Introduction
Anyone looking to specify or procure a fiber-reinforced thermoplastic pipe for the first time faces an unfamiliar task: What winding angle do I need? What tape width is sensible? What does "mother pipe" mean? And why can a higher quantity suddenly increase the unit price?
The Alformet Tube Designer – the online configuration tool for CFR-TP composite pipes from the LATW process – gives engineers and buyers the ability to independently configure and order pipes directly. To achieve this, a fundamental understanding of the process and its parameters is required. This article provides exactly that.
What is Laser-Assisted Tape Winding – and why is it relevant?
Laser-Assisted Tape Winding (LATW) is an automated manufacturing process in which unidirectional thermoplastic prepreg tapes (UD-tapes) are consolidated in-situ using a laser and wound onto a rotating mandrel. The result is a continuously fiber-reinforced thermoplastic pipe – without autoclave, without post-pressing step, with complete process documentation.
Alformet relies on machines from the parent company AFPT GmbH, one of the world's leading developers of LATW technology (laser-AFP). This background is not a marketing argument, but a technical advantage: Process control – especially laser regulation – is crucial for consolidation quality, and this is precisely where the strength of the system lies.
The most important terms at a glance
Before using the configurator, it is worthwhile to understand the basic terminology. It determines which parameters are entered – and what they mean in the process.
CFR TP – Continuous Fibre Reinforced ThermoPlastic: Composite material made of continuous fibers in a thermoplastic matrix. Recyclable, weldable, formable.
Mandrel – The rotating tool onto which the tape is wound. The inner diameter of the finished pipe is determined by the mandrel – manufactured to tight fitting tolerances.
Track – A single tape strand that is wound over the entire length of the component.
Layer – A complete wrapping of the mandrel by multiple tracks – without gaps or overlaps.
Step – A group of layers with the same winding strategy.
Winding – A complete production cycle on the mandrel that produces one or more components.
Mother Pipe – A single winding that contains multiple components in a long pipe that is then cut to length.
Good Length – The actually deliverable component length after removing the process-related waste lengths at the ends.
Waste Length – The end areas of the pipe where the process is not stable. These are removed before delivery and are dynamically calculated in the configurator.
Effective Winding Angle – The actually achievable angle that allows for a seamless position without overlap – depending on target angle, mandrel diameter, and tape width.
Production certificate – A complete quality document with actual winding angle, consolidation pressure, winding speed, material batch, and process limits.
The hierarchical structure of a winding operation is: Track → Position → Step → Component → Winding → Order.
Cost optimization: Tape width and component length as levers
Two parameters have the strongest influence on the unit price – while also offering the most design freedom:
Tape width
UD tapes in the LATW process typically have a thickness of 0.15–0.25 mm and a width of 6–50 mm. In the Alformet webshop, two width classes are available:
Narrow tapes (10–15 mm, incl. ½ inch): Preferred for small mandrel diameters, as the conformity on the surface is better and the quality increases.
Wide tapes (20–26 mm, incl. 1 inch): Higher yield rate, faster production, lower unit costs – ideal for medium to large diameters.
The choice of tape width is therefore not just a material technology issue, but a direct lever on production speed and component quality.
Component length and quantity
In a high-mix/low-volume environment, a significant portion of the total costs is attributed to setup and auxiliary times. Individual parts that require their own winding are correspondingly more expensive.
As soon as multiple components can be manufactured in a mother tube, setup and waste costs are distributed over several units – the unit price decreases. However, there is an important peculiarity:
Caution with increases in quantity: If an additional unit requires a second winding without fully utilizing the mandrel, the unit price increases sharply. Only when the second winding is also completely filled does the price drop back to the optimum. These "price jumps" are visible in the configurator and should be considered in quantity planning.
Angle Winding vs. Cross Winding: Quality or Efficiency?
In the LATW process, two fundamental winding strategies are available:
Angle Winding (Winkelwickeln)
In angle winding, each layer is completed individually and fully. The process runs as follows:
Tape is automatically fed and attached "on-the-fly".
The track is wound over the entire length and cleanly separated at the end.
A return run to the starting point prepares the next layer.
This strategy allows for highest component quality – each layer is precisely defined, the wall thickness tolerance is ±1 tape thickness. The disadvantage: The empty runs increase the process time.
Cross Winding (Kreuzwickeln)
In cross winding, the tape runs continuously in both directions – over so-called turning zones. Positive and negative angles alternate, creating a braid-like pattern. Advantages:
No idle time → higher efficiency and lower costs
Suitable for less demanding applications
Disadvantages: Fiber undulations occur at the intersections and a greater wall thickness adjustment possibility (±2 tape thicknesses) arises, as cross layers are always applied in pairs (positive + negative angle).
Both strategies can be combined – through the step function, angle and cross winding layers can be specifically combined in a component.
Tolerances: What is realistic?
Inner diameter
The inner diameter is determined by the mandrel and is usually within an h7 fit tolerance. For larger mandrels, the thermal expansion coefficient of the steel may play a minor role – depending on the preheating temperature of the tool.
Wall thickness and outer diameter
The wall thickness results from the number of layers multiplied by the tape thickness. The tolerance is:
±1 tape thickness for angle winding
±2 tape thicknesses for cross winding
If a specific outer diameter is functionally critical, it can be specified in the comment field of the configurator – including the desired tolerance direction (plus, minus, or middle tolerance).
Conclusion: The configurator as an entry into the thermoplastic composite world
The Alformet Tube Designer is more than an ordering tool – it is a structured introduction to the logic of the LATW process. Those who understand how tape width, winding strategy, and quantity interact can optimize specifically: for quality, for cost, or for both.
For applications outside the standard configuration – such as very small or very large diameters, special materials, or structural requirements – the Alformet team is available for direct consultation.