Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02884674 2015-03-10
Method for the automated surface treatment of a profiled large component of a
wind
turbine, treatment device and treatment system.
The invention relates to a method for the automated surface treatment, in
particular
grinding, of a profile component in the form of a profiled large component, in
particular of
a rotor blade of a wind turbine, as well as to a respective treatment device
and a
treatment system along with the treatment device.
Such a device and such a method are known from WO 2008/077844 A1. The
disadvantages of the method disclosed in WO 2008/077844 A1 are the following:
- the grinding gantry runs on tracks and, therefore, cannot be transported
to other
manufacturing sites;
- since the grinding heads can only be moved horizontally, the entire
profile contour
o cannot be ground;
- if the cross-section or the length of the rotor blade is increased, the
entire gantry
must be adjusted.
The often complex and, depending on the type of the wind turbine, the variable
profile of
the large component can indeed be a problem, even in the case of a profiled
large
component of a wind turbine -- as, for example, in the case of a rotor blade,
but also, if
applicable, in the case of another large component of the wind turbine, such
as a spinner
cover, a hub, a nacelle cover or a tower segment or the like. The profile of a
rotor blade,
for example, is complex and, depending on the wind turbine, may actually be
subject to
variations, the consequence of which might be that they cannot be treated with
a
comparably inflexible treatment device of the type described above.
It is the object of the invention to specify a method and a device, which,
with regard to
prior art, are improved and which, however, address at least one of the
problems
described above. At least one alternative solution for a solution known in
prior art shall be
proposed. It is, in particular, the object of the invention to provide a
treatment and/or a
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treatment device and a method enabling more flexibility in the treatment
and/or
processing of profiled large components of a wind turbine. In addition, it is
particularly the
object of the invention to design the device and the method for as efficient,
yet preferably
still as precise, a treatment and/or processing of the large component as
possible. In
addition, it is particularly the object of the invention to specify a method
and a device, by
means of which an automated surface treatment of the large component can be
performed in a comparably precise position and/or evenly by means of a
treatment tool.
The object regarding the method is achieved by the invention through a method
for the
automated surface treatment, in particular grinding, of a profile component in
the form of
a profiled large component, in particular of a rotor blade of a wind turbine,
with a
treatment device comprising a moving gantry, a robotic system with a control
system and
a treatment tool of a tool head, comprising the steps of:
- moving the moving gantry as a moving carriage, generally free from any
mechanical limitation, along a profile surface of the profile component
moving the treatment tool essentially transversely to the profile surface of
the profile component by means of feed motion robotics that can be activated
between
the moving carriage and the treatment tool
- areal treatment of the large component by the treatment tool, wherein
movement of the moving gantry is driven by the control system, and feed motion
of the
treatment tool is driven by the feed motion robotics, as defined by a model of
the profile
surface of the profile component, wherein
- a number of areal treatment strokes is performed on the large component.
The object regarding the device is achieved by the invention through a
treatment device
for the automated surface treatment of a profiled large component of a wind
turbine,
comprising a moving gantry, a robotic system with a control system and a
treatment tool
of a tool head, characterized in that
- the moving gantry is designed as a moving carriage, which, in a work
area,
can be moved generally free from any mechanical limitation along a profile
surface of the
profile component.
the robotic system comprises feed motion robotics that can be activated
between the moving carriage and the treatment tool, by means of which the
treatment
tool can be positioned essentially transversely to the profile surface of the
profile
component, and
the treatment tool is designed for the areal treatment of the large
component, wherein
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- the control system is designed to perform movement of the moving
carriage
and feed motion of the feed motion robotics as defined by a model of the
profile surface
of the profile component,
a number of areal treatment strokes can be performed on the large
component.
The design of the invention also introduces a treatment system as described
above with a
retaining gantry connected so as to control the finishing device, in
particular a pivoting
device of the retaining gantry that can hold the profiled large component of a
wind turbine
such that it can rotate.
In order to eliminate the above mentioned disadvantages, the concept of the
invention
provides for the grinding robot to be mounted to a moving carriage so that it
can drive to
any position of the rotor blade.
The invention has realized that the efficient and exact guidance of the
treatment tool is
possible through the use of a freely movable moving carriage. According to the
invention,
the control system will drive movement of the moving gantry and feed motion
robotics will
drive feed motion of the treatment tool, as defined by a model of the profile
surface of the
profile component.
In principle, an area means any flat or, in most cases, three-dimensionally
curved,
particularly complexly arched area pursuant to a profile surface, in
particular a surface of
the large component, in particular a complexly arched area such as the surface
of a rotor
blade. Thus, an areal treatment stroke may, in principle, comprise the
treatment of a
randomly arched area or line in space.
This and other advantageous further embodiments of the invention can be
inferred herein
and specify in detail advantageous options for realizing the invention design
in the context
of further embodiments while specifying further advantages.
It has also turned out in particular that it has to be ensured -- in
particular prior to the
areal treatment of a large component -- that treatment strokes covering at
least significant
percentages of the area of the large component are performed as evenly as
possible. In
this context, a problem arises, since, on the one hand, in order to ensure
more flexibility
the movement of the moving gantry is generally free from any mechanical
limitation, but,
on the other hand, the moving and the guiding of the treatment tool have a
visible impact
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on the quality of the treatments and/or processing of the profiled large
component after
all, so that they should, at the same time, be performed as exactly and evenly
as
possible.
Preferably, wear to the treatment tool can be assessed between a first and a
second
treatment stroke.
A treatment and/or processing can comprise for example surface finishing such
as
grinding, finishing, painting or the like. A treatment and/or processing of
the large
component, for example in the context of a general manufacturing process, may
also go
deeper into the large component, i.e. underneath its surface. This may, for
example,
comprise a treatment building the large component, such as the insertion of
laminate
layers or a similar layered construction of the large component (laminating).
Preferably, the treatment tool shall be guided into a precise position and/or
evenly over a
large part of the area of the large component. Preferably, for exact
positioning, the robotic
system can be adjusted with regard to its position prior to the initiation of
a treatment
stroke to a fixed position, in particular, a real position of the treatment
tool in relation to
the large component can be adjusted to a virtual position of the treatment
tool in relation
to the model. In addition, a further embodiment recognized that, as soon as a
treatment
tool -- between a first and a second treatment stroke that can be set at will
(e.g. with
regard to time, location or treatment system or the like) -- is subject to
wear and tear or
the like during a longer lasting large-area treatment, the quality of the
treatment will be
directly impacted. It turns out, for example, that, in the case of a grinding
process, wear to
a grinding tool (such as a grinding roller or a grinding plate tool) directly
impacts the
quality of the treatment, due to the changing peripheral speed on the grinding
surface of
the grinding tool (in the case of tool mass rubbing off).
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The further embodiment specifies that a number of areal treatment strokes are
performed
on the large component and that wear to the treatment tool is assessed between
a first
and a second treatment stroke.
Below, treatment shall mean, in principle, any treatment of a large component
removing
material as well as any treatment adding material and also any sole treatment
measure
as such, which essentially does not change the existing material of the
profile component
but, if need be, merely modifies it. Furthermore, treatment can mean any type
of cutting
or non-cutting treatment.
Selecting a time to assess wear to the treatment tool between a first and a
second
treatment stroke can be determined in different ways. For example, it can be
specified
that, in the context of fixed cycles, e.g. after each treatment stroke set
with regard to the
treatment system (e.g. termination of a movement direction at a reverse point)
an
assessment of the treatment tool is performed, before the performance of the
next
treatment stroke. In the case of a grinding process, a rotor blade can, for
example, be
ground along its longitudinal axis, which would define a treatment stroke
between two
reverse points of the tool head, which could, for example, be at a blade root
and at a
blade tip, but terminal points of a shorter travel, which can be determined at
will, may also
limit a treatment stroke between two reverse points. Each grinding process
performed on
the rotor blade in longitudinal direction would then lead to a constant
quality of the surface
in the context of the grinding process.
In an alternative version, a fixed assessment time can also be, for example in
accordance
with the empirical values of a grinding path or the operating time of the
treatment tool
which is suitable for the assessment thereof. If the values estimated for the
grinding path
or the operating time are too high -- and if, as a consequence, a relatively
significant
change occurs in the treatment tool due to abrasive wear -- this could lead to
decreasing
treatment quality. However, this could be prevented by adjusting the cycles,
since, in
general, such a process can be designed to be adaptive, so that characteristic
maps
characteristic of a specific treatment tool and a specific large profile
component, such as
a rotor blade, can be created in the course of performing the process.
However, as
proposed by the invention, it is especially preferable to assess wear to the
treatment tool
between a first and a second treatment stroke.
Preferably, wear is assessed, with the assessment featuring the following
steps:
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moving the treatment tool on a reference body after the first and before the
second
treatment stroke
measuring a pressure between the treatment tool and the reference body and/or
- measuring a distance between the treatment tool and the reference body
and/or
- measuring another reference parameter between the treatment tool and the
reference body.
Preferably, a reference parameter between the treatment tool and a reference
body can
be determined after the first and the second treatment stroke. If in a
comparison of a wear
parameter determined on the basis of a reference parameter with a wear
threshold value,
the wear threshold value is exceeded, the treatment tool can be replaced or
the treatment
tool can be adjusted at the tool head, in particular in such a way that, in
the second
treatment stroke, the treatment values of the reference parameters remain the
same as in
the first treatment stroke. Thus, during the areal treatment of the large
component,
consistent surface quality of the profile is guaranteed for all treatment
strokes.
In particular, wear can be further assessed, with the assessment using the
following
steps:
- determining a wear pressure and/or wear distance or other wear parameter;
- comparing the wear pressure with a pressure threshold value and/or the
wear
distance with a distance threshold value and/or other wear parameter with a
wear
threshold value.
In addition, replacing and/or cleaning the treatment tool has proven to be
advantageous if
the pressure threshold value and/or distance threshold value is exceeded, in
particular
during and/or prior to the second treatment stroke.
Preferably, the control parameter of the treatment tool on the basis of the
wear pressure
and/or wear distance and/or the other wear threshold value can also be
adjusted during
the second treatment stroke.
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In the context of an especially preferred further embodiment, a contour of the
profile
surface according to a virtual model of the profile surface of the profile
component will be
stored in the control system and the treatment tool will be guided along this
contour. In
the context of a further embodiment, storing a contour and/or profile surface
as defined by
a virtual model of the profile surface of the profile component in the control
system has
proven to be advantageous. Thus, on the one hand, extensive calculating time
for the
movement is kept to a minimum. On the other hand, this time can for example be
invested in adaptive control of the feed motion, which in turn is decisive for
the actual
treatment quality. This leads, in particular, to a control system that is
relatively effective in
terms of calculating time.
Preferably, the identifier of a virtual model of the profile surface of the
profile component
and/or of a contour in the control system derived from it will be compared
with an
identifying characteristic -- which will specifically be installed on the
profile component,
but can, in principle, also be used at another workplace location or at a
location
accessible to the robotic system. The identifying characteristic can also
comprise the
function of the above mentioned fixed position for adjusting the position of
the robotic
system and may, but does not have to, be installed on the large component. In
particular,
the areal treatment of the large component with the treatment tool can only be
performed
if the identifier can be positively attributed to the identifying
characteristic. Preferably,
positive attribution will ensures that the contour and/or the virtual model of
the profile
surface of the profile component in the control system fits the profile
component. To this
end, an identification sensor is provided on the treatment device, in
particular on the tool
head, in order to read the identifying characteristic. Preferably, the
identifying
characteristic can be realized as bar code, surface code or a similar simple
identifying
characteristic. A more complex data exchange during an authentication process
can also
be used as comparing process. In particular, a virtual model of the profile
surface of the
profile component and/or contour of the profile surface (e.g. a header of the
profile
surface) that has been completely or partially uploaded to the identification
characteristic
can also be, first of all, uploaded to the control system of the treatment
device during the
comparison or be completely or partially replaced and be used for the positive
attribution.
Especially preferably, non-inherent obstacles, in particular obstacles in the
form of
persons, are identified by the treatment device. This ensure that movement of
the moving
carriage intended to be generally free from any mechanical limitation and to
be along a
profile surface of the profile component and/or a work movement of the feed
motion
robotics does not cause any undesired damage to obstacles or persons. In
particular, a
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identification sensor system can be designed to identify obstacles, in
particular obstacles
in the form of persons, in an immediate motion area of the moving gantry
and/or the
robotic system.
Especially preferably, a contour along which the treatment tool is guided
comprises a grid
with points, in particular with points arranged on the longitudinal side of
the profile surface
-- which can be attributed to the trajectory of a treatment stroke -- and
points facing each
other -- in particular reverse points for the tool head -- which are relevant
to limiting the
treatment stroke of the treatment tool.
Especially preferably, the large component, in particular a rotor blade, is
held in a pivoting
device of a retaining gantry connected in a controlling manner with the
treatment device,
wherein a contour, along which the treatment tool is guided, comprises a grid
with points
framed by reverse points assigned to the circumference of the profile surface -
- in
particular reverse points for the tool head -- onto which the treatment tool
is placed after
the large component has been turned around and prior to a treatment stroke.
Especially preferably, movement of the moving gantry and feed motion of the
treatment
tool are performed with the performance being corrected by means of an
adaptive
algorithm.
Especially preferably, the treatment tool is a grinding tool. The treatment
tool is cleaned
by blowing in pressurized air.
In particular, one control parameter of the treatment tool is a peripheral
speed of the tool,
wherein the peripheral speed is adjusted in such a way that the peripheral
speed is
essentially the same during the first and the second treatment strokes.
Preferably, a distance and/or a pressure and/or another treatment tool control
parameter
can be controlled, in particular in relation to the profiled large component,
and in particular
in a constant manner.
Further details and advantages of the invention are disclosed in the exemplary
embodiments according to the drawing. Exemplary embodiments of the invention
will now
be described below based on the drawing. This is not necessarily intended to
illustrate
the exemplary embodiments to scale, but where it serves as an explanation, the
drawing
is rather presented in a schematic and/or slightly distorted form. In regard
to amendments
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to the templates which are directly recognizable from the drawing, we refer to
the
applicable prior art. In this context, it has to be considered that a large
variety of
modifications and changes regarding the form and the detail of an embodiment
can be
made without needing to deviate from the general idea of the invention. The
features of
the invention disclosed in the description, in the drawing and in the claims
may be
essential for the further embodiment of the invention individually as well as
in any
combination with each other. Furthermore, all combinations of at least two of
the features
disclosed in the description, the drawing and/or the claims fall within the
scope of the
invention. The general idea of the invention is not limited to the exact form
or the detail of
the preferred embodiment shown and described below, nor is it limited to
subject matter
which would be limited in comparison to the subject matter asserted in the
claims. Within
a specified range of dimension values, values within the specified limits
shall also be
disclosed and be able to be used and asserted at will as threshold values.
Further
advantages, features and details of the invention can be inferred from the
following
description of the preferred exemplary embodiments as well as from the
drawing; the
drawing shows in:
Fig. 1 a preferred embodiment of a grinding device in a perspective top
view,
Fig. 2 a perspective view of the grinding head of the grinding device
from Fig. 1,
Fig. 3 a side view of the grinding head of the grinding device from Fig.
1, and
Fig. 4 a bottom view of the moving carriage of the grinding device from
Fig. 1,
Fig. 5 a flow chart of a preferred embodiment of a treatment method in
the form of
a grinding method for a rotor blade of a wind turbine;
Fig. 6 a schematic view of a treatment system consisting of a treatment
device and
a pivoting device of a retaining gantry for a rotor blade of a wind turbine,
to
illustrate an especially preferred grinding process while also showing a
schematic view of a preferred control concept for the treatment method.
Fig. 7 a diagram (A) and a flow chart (B) of a preferred assessment
method for
determining wear to the treatment tool between a first and a second
treatment stroke if the treatment tool is designed as a grinding tool.
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The device for grinding rotor blades for wind turbines illustrated in Fig. 1
consists of a
grinding robot 2, to the arm of which a grinding head 1 is attached. The
grinding robot 2
and the suction container 3 are mounted to a moving carriage 4. For reasons of
work
safety, the whole device is edged with a protective cover 6, so no employees
enter the
carriage during operation. The moving carriage 4 can be steered in any
direction by a
remote control, which can also be designed as a radio remote control. The
grinding head
is mounted to the head of the grinding robot 23 so that it can rotate.
Basic design:
The entire treatment system, presently designed as a grinding machine,
practically
io comprises three components (i) the robot 2 including a grinding head 1,
which is mounted
on a moving carriage 4, (ii) the moving carriage 4 with control of the robot 2
and the
suction unit 21 for the dust from the grinding unit and all power electronics,
and (iii) a
pivoting device of a retaining gantry, in this case a blade support 7, for the
rotor blade.
Generally, in the installation, the robot can also be partially guided on
tracks; however,
preferably it is designed to be freely movable. The moving carriage 4 can be
coupled with
the control cabinet or one control cabinet by a cable. Preferably, the control
cabinet will
serve to consolidate and monitor the safety device and, respectively, bring
the robot 2 or
the moving carriage 4 to a standstill in case of danger.
Preferably, this control cabinet will be mounted directly on the moving
carriage 4. A
zo compressor unit, designed to control all mechanics in the robot 2, is
also mounted on the
moving carriage.
Fig. 2 shows a perspective view of the grinding head 1. The grinding head is
mounted to
the robot arm adapter 23 so that it can rotate. The grinding roller with the
grinding tool 20
is located in the grinding head 1. The grinding roller protrudes from the
grinding roller
housing 24. The suction device 21 is installed in the lower area of the
grinding roller
housing 24. The suction device serves to move the dust created during the
grinding into
the suction container 3. To this end, the suction device 21 is connected to
the suction
container by a hose.
Regarding the design of the tool head, in this example designed as a grinding
head:
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The treatment tool, which, in this example is designed as a grinding roller,
is installed to
be movable within the grinding head 1 so that it can move forwards or
backwards. The
roller itself is adjusted back and forth by a valve and a lever arm. During
this, contact
pressure is to be kept constant, which is carried out in this example by an
adaptive
5 control. Contact pressure can be controlled by the mechanical system and
can be set
with proportional valves. This means that if the contact pressure becomes too
strong --
i.e. the contour has changed in some way -- the pressure in the proportional
valve will
also increase and the grinding carriage will be moved back accordingly. lf,
for example,
more than one distance threshold value of 5 cm from the radius of the grinding
roller is
10 worn, the grinding roller will be replaced; for wear distances below
this, it may not be
possible to adjust the grinding roller.
Fig. 3 shows a side view of the grinding head 1. The grinding roller is driven
by a motor
31 and a drive belt 33. Alternatively, the drive belt can also be designed as
a chain drive.
The grinding roller housing 24 is moved by a pneumatic cylinder 32. The
pneumatic
cylinder is connected via the grinding head pivot drive.
Fig. 4 shows a bottom view of the moving carriage 4. The moving carriage is
driven by
the drive 40. The moving carriage is steered via steerable rollers 41. The
drive and the
control are powered by the energy storage system 42.
Fig. 5 shows the process of a grinding method according to a preferred
embodiment:
In the initial position, the rotor blade is positioned at POS-P in step S1 and
the grinding
robot is positioned at POS-R in step S2. In step S3, the grinding robot
determines a
relative position relPOS, in this example by scanning the rotor blade, i.e.
its position in
relation to the rotor blade, three times.
In step S4, the grinding program is run on the basis of this determined
position relPOS;
namely a synchronized first and second grinding program PV, PA for the moving
carriage
4 and the feed motion robots, in this example the robot arm and the grinding
head. In step
S02, the contour CONTOUR is already stored in the program for the grinding
robot. Thus,
in this case, no automatic scanning of the profile takes place, but the
positions for starting
up and grinding have been fed into the program as defined by a model MODEL in
step
S01. Accordingly, the surface of the rotor blade is ground in a zigzag shape.
After each
grinding procedure, split in a manner reasonable in terms of the work, and in
this
document referred to as a treatment stroke, wear to the grinding head is
determined.
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Fig. 6 shows the schematic view of an embodiment of a breakdown of treatment
strokes.
The contours CONTOUR, or the coordinates of the contours CONTOUR, are stored
in
the robot program PA, PV. The individual points Pi of this contour CONTOUR are
derived
from the computer model MODEL of the rotor blade; preferably automatically,
and if
applicable also manually. If a new rotor blade has to be adapted to, the
computer model
and the contour CONTOUR based on it are adjusted accordingly. Automatic
adjustment
of the computer model MODEL and the robot program CONTOUR of the robot is
generally possible, but, depending on the complexity, the adjustment may also
be
performed manually in a separate design process.
Positioning of the robot in relation to the rotor blade:
The rotor blade 5 is clamped into a preferably 1100 pivoting device 50 of a
retaining
gantry, so that it can be approached from each side. In principle, a pivoting
device 50
designed to pivot the rotor blade about its axis at a rotation angle up to a
certain value
can be provided. In principle, the range of the rotation angle may be chosen
at will and so
that it is suitable with regard to the reach of the robot. Preferably, the
range of the rotation
angle comprises rotation angles at least up to and/or above 90 , especially
preferably up
to 1100 (in accordance with the above mentioned preferred 110 pivoting
device),
preferably also up to 180 . Depending on the treatment state, a suitable
rotation angle
can be selected for a specific position of the rotor blade and then be changed
for another
position. During grinding, the rotor blade 5 constantly remains in one
position. The
grinding robot 2, i.e. the moving carriage, moves, while pressing the grinding
head 1 to
the rotor blade, from the blade root 5.1 to the blade tip 5.2 and grinds one
side or one
contour of the rotor blade. To this end, reverse points Ug1, Ug2 close to the
blade root
5.1 and the blade tip 5.2 for longer trajectories Tg, but also reverse points
Uk1, Uk2 for
shorter trajectories Tk are possible and, depending on the geometry of the
profile,
reasonable. Once the robot has reached the end of a treatment stroke, i.e. of
the rotor
blade at the reverse points Ug1, Ug2 or in between at reverse points Uk1, Uk2
located in
between, it moves back and sends a signal that the rotor blade 5 can be
pivoted further to
a certain position by the pivoting device 50. This may performed manually as
well as,
preferably, automatically; to this end, a communication channel 52 is
installed accordingly
between the robot 2 and the 110 pivoting device of a retaining gantry. If the
robot 2
communicates that it has completed a treatment stroke, the rotor blade 5 will
be pivoted
into another position and then will once again move automatically along this
trajectory Tg,
Tk of the contour.
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The coordinate systems:
The rotor blade 5 has a fixed coordinate system just as the robot 2 does at
POS-P or
POS-R. By determining the position relPOS of the rotor blade 5 in relation to
the robot 2,
the difference between these two coordinate systems is determined. Thus, once
the robot
2 knows in which position relPOS it is in relation to the rotor blade 5, it
moves along the
individual points of the contour and thus grinds the rotor blade 5. An exact
adjustment of
the rotor blade 5 to the grinding robot 2 is therefore reasonable; the the
grinding robot 2 is
movable and, thus, the grinding robot 2 is adjusted to the rotor blade 5. The
distance
between the grinding robot and the rotor blade can vary, but does not have to
vary; the
contact pressure or the compensation of smaller obstacles can be closely
adjusted by the
above mentioned adaptive control and in accordance with the program PA.
Fig. 7 shows in (A) a diagram of a test bench for determining wear to a
treatment head
and in (B) a flow chart for assessing wear to the treatment tool between a
first and a
second treatment stroke. To this end, in the first step P1, the tool head is
located at a
position POS.
In order to determine wear to the grinding head 1, the robot 2 moves the
grinding head 1
on a reference body 60, in this example on a plate, in step P2. Using an
integrated
measuring system 70 in a pressure cylinder of the robot 2, preferably on the
tool head, or
-- as in this example -- directly on the treatment tool, the wear is
determined. The grinding
head 1 is slowly pressed to the plate and -- using the pressure p and the
distance d
determined by the measuring system in step P3 -- the amount of wear ABN on the
roller
is assessed in step P4. If it is found in step P5 that a wear distance d of
more than the
distance threshold value of 5 cm from the radius of the grinding roller is
worn, the grinding
roller should be replaced in step P6.
The frequency of wear assessments may vary. A time-controlled manual
assessment is
conceivable, as well as an assessment based on how often the contour was
traced or
how many treatment strokes there were after the assessment. This can also
depend on
the frequency of readjustment options in step P7 as long as there is a wear
distance d of
less than a distance threshold value of 5 cm.
The grinding tool can be a commercially available grinding tool as well as a
pressure
cylinder.
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In addition, a device for cleaning the grinding head is provided, where
pressurized air is
blown into the grinding space to remove any dust from the grinding roller.
Cleaning may
also be performed manually, but preferably cleaning is also time-controlled or
controlled
based on grinding instances.
It turns out that, advantageously, the concept is designed to indirectly make
allowance for
the peripheral speed of the grinding roller to provide a clean grinding
pattern. If possible,
the peripheral speed should be kept constant for all treatment strokes, e.g.
at a three- or
four-digit rpm value. Since the circumference of the grinding tool changes as
the duration
of the grinding process increases, it is specified that, preferably, the
peripheral speed be
adjusted accordingly or that the grinding tool or equivalent treatment tool be
replaced or
readjusted. The peripheral speed is preferably adjusted every time after wear
to is
measured, as illustrated in Fig. 7 (AB).
