Fabric Joints in Belt Manufacture

Posted in: , on 28. Mar. 2006 - 07:38


Is it a common practice for belt manufacturers to build the up the full width of a ply using 2 or more separate pieces of fabric of different widths? Section 6.7.1 of DIN 22102 Part 1 appears to address this. My questions are

1. How will this affect the ultimate breaking and the overall lateral strengths of the belt compared say to one where the ply is constructed using a single piece of fabric?

2. How will this affect the lifespan of the belt given the possiblity of tear across and shear along the longitudinal joints.

3. How will the minimum pulley diameters, load support and troughability properties of the belt be altered.

4. Can a conventional n-1 stepped splice be performed assuming the carcass has more than 2 plies? Or are there any special requirements?

Best regards.

Barry Chung

Belt Etc.

Erstellt am 25. Jul. 2006 - 05:09

I just saw your posting-shame on me I only look at the new postings anymore now that Herr Wolbier has installled that feature :^(

Your belt sound like its something you should run away from as soon as possible :^)

The biggest factor is belt life of course as every inch of that belt goes overe the head pulley through the drive pullies and around the tail pulley thousands of time a day or week I woul dbe worried about longtitude cracks in the carcass on both sides of the belt and stress on the mechanical splices. Are you using Flexco splices

for your belt?

If it were me I would be checking that belt and the splices every day with out fail-

Re: Fabric Joints In Belt Manufacture

Erstellt am 25. Jul. 2006 - 05:54

Dear Izaharis,

Appreciate the advise. However, if that is so, why does DIN allow it?



Ply Splices

Erstellt am 28. Jul. 2006 - 09:10

Barry, it is allowed for becuase conveyor belts carry a wide variety of applications. If you are handling carrots, the ply splices will have a minimual effect on belt life. Although the comment about having to go around the pullies millions of times is valled and will cause the factory splices to fail, it will only shorten the belt life by, say, 5%. Now if you are droping 12" minus ore on a belt, the factory splices will fail very quickly, resulting in a 75% or so loss of belt life.

Mfg. use factory splices in the plies to minimize fabric shorts or drops. What ever the reason, seak out belt manufacturers that do not do factory splices.

Ron Marler

Legg Co. Inc.


Re: Fabric Joints In Belt Manufacture

Erstellt am 1. Aug. 2006 - 01:27

I have seen a lot of belt's with ply joins, especially once you start looking at belts over 1600mm, never seen to many issues with it.

I am curious how the belt manufacturers complete these ply joins


Factory Splices

Erstellt am 3. Aug. 2006 - 08:48

Hello Shane,

If you are refering to longitudinal splices, (since 1600mm is only 63" I'm going to assume you are refering to a longitudinal splice) it's usually a socondary post cure process. The method is the same as with a lateral field splice. It involves plying down the belt carcass, buffing, cleaning, applying cement, drying, apply new skim rubber, and cook it or re-vulcanizing for lack of a better term, usually accomplished in an I-Beam press. Typically, and in our case exclusively, this is done by an indipendent distributor with those capabilities. There are a few things that can be done during the manufacturing process to help reduce labor at the distributor, but mostly it's just like a field splice only it lasts for weeks.

If you are refereing to a lateral ply splice, this is done by butting the ply ends, cut on a bias, in the laminating or lay up process. The orginal vulcinization of the rubber holds the ply splice. It will put a weak point in the belt, and as everyone knows, the weakest link is usually where the failure will occur.

Longitudinal splices do perform very well in the field. We had a distributor do a large run of profiled belt for a new chip plant in Ont. requireing very wide belt, it has ran for several years now with no problems. It's the lateral splices that will get you in trouble both from and impact and flex fatigue stand point.


Ron Marler

Legg Co Inc.