Processing welding seam with grindings discs is a very common
technique, but it is not a particularly popular job. While vibrations
strain muscles and joints, you have to apply just the right pressure
to process the work piece accurately. If the pressure is too high,
heat-related discolouration results, if too low, the disc bounces, the
seam becomes wavy and grinded unevenly. With just a few basic
principles you can grind more efficiently and more successfully.
Here are our tips.
Tip 1: Only use grinding discs
When using a hand-operated angle grinder, only use grinding discs
and never, ever, cutting wheels! Again and again we hear from
operators, that – in order to avoid the disk change – they quickly do
the roughing job using an already affixed cutting wheel. But this can
easily go wrong and is dangerous. Please follow the recommended
safety regulations precisely, and let the angle grinder test run for at
least 30 seconds before every job.
Tip 2: Choose the right grinding material
Tests have shown that high-performance ceramic abrasive grains,
like 3M™ Cubitron™ II, can triple the tool lifetime and halve the
machining time. The reason for this is the absolute regular structure
of the 3M™ Cubitron™ II grain. Conventional abrasives require a
significant amount of pressure to break up the abrasive structure,
to become a useful cutting surface in the first place.
The precision-shaped 3M™ Cubitron™ II grain, however, stays – put
in simple terms – continuously sharp. The contact pressure is
immediately converted into cutting power, so the grinder needs much
less force to achieve a constantly high level of abrasion. At the same
time less heat is produced, so the risk of annealing colours, or even
damage to the metal structure, is reduced. We recommend abrasives
with high-performance ceramic abrasive grain as a standard for all
scale-free work pieces like scale-free steel profiles, sheets, pipes and
containers. For heavily scaled and mineralised surfaces you should
use silicon carbide grinding wheels, since these penetrate the
oxide/carbide scale layers without vitrifying and blunting.
Tip 3: It’s posture that counts
Operate the angle grinder with downward pressure when moving it
towards yourself and more lightly away from you, as appropriate to
each phase, and hold it correctly. The perfect angle to the work piece
is about 30 degrees. For coarse grinding pull the machine towards
yourself while applying pressure. This helps to avoid the disc “biting”
into the work piece. Once the coarse work is done, push the machine
across the welding seam evenly away from you. This way you can
rapidly achieve a cleanly ground surface. During all phases take
care to use the right pressure; just use enough pressure so that the
machine doesn’t start to “jump”. If you have the feeling you need to
apply too much pressure, you may need to switch to a higher quality
abrasive. Too much pressure causes damages, as described above.
Listen to your machine: If the angle grinder struggles, you’re pressing
too hard and are removing less material – your effort is just reflected
in increased heat generation and not in cuts. Cutting is only easy with a well running machine that has an even rotation and regular sound.
Tip 4: Safety first!
An important note for all grinding work: Always wear the appropriate
protective equipment (goggles, ear protection, gloves, mask).
Just once without protection can be once too many.
Do you have questions about coarse grinding for welders?
We’ll gladly and give you personal advice.
Ask for information and advice now!
Note: The quality of our product is kept under constant review and strict supervision. All information and suggestions are given in best conscience
and are based on our practical expertise. Nevertheless Krückemeyer does not assume any liability for the correctness of statements
provided, especially in terms of fitness for a particular purpose. With regard to the usability, we thus recommend carrying out appropriate
trials. For further information our advisors and field representatives will be pleased to help you. © Reinhard Krückemeyer GmbH & Co. KG,
Photos © 3M, Germany