Struers Discotom-2 User manual

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Instruction Manual
Gebrauchsanweisung
Mode d’emploi
Mode d’emploi no.: 17001
Date de parution ..200
Spare Parts and Diagrams

Discotom-2
Instruction Manual
Instruction Manual
Table of Contents Page
User’s Guide...............................................................1
Reference Guide.......................................................17
Always state Serial No and Voltage/frequency if you have technical questions or when ordering spare parts.
You will find the Serial No. and Voltage on the type plate of the machine itself. We may also need the Date
and Article No of the manual. This information is found on the front cover.
The following restrictions should be observed, as violation of the restrictions may cause cancellation of
Struers legal obligations:
Instruction Manuals: Struers Instruction Manual may only be used in connection with Struers equipment
covered by the Instruction Manual.
Service Manuals: Struers Service Manual may only be used by a trained technician authorised by Struers.
The Service Manual may only be used in connection with Struers equipment covered by the Service Manual.
Struers assumes no responsibility for errors in the manual text/illustrations. The information in this manual is
subject to changes without notice. The manual may mention accesso
ries or parts not included in the present
version of the equipment.
The contents of this manual is the property of Struers. Reproduction of any part of this manual without the
written permission of Struers is not allowed.
All rights reserved. © Struers 2009.
Struers A/S
Pederstrupvej 84
DK-2750 Ballerup
Denmark
Telephone [phone]
Fax [phone]

Discotom-2
Instruction Manual
Discotom-2
Safety Precaution Sheet
To be read carefully
before use
1. The operator(s) should be fully instructed in the use of the apparatus,
according to the manual. The operator(s) should be fully instructed in
the use of the cut-off wheels used for Discotom-2.
2. If Struers cut-off wheels are not used, the operator(s) should notice
whether they contain materials which give off harmful vapours or dust
requiring special ventilation. If Struers cut-off wheels are not used, the
wheels must be approved for a spindle speed of minimum
3400 rpm/45 m/s.
3. Make sure to have a suitable ventilation when cutting materials which
give off harmful dust or vapours - see Safety Data Sheet for the
materials in question. When cutting Magnesium and the like, no
aqueous cooling agent must be used because of the danger of
explosion. If Discotom-2 is to be used for cutting such materials, please
contact Struers for instructions with respect to choice of cooling agent.
4. Observe the current safety regulations for handling, mixing, filling,
emptying and disposal of the cutting fluid in question. Store the cutting
fluid and use it as indicated in the instructions for the cutting fluid in
question so that harmful bacterial growth and contact with the skin is
avoided.
5. Do not open the protection screen before the cut-off wheel has stopped
completely.
6. Place the machine on a safe and stable support. Take care that the
safety functions and screen of the machine are in order. Big/heavy/
sharp work pieces must be handled in a safe way. Screen or mark
protruding work pieces.
The equipment should only be used for its intended purpose and as detailed in the Instruction Manual.
The equipment is designed for use with consumables supplied by Struers. If subjected to misuse, improper
installation, alteration, neglect, accident or improper repair, Struers will accept no responsibility for
damage(s) to the user or the equipment.
Dismantling of any part of the equipment, during service or repair, should always be performed by a qualified
technician (electromechanical, electronic, mechanical, pneumatic, etc.).

Discotom-2
Instruction Manual
1
User’s Guide
Table of Contents Page
1. Getting Started
Checking the Contents of Packing.....................................................2
Recirculation cooling unit..........................................................2
Assembly of Discotom-2 and
Connection of Recirculation Cooling Unit...........................................3
Power Connection..............................................................................3
Cutting Liquid.....................................................................................3
2. Operation
Introduction ........................................................................................4
Recirculation Cooling Unit..................................................................5
Controls..............................................................................................6
Front Panel Controls.................................................................7
Clamping of Specimens .....................................................................8
General Rules ....................................................................................9
Failure During Cutting......................................................................10
Wheel breakage......................................................................10
Discoloration of the specimen.................................................10
Excessive wear on the wheel..................................................10
Undue burring.........................................................................10
Daily Routines..................................................................................11
Mounting of Cut-off Wheel......................................................11
Consumables and Accessories........................................................11
Consumables..........................................................................11
Choice of Cut-off Wheel...................................................................12
3. Maintenance..........................................................................13
4. Trouble-Shooting..................................................................14
5. Technical Data......................................................................15

Discotom-2
Instruction Manual
2
1. Getting Started
In the packing box you should find the following parts:
1 Discotom-2 (fastened to the bottom by 4 screws)
4 Rubber mounting pads (fig. 2.1)
1 Feed hose 3/4"/19 mm dia. (fig. 2.2)
2 Hose clips 17 mm dia.
1 Return hose 1"/25 mm dia. (fig. 2.3)
1 Elbow pipe for drain (fig. 2.4)
3 Hose clips 20-32 mm (fig. 2.5)
1 Spanner, 27 mm (fig. 2.6)
1 Sieve for cooling liquid (fig. 2.7, 13.2)
1 Water guide plate (fig. 13.1)
1 Grease gun (fig. 2.11) for quick-clamping device and tilting
bearing (fig. 13.3)
1 Allen key for quick-clamping device, 3 mm (fig. 2.12)
1 Tank
1 Tank lid
1 Pump
Checking the Contents of
Packing
Recirculation cooling unit

Discotom-2
Instruction Manual
3
Discotom-2 should be placed on a sturdy table, such as the Struers
laboratory cabinet, this accommodates recirculation unit, cut-off
wheels, tools, etc.
Place Discotom-2 on the 4 rubber mounting pads supplied with the
machine (one in each corner). The pads serve to dampen the noise
and, in addition, provide adequate ventilation of the motor. Mount the
sieve and water guide plate as shown in fig. 13. Fit the thin hose (the
feed hose) between the outlet branch of the pump and the inlet
branch of Discotom-2. Use hose clips. Take the return hose from the
outlet branch of Discotom-2 to the inlet branch on the lid. The elbow
pipe supplied with the machine may be inserted in the return hose to
assist bending. Hose clips may be used, they should only be slightly
tightened.
In Discotom-2 the two units can be made to start simultaneously.
This is effected by connecting the pump motor to the free terminal
screws in the connection box at the rear of Discotom-2 (use the
upper cable entry fig. 3/see mains circuit diagram).
Before connecting Discotom-2 to the recirculation unit, check that the
voltage and frequency stated on the type plates correspond to the
local voltage and frequency.
Fig. 3 also illustrates how to connect Discotom-2 through the lower
cable entry (see mains circuit diagram). When looked at from the left,
the cut-off wheel should rotate clockwise.
The pump should rotate in the direction indicated by the arrow. The
rotational directions are reversed by changing over two phases.
Green/yellow is earth.
(from Axitom)
It is important to provide effective cooling during the cutting of
metallographic specimens.
The best coolant is water to which an additive is added to avoid
corrosion. Therefore always operate the Discotom-2 with a
recirculation cooling unit. Discotom-2 is supplied with a bottle of
additive containing both a corrosion inhibitor and a wetting agent, a
quantity of which should be added to the cooling water according to
the directions on the label. Emulsified oils may also be used and will
provide good protection, but as these oils greatly reduce the cooling
effect, we strongly recommend the use of Struers "Additive for
Cooling Fluid".
Assembly of Discotom-2 and
Connection of Recirculation
Cooling Unit
Power Connection
Cutting Liquid

Discotom-2
Instruction Manual
4
2. Operation
Discotom-2 cut-off machine is designed for rapid cutting of
metallographic, mineralogical and ceramic specimens. The cutting
operation is performed with a rotating cut-off wheel (Al2O3, sic or
diamond), the cut and wheel being cooled with a recirculation cooling
liquid to prevent changes of the microstructure of the specimens as a
result of the heat generated by the cutting.
Cutting handle
Locking pin
Quick-clamping device
Tightening handle
Protection screen
Cutting chamber
Left-hand side screen
Handle for left-hand side screen
Front panel
Controls for Discotom-2
Controls for Autofeed
Introduction

Discotom-2
Instruction Manual
5
The cut-off wheel is fixed on a spindle driven by an electric motor via
two V-belts. Spindle and motor are mounted so as to allow the cut-off
wheel to be moved up to the specimen to be cut by means of a
handle. The specimen is fixed in the front of the cutting table by
means of the two-vice quick-clamping devices. A counter balanced
protection screen shields the cut during the operation.
The recirculation cooling unit comprises a tank, a pump and an
efficient system of compartments for purification of the liquid by
sedimentation. When the pump is connected electrically to Discotom-
2, it will start automatically, being protected against overloading by a
thermal relay in Discotom-2.
Recirculation Cooling Unit

Discotom-2
Instruction Manual
6
A main switch is located on the front plate, also serving as
emergency stop, with indicator lamp POWER, push buttons for start
and stop and warning lamp AUTOSTOP for open protection screen
or overloaded motors (cutting motor and pump motor are protected
by automatic thermal relays). When the warning lamp is on, the
motors cannot be started. The front plate further accommodates a
control current fuse. In addition, Discotom-2 is provided with a valve
for controlling the rate of flow of the cooling liquid and a tommy bar
for locking the spindle during mounting and removal of cut-off
wheels. Exchange of cut-off wheels is carried out through a door in
the left-hand side.
Controls

Discotom-2
Instruction Manual
7
Name Key Function Name Key Function
Discotom-2
Autofeed

MAIN
SWITCH
Turns the main power of the
machine on/off. The main switch
is located on the front plate of
the machine also serving as an
emergency stop.

PRESSURE Adjusting knob for setting the
pressure.

POWER The power indicator lights when
the main power is on.

STOP/
MANUAL/
AUTOMATIC


AUTOMATIC to operate the
machine with the AUTOFEED
functions. STOP/ MANUAL to
operate the machine without the
AUTOFEED functions.

START  Push button for starting the
machine.

FEED -
RETRACT
When set to FEED the cut-off
wheel is moved in forward
direction. When set to
RETRACT the cut-off wheel is
retracted.

STOP  Push button for stopping the
machine.

FEED Adjusting knob for setting the
feed speed of the cut-off wheel
in forward direction.

AUTOSTOP/
OVERLOAD
SCREEN OPEN
The machine cannot be started.
due to either AUTOSTOP (the
cutting process is completed),
OVERLOAD (of motors) or
SCREEN OPEN.

Front Panel Controls

Discotom-2
Instruction Manual
8
It is very important to make sure that the object is firmly and
immovably fixed in the clamping device. Discotom-2 is provided with
a two-vice quick-clamping device capable of handling almost any
kind of object.
Normally, where a flat object is involved both vices are used. If the
object is not quite flat, only the right-hand side vice is to be tightened.
This is done to avoid the risk of destroying the cut-off wheel through
jamming when the part of the object being cut off is forced
downwards by the left-hand side vice. The object should be placed in
such a way that it rests firmly against the plates against which the
vices of the quick-clamping device slide. This ensures that the cut
will be carried out at right angles to the longitudinal axis of the object.
When cutting a number of identical specimens, it may be helpful to
fasten a stop block in the left-hand side vice, using the right-hand
side one to hold the object. Objects too delicate to be fixed in the two
quick-clamping devices may advantageously be placed on or
between two plates of expanded polystyrene. Objects mounted like
this require careful cutting, being less firmly held than when properly
clamped.
To avoid facetting the object may be securely clamped, for instance
in the right-hand vice, tightening the left-hand vice just enough to
prevent the cut part of the object from shifting on being cut.
Leave open the protection screen when the machine is not used, in
order to avoid corrosion of the cutting table by condensed water.
Clamping of Specimens

Discotom-2
Instruction Manual
9
Choose a cut-off wheel of appropriate hardness for the task.
Check that the hole has the correct diameter and never use
wheels in which the hole does not fit perfectly! Fit cardboard
washers on both sides of the wheel and tighten the nut slightly.
This is usually enough to ensure that the cut-off wheel will not
slip on the spindle. If the nut is tightened too much, the wheel
may be damaged.
Be meticulous and careful when positioning and clamping the
object to be cut, preferably it should be placed so as to obtain
equal support on both sides of the cut. Check that the surface of
the object is flat against the table before tightening the quick-
clamping devices.
Check the proper functioning of the recirculation cooling unit and
the free passage of coolant from the jets of the two pipes. Make
sure to clean the sieve frequently and to replenish the system
with coolant whenever necessary.
Take the cut-off wheel slowly up to the object. Press it so hard
against the object that it literally bites into the material and not
just "drags" against it.
Keep the cut-off machine and the recirculation cooling unit clean
and in good repair.
General Rules

Discotom-2
Instruction Manual
10
Wheel breakage is usually the result of one or more of the following
conditions:
Use of unsuitable cut-off wheels designed for a rotational speed
of less than 3450 rpm (45 m/s).
Improper mounting of the wheel.
Improper clamping of the object. Only one of the quick-clamping
devices should be tightened, unless the object is completely flat.
Rough handling of the cut-off wheel during mounting or cutting.
Machine in bad repair.
Irregular coolant distribution. The cooling system should be
cleaned frequently. The sieve in the drain pan should be cleaned
whenever it is covered by chips.
Excessive feed speed.
Wheel too hard.
The wheel hardness was inappropriate for the hardness or
dimensions of the specimen, causing the motor to become
overloaded and the speed to fall below the permissible minimum.
Insufficient wheel pressure. If the wheel is not held against the
specimen with sufficient pressure, it will drag instead of bite,
which leads to overheating.
Inadequate cooling (cf. above).
The wheel is pressed too hard against the specimen.
Inadequate cooling (cf. above)
The wheel is too soft for the task.
Machine vibrations (worn bearings).
Wheel too coarse
Wheel too hard
Too much pressure on the specimen towards the end of the
operation. Where possible, the specimen should be fastened and
supported on both sides of the cut.
Failure During Cutting
Wheel breakage
Discoloration of the specimen
Excessive wear on the wheel
Undue burring

Discotom-2
Instruction Manual
11
Open the left-hand side door (fig. 2.13), take the spindle handle to its
rear most position and depress the tommy bar and turn it approx. 90°
so as to keep it down. The nut on the spindle shaft (which has a left-
hand thread) may now be slackened by means of the spanner, the
shaft being fixed by the tommy bar. Remove nut, washer and flange
(fig. 2.14). Mount the cut-off wheel, placing a cardboard disc on
either side of the wheel to prevent damage to the cut-off wheel.
Refit flange, washer and nut, tightening the nut slightly with the
spanner.
Finally, close the door and release the tommy bar by turning it
approx. 90°, this causes it to "come out" again. Always remember to
do this before starting the motor after exchange of cut-off wheel to
avoid blocking of the motor.
Abrasive cut-off wheels are made from abrasive grains set in a
bonding material processed into a thin disc.
The abrasive material is generally either aluminium oxide (Al2O3) or
silicon carbide (SiC). Being more brittle than Al2O3, SiC is mainly
used for relatively soft and short-chipped materials like copper,
copper alloys, cast iron, (stain less steel), tungsten, titanium,
zirconium (refractory metals), whereas Al2O3is used mainly for
carbon steel, cast iron, stainless steel, nickel (refractory metals).
Usually the bonding material is either bakelite or rubber, but since
rubber gives off an unpleasant smell, all of Struers cut-off wheels
have a bakelite bond. To provide a range of cut-off wheels of
different properties matching different materials we produce a variety
of bonds, differing with respect to hardness and porosity. The
hardness and the porosity are adapted in such a way that the bond
will disintegrate at the same rate as the abrasive grains are wearing
out. Thus the grains will fall out when they have lost their cutting
ability, and fresh and sharp grains are revealed. Wheels made of a
slowly disintegrating material are referred to as hard wheels,
whereas those made from rapidly disintegrating material are called
soft wheels.
Daily Routines
Mounting of Cut-off Wheel
Consumables and Accessories
Consumables

Discotom-2
Instruction Manual
12
During the cutting operation the following factors, among others, may
affect the cutting rate of the wheel:
The hardness of the cut-off wheel
The hardness and properties of the specimen
The size of the specimen
The force at which the cut-off wheel is pressed against the
specimen
The quality and condition of the machine (thus, for instance,
worn bearings will cause vibration)
It is very difficult to decide in advance which cut-off wheel to use for a
given specimen. Also, it largely depends on which type of cutting is
desired and on the purpose for which the specimen is being
prepared. For these reasons more than one type of cut-off wheel
should be used. The following properties are determining in the
choice of cut-off wheel:
The ability of the wheel to effect a cutting without deformation of
the specimen surface and without change of the metallographic
structure, e.g. by overheating.
The ability of the wheel for fast cutting.
The ability of the wheel for cutting a wide variety of metals.
The ability of the wheel to resist wear.
These criteria form the basis for Struers program of cut-off wheels. A
general rule applies to the choice of cut-off wheels for specific tasks:
Hard specimens - soft wheels
Soft specimens - hard wheels
Generally, the hardest wheel, producing a flawless cut should be
selected for any given material. At the same time consideration
should be given to the most suitable type of abrasive agent for the
material to be cut.
Diamond cut-off wheels are used for materials too hard for ordinary
cut-off wheels with Al2O3or SiC grains.
The "Rimlock" type is a metal wheel in which diamond particles are
lodged in small pockets near the periphery. It is a low-cost diamond
wheel, mainly used for mineralogical purposes.
In the "Continuous Rim" type the diamonds are arranged in a soft
metallic or plastic bond forming the periphery of a steel disc. This
type of wheel provides cutting of very high quality and is used for
silicon, germanium, mineralogical and geological materials, etc.
Please refer to the Selection Guide in the Struers Cut-off Wheels
brochure.
Choice of Cut-off Wheel

Discotom-2
Instruction Manual
13
3. Maintenance
Due to its sturdy structure and the sealed ball bearings requiring no
extra lubrication, the general maintenance of Discotom-2 can be
confined to cleaning of the machine and the cooling system,
lubrication of the quick-clamping devices, oiling of the cutting table
and tightening (exchange) of belts.
Cleaning consists in removal of abraded particles from the cutting
table, the sieve and the bottom of the wheel chamber. After cleaning
unpainted surfaces should be oiled to avoid corrosion. Painted
surfaces may be cleaned with a damp cloth. The cooling water
should always contain a quantity of Additive for Cooling Fluid, the
required concentration being stated on the packing.
The quick-clamping device should be greased at intervals of two to
five days, depending on usage. The spindle tilting bearing (fig. 12.5)
should be greased through the nipple (fig. 13.3) every six months.
Belt tightening (belt exchange) is effected by detaching the front
plate and the rear part of the cabinet (the main switch must be
blocked with a padlock before the front plate is removed) and
slackening the four bolts securing the motor. Then the motor can be
pushed rearward to tighten the belts, after which the motor is
secured again. The pressure of a finger applied to the belts about
half-way between the pulleys must cause them to yield only approx.
10 mm. The belts should be tightened every six months, or so, or
whenever they screech under load.

Discotom-2
Instruction Manual
14
4. Trouble-Shooting
Error
Cause
Action
No light in mains lamp. Control current fuses or lamp may
have blown. Replace fuse or lamp.
Red warning lamp lights up. Movable screen or wheel chamber
door open. Close the screen or door completely.
Principal motor or pump motor
overloaded. Wait 5-10 min till the light goes out automatically.
Micro switch stuck. Lubricate or replace micro switch.
The specimen is overheated. Deficiency of water due to blocked
up jets or closed valve. Open valve. Clean jets.
Water leaks out of the wheel
chamber. Sieve blocked up. Return hose or branch blocked up. Clean sieve. Clean branch and place the hose with a gradual slope
towards the recirculation unit. Use
elbow pipe (fig. 2.4).
Quick-clamping device unable to
hold the object. Out of adjustment. Behind the clamping column is a screw for adjustment of the clamping
heart. Use the 3 mm hexagon key.
Clamping heart worn. Remove the quick-clamping device,
take off the plastic knob and pull the
clamping column out. Then replace
the clamping heart.
Protection guard falls down or opens
during cutting. Torsional spring out of adjustment. Remove the rearmost part of the cabinet and close the protection
guard. Tighten or loosen the spring
by turning the pipe around which the
spring is mounted. The pipe can be
turned after slackening the bottom
screw in the pipe.
Loud machine noise when the motor
is started. Failure to release tommy bar for locking the under the cut-off wheel. Turn tommy bar until it comes out by itself.

Discotom-2
Instruction Manual
15
5. Technical Data
Subject Specification
Metric US
CUTTING SPECIFICATIONS
Workpiece
Dimensions (Max) Quick clamping device: Max height of work piece:
Max. cutting depth:
Max. solid dia. to be cut:
for motor 3.68 kW (5HP)
85 mm
75 mm
60 mm
3.4"
3"
2.4"
PHYSICAL SPECIFICATIONS
Max. Power
Consumption 3.68 kW (5HP) S3 15% 10 min
Motor Effect Spindle speed:
Cutting speed: 3440 rpm 45 m/s
Cut-off Wheel Cut-off wheel dia.:
Mounting shaft dia.:
(with special flanges)
250 mm
32 mm
(22 mm)
10"
1.3"
(0.9)
Dimensions and
Weight Height (with open screen)
Width
Depth
Weight
600 mm
(920 mm )
575 mm
500 mm
118 kg
24"
(36")
23"
20"
260 lbs

Discotom-2
Instruction Manual
16
Subject Specification
Electrical Data Voltage / frequency:
3X220V 50HZ 13.2 A
3X220V 60HZ 7.6 A
3X380V 50HZ 6.9 A
3X415V 50HZ 7.6 A
3X440V 60HZ 6.0 A
3X480V 60HZ 5.5 A
Mains Cable
Recommendation Min.
Fuse
size
Minimum cable size
@ Min. fuse Max. Fuse size Minimum cable size @ Max. fuse
3X220V 50HZ 16 A 3x1,5mm² + PE 25 A 3x1,5mm² + PE
3X220V 60HZ 15 A 3xAWG14 + PE 25 A 3xAWG14 + PE
3X380V 50HZ 10 A 3x1,0mm² + PE 25 A 3x1,0mm² + PE
3X415V 50HZ 10 A 3x1,0mm² + PE 25 A 3x1,0mm² + PE
3X440V 60HZ 10 A 3xAWG16 + PE 25 A 3xAWG14 + PE
3X480V 60HZ 10 A 3xAWG16 + PE 25 A 3xAWG14 + PE
Important:
Local standards may overrule the recommendations for the main supply cable.
If necessary, please contact a qualified electrician to verify which option is suitable for the
local installation setup.
Residual Current
Circuit Breaker type A, 30 mA (or higher) is recommended.
Environment Noise level Max. 80 dB (A) at a distance of 1 m from the machine
Safety standards Please refer to the Declaration of Conformity
Recirculation cooling unit
Voltage / frequency: 3 x 110-120 V/50-60 Hz
3 x 220-415 V/50-60 Hz
3 x 420-480 V/50-60 Hz
3 x 500-580 V/50-60 Hz
Motor Output 140 W
Pump Capacity 57 l/min at 1 m water column
Rate of Protection IP 44
Dimensions and Weight
Height
Width
Depth
Weight
Metric
410 mm
400 mm
500 mm
7 kg
Imperial
16"
16"
20"
15 lbs
Autofeed
Air Pressure:
Max. consumption: Min. 4 bar, max. 9.9 bar approx. 5l/min