TPT May 2012

122

2012

rticle

The rolls are installed in the stands in advance. To change rolls, both

the base and the stands are replaced, and the drive shaft connects

automatically. In terms of online roll change, this kind of mill is also

counted as the automatic roll change. But the removed stands need

to have secondary roll change. This kind of equipment was made

by Abbey Etna.

The mill without roll change is also what people have been pursuing

for many years. Mills without roll change for round tubes are

limited in break down section. Many rolls outside this area need

to be changed. Small and medium-sized tube welded mills have

higher precision, better quality products, wider size ranges, more

specifications with low equipment and maintenance costs.

be separate. This is troublesome although this operation can be

simplified via some special designs. Moreover, to have a smooth

shaft change, the clearance between the slide block and the stand

must be increased, which affects the system precision

and rigidity. These two roll change types are used

mainly for the design of large mills, for the rolls of

large mills are heavier and the shafts are longer, so

the shaft change may be easier than roll change.

Base plate change is also a common rapid roll change

unit. There are at least one set of standby base plate

containing all stands to achieve rapid roll change. To

lessen deformation, usually two to three horizontal roll

stands and several vertical roll stands are installed

on one base plate. The stand is installed with rolls

beforehand. When rolls are changed, the stand and

the base plate will be replaced together. The replaced

stand shall have a secondary roll change. OTO Mill

and FD Machinery are manufacturers of two different

base plate change mills. The drive shaft of OTO Mill

is installed on the base plate and FD Machinery has

three mill housings for each horizontal stand. The

one near the drive side separates and connects the

horizontal shaft and the drive shaft automatically

via movement forward and backward, which is not

changed together with the base plate.

There are few rapid roll change mills with base change

available, which has at least one set of standby base

installed with all stands. Usually there are two bases,

namely, the forming base and the sizing base.

DNSA mill: Turks head

DNSA mill: Guide roll and impeder

Vehicular side roll change unit of DNSA mill