Reliable thermowelding of the belt profiles and conveyor belts is imperative to ensure process reliability in the application.
That is why BEHAbelt offers an extensive range of specially developed thermowelding tools. On this page we provide information about the different joining techniques, show tutorial videos, answer frequently asked questions and give product advices.
Of course, our technical team is at your disposal at +49 7684 907 170.
Regardless of whether you are using unreinforced belts or reinforced belts, we distinguish the following connection methods: butt and overlap welding.
Two connection methods can be used on profiles with reinforcement. Butt welding to reduce elongation without changing the belt strength. Overlap welding to reduce elongation and increase the belt strength.
(Standard)
Butt welding to reduce elongation without changing the belt tensile force.
Overlap thermowelding to reduce elongation and increase the belt tensile force.
Belt without reinforcement (here: orange special profile “Corn Belt“)
Belt with reinforcement (here: Sapphire blue V-belt with reinforcement polyester
Elastic monolithic PU conveyor belts from BEHAbelt offer new possibilities for endless joining due to the full PU belt construction. Due to the belt design without traction-layer, a connection by finger welding is no longer necessary, as the monolithic belt is a homogeneous belt design in itself – even in the joining area.
A preferably homogeneous design of the joint is a quality criterion both functionally and with regard to the elastic elongation behaviour of the monolithic strip.
In principle, this potentially “inhomogeneous“ area should be as narrow as possible, since the relatively large pretensioning force applied to monolithic tapes of 0.5…4% inhomogeneity in the belt is very quickly visible in the tensioned state.
with hot air
Below you will find a list of representative welding tools for the respective categories friction welding machines, welding paddles, hot presses, guide clamps, scissors and useful accessories. Of course, you will also receive corresponding spare parts, such as paddles, adapters or batteries.
Unique tool that enables fast butt welding of PU profiles with high repeatability.
Specially developed paddle welder for butt splices with ergonomic shape and very fast heat-up time.
Professional hot press with external temperature control for overlap welding.
Compact, transportable welding unit for butt welding of elastic conveyor belts.
Handy guide clamp with interchangeable locking jaws for different belt profiles.
Useful accessory for exact preparation of belt ends for overlap welding.
Robust scissors with angle stop for cutting the belt ends for welding.
Manual welding unit for overlap welding of belt profiles by means of Z-welding paddle.
In the videos listed below, we show you in detail how professional thermowelds are e.g. with round belts or bands. You are also welcome to visit our YouTube channel here or subscribe. We always post our latest videos here.
Butt welding of a round belt with friction welding machine RS02
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Butt welding of a conveyor belt with the HS400 welding unit
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Butt welding of a V-belt with the paddle welder EErgo
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Overlap welding of a reinforced V-belt with the HP01 hot press
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Below we answer important technical topics on the welding of belt profiles and belts. If you miss a topic or have questions about an area, the technical team is very happy to hear from you (+49 7686 907 170 or info@behabelt.com).
To ensure that the welded joint on the belt is carried out reliably, we recommend the following temperatures: For PU (polyurethane) 285°C (approx. 275…295°C) or 545°F (approx. 527…563°F) and for TPE (polyester) 235°C (approx. 225…250°C) or 455°F (approx. 437…482°F).
In general, it is recommended that the belt to be welded is at least at room temperature.
Too high temperatures “burn” the welding material, too “low” do not produce the sufficient fusibility.
The battery-powered friction welding machine is particularly suitable for this. This cordless machine requires no heating time and the guide clamp is already integrated. This makes handling in confined spaces much easier and the welding is done within seconds.
Alternatively, manual welding can also be carried out with guide clamp and a hot paddle welder.
If the welding is done correctly (e.g. temperature, contact pressure, holding time, cooling time), the splice is almost as strong as the rest of the belt. Often, the belt tends to break at a different point if the load is too high.
No, this makes no difference with non-reinforced belt profiles. In addition, the execution of an angled weld on profiles would be very difficult.
Yes, and they are mechanical connections. In general, however, these are intended more as a quick bridging option in the event of a belt break. BEHAbelt offers so-called twisted round belts or hook belts. These are twisted and connected with a metal hook.
The other alternative is the hollow round belt. Here the inside of the round belt is hollow. A nipple is placed inside, which holds both belt ends together.
Generally, butt welding is sufficient for belt profiles without reinforcement. It is irrelevant whether the belt profile is a round belt or a V-belt, for example.
Butt welding can also be carried out on belt profiles with reinforcement, but it must be noted that the reinforcement itself cannot be welded (aramid, polyester or steel). Only the patented glass fibre PU reinforcement from BEHAbelt can be welded.
In principle, the welding process can be roughly divided into four steps:
You can find instructions for butt welding with BEHAbelt EErgo paddle welder here as a video.
The fundamental difference between these two processes is the type of welding:
In paddle welding, a Teflon plate is heated up to the desired temperature. Once this temperature is reached, welding of PU or TPE can begin.
With the friction welding machine, the heat or melting of the belt ends made of PU (TPE not possible) is achieved by means of friction. This saves the heating time and due to the automatics (0-position, contact pressure, frequency of friction) the repeatability is also given.
The welding paddle always comes with a separate guide clamp, which makes the field of the different profiles to be welded very variable. In principle, any profile can be welded thanks to individually exchangeable inserts for the guide clamp. Flat belt strips up to a width of 80mm are also possible.
On the RS02 friction welding machine, the clamping jaws can also be exchanged; however, due to the design of the machine, the bandwidth is somewhat more limited than with the separate guide jaws for welding paddle (geometries for RS02: round belts 6-20, V-belts: 6×4 – 22×14, in addition, various special profiles such as ridge top V-belts, twin V-belts, T-profiles and also, for example, square or U-profiles).
As the welded profile requires a cooling time for further processing, it must remain in the friction welding machine, contrary to the use of a welding paddle, as the guide unit is integrated there. Thus, for series welding in larger quantities, the welding paddle is the better choice. There, the welded belt remains in the guide clamp and additional belts can be joined quickly with additional guide clamps.
Finally, the purchase price is another factor in the decision-making process. The RS02 friction welding machine or RS02 AKKU cost considerably more than the combination of welding paddle and guide clamp.
Since the reinforcements (aramid, polyester, steel) themselves cannot be welded, the belt should be drilled out to improve the connection. This prevents the two reinforcements from lying against each other without a connection and instead fills this area with PU, which itself can be completely welded.
You can find detailed instructions for this step here.
In principle, the welding process can be roughly divided into four steps:
You can find instructions for butt welding with the BEHAbelt RS02 friction welding machine here as a video.
For belt profiles with reinforcement, the overlap welding offers an increase in tensile force. Belt profiles with reinforcement are used in applications that require a higher tensile force. The reinforcement (e.g. aramid, polyester, steel) itself cannot be welded.
In general, the following two parameters should be taken into consideration when making a decision:
The belt length and the weight to be conveyed.
The following two recommendations apply to the belt length:
Belt length < belt diameter x 1000 => none
Belt length > belt diameter x 1000 => recommended
Example: Round belt 12mm x 1000 = 12000mm = 12m
(Note: For V-belts, the height is given as the diameter).
The conveying weight can be matched with the respective Fmax value (butt / overlap) of the belt profile.
Example:
PU V-belt with the following Fmax values (butt 15.4kg, overlap 30.0kg).
Conveyor weight is 21.0kg.
Thus, the overlap welding would be mandatory because the weight load would be too high for the pure butt welding.
“Every belt is only as strong as its splice”. As there are many different ways of welding, we are happy to help you with our decades of experience. We look forward to your request.
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