Single block machines

Bull Block single die.

The wire enters the block via a die and on to the block where it collects.

Overtop block on single vertical shaft with 2 dies -

From 1st die wire enters a block with an 18" race the Wire wraps round the

race 3-5 wraps and then exits out via the pulley on the left of the machine

from which it enters the 2nd die and on to the upper block race that has a

diameter of 24". Note that while the area reduction through the first die can

vary from around 25% up to about 35% the area reduction in the 2nd die must

be bigger than 25% i.e. exceed the elongation of the block ratio 24" to 18"

This means that the area reduction must be 1-18"/24" + a slip of ca. 2%

The wire then wraps around the 2nd block race which is slightly tapered so that

the wire can slip upwards on to 4-6 collector pins where the wire accumulates.

The wire then exits the upper section (or collector pin section via a spinner

arm and over the payoff pulley located over top. The spinner back tension can

be adjusted via a disc brake.

Bull Block with riding stripper equipped to operate with either 1, 2 or 3

dies.

This type of machine is popular among producers of rebar and weld-mesh.

Note the inlet roller gate on the first die box that can direct the wire either to

the 1st (16") 2nd (22") or 3rd (30") draw-race allowing any wire size from 25mm

down to 3.25 mm to be produced in one single operation from wire rod that

range in size from 32mm - 5.5mm.

View of large riding stripper of collapsible type.

Before the operation starts the stripper is placed on top of the stripper block

and secured (see picture above). During processing wire will collect on the

block and the stripper. When full the stripper will be lifted by a crane and the

wire stripped off the block. The stripper with the wire is then moved over a

tubular carrier and collapsed where by the wire drops down over the carried.

View of Inverted Bullblock or Gravity Block

Inverted drawing machines (or Gravity Blocks) have a special range of

applications.These machines are mainly used for coarse wire sizes, which

have to be delivered on carriers with higher weights as achievable with a

stripper block. Used in place of the conventional vertical type block for

drawing or coiling wire that requires a mar free surface such as a plating

quality wire.

View of Bullblock mounted on horizontal shaft

The drawing block can also be placed on a horizontal shaft with the wire

moving axially along the block from which it falls off the block on to a carrier.

These kind of machines are commonly used for cold heading wires with wire

inlet diameter sizes of up to 50 mm

Continuous multi die wire drawing machines.

In order to draw wire through a number of sequentially placed drawing blocks

an array of different machine types have been developed. As drive motors

and controls became more affordable machinery builders were able to

develop machinery that were both faster and more productive requiring less

and less labor per ton produced. However a lot of machinery are still in

operation why it is warranted to describe the more common types.

8-block wire drawing machine of overtop type

The author believes that this was the first or at least one of the first continous

wire drawing machine with individual drive motors to each block.

3-block Morgan wire drawing machine

The wire pass on these type of machines differs from other machines in that

the wire is pulled through the die wraps round the block that is slightly tapered

allowing the wire as it accumulates to climbed and push the wire upwards and

as it does the back tension diminishes so that it can be passed over a

mushroom like hat and down through the block shaft that has a hollow center.

The wire then passes over a pulley located under each block and the out in

front of the machine and enters the next die via an inlet guide pulley on to the

next block. Originally the machine had a single drive motor for all blocks and

the blocks could be disconnected from the common drive shaft via a clutch.

Later models had individual drive motors. These type of machines were

particularly well accepted by makers of high carbon spring wire and the

Morgan company has sold hundreds of these machines over the years.

8-block wire drawing machine of B-B or Double accumulating type

The first B-B Block machine was built in the late 30s by Marchal Richard

Barcro. The machine quickly gained wide acceptance since it provided

excellent cooling and eliminated the twist between the blocks something

particularly appreciated by manufacturers of high carbon wire such as rope

wire.

5-block Vaughn loop arm regulated wire drawing machine.

Note that the first block on the machine has 2 drawing races allowing the inlet block to pass 2

consequtive drawing dies before entering block 2. The wire exits the first block via a stationary pulley

makes a loop round a pulley mounted on a springloaded arm and then enters the next die via a pulley

placed on the soap box goes through the die and on to the 2nd block. The positioning of the loop arm on

block 1 regulates the speed on the second block and the positioning of the loop arm on block

secondblock regulates the speed on the following (3rd) block etc. The main feature with the loop arm

machine was that it allowed the wire to pass from block to block in a straight line without the twist in

the earlier overtop machines. A feature shared with the B-B machine shown but with the added

advantage of less maintenance. When the Vaughn machine company originally introduced the machine

it was powered by a DC motor generator set that fed a common armature voltage to all the individual

drive motors and the positioning of the loop arm regulated the motor field voltages. Thousand of these

machines were built until 1976 when the company went out of business. We show this machine simply

because 25 years later there are still many machines in operation.

8-block wire drawing machine of tuner line type

The first TUNERLINE was built in the late 70s by Ernst Koch and since then

KOCH has sold more than 400 machines world-wide, The advantage with this

machine is the very small moments in the tuner roll assembly

Several suppliers to day offer sensor roll control machines. Below is a photo

of Eurodraws MTS 1200 machine

Wire drawing machines with sensor arm control

and Horizontal axis blocks

GENERAL FEAUTURES

The MTO machine by Euraw draw is a multiple-block machine with horizontal-

axis drawing capstans, sensor arm speed synchronization and an additional

dancer arm on the finishing block. The high degree of automation and

remarkable efficiency of MTO drawing machines, coupled with their sturdy,

low-maintenance mechanics, contribute to achieve high quality production at

the lowest possible operating cost.

DRAWING BLOCKS

The drawing blocks are made of forged C 50 carbon steel, induction tempered

at medium frequency, to obtain a surface hardness of approximately 60 HRC.

With this hardness, block wear is about three times less than that evidenced

in blocks made of cast iron. Each drawing head is balanced statically and

dynamically. Capstans are set in two parallel rows.

MAIN BLOCK FRAME

The following units are mounted on the main block frame: capstan cooling

water and ventilation ducts; bush, bearing, junk ring and shaft of drawing

capstan; mechanical transmission (see below).

TRANSMISSION

Motor power is transmitted to capstans by V-belts, in some instances assisted

by a reduction gear lubricated in an oil bath.

MAIN MOTORS

Each capstan is driven by an AC motor. Motor power is calculated with an

ample margin to ensure maximum security even in the most exacting

operating conditions. Motors are generally installed horizontally on a slide rail

for belt adjustment purposes.

SENSOR ARMS

Capstan speed is synchronized by sensor arms. An induction proximity switch

on each sensor arm adjusts the speed of the drawing block according to the

position of the sensor itself. Backpull can be adjusted to 10-15% of wire pull

by rotating the relative spring mounted on each sensor arm. High working

speeds can be achieved and the machine can be stopped in case of

emergency without wire breaking.

DIEBOXES

The dieboxes, made of normalized cast iron, are equipped with a lid to avoid

dispersal of soap dust in the working area. The dies are cooled directly with

running water and are set in an easily removed die cartridge equipped with

quick couplings. Dies are adjustable on three planes to ensure correct wire

alignment. Motorized rotating dies with soap agitators, etc., are available on

request.

SAFETY GUARDS

The machine is totally enclosed by a sliding gate with inspection windows.

WATER COOLING AND VENTILATION

The combined action of water and air cooling makes it possible to keep die

wear low even at high working speeds. Capstans are cooled internally by a

high-turbulence, "narrow gap" water cooling system, while the entire external

pulling surface of the block is air cooled. The flow of air is directed at the

motors and capstans through two separate conduits.

ELECTRIC EQUIPMENT

Most suppliers offer a choice of all major brand name electric equipment and

the selection is based on local servicibility. Most equipment has a "self-

diagnosing" feature that alerts operators to any malfunction, making timely

maintenance possible. The electric equipment transforms the alternate current

of the mains into direct current for the motors. Each motor has its own static,

three-phase, fully controlled, stabilized and protected drive. AC motor

powered machines are equipped with vectorial inverters.

Speed is adjusted as follows:

with constant torque: from 0 to max. speed with constant power: max. speed + 50% The stability

and synchronism of each motor is controlled by an electronic data processing system which

compares the reference signals with the data coming from the A.C. motor taco generators and

angle transducers on the sensor arms, and acts on the motors accordingly. The angle transducers

are specifically installed to achieve the area reduction range specified in the drafting table. The

sensor arms are automatically centered while the machine is running. The dimensions of the

electric cabinet comply with container shipping requirements (max. height 2000 mm). Standard

machine is colored in blue, yellow and white, with oven-dried epoxy powder The electrics are

contained in a modular, dust-proof cabinet equipped with an air/water heat exchanger, access

doors at both front and back, and removable side panels.

15-block wire drawing machine with horizontal block shafts

One advantage with this block configuration is easier string up and that the

wire pass through the soap boxes are verticle eliminating the risk for tunneling

Common for all types of wire drawing machines is to make sure that the wire has a straight pass from the inlet guide pulley through the wire die on to the block. This is achieved by adjustments on the inlet pulley, the soap box and the die holder. The operator has to watch that there is lubricants in the soap containers and he has to constantly keep watch and regularly check that the wire is round. These aspects will be covered in greater detail in separate

chapters. Production speeds have increased as the drive technology improved