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To specify & explain conditions under which
Roundness, Ovality of less than say 2 micron
guaranteed?
Input condition of the components centers must be
cleaned surface
Both Centering in the same setup and must be in true
axis
Input condition component run out should be within
less than 0.1mm
Interrupted and plain Dia. If ground in single
plunge set, ovality will be 3-4 micron.
What is the guaranteed geometrical Cylindricity?
Depends on the grinding length of the component
Incase of Tool Room application 0.002/400,
0.004/500, 0.008/1000
In Auto Production cycle it depends on the job.
Clarity on machine repeatability and job size
consistency?
Size consistency for batch production w/o gauge?
Criteria for gauge selection based on size?
Machine repeatability is the repeat positioning of
the wheel slide, which is within 2 micron taken over
6 readings.
Job size consistency depends on:
For tolerance more than 12 micron on diameter gauge
is not required.
For Tolerance over 20 microns Cpk 1.33 is also
achievable without gauge in condition that the size
is checked and corrected on the mean dia.after every
dressing.
Why do we need constant surface speed and various
options?
As wheel get reduced in Dia. The cutting speed
changes which effects the behavior of the wheel
Hardness and results inaccuracies.
Ballscrew type & class, what is the technical
explanation?
Ballscrew C3 Class (minimum pitch error) is used
make THK dia. 32 & 40. These are auto lubricated. In
addition wheel dressing profile accuracy is improved
through pitch error correction by Laser
Interferometer.
What is the lubrication system for the critical
elements?
Dropco/.Cenlube for Wheel head and also separate
unit for Ballsrews and X & Z axis slide
Type of Linear bearings we are using and their
reliability?
Schneeberger Needle roller bearings are used these
are greased packed for life.
Various types of work drivers?
Standard drivers, Collet type, Internal teeth type
driver for gears/spline shaft, spring loaded
automatic type driver, special work drivers
depending on the component
Why do we need linear scale, when it is must?
We need linear scale for proper dressing of
intricate profiles having multiple dias and face
lengths.
Machine geometrical accuracies ex. on
perpendicularity of Dia. & Face?
As per standard chart we provide perpendicularity
within 0.010/100 length, but this is adjustable
since the wheel slide is swivel.
Various types of coolant filtration system?
Paper cum magnetic coolant filtration system :
Application where high production of steel
components, application where surface finish
requirement is high
Magnetic separator with Standard coolant tank: Low
cost solution to PBMF application where wheel wear
less ex. soft stage grinding.
Selection of workhead Hydrodynamic & Antifriction
depending on application?
Application where small job having weight less than
30 kg and work rpm required more than 56
Hydrodynamic is recommended. Other cases where
weight is more than 30 kgs and rpm is less 56
Antifriction is recomended
Live and Dead Center grinding?
Any Chuck & collet clamping jobs, Internal Grinding
jobs Live centers. All between centers jobs needs
dead center work head.
Angular & Straight wheel grinding?
Where Face and OD is ground simultaneously Angular
wheel head is required. If only OD grinding Straight
wheel will work
Type of flagging device & their application?
Active Flagging – Wheel head mounted cheaper
solution but limitation that it can flag only the
open area
Passive Type – Table mounted can flag both open and
interrupted grooves.
Effect of V & Flat Vs LM Guideways for Infeed
slide?
For Heavy-duty application V & Flat guide ways are
recommended these are Turcite coated for stick slip
free movement.
For Medium and light duty application Guide ways
recommended with SCHNEEBERGER LINEAR BEARINGS for
LESS FRICTION compared to CI to C.I contact guide
ways.
How to decide appropriate spark out time?
Thumb rule for Sparkout time is 15-20 revolutions
depending upon the rigidity of the component.
Ex.
For Dia. 20mm Job
The rpm calculated as 300 considering Cutting Speed
18m/min for normal steel
Rotation per second 5
For 20 rotation sparkout time to be set for 20/5 = 4
Seconds
Crash detector being not a preventor, should we
recommend please explain?
Yes we should recommend crash detector since this
limit the extent of damages.
What is the Dia & Length range with our standard
Internal Grinding spindle?
Refer Handouts
What is peripheral grinding?
Grinding Job face by Wheel OD. The Grinding is done
by line contact by angular wheel 30/45/90 degree.
This type of grinding eliminates the cross marks
possibilities. Application where face sealing is
required.
L/D ratio & use of steady rest?
L/D ratio Bore to length 1:5 maximum in Internal
Grinding.
L/D ratio OD to length 1:10 maximum in External
Grinding beyond that steady is recommended.
Variable speed drive on eco 200 - has it been
removed as Std accessory Why?
Yes! This has been removed since the workhead is
designed for small components where normally the
rpm’s are higher, the Variator is normally
recommended for Small rpm heavy-duty jobs.
Max Taper that can be corrected using Microtaper
correction in all m/cs
+ 0.040 on Diameter
Can we achieve a surface finish of 0.1 Ra?
Yes! Even 0.05 Ra is possible; it depends on the
material, hardness, wheel selection, dresser,
coolant, various feed rates and complete grinding
cycle. Bansal Brothers is achieving this surface
finish on our machine.
When do we need Sine Bar attachment?
When workhead needs to be set at an accurate angle
in live chuck/collet grinding.
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