Soyer BMK-8 U User manual

Operating Instructions
BMK-8 U
BMK-12 W
Stud Welders

BMK-8 U / BMK-12 W
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BMK-8 U / BMK-12 W
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Operating Instructions
BMK-8 U
BMK-12 W
Stud Welders
Serial number*
Stud welder BMK- _________________________
Please enter your type of stud welder and serial number here, so that these
data are immediately available if you need service support.
Survey of stud welder types
Order no.
Code designation
Note
P01315
BMK-8 U
Standard device 3 x 230 up to 500 V power supply
P01331
BMK-12 W
Standard device (3 x 400 V power supply)
P01332
BMK-12 W automatic
Standard device (3 x 400 V power supply)
and automatic set for stud reload
P01333
BMK-12 W universal
Special device (3 x 230 up to 500 V power supply)
P01334
BMK-12 W universal
automatic
Special device (3 x 230 up to 500 V power supply)
and automatic set for stud reload
P01337
BMK-12 W / C
Special device (3 x 400, 460, 600 V power supply)
Heinz Soyer Bolzenschweißtechnik GmbH
Etterschlag
Inninger Straße 14
82237 Wörthsee
Telephone [phone] - 885 - 0
Telefax [phone]
www.soyer.de

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Congratulations on purchasing a SOYER stud welder. You have made an excellent
choice. Your SOYER stud welder was specially developed for the high-speed
fastening of SOYER welding studs in compliance with DIN EN ISO 13 918 on metallic
workpieces.
Our devices have been tested with regard to safety requirements and corres-
pond to the currently valid European and national guidelines. Proof of
conformity has been established and the manufacturer is in possession of the
corresponding documents.
FOR YOUR SAFETY
Read all of these operating instructions prior to start-up. Please
follow all safety precautions as well as all chapters of these
operating instructions before starting to weld. Non-compliance
with the safety precautions can result in serious personal injuries
or death.
SOYER®is a registered trade mark of Heinz Soyer Bolzenschweißtechnik GmbH.
It is prohibited to transmit or reprint this document, as well as to utilize or disclose its
contents, unless this has been expressly granted.
Non-compliance with this regulation is liable to compensation. All rights reserved,
particularly in the case of a patent grant or a GM registration.
We have verified that the contents of this pamphlet correspond to the hard- and
software described. Deviations, however, cannot be excluded so that we cannot
warrant for absolute compliance.
The illustrations contained in this instruction manual may vary in some details from
your product. This, however, has no influence on the handling of the machine.
The data in this documentation have been verified regularly and necessary corrections
will be incorporated in future impressions. Any suggestions for improvement will be
appreciated.
Date of issue: August 01, 2006
Revision
© Heinz Soyer Bolzenschweißtechnik GmbH 2006 · All rights reserved
Printed in the Federal Republic of Germany

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Heinz Soyer Bolzenschweißtechnik GmbH
Inninger Straße 14
82237 Wörthsee
CE Declaration of Conformity
We herewith declare that the machine described in the following and the version available on the
market correspond in design and construction to the safety and health requirements of the listed
guidelines and standards. Any unauthorised modification to this machine automatically annuls this
declaration.
Designation of machine : Stud welding device
Machine type : BMK-12W
BMK-12W automatic
BMK-12W universal
BMK-12W universal automatic
Machine no. : ______________________
Applicable EU directives : RoHS Directive (2011/65/EU)
Low Voltage Directive (2014/35/EU)
EMC Directive (2014/30/EU)
Applied harmonised : EN 60 974-1:2012
standards, in particular EN 60 974-10:2008
Applied national standards : DGUV Regulation 1
Date : 16 July 2015
Producer’s signature : ____________________
Signer’s function : Managing Director

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Table of contents
1Safety precautions.............................................................................................. 8
1.1 Description of reference signs in the operating instructions........................................ 10
1.2 Staff qualification and training...................................................................................... 11
1.3 Dangers in the case of non-compliance with safety instructions................................. 11
1.4 Before starting to weld................................................................................................. 11
1.5 Working with the stud welding equipment ................................................................... 11
1.6 Inadmissible operating methods.................................................................................. 11
1.7 Stopping the stud welder ............................................................................................. 11
2General............................................................................................................... 12
2.1 The following should be principally observed.............................................................. 12
2.2 Application ................................................................................................................... 12
2.3 Marketing and service.................................................................................................. 12
2.4 Information on the documentation ............................................................................... 13
2.4.1 Information on operating instructions........................................................................... 13
2.4.2 Conduct in the case of malfunctions............................................................................ 13
3Description of stud welder............................................................................... 14
3.1 Short-cycle drawn arc stud welding technology .......................................................... 14
3.2 Stud welding ................................................................................................................ 15
3.2.1 Short-cycle drawn arc welding with shielding gas ....................................................... 15
3.2.2 Short-cycle drawn arc welding with ceramic ferrules................................................... 15
3.3 Construction of the BMK-8U / BMK-12W stud welders ............................................... 15
3.4 Technical data.............................................................................................................. 16
3.5 BMK-12 W interfaces................................................................................................... 17
3.5.1 CNC interface .............................................................................................................. 17
4Installation of stud welder ............................................................................... 18
5Start-up.............................................................................................................. 19
5.1 Front and rear view...................................................................................................... 19
5.1.1 Operating elements...................................................................................................... 21
5.1.2 Display elements.......................................................................................................... 21
5.1.3 • LCD display ............................................................................................................... 22
5.1.4 Symbols ....................................................................................................................... 23
5.1.5 Fuses (items 1 and 3, chapter 5.1).............................................................................. 24
5.1.6 Earth connection.......................................................................................................... 24
5.1.7 Connection of stud welding gun................................................................................... 25
5.1.8 Mains supply................................................................................................................ 25
5.2 Adjustment of operation modes................................................................................... 26
5.2.1 Starting the stud welder............................................................................................... 26
5.2.2 Operation modes / parameters.................................................................................... 26
5.3 Special functions.......................................................................................................... 29
5.3.1 Special function "Erasing the working storage"........................................................... 29
5.3.2 Special function "Display of operating counter"........................................................... 29
5.3.3 Special function "Setting the type of feeder and its functions" .................................... 30
5.3.4 Special function "Selection of language. Display of software version number"........... 31
5.3.5 Special function "Setting the feeder operation" ........................................................... 32
5.3.6 Extended special functions.......................................................................................... 33

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6Operation........................................................................................................... 34
6.1 Standard operation ...................................................................................................... 34
6.1.1 Setting welding parameters for standard welding operation........................................ 34
6.2 Welding parameters for welding operation .................................................................. 36
6.2.1 Minimum sheet thickness when welding with drawn arc operation............................. 36
6.3 Important information for standard welding operation (stud welding).......................... 37
6.4 Welding operation with shielding gas .......................................................................... 37
6.4.1 Preparation of gas supply............................................................................................ 38
6.4.2 Instructions for welding with shielding gas................................................................... 38
6.5 Welding operation with ceramic ferrules...................................................................... 39
6.5.1 Instructions for welding with ceramic ferrules.............................................................. 39
7Quality control .................................................................................................. 41
7.1 General ........................................................................................................................ 41
7.2 Demands on the company........................................................................................... 41
7.3 Test execution.............................................................................................................. 41
7.3.1 Production of samples ................................................................................................. 41
7.3.2 Visual inspection.......................................................................................................... 42
7.3.3 Bend test...................................................................................................................... 43
7.3.4 Tensile test................................................................................................................... 43
8Maintenance...................................................................................................... 44
8.1 Important instructions................................................................................................... 44
8.2 Important instructions for all service works.................................................................. 44
8.3 Cleaning....................................................................................................................... 44
8.3.1 Detergents ................................................................................................................... 44
8.4 Replacement of components....................................................................................... 44
9Troubleshooting ............................................................................................... 45
9.1 Malfunctions................................................................................................................. 46
10 Transport and storage...................................................................................... 49
11 Terms of warranty............................................................................................. 49
12 List of standards and guidelines .................................................................... 50
Appendix A /
Adjustment of short-cycle drawn arc welding guns Appendix A

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1 Safety precautions
These safety precautions are for your safety.
General safety instructions
Become trained and read and follow all safety precautions listed below as well as all
chapters of this manual before starting to weld.
Non-compliance with the safety precautions can result in personal injuries or
death.
Only qualified persons are allowed to install, operate and maintain the equipment.
Keep away children and juveniles under the age of 16 years from the equipment.
WARNING
It is prohibited to open the stud welder.
The service personnel are required to meet special qualifications.
Our after-sales service has adequately trained personnel, suitable service equipment
and the means to carry out all necessary works.
Warning of electromagnetic fields
Keep sufficient distance from electronic devices. When stud welding, highly intensive
electromagnetic fields are created which may permanently damage these devices
(e.g. television sets, airbags).
Ensure that the welding equipment is not operated near electronically sensitive life-
supporting equipment, such as in intensive care units in hospitals.
Persons with pacemakers must neither operate the stud welding equipment nor stay
near it while it is running.
Electric shock can cause death
Prevent electric shock by insulating your body from work and ground. Stand on dry
insulating material and wear rubber soled shoes.
Be sure power source is properly connected to the ground system of the power
supply.
Inspect all cables including power cord for damage, wear or bare wiring. Immediately
replace damaged or worn cables.
Always ensure the correct supply voltage in accordance with the data plate. Never
connect the stud welder to a power supply network with incorrect supply voltage.
Always disconnect the mains cable from the mains supply before starting any cleaning
works. Only trained and appropriately qualified personnel are allowed to carry out
works at the electric mains supply and welding system.
Do not touch live electrical parts with bare hand. Wear dry, hole-free insulating gloves.
Do not wear rings, watches or electrically conductive jewellery.
Keep the work area, studs, stud holders, guns, cables, power source as well as your
clothes dry.

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Fumes and gases can cause damage to your health
Fumes and suspended matters may be generated during welding. Beware of fumes
detrimental to health, particularly when using surface treated materials. If possible,
only weld in rooms which are higher that 3 m. Please also observe the safety
regulations applicable for your country.
Do not breathe fumes and gases. Use adequate ventilation in the work area to remove
fumes and gases.
Welding can cause fire and explosions
Welding sparks and heat from flames and arcs can cause fires. Have a portable fire
extinguisher handy for immediate use. Be sure you are trained for properly using it.
When welding, do not wear clothes soiled with easily combustible substances such as
oil, grease and paraffin oil etc.
Comply with the fire regulations and do not weld, for instance, in hazardous locations.
Pay attention to flammable objects at the welding place. All flammable materials and
liquids, such as oil, fuel, etc. must be removed prior to the start of work.
Electronic equipment (e.g. airbags) and the use of explosive substances for fuel
supply require further safety precautions when carrying out welding operations on
cars. Appropriate information can be obtained from the trade associations or the car
manufacturers.
Skin and eye protection
Arc rays and welding spatters can injure eyes and skin.
Wear safety glasses with side shields and protective goggles with correct shade of
filter to protect your eyes from welding spatters and flashes of light that are generated
during the welding process.
Wear gauntlet gloves made of leather and non-combustible closed working clothes
such as heavy long-sleeve shirts, cuffless pants and safety shoes.
Wear a leather apron to protect your clothes from welding spatters.
Keep sleeves and collars buttoned and remove open pockets from the front side of
your clothing.
We recommend using ear protection. Some welding and working processes may
generate loud noises.
Movable parts can cause injury
Beware of movable parts such as fans. Keep hair, hands, loose clothing, and any tools
away from the air apertures.

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1.1 Description of reference signs in the operating instructions
The non-observance of safety instructions such as pictographs and warning words can cause damage
to persons. The safety instructions of this manual describe the following:
Safety instructions
Danger!
Warning!
Immediate hazards which could result in serious personal injuries or loss of
life.
Potential hazards which could result in serious personal injuries or loss of
life.
Caution!
Caution!
Potential hazards which could result in minor personal injuries.
Beware of property damage
Note!
Important!
Potential detrimental situation which may cause damage to the product or
to an object surrounding it.
Instructions for application and other useful information facilitating the
proper use of the product.
Safety symbols
The following pictographs for warnings, bans and decrees are used in this manual:
Ban for persons with
pacemakers
Ban (only in combination
with an additional safety
symbol)
Do not touch
Housing is current-
carrying
Fire extinguisher
Warning of a danger
spot
Beware of dangerous
electric voltage
Beware of
electromagnetic field
Beware of movable
parts
General ban (only in
combination with an
additional safety
symbol)
Beware of inflammable
substances
Beware of explosive
substances
Eye protection
required
Protective clothing
required
Ear protection
required
Protective gloves
required

General instructions are marked with the hand symbol.

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1.2 Staff qualification and training
The staff responsible for operation, maintenance, inspection and assembly must have the respective
qualification for carrying out these works. Field of responsibility, competence and the supervision of
staff have to be exactly regulated by the user. If your personnel do not have the necessary knowledge,
they have to be trained and instructed. If necessary, this can be done by the manufacturer/supplier on
behalf of the user. Furthermore, the user must ensure that the contents of the operating instructions
are fully understood by the staff.
The society of welding institutes (GSI: Gesellschaft der Schweißtechnischen Institute mbH) offers the
appropriate training courses for your personnel.
For information on branches, please refer to website http://www.dvs-ev.de.
1.3 Dangers in the case of non-compliance with safety instructions
The non-compliance with safety instructions may not only endanger persons, but also the equipment
and its environment. Any non-compliance with safety instructions may result in a complete loss of
damage claims.
Non-compliance with safety instructions may have the following consequences:
• Failure of important system functions
• Failure of prescribed methods for maintenance
• Danger of persons through electric, mechanic, thermal and acoustic influences
1.4 Before starting to weld...
• Check the state of all cables and cable connections before starting to weld.
• Immediately replace defective cables and cable connections.
• Ensure that the air apertures of the housing are not covered. Heat accumulation may damage the
stud welding device.
1.5 Working with the stud welding equipment
• Comply with all accident prevention regulations which apply to the operation of your welding device.
If an accident happens,
• switch off the welding device and disconnect it from the mains supply and
• call a doctor.
1.6 Inadmissible operating methods
Limit values
Working safety of the stud welding equipment supplied can only be guaranteed when the system is
used in accordance with its purpose. The limit values indicated in the chapter “Technical data” must
never be exceeded.
1.7 Stopping the stud welder
• Switch off the main switch of the stud welder
• Disconnect the mains plug from the socket.
• Disconnect
- the control cable
- the welding cable
- the earth cables
from the stud welder.
• Disconnect gas supply and compressed-air supply from the stud welder, if connected.
• Roll up the cables without buckling them.
• Make sure stud welder can not be used by unauthorized persons.

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• Check welding cable and connections of the stud welder for damage such as burn-off, mechanical
wear etc. and have damaged parts replaced by the SOYER customer service.
2 General
2.1 The following should be principally observed...
With this stud welder you have purchased a product which
• is state-of-the-art technology
• fully complies with the current safety requirements and
• enables successful working
Before installing the stud welder, please observe the following:
• Store the operating instructions in a place accessible to every operator.
• Ensure that the respective operator has read and understood the operating instructions prior to
installation. Each operator should confirm this per signature.
• Prevent the stud welder being operated by unauthorized personnel.
• Only trained personnel may operate the stud welder.
• Call a doctor in case of an accident.
2.2 Application
The BMK-8 U / BMK-12 W SOYER stud welders for short-cycle drawn arc welding allow SOYER
threaded studs made of plain steel, stainless steel and heat-resistant steel as per DIN EN ISO 13918
to be welded on different workpieces (sheets, tubes, steel girders etc.).
Usually round pins with or without thread are welded. You may also weld fasteners with different
cross-sectional shapes. For this purpose, however, special stud holders and ceramic ferrules or gas
shrouds are required.
With the BMK-8 U / BMK-12 W SOYERstud welders it is also possible to weld studs of other metallic
materials than steel. It is, however, necessary to first carry out experimental welds and to inspect
them.
2.3 Marketing and service
If you have any questions regarding the operation of the BMK-8 U / BMK-12 W stud welders, retrofits
for special applications or if you require service, please contact your responsible service office or the
following address:
Heinz Soyer Bolzenschweißtechnik GmbH
Inninger Straße 14
D-82237 Wörthsee
Telephone [phone] Telefax [phone]
www.soyer.de [e-mail]

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2.4 Information on the documentation
The following operating instructions are supplied with the BMK-8 U / BMK-12 W stud welders:
• Operating instructions for BMK-8 U / BMK-12 W Order no. P00220
2.4.1 Information on operating instructions
Legal relationship
We draw your attention to the fact that the contents of these operating instructions are neither part of
any former or existing arrangement, pledge or legal relationship nor are designed for modifying the
latter. All obligations of Heinz Soyer Bolzenschweißtechnik GmbH result from the respective contract
of purchase which also comprises the complete and generally valid warranties. These contractual
warranty terms are neither extended nor restricted by the implementation of these operating
instructions.
CAUTION
Do not carry out any actions on the stud welding equipment without specifically
knowing the operating instructions or the respective part. Ensure that only qualified
personnel familiar with the operating instructions and the necessary technical
activities (training!) operate the system.
2.4.2 Conduct in the case of malfunctions
If malfunctions occur, first try to detect and eliminate the causes according to the "Troubleshooting" list
in chapter 9 of these operating instructions. In all other cases, please contact our service department.
If you require our service, please make sure that you supply us with the following information:
• Customer number • Product designation / options
• Serial number • Year of construction
• Stud and workpiece material • Stud dimensions
This information will help us both to save time and unnecessary costs, e.g. caused by delivering the
wrong spare parts.

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3 Description of stud welder
3.1 Short-cycle drawn arc stud welding technology
Illustration 1: Short-cycle drawn arc stud welding technology
The BMK-8 U / BMK-12 W SOYER stud welders run according to the principle of short-cycle drawn
arc stud welding.
A d.c. power supply provides the welding current. For detailed information, please refer to the
following regulations:
•DIN EN ISO 14555, "Arc welding of metallic materials"
• DVS Information Sheet 0902, "Drawn arc stud welding"
1. When welding, the stud is positioned on the workpiece.
2. The preweld current is ignited and the stud is lifted off the workpiece.
3. The subsequent ignition of the main current creates a molten pool between stud and
workpiece.
4. The stud immerses in the liquid molten pool and the material solidifies.
This method allows manual, semi-automatic and fully automatic inseparable welding of threaded
studs, pins, tapped studs, insulating pins, special studs and many other fasteners made of steel, CrNi
steel, heat-and acid-resisting steel with the workpieces. Conditionally it is also possible to weld nickel
and titanium depending on the respective requirements. Standard studs for drawn arc and capacitor
discharge welding in compliance with DIN EN ISO 13918 can be welded without requiring any
auxiliary aids. The application of shielding gas or ceramic ferrules is recommended for studs with a
diameter of more than 6 mm to prevent pore formation and to optimise the formation of bulges.
The standard BMK-8U / BMK-12W stud welders are suitable for operation with shielding gas and
ceramic ferrules. A d.c. power supply provides the welding current. The weld duration can be selected.
Owing to the low penetration depth of about 0.4 mm, this method can be applied from a sheet
thickness of 0.6 mm on. It guarantees particularly safe, uniform and reproducible stud welded joints
without high requirements to setting accuracy and stud tip quality. Application is especially
recommended for workpieces with difficult surface characteristics, e.g. oil, grease, zinc and other
galvanic treatments as well as rolling scale, electroconductive priming coats, forging scale, oxide films,
etc. The ratio of minimum sheet thickness and stud diameter amounts to 1:8.
IMPORTANT INFORMATION
Ensure that the surface is electroconductive.
Grind hot galvanized parts.

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The following welding methods are possible when using the BMK-8U / BMK-12W SOYER stud
welders:
• Short-cycle drawn arc stud welding without shielding gas and ceramic ferrules.
• Drawn arc stud welding using ceramic ferrules as auxiliary aid.
• Drawn arc stud welding using shielding gas as auxiliary aid.
Preferably use shielding gas as auxiliary aid. The use of ceramic ferrules as auxiliary aid, however, is
necessary when carrying out particularly critical welding works as e.g. welding works during which the
gun has to be held in a horizontal position or above the head.
3.2 Stud welding
The PH-3N stud welding gun with control cable and shielding gas equipment is the standard gun to be
connected to the BMK-8U / BMK-12W stud welders. These operating instructions only refer to the
BMK-8U / BMK-12W stud welders.
For information regarding the stud welding guns to be used and their setting, please refer to the
respective operating instructions.
3.2.1 Short-cycle drawn arc welding with shielding gas
With this method, a gas mixture containing 82% of Argon and 18% of CO2(e.g. Corgon®18*) is used as
auxiliary aid.
This shielding gas protects the welding point from the atmosphere and simultaneously supports the
weld pool. Moreover, it ensures a concave fillet weld upset formation with a blank metallic surface,
thus reducing the risk of corrosion and obtaining an improved dynamic behaviour of the welded joint.
An accurate bulging, to scale or in a calibrated or reproducible type, is not possible when welding with
shielding gas without using any auxiliary aid. Stud welding with shielding gas can be carried out at
much shorter intervals as no ceramic ferrules have to be fitted and removed in each welding process.
*) Corgon®18 is a gas mixture of Linde AG in D-82049 Höllriegelskreuth
R
3.2.2 Short-cycle drawn arc welding with ceramic ferrules
The ceramic ferrule fulfils the following functions:
• It centres the electric arc.
• It protects the welding point from the atmosphere.
• It ensures the exact formation of the weld upset.
• It prevents too rapid cooling of the weld pool.
• It partially protects against spraying sparks.
To ensure a perfect and accurate weld upset, each stud requires a ceramic ferrule matching its
diameter and shape. After every welding process, the ceramic ferrule must be knocked down and
replaced by a new one. Usually this method allows you to weld in any position.
IMPORTANT INFORMATION
Ensure ceramic ferrules are absolutely dry.
3.3 Construction of the BMK-8U / BMK-12W stud welders
The BMK-8U / BMK-12W stud welders have a handy, compact and robust design.
The carrying handles on the top of the housing allow easy transport so that the stud welders can be
used at different work places.

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3.4 Technical data
Designation
BMK 8 U
BMK 12 W
Welding process
Short-cycle drawn arc stud welding
Welding range for SOYER
threaded studs, DIN EN ISO
13918
M3 –RD 10 or. 2 –9 mm
M3 –RD 12 or. 2 –11 mm
Material
Steel, stainless steel and heat-resistant steel (aluminium
conditionally depending on respective requirements
Source of current
Transformer / Rectifier
Welding current
600 A
800 A
Welding time
1 up to 1000 ms
Welding sequence
15 –30 studs/min with M3
up to 3 studs/min RD 10
15 –30 studs/min with M3
up to 3 studs/min RD12
Standard gun
PH-3N stud welding gun
Power supply
CEE 16 A (3P + protective
earth conductor)
3 x 400 V 50/60 Hz
3 x 230, 3 x 440 or 3 x 500 V
50/60 Hz possible
CEE 32 A (3P + protective
earth conductor)
3 x 400 V 50/60 Hz (standard)
3 x 230, 3 x 440, 3 x 460, 3 x
500 or 3 x 600 V 50/60 Hz
possible, depending on the
special type (OPTION)
E-constant current
0.3 A / phase
E-constant power
200 VA
E-peak current
45A / phase with 3 x 400 V
(short-time operation)
60A / phase with 3 x 400 V
(short-time operation)
Open-circuit power
76 V / DC
System of protection
IP21
Fuse element at front panel
F1 = 0.315 A slow-blow F2 = 2 A slow-blow (with 400V mains
supply)
F2 = 3.15 A slow-blow (with 230 V mains supply)
Interfaces
Feeder interface: 15-pole socket
CNC interface: 9-pole socket
RS 232 interface: 9-pin plug (no function)
Compressed air supply
max. 6 bar (compressed air only with optional automatic set)
Shielding gas supply
max. 4 –5 l/min.
Dimensions
360 x 325 x 500 (w x h x d)
Weight*
41 kg
48 kg
Colour
RAL 5009 azure
Subject to technical changes
* Slight deviations are possible depending on accessories.

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3.5 BMK-12 W interfaces
3.5.1 CNC interface
CNC-interface
9-pole D-Sub socket terminal strip
Release
Start
SOW
FC
Customer control
1
6
2
7
3
8
4
9
5
Start
SOW
+U external
FC
+U external
Terminology:
SOW Stud on workpiece
Shows contact between stud and workpiece. Contact is necessary to start welding
process via the starting signal.
Start Contact releases the welding process.
EP(FC) End of welding process
Contact is closed after welding to show the end of this specific welding process (new
welding process can be started now).
Timing diagram:
SOW
Start
Weldingin
operation
FC

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4 Installation of stud welder
The top of the BMK-8U / BMK-12 W stud welders is equipped with two plastic carrying handles.
CAUTION
These handles are intended for transport by hand only. Never pull ropes through these
handles to lift the stud welder by means of a crane to the installation site. The stud
welder would become instable and might tilt from its original position. As a result the
handles could rip and the system would fall on the ground.
• Only install the stud welder on an even surface. The anti-vibration pads located on the bottom of the
welding equipment guarantee its anti-skid position and serve as vibration dampers.
• Although the stud welder is resistant to environmental influences, it should be protected against
dampness and dust.
• Please pay particular attention to the bearing strength of the workshop furniture and ensure a safe
and stable position of the welding equipment.
• Make sure there is sufficient free space around the air apertures, otherwise the excess temperature
safety mechanism will respond and interrupt the welding process. This state, represented as
"Transformer overheated, please wait", is shown alternately with the current operation mode on the
display.
Only when this information is no longer shown on the display, is it possible to continue the welding
operation.
• Install the stud welder close to the welding location.
• Ensure correct connected loads for electrical connections:

The stud welder has a four-core connecting cable: 3 phases + protective earth conductor.
Please also refer to “Technical Data”.
Make sure mains socket and welding system are properly grounded.
• Please observe that additional extension cables cause a voltage drop, possibly leading to system
disturbances.
• When welding with shielding gas, make sure the gas cylinder is installed safely in its admissible,
accident-proof installation device.
CAUTION
The gas cylinder must be protected against tilting when being installed vertically. It must
not be installed in a horizontal position since the gas cylinder connection and/or
manometer could be easily damaged.
• Ensure sufficient ventilation of the working room when operating the welding system.
NOTE
The housing of the stud welder corresponds to safety class IP 21. Please observe that
this system of protection is not suitable for being operated or transported in the rain.

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5 Start-up
5.1 Front and rear view
1 2 3 4 5 6
13 12 11 10 9 8 7
Front view of BMK-8U / BMK-12 W (above illustration of BMK-12W corresponds to BMK-8U)
1 • Fuse element F1
2 • Main switch (switch stud welder on)
3 •Fuse element F2
4 • LCD display
5 • Indicator lamps for function control
6 • Function keys for setting the welding parameters
7 • Air function "forward" (option)
8 • Air function "backward" (option)
Connection for welding guns or heads with automatic stud feed
9 •Control cable connection
10 • Welding cable socket
The control cable connection and the welding cable socket serve to connect the stud welding
guns or heads to the stud welder.
11 • Gas connection socket
Before welding with shielding gas, connect the gas hose of the welding gun or head to the gas
connection socket.
12 • Earth cable connectors
The earth cable connectors serve to connect the earth clamps to the stud welder.
13 • Mains cable
The mains cable is a four-core (3P + PE), highly flexible connecting cable for connecting the
stud welder to the mains supply.

BMK-8 U / BMK-12 W
20
14 15 16 17 18
20/21 19
Rear view of BMK-8U / BMK-12 W
14 15-pole connecting socket / feeder interface (OPTION)
The feeder interface serves to connect the feeder control to the stud welding device.
15 9-pole connecting socket / CNC interface (OPTION)
The CNC interface serves to be connected with an external control system to control the stud
welding process.
16 9-pin connector, interface RS 232 (OPTION)
This interface serves to be connected with an external control system.
17 Danger sign
18 Type plate
19 Shielding gas connector
This connection serves to supply the stud welder with gas by means of a pressure reducer.
The admissible gas flow value ranges between 4 and 5 l/min.
20/21 Compressed-air supply connection (OPTION)
This connection serves to supply the stud welder with compressed air and to connect the
compressed air lines of the feeder control to the stud welder. The admissible supply pressure
amounts to a maximum of 7bar.