Screens & Accessories

 

  The Tension Meter

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.

If you wish to have the calibration recertified, we will provide that service annually at no charge to you. You will pay only for the shipping charges.

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.



E-mail inquires to sales@cosmexgraphics.com

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Tel:(514)745-3446 or 1-800-263-1173
Fax:(514)745-3449


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