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Thread: Slitting of Belt

  1. #1
    Join Date
    Jun 03
    Posts
    19

    Slitting of Belt

    Can any one suggest , what problems we may encounter, if we slit a EP-belt along it's length (after it is cured) and then use it?

    Best wishes to all of you..

  2. Dear Shri Das,

    As I know, the belt manufacturers regularly do the belt longitudinal cutting operation, to trim edges or to derive different sub-widths.
    General understanding suggests that the operation will need specific equipment (or attachment, tools, etc) so that the cut edges are straight and with proper finish. I suggest you to contact your belt suppliers who can provide reliable information, to do the operation at your place if it is feasible.
    If need be, you can send the belt to the willing nearby manufacturer / supplier of the belt to undertake the operation.

    Regards,
    Ishwar G Mulani.
    Author of Book : Engineering Science and Application Design for Belt Conveyor.
    Advisor / Consultant for Bulk Material Handling System & Issues.
    Email : parimul@pn2.vsnl.net.in
    Tel.: 0091 (0)20 5882916

  3. Dear Shri Das,

    Belt slitting is commonly done without any deliterious effect on performance.

    It is important to keep the belt straight during the slitting process to avoid inducing a bow in the end of the belt. If that is done, the splice area will mistrack on the system -- even though the splice itself is straight. This can be avoided by maintaining tension on the belt throughtout the slitting process.

    Hope this helps.

    Regards,
    Dave Miller
    ADM Consulting
    10668 Newbury Ave., N.W.,
    Uniontown, Ohio 44685 USA
    Tel: 001 330 265 5881
    FAX: 001 330 494 1704
    E-mail: admconsulting@cs.com

  4. #4
    Lawrence K. Nordell

    Lawrence K. Nordell

    President and CEO

    Conveyor Dynamics Inc. [eDir]

    Conveyor Dynamics Inc.

    Professional Experience 58 Years / 8 Month Lawrence K. Nordell has 58 Years and 8 Month professional experience

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    In addition to the above, a couple of points on slitting of fabric belt:

    Although practiced with highly compliant NN / EN belt, care should be taken with the type of fabric and the way the fabric has been handled by the mfg. Prestretching and conditioning or treating the fabric before press fabrication will minimize some difficult conditions such as: a) differential stretching across the width in the pretension phase causing tracking problems, b) axial folding of the fabric in the press line - although a no-no, sometimes the press operator cuts the fold to pull it back into place -- caused by weaving errors or equi-tensioning of axial weave fibers, c) flow of rubber in the press with fabric interaction

    Highly compliant belts suffer less from tracking due to differential stretching errors.

    Should not be done with steel cord. Mfg. still dont know the physics of rubber flow in the press. You can get a big banana belt.

    Lawrence Nordell
    Conveyor Dynamics, Inc.

  5. #5
    Join Date
    Jun 03
    Posts
    19
    Thank you all for your suggestions.

    May I request you to explain the terms 'highly compliant' & 'differential stretching errors' a bit more for me to understand. Besides NN/EN belts, can I consider EP belt also to be higly compliant?

    With Best Regards
    S Das

  6. #6
    Lawrence K. Nordell

    Lawrence K. Nordell

    President and CEO

    Conveyor Dynamics Inc. [eDir]

    Conveyor Dynamics Inc.

    Professional Experience 58 Years / 8 Month Lawrence K. Nordell has 58 Years and 8 Month professional experience

    Discussions 2608 Lawrence K. Nordell acceded to 2608 discussions, Articles 0 Lawrence K. Nordell wrote 0 articles, Publications 0 Lawrence K. Nordell Nordell released 0 publications

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    Know-How Design (1521) Lawrence K. Nordell used this tag 1521 times, Pipe Conveyor (238) Lawrence K. Nordell used this tag 238 times, Chutes (119) Lawrence K. Nordell used this tag 119 times

    Dear Das,

    Highly compliant pertains to stretch or apparent elasticity that is measurable or observable, which in this case means the interaction of fabric material of construction, treatment of fabric material, weave construction, and orthotropic behavior.

    Differential stretch occurs from the nature of the weave and tensioning system during the belt's construction. Pretensioning the fabric can introduce non-uniform elongation of the fabric across its width. The multiple fabric strands, denier variations and loose weave in spotty regions contribute to the variability of a uniform elasticity. Highly compliant fabrics and fabrics that are not presrunk, prior to use in the belt, are more prone to exhibit this condition.

    Wider belts are more likely to produce axial folds and slack regions than narrow belts.

    Presrunk belts, such as those treated with Resorcinol, exhibit superior uniform stretch.

    Polyester belts are more compliant than steel cord or Kevlar, but less so than Nylon and its derivatives. Note some highly compliant fabrics can be produced to have very uniform stretch properties due to their weave and presrunk process. These belts don't have the suggested problems. The producers of these belts take the proper steps to control variability.

    Lawrence Nordell
    Conveyor Dynamics, Inc.
    www.conveyor-dynamics.com

  7. #7
    Dear Shri Das,

    Slitting Polyester-Nylon and Nylon-Nylon conveyor belting is a very common practice and will work if you are using a quality product and you slit the belt correctly.

    A significant portion of the fabric conveyor belting installed in North America was manufactured at 60", 72" or 84" and slit down to the installed width at a distributors location. Without the ability to slit the conveyor belt the current distribution model in North America would not be present.

    You will also find a significant amount of used belting being slit for a second life. For example from 60" down to 54" or 48".

    As Mr. Nordell states slitting steel cord belt has not been mastered by the manufactures and is not recommended.

    Folded fabrics are a very rare issue for us and should not be expected in first quality belting.

    A final recommendation that we find useful: If you are slitting a wider belt into 2 pieces for use on the same conveyor, for example a 72" wide belt slit down to 2 x 36" wide, we recommend that the belts are spliced so that the slit edge is matched to the slit edge. This will minimize the variations in tension that may occur in the belt or during the slitting process.

    Regards,

    Andrew Hustrulid
    Fenner Dunlop Conveyor Belting

  8. #8
    Join Date
    Jun 03
    Posts
    19
    Dear Mr Andrew

    Thank you for your reply to our query. I understand that, if the qulality of the belt is OK, and slitting is proper, there should not be any problem.
    Besides the fabric quality, can you cite me a few check points to be monitored during belt manufacture and slitting, that may affect a quality belt to be used for slitting?

    With Best Regards
    Saugata Das

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