60% in case
of steel rings and by up to 90% in case of
high-strength materials such as titanium or
nickel-based alloys. Also, non-productive
times can be markedly reduced – by more
than 40%, in case of six rings cut from a
sleeve, for example.
We enable our customers to manufacture rings
on just one single machine, while in the past
they usually needed three separate ones.
Boris Marcukaitis, sales engineer at Dango & Dienenthal
Further benefits of sawing over turning
include: during sawing, the material in the
kerf hardly increases in temperature, and
a circular sawing blade – by nature –
achieves a much better surface quality,
resulting in a high plane-parallelism of the
finished rings and practically totally dispensing
with the need to rework the cut
rings.
Moreover, the service life of a circular
saw blade is much longer than that of a
grooving tool. Sawing is also much safer
than grooving because it does not produce
one single large chip but many small chips,
which are removed from the kerf by the
circular saw blade.
A cutting machine serving as a
machining centre
RTM 30-8 ring cutting machine: clamped on the turntable the sleeve is cut by a circular
saw (Picture: Dango & Dienenthal)
Upgraded to a machining centre, the ring
cutting machine provides a whole lot of
additional benefits: Fitted with specific
attachments – and without having to reclamp
the work piece – it performs many
STEEL + TECHNOLOGY 1 (2019) No. 4