DRONCO GmbH
Wiesenmühle 1
D-95632 Wunsiedel

Summary
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The company
DRONCO GmbH
Foundation: 1962 by Dr. Otto Nothhaft
Transformation into a LLC: 01.09.2013
Board of management: Jakob Jürgens,
Manfred Eisenberger
Staff: 300 people
Capacity / daily output: 250,000 discs
Turn-over: 2013 : 40 Million Euros
70% Export sales
30% Domestic sales
Subsidiaries:
.
DRONCO Abrasives UK Ltd.
DRONCO France EURL
DRONCO Scandinavia AB
Leurop.de diamond tools

The company
Specialist for the manufacturing of tools in the sector of
Cutting metals
Cutting stone
Grinding
Problem-solvers for the work on metal, stone, wood and lacquer.
DRONCO - Range
• Cutting and grinding wheels
• Flap discs
• Diamond tools
• Flexible and semi-flexible abrasives
• Ceramic bonded abrasives
• Coarse cleaning fleeces
• Technical brushes

Product Lines
Cutting wheels
Grinding wheels
Flap wheels
Diamond cutting wheels
Perfect Evolution Special craftsmen universal for all kind of metals and stone
High End universal for all kind of metals
Special range for craftsmen and industry special for different metals, stone,
Concrete and asphalt metals for different metals, stone for metals, stone,aluminium, plastic for mild and stain-
Less steel and other metals for stone, concrete for stone, concrete for stone, concrete, special applications
Characteristics

Grains
Aluminium oxide
Al
2
O
3
Zirconium
ZrO
2 /
Al
2
O
3
Silicium carbide
SiC

Grains
Working on metal
Abrasive grain
Working on stone
NK
Corundum
HEK
EK
(pink, white)
NK
(HT- grain)
SiC black
Silicon carbide
SiC green
Increasing grain endurance
Increasing hardness

Grains
Raw material: Bauxit (contains Aluminium oxide Al
2
O
3 and other compounds, e.g. iron oxide)
The raw material is melted in electric furnaces at a temperature of approx. 2000 ° C. Corundum emerges in different qualities, in accordance to the degree of purity.
Special corundum white > Special
Special corundum pink > Special
Normal corundum >Perfect
Blocks of approx 5 tons are crushed and sieved.
In the thin discs and the Evolution products we are using special treated grains ( heated, coated ) which are generated by refining processes . These abrasives are very performant and durable.

Grains
Raw material: glass sand and petroleum coke
Silicon Carbide is produced in resistance furnaces, where exact mixtures of petroleum coke and siliceous sand are burned.
Silicium Carbide arises by the following chemical reaction :
Si O
2
+ 2C --> SiC + CO
2
After the melting the SIC pieces are assorted according to their purity. For abrasives the minimum content is 98 % SIC. For metallurgical purposes it can be lower ( 90 % ). The pieces are crushed and assorted to grains

Grains
10
9
8
7
6
5
4
3
2
1
0
Fl in t
Ko ru nd
Degree of hardness
1
2
3
4
5
Test material according to
Mohs
Tallow
Common salt
Calcite
Fluorite
Apatite
6
7
8
9
10
Feldspar
Quartz
Topaz
Corundum
Diamond
Si
C nk or un d
Di am an t
Zi rko
Everyday objects as alternative verification
Finger nail
Finger nail / Brass nail
Iron nail / Brass nail
Iron nail, standard steel (penknife)
standard steel (penknife), hardened steel (rasp) hardened steel (rasp) hard alloys of Wolfram, Titanium,
Vanadium, Molybdenum and others e.g. Widia
Electro Corundum (synthetic alumina)
SiC or Boron Carbide

Grains
8
6
4
2
0
SiC al uminium oxide zirconium

Cutting and grinding wheels
Label
Glassfibre reinforcement
Mass
Ring
Glassfibre reinforcement
(laminated with paper)
70% Abrasive Grain (corundum / silicon carbide)
15% Resin (fluid / powder)
15% Filling material (Feldspar, Pyrite or similar)

Cutting and grinding wheels
Free-hand cutting wheels
- Glassfibre reinforcement, laminated with paper
- Substance (mass)
- Glassfibre reinforcement
- Label
- Ring
Stationary cutting wheels
- Small glassfibre reinforcement, laminated with paper
- Substance (mass)
- Large glassfibre reinforcement
- Substance (mass)
- Small glassfibre reinforcement
- Label
- Ring
Grinding wheels (up to a thickness of 8mm)
- Glassfibre reinforcement, laminated with paper
- Substance (mass)
- Glassfibre reinforcement
- Substance (mass)
- Glassfibre reinforcement
- Label
- Ring

Cutting and grinding wheels
Stock of raw materials
Incoming check
Mixing
Check
Pressing Unit
Check
Baking
(Hardening in electric ovens at approx. 185 °C, approx. 14 hours)
Packing,
Dispatch
Automatic steering of the furnaces
Final
Check

Cutting and grinding wheels
1. Product lines: There are 3 product lines - Perfect, Evolution,
Special
2. Type designation: Divided into 4 statements
A: Aluminium Oxide is the abrasive used to cut metal.
24: Indicates the grain size. The higher the number, the finer the grain.
R: The second letter indicates the hardness of the disc. The further into the alphabet, the harder the disc.
BF: Resin bonding, glassfibre-reinforced.
3. Measurement: Comprise of [diameter of the disc] x [disc thickness] x [bore size]. Measurements given in mm.
4. max r.p.m.: Indicates the permitted maximum r.p.m.

Cutting and grinding wheels
5. Red bar: Indicates 80 m/s as permitted peripheral speed.
Green bar: Indicates 100 m/s as permitted peripheral speed.
6.
Background: Blue = cutting metal
Green = cutting stone
Red = grinding
7.
oSa: The disc is manufactured according to the regulations of the Organisation for Safetey of Abrasives.
8.
Icons: Indicating safety information and application.
9.
Made in Germany: Stands for proven quality - our products are all manufactured and tested in germany.
10. www.dronco.de: Our address in the Internet - we are always there when you need us.
11. Item code

Cutting and grinding wheels
The hardness is indicating the resistance of the abrasive grain against breaking out of the bonding.
It is indicated by letters, whereby the following is generally applicable:
A = lowest hardness
Z = highest hardness
Common in resin-bonded discs:
Q = soft wheel
R = medium hard wheel
S = medium hard to hard wheel
T = very hard
Wheels with a hardness of “R” and “S” are usually applied universally.
Soft wheel for hard material.
Hard wheel for soft material.
The hardness is of relevant importance and influence for the process of cutting and grinding. It is determined by the shape and proportion of the bonding as well as the grain size and the porosity of the wheel.
Hard abrasives are more lasting, but they cut/remove less material per unit. Soft abrasives cut/remove quicker, but due to the fast abrasion of the wheel the costs for the tool rises.

Cutting and grinding wheels
for working on metal for working on stone grinding
Do not use damaged wheel!
Stationary cutting
Do not grind!
Respect saftey information of manufacturer.
Wear protection clothes and equipment.

Cutting and grinding wheels
Safety has got the highest priority!
Our production is done in accordance with the following regulations, instructions and standards :
Dronco is member of the
Organisation for safety in Abrasives
EN 12 413
EN 13743
EN 13236
European Standard for resin- bonded discs
European Standard for flap- discs
European Standard for diamond tools
DIN 69 107 German Institute for Standards,
Tolerances within Abrasives
DIN EN ISO 9001 International Standardisation Organisation,
Quality Management for Manufacturers
ANSI B 7.1
American National Safety Instruction
Internal tests:
1‰ of the daily production are used for a test on the maximum r.p.m. (speed or burst test)
- daily test of lifetime
- 100% optical check before packing

Cutting and grinding wheels
Indicates the ratio
= Indication of the lifetime
Q = 2
Wheels decreases by 0.5mm² on 1mm² of material.
Q = 1
Wheel decreases by 1mm² on 1mm² of material.
Q = 0,5
Wheel decreases by 2mm² on 1mm² of material.
Comparison of the Q- factors
Evolution
Special
Perfect
0 0,5 1 1,5 2 2,5 3
Q- factor

Cutting and grinding wheels
The cutting efficiency describes the cutting speed of a wheel in a time unit per cut.
Cutting wheels
Cutting efficiency = mm² / sec
(or simply)
= seconds per cut
Grinding wheels
Cutting efficiency = abrasion in gram (gr) per time unit
Economy = Life time and cutting efficiency
Qualitity = Economy and safety

Cutting and grinding wheels
Transport and storage
The abrasives are
• to be treated with care
• to be stored dry, straight and frost-free
• not to be exposed to high changes in temperature.
Old stock has to be used first.
Outer mechanical influences (push, punch) are to be avoided.

Cutting and grinding wheels
• The wheel has to be mounted with the ring towards the grinder.
• Use only undamaged original flanges, the flange may not have any edges. Obey the hints of the manufacturer.
• Use the applicable wheel. The r.p.m. of the grinder must not exceed the r.p.m. of the wheel.
• Use the protection feature of the grinder.
• Wear goggles and protective garment.
• Cut like you use a saw.
• Guide the freehand cutting grinder that the flow of sparks is directed away from your body.
• Guide the freehand cutting machine in that way that the direction of rotation leads into the material.
• Do not grind with cutting wheels.
• Do not twist the wheel - guide the wheel straight into the cutting gap.
• Do not press the machine, the weight of the grinder is normally sufficient.
• While grinding use a grinding angle of about 30 °.

Cutting and grinding wheels
• Obey the restrictions and icons on the label.
• Obey the coloured bar
Red = 80m/s
Green = 100m/s.
These working speeds may not be extended.
• Make sure that the material you are working on is fixed.
• Within the flow of spark there must not be any flammable materials.
•
Put down the grinder only when it has stopped completely.
• Before using a ceramic bonded wheel do the sound test.
The wheel must sound proper.
• Obey the expiry date (3 years). After the expiry date the wheel should not be used.

Claims
The wheel breaks or fringes!
Possible reasons:
- The wheel has been jammed or twisted!
- Grinding with cutting wheels!
- The grinding angle has been to small!
(see drawing) correct
The wheel does not cut!
Possible reasons:
- Wrong type of wheel!
- Wrong setting of the wheel on to the material. The wheel drifts away!
(see drawing) correct wrong
The ring breaks out!
Possible reasons:
- Wrong or faulty flange. The wheel has not been fitted correctly on the machine, the wheel is made to brake or spins off.
- Too much lateral pressure!
wrong

Claims

Claims

Claims
Problem: Square grinding disc after use
The workpiece which was to be treated by this grinding disc was not fixed at all, or the fixation was too far away from the part to be treated.
The workpiece started to oscillate/vibrate and was beating against the grinding disc from below. The consequence was a damage of the disc.
Advice: Always strongly fix the workpiece close to the part to be treated. It is not enough to put the foot onto the workpiece as a fixation.

Claims
Problem: Breakout of the edge of the disc after use
The machine was stopped in the slot of the cut (disc immediately stops when pressure is put on it) or started. In every case the disc shows those typically damages.
Advice: Start or stop the machine only, if the disc is not in the workpiece.

Claims
Problem: Breakout of the edge and fringy reinforcement
This cutting disc was used for grinding.
The outer edge of the disc was damaged and the mass of the disc was taken away from the reinforcement. This bad habit of grinding with a cutting disc is unfortunately very popular.
This habit is very dangerous for the user, as big parts of the mass and of the reinforcement can break away from the disc and can dash in the face of the user.
Advice:
Never grind with a cutting disc.
Always use the right disc for every application.

Claims
Problem: Breakout of the ring
This cutting disc was put into the workpiece up to the fixing flange.
The disc was mechanically overstrained what can clearly be seen at the damaged edge.
If the disc gets additionally jammed, it can be blocked in the workpiece. If the machine is strong enough, it continues to turn and breaks out the ring (in the center) of the disc.
Advice: Put the cutting disc into the workpiece only as deeply as necessary. Don‘t jam the disc
(pay attention to a solid fixation of the workpiece). Firmly hold the angle grinder and don‘t try to cut in curves.

Contact
DRONCO GmbH
Wiesenmühle 1
D-95632 Wunsiedel
Tel.: +(49) 92 32 609 - 0
Fax: +(49) 92 32 609 - 246
E-Mail: info@dronco.de