In adhesive tape converting, there is a lot of talk about materials: adhesive systems, carriers, liners and multi-layer structures. What is often underestimated, however, is a relatively short section of the process – the roll change. More specifically: the splice.
Yet it is precisely this transition that determines whether a process runs smoothly or comes to a regular standstill. Splicing is not a minor detail, but a key factor in series production capability and process reliability.
Splicing involves joining two adhesive tape strips together to enable continuous processing.
Specifically, this means that a roll of adhesive tape runs through the machine. When this roll is used up, a new roll must be attached so that the process is not interrupted. To do this, the end of the current roll is connected to the beginning of the new roll – this transition is called a splice.
This typically occurs during roll changes, either when the machine is at a standstill or while it is still running.
Important to note: The splice is not a product feature, but rather a process-critical transition within manufacturing. It does not affect the end product itself, but it does affect the path to getting there.
An incorrectly laid splice can cause the web to tear, the machine to stop, tools to be damaged, or dimensional deviations and rejects to occur.
In butt splicing, two ends of material are joined together without overlapping.
The ends are cut at right angles and then pressed together.
Advantages
Disadvantages
Butt splices are particularly suitable where
changes in thickness are critical.
In an overlap splice, the new material overlaps the old
material, usually connected by a splice tape.
Advantages
Disadvantages
The choice between butt splicing and overlap splicing is always
a process-dependent decision.
The most common variant. Splice tapes are special double-sided adhesive tapes with:
The decisive factor here is not only liability, but also:
Here, the connection is made exclusively via the cover liner, not via the product itself.
Advantages
Restrictions
Liner splices are used when the product itself must not be affected.
The splice is made directly using the adhesive tape product.
This variant is possible, but critical and rarely used:
Product splices are usually only acceptable if the splice point is later safely removed.
A splice is unavoidable. However, the crucial factor is where it occurs in the process.
An incorrectly positioned splice can damage the tool, cause dimensional deviations and trigger unplanned downtime.
In practice, this means:
In order for a splice to be processed in a controlled manner, it must first be detected. The aim of detection is not to avoid the splice, but to guide it through the process in a targeted manner.
Typical methods:
A detected splice enables a timely response before critical process steps are reached.
Many splicing problems do not become apparent immediately,
but only during series operation:
Often, the cause lies not in the material, but in a lack of
understanding of the interaction between material and process.
Splicing is not a minor issue in adhesive tape converting, but rather a decisive factor for process stability and series production capability. A good splice is characterised by its reliable hold. However, a very good splice goes even further: it is planned from the outset, precisely positioned and reliably detected.