BIAX BS-40M Traduction Du Manuel D'utilisation Original page 28

Where the interruptions are caused by lubrication
slots, always make sure that a blade with a large
cutting curvature is used. This will prevent sticking in
the lubrication slot. To facilitate scraping, the
lubrication slot should, if possible, be milled after
scraping.
Scraping dovetail and vee guideways
Dovetail guideways which are frequently encountered
in machine tool manufacture are difficult to scrape by
hand because they are hard to access. That is why an
angled tool holder extension has been developed for
scraper BL-40M. The blade is fitted with a thin carbide
insert to enable the dovetail to be machined down to
an acute angle.
If the dovetail or vee guideway is readily accessible,
use of a tool twisted through 90° is recommended.
This version does not obstruct the operator and gives
a good view of the workpiece. Dovetail guideways
must not be scraped at too acute an angle.
Experience shows that a scraping direction of less
than 45° in relation to the guideway is best.
Refurbishment of machine tools
When machine tools are repaired, dismantling is no
longer necessary to rework worn slide surfaces on a
planing machine. Compressed material caused by
wear of the slide surfaces is generally very hard. Such
surfaces can be machined with the BIAX electronic
scraper BS-40M. For this purpose use of a carbide
tipped scraper blade or a carbide insert in conjunction
with the clamping holder KL 130 is advisable.
The blade width and blade radius depend on the
workpiece size. The cutting angle is selected in the
negative range of 0-5° to enable large amounts of
material to be removed. A long stroke is chosen to
remove the worn hard surface.
The BIAX electronic scraper BL-40M is then used in
conjunction with a resilient shaver blade to ensure
final scraping to the desired quality standard.
Scraping on vertical surfaces
Unlimited mobility also makes the BIAX precision
scraper perfectly suitable for work on vertical
surfaces. As manual scraping of vertical surfaces
involves great physical effort, the energy saving
operating mode of the machine is particularly useful
here. For vertical scraping, the BIAX scraper is used
in conjunction with a spring tensioner system which,
provided that it is correctly adjusted, enables the
scraper to be used in a practically weightless state at
every height. Scraping can proceed both upwards and
downwards with a cross-cutting motion.
The spring tensioner is suspended at the appropriate
height from an existing cross-beam in the factory bay,
from a tripod stand or better still from a stand with a
swivelling jib. Suspension should always be effected
in such a way that the machine barely touches the
surface to be scraped and hangs freely.
Hints for scraping
Uniform lighting at the workplace without shadow
formation is important.
Operating instructions for scrapers
Large areas are easier to scrape than small
interrupted surfaces. Dovetail and vee guideways,
indentations and vertical surfaces are harder to
scrape.
The scraping time does not consist solely of scraping
work, but also includes preparation and spotting of the
workpiece; checking the scraped surface for bearing
points; measuring parallelism and position accuracy;
sharpening the scraping tools.
Scraping tools must be sharp to remove small
particles and give a good result with minimum effort.
Sharpen the cutting edge of the carbide scraping tools
in good time using the BIAX scraping blade grinding
and lapping machine.
Scrape over all visible grooves caused by grinding,
planing, milling etc. at an angle of 45°. Choose a long
stroke with a BIAX clamping holder KL 130 and BIAX
scraping insert 25 x 30 mm.
The scraping depth can be determined by means of a
roughness depth measuring gauge.
Cleanly lapped blades enhance the smoothness of
the scraped surfaces, simplify scraping and prevent
groove formation.
Scrape over the surface until the entire area has a
bearing effect and then work on the supporting points.
Change the scraping direction after each pass so that
the scraping tool does not stick in the indentations of
the previous pass.
For work on grey cast iron, all rigid plastic materials
and non-ferrous metals, use carbide scraping tools.
Hard steel should be scraped only with carbide
scraping blades or inserts with a negative cutting
angle. The use of lubricants achieves a better chip
removal effect.
Repeat the scraping operation as often as is
necessary until the sliding surfaces have a maximum
bearing component of 40% or, in the case of flange
surfaces, up to 90%.
For spotting work, guide the spotting plate with
uniform movements and without applying pressure
across the surface. Excessive or uneven pressure will
give an incorrect bearing pattern.
Do not move the spotting plate too far across the
corners; higher weight and pressure cause the
scraping pattern to become blurred.
Ink the spotting tools lightly with the inking roller. If the
spotting ink is applied too thickly or unevenly, the true
size of the bearing points will not be identifiable.
Clean the spotting plate frequently with cleaning fluid.
After scraping and before spotting, remove all the
material chips.
Remove scraping residue with a fine grindstone.
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