The
Tension Meter is designed to measure , translate and
display differences in fabric depression. It does this in increments
only one-eighth the with of a human hair. Any object that interferes
with it's ability to make minute measurements will cause inaccurate
readings.
The meter
touches the screen fabric with three stainless steel elements:
two cylindrical rods embedded in the base and a sensor button
at the center of the base.
Your screen
room has many substances that can easily attach themselves to
the screen contact elements. Emulsion, ink, screen adhesive, tape,
or tape-adhesive residue, when attached to the contact elements,
will affect the accuracy of your measurement. A fragment of masking
tape, inadvertently stuck to any of these elements will cause
readings that are higher or lower than that of the true reading.
A piece of masking tape attached to the sensor button will set
up an inaccurate reading. (the meter might tell you that a screen
had tension of 35 N/cm. Of tension when it actually had 30 N/cm.)
This problem is increasingly serious when working with higher
tension. The solution to the problem is obvious, of course. Keep
the contact surfaces clean.
Note:
This phenomena is not unique to this particular brand of meter.
Narrow-based meters (other brands) are even more prone to this
problem.
Clean
the contact surfaces with appropriate chemicals. Emulsion stripper,
mineral spirits, lacquer thinner, or isopropyl alcohol will not
harm the contact elements, or the paint on the body of the meter.
Use the chemical sparingly on a Q-tip or small cotton ball.
HOW YOUR TENSION
METER WORKS
The instrument
provides a carefully calibrated downward force through it's plunger
mechanism. When the instrument is placed on your screen fabric,
filter media or other membrane, the fabric will be slightly depressed
by the plunger. More fabric tension will allow deeper fabric depression.
The indicator mechanism measures depth of depression and translates
the measurement to specific tension readings.
PROPER CARE FOR YOUR TENSION METER
Do not
store your meter on it's feet for long periods of time. Store
it on it's back, preferably in the padded case.
Do
not oil any part of the instrument.
There
is no need for frequent adjustment. On occasion you may wish to
verify “zero” adjustment. To do so, follow these instructions:
Place the meter on a perfectly flat surface such as a piece of
¼ inch plate glass. The “zero” position is
indicated by one of the following symbols: ( ! + ) This “zero”
position is at the top of the dial (approximately 12 o'clock position).
There is almost never any need to adjust the meter.
If adjustments
is necessary, loosen the small clamp screw at the upper right
of the dial rim. Rotate the serrated rim so that the large indicator
needle points to zero. Re-tighten the small clamp screw. All meters
are factory zeroed with the main indicator hand pointing straight
up. Meters that require bezel adjustment exceeding three or four
degrees of rotation will need factory attention
When you
“zero” the meter, a very smooth, flat, surface must
be used. Neither a table top, frame sidebar, or press bed is flat
enough, The instrument discriminates differences of less that
one-half thousandth of an inch (0.0005”), so flatness is
essential.
SPECIAL
NOTE! When holding the meter in your hand, or when it is lying
on its back, (contact button at bottom of instrument is not depressed),
the indicating hand will point to the top of the dial. It may
not rest at exact “zero” . Do not adjust meter on
this account. Do not be concerned as this is normal.
USING YOUR
METER
Select
the location of the screen that you wish to analyze. Place the
meter gently in that location. The meter will register tension
of the threads running between the stainless steel “feet”,
and over the indicator button at the bottom of the meter.
Special notes
for Tension Meter Models 750-B and 770:
Model
750-B and 770 tension meters are the last word in sensitivity
and compliance. Calibration marks are more widely spaced than
on ordinary tension meters. That feature makes the meter easier
to read. The large indicator hand makes about one and one-half
revolutions of the dial, while traversing the tension. Because
of this advanced feature, the indicator/measuring head shows a
smaller, inner dial to associate with the (dot.), or absence of
the (dot.), next to each number on the dial.
In other
words, the value 9 N/cm . Will be read when the small hand is
in the range showing the (dot.), and the large hand is on the
(dot.) by the number 9.
When the
small hand does not appear in the . Window, the measurement reading
will be associated with the numbers that do not have the (dot.)
beside them.
Measure
tension in the warp yarns: Place the meter on the screen with
the face of the instrument parallel with the warp yarn direction.
Measure tension in the weft yarns: Rotate the meter so that the
face is parallel to the weft yarns. The meter will quickly reveal
tension differences in warp and weft directions. Normally, the
meter is to be placed parallel to the frame sidebars. If the meter
is placed diagonally, it will automatically average the warp and
weft tension. Warp/weft tension is co-dependent in woven fabrics.
That means that tension change in one direction will influence
tension in the other direction. Warp tension affects weft tension,
and visa-versa. The meter will reveal the co-dependent phenomena.
You may
measure tension from either side of the screen (print side or
squeegee side). Small wood blocks may be placed under the ends
of the frame sidebars to elevate the screen if necessary. Just
be sure there are no obstructions touching the screen area.
It is advisable to measure the screen tension at several places
in the stencil image area. Check the geometric center of the screen
in both directions. Check both directions at the center of each
screen quadrant. Greater sensitivity can be affected by tapping
the screen near the center of the meter base. Tap lightly with
one finger.
Note:
A properly tensioned screen may give erroneous readings near the
edges of the frame sidebars. It is not necessary to measure those
locations. Measure tension in the actual print area only.
If your
meter becomes damaged or inoperable, Do not disturb the set screws
in the back of the base or in the plunger. To do so will de calibrate
the instrument and void your warranty. Please communicate with
us if your have any difficulty. You can get additional information,
assistance, or suggestions with a phone call, fax or letter. Our
staff is very well versed in matters that relate to screen technology.
