Connect. Contend. Create.

More can be achieved together.
We combine our strengths as part
of the plastics holding addfinity testa.

addfinity testa is a growing industrial holding of small and medium-sized companies with a focus on the plastics-processing industry.

We see ourselves as an initiator, motivator and shaper of the future for the companies in our Group, which operate on the market in a financially independent manner.

Our actions focus on the forming of connections, the establishment of a culture of collaboration, and the mobilising of value-creating synergies.

In doing so, we draw on the size and diversity of the Group, while also maintaining the typical strengths of the SME sector.

Find out more:

Product diversity

Whether for vehicle construction or other industries – as a specialist in injection molding and assembly engineering, rely on us as your partner when it comes to the finest plastic parts.


We know what really counts for our customers, which is why we make innovation, precision and swift on-time delivery our top priorities.




Innovation is what drives us and we remain at the cutting-edge, thanks our use of the best available technology, and employees who are constantly developing.



For us, only the most accurate sizing and the very top quality will do when manufacturing our products.



Product diversity

From consulting and planning to serial production, we offer you the best service. Our modern machinery meets all the stringent requirements for manufacturing precise molded parts or tool parts.

One of our specialty areas is injection parts of such outstanding quality that they can be decorated with special third-party applied surfaces in external enhancement stages.


For us, investing in innovative production processes, modern monitoring systems and continual technical production improvements is second nature.

The key to supplying quality within deadlines is the ability to combine professional insight and competence all in one. Trust in our expertise and hunger for innovation.


Further training and investment in modern technology are always on our agenda and nothing is more welcome than new challenges.

No matter what project you have in mind, solving it with you is our pleasure, while nothing less than a win-win is guaranteed from close collaboration with ourselves and our suppliers and partners. Why not get in touch.


We plan our stages of production while keeping feasibility and all possible risks in mind every step of the way. The entire production process is regularly checked and assessed in accordance with a carefully compiled schedule and quality demands. We are also certified in accordance with TS 16949.

All this underpins the consistently outstanding product quality which we guarantee to our customers.


Plastic solutions.

We design complex injection molding tools using our own construction set-up and oversee every aspect of project management right up to series production, which lets us optimally monitor production time, costs and quality. Our in-house toolmaking section can swiftly carry out in-process maintenance and alterations or modifications to tools at any time. Moreover, we have nurtured long-standing partnerships with experienced mold makers domestically and overseas to facilitate the construction of complex tools.

We employ state-of-the-art machinery for production technology and, thanks to the use of injection molding machines with clamp forces ranging from 35 to 1500 tons, no company is better equipped than us for high-quality injection molding production. Get to know us better!

Sonnplast Produkte


To meet the stringent quality demands of our customers, we produce interior and exterior parts with unrivaled precision and use cutting-edge machinery to produce exceptional components for you.





  • Injection molding of all common
    engineering thermoplastics
  • Vertical machines
  • 2K and 3K up to 500t
  • MuCell up to 900t
  • Metal insert molding
  • Internal gas pressure
  • Ultrasonic welding
  • Mirror welding
  • Friction welding
  • Assembly injection,
    e.g. overmolding
  • Module assembly
  • Process development
  • Injection molding simulation
  • Rivets


  • Surface, design parts
    • Sets of parts (painted, chrome-plated...)
    • Decorative panels
    • Seat covers add-on pieces
    • Cockpit
  • Functional parts
    • Kinematic assemblies
    • Sealing lips
  • Vehicle lamps
  • Module assembly


  • Tool planning and design (Catia V5)
  • Project management
  • Simulation
  • Thermal imaging
  • Test laboratory & 3D measurement
  • Fixture & automation construction
  • Process development
  • In-house further technical training
  • Optical parts monitoring
  • TS 16949 certification
  • EDIFACT-capable


Sonnplast GmbH is a manufacturer headquartered in Sonneberg (Thuringia) and producing technical molding parts of unrivaled precision from thermoplastic polymers via single- and multiple-component injection molding methods. The company has established itself on the market as a supplier for automotive manufacturers and well-known automotive suppliers, boasting a wide-ranging product portfolio including seat trims, ventilation flaps and cup holders.




Facts & figures.

Sonnplast to the point.


Founding as NS-Kunststofftechnik e.k.

Taken over by SONNPLAST GmbH


Leonhard Ritzhaupt


> 300



Sonnplast GmbH
An der Müß 42
96515 Sonneberg

Standort Sonnplast



Apply today!

Unsolicited Application

We are constantly looking for specialised, qualified, motivated personalities with industry experience even if there is currently no job offer advertised.

With your defined professional career ambition in mind, there is no need to wait for suitable offers from us. Seize the initiative and feel free to apply!

Please send your unsolicited application in writing
or by e-mail to:

Sonnplast GmbH
An der Müß 42, 96515 Sonneberg


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© 2008 by
An der Müß 42
96515 Sonneberg
Phone: +49 3675.8953-0
Fax: +49 3675.8953-53

Legal notice.

Legal information on Sonnplast GmbH.


Sonnplast GmbH
An der Müß 42, 96515 Sonneberg

Phone: +49 3675.8953-0
Fax: +49 3675.8953-53

Commercial register:
Jena Local Court,, HRB 508765
Leonhard Ritzhaupt
Sales Tax No.: DE 815409623


Any contents of linked external pages fall within the exclusive responsibility of the respective provider.

We prepared the contents of our pages with utmost care.

However, no responsibility can be taken for the correctness, completeness and actuality of this information.

General Conditions of Purchase

You will find our general conditions of purchase under following link: 

To open you need the Adobe PDF Reader.

General Conditions of Purchase (in german)

© Sonnplast GmbH 2016

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