Crystal Welding Machine: Precision with Clear PVC

Product Stories24 Nov 2023
Welding PVC Crystal Clear tightly and in an aesthetically pleasing way is a challenge due to the special material properties. Leister's range of crystal welding machines, including hot air and hot wedge welding options, are tailored for these challenges. Our solutions ensure tight, visually pleasing welds for PVC Crystal Clear applications, overcoming the common hurdles in welding transparent PVC. Experience the efficiency and quality of Leister tools in handling the specific requirements.

Author: Mariateresa Pirozzi, Marketing Specialist, Leister Technologies AG, Italy

The transparent material PVC Crystal Clear is often used to manufacture the following products due to its special properties:

  • Tent window
  • Transparent curtains to protect against wind and cold and as a connection between indoor and outdoor areas
  • Industrial doors
  • Pergolas
  • Pavilions
  • Tension structures and inflatable structures (inflatables)

In brief: Thanks to its weather resistance and transparency, PVC Crystal Clear is versatile, highly valued and widely used. But there is a catch. Anyone who wants to weld the material faces various challenges due to its special properties: Because PVC Crystal Clear is not a coated fabric, it has no supporting pattern and tends to warp when heated. It therefore requires special attention when welding. This is because it tends to form unsightly folds or waves both when welded to other Crystal material and when bonded to coated PVC material.

Advantages and disadvantages of welding with high-frequency welding machines

If PVC Crystal Clear is welded with high-frequency welding equipment (HF welding equipment), this has advantages and disadvantages: HF welding machines are particularly suitable for straight seams and are easy to operate. This means that they can also be used by inexperienced users. On the other hand, their purchase price is high, which means they are not affordable for every company. The operating costs can also be significant. In addition, HF welding machines are efficient when welding straight seams, but are less suitable for curved seams because special devices are required for this and two users often need to be present at the same time. In addition, the aesthetic results are not always perfect; the welding zone may look dull or show visible traces of the fusion process.

SEAMTEK - the efficient solution for versatile and frequent applications

The SEAMTEK welding machine from Leister is the ideal solution for anyone who frequently welds Crystal. The innovative, stationary welding machine is designed to weld even large and complex thermoplastic materials efficiently, safely and in a visually appealing way.

Leister sells the SEAMTEK welding machine in two versions: SEAMTEK 900 AT with hot air and SEAMTEK W-900 AT with hot wedge technology. The latter is the ideal tool for welding Crystal thanks to its heating wedge.

Quiet and fast, the SEAMTEK W-900 AT offers users plenty of freedom when working and is ideal for welding large, even three-dimensional objects. Ergonomic and safe, it enables welding without producing smoke or unpleasant odors. Thanks to its PLC control, the welding parameters can be easily and immediately adapted to individual requirements. The heating wedge control is quick and easy, as is changing the rollers. This increases efficiency during use.

Another important point for strengthening competitiveness is lower energy consumption. With the SEAMTEK W-900 AT, this is definitely low thanks to the split-second regulation of the heating wedge. Thanks to greater efficiency in use and energy consumption, the investment in this welding machine is worthwhile because the purchase costs are quickly amortized, depending on the frequency of use. Last but not least, the SEAMTEK W-900 AT from Leister has a PLC interface, allowing it to be connected to the company's IT systems and adapted to the requirements of Industry 4.0.

UNIPLAN 500 and VARIANT T1 - the solution for occasional applications

PVC Crystal Clear is often used in production environments where mainly straight seams are required and the objects to be welded are not so large, e.g. E.g. for welding windows for pergolas and verandas or industrial doors. Sometimes this work is not part of the company's daily operations, but is offered as a supplement to the product range. In such cases, the investment in an HF welding machine may be too high. The purchase of a SEAMTEK could also raise concerns about the amortization period of the costs incurred.

In this case, Leister's wide range offers more cost-effective alternatives: The two automatic welding machines UNIPLAN 500 and VARIANT T1 are perfect for processing tarpaulins and technical fabrics. And they weld PVC Crystal Clear with perfect results, both aesthetically and functionally.

UNIPLAN 500 from Leister


The Leister UNIPLAN 500 automatic welding machine is ideal for welding truck tarpaulins, sun protection, pavilions, tension structures and banners. The robustness and reliability of the UNIPLAN 500 guarantee high and constant performance.

The automatic welder has a modern electronic control system that allows the welding parameters to be set quickly. When welding a material as special as PVC Crystal Clear, this is crucial so that users can make the necessary adjustments to achieve the desired result.

VARIANT T1 from Leister


The VARIANT T1 is the top model among Leister's automatic welding machines. Designed for overlap welding, it enables fast welding with maximum productivity and very precise results.

"To weld PVC Crystal Clear well, it is not necessarily necessary to invest in complex and expensive technologies," explains Danilo Sirna from Tendenze d'arredo, an Italian company that is highly regarded for the precision of its work on curtains and sun protection. "The manual skills of our employees combined with the reliability and user-friendliness of the VARIANT T1 enable us to produce perfectly welded windows with a weatherproof seal and flawless surface."

Conclusion: Leister has welding machines and automatic welding machines for companies of all sizes, with which users can perfectly weld even difficult-to-process materials such as PVC Crystal Clear.