Thanks to flexible prototype development using 3D printing, we could deliver an ideal series product to our customer.

With the help of rapid prototyping, Würth Industrie Service developed a customised exhaust plug for Vaillant quickly and cost-effectively.

Initial situation: Solution needed for sealing exhaust pipe

For the safety of the service staff, Vaillant, which is internationally operational in the sector heating and climate technologies, has long been looking for a solution for reliable, gas-tight and acid-resistant sealing of exhaust pipes during the time window of maintenance and cleaning. Here, the challenge is that the pipe diameter of the standard exhaust pipe is bigger than the diameter of the maintenance openings.

Vaillant could not find or develop a product on its own, which can be inserted and removed during every maintenance and at the same time can seal the exhaust pipe completely and securely against flue gas, maintain temperatures from 10 °C to 90 °C and is acid-resistant. Besides, there should also be a visual signal from the outside when the component is inserted in the pipe, so that when the maintenance staff closes the lid, it is not forgotten inside the pipe.

Prototype development by Würth Industrie Service

Würth Industrie Service undertakes design, development and prototype printing

As Würth Industrie Service has been working with Vaillant since a few years in international C-Parts Management, they approached Würth Industrie Service with the product requirement. The department "Design and Development" of Würth Industrie Service defined the technical and organisational framework for the product together with Vaillant and undertook the design and development.

Very soon after that, the first prototype was manufactured with the help of an in-house 3D printer with the elastic material TPU (Thermoplastic Polyurethan- Elastomere). This prototype was used for “look & feel” and for further optimisations. A waterproof printed pipe plug was mounted with four flexible slats on a printed handle. To gas-proof the pipe, the slats should be compressed during application and removal through the maintenance opening of the exhaust pipe. In the pipeline itself, they should again revert to the original state corresponding to the inner diameter. Additionally, an optical aid was installed upon the request of the customer to ensure that the component was not forgotten in the exhaust pipeline system at the end of the maintenance.

A second prototype followed which was already functional due the reduction in the wall thickness of the slats; however, it was still not made out of appropriate material needed for gas-proofing and acid-resistance. The additive handle was replaced by a wooden handle which was connected to the plug with a coupling mechanism and an adhesive surface, which in turn would prevent opposite torsion of both the components while inserting the plug in the pipeline system.

Final prototype wins over in design and features

Final prototype development

With the use of suitable materials and a process changeover while 3D printing, the fourth product could be manufactured as the functional prototype and sent once again to Vaillant. Vaillant carried out leak tests and deemed the prototype as final.

Final product via injection moulding

Series production in the injection moulding process

Because of the yearly purchase quantity, the injection moulding process has economic advantages over additive manufacturing in the production of exhaust plugs, which is why Würth Industrie Service suggested the process changeover to Vaillant and undertook the production in cooperation with a partner company.


Factors of success - success story:

Factors of success:

With the use of additive manufacturing technology in the prototype development, a final prototype could be presented to Vaillant in a short time. Thanks to the experience with conventional manufacturing processes, it was possible for Würth Industrie Service to choose the best possible process for series production.

Würth Industrie Service supplies exhaust plugs to Vaillant as completely assembled, individually packaged, in the quantity required and at the desired delivery time.

Additional information

Würth Additive Manufacturing
CPS®WAM - Würth Additive Manufacturing
Topology optimisation
Component optimisation with additive manufacturing technology
Product development using 3D printing
Customised product development using 3D printing
Spare parts manufacturing using 3D printing
Easy spare part manufacturing using 3D printing