Back-injection and
plastic hybrid composites

In our in-house plastic injection-moulding production, we produce customised components for individual or subassembly production as well as fan wheels for the blower technology applications. We also use back-injection technology to combine metals and metal foils with different plastics and to integrate specific sensors or lighting elements.
This results in sealed and durable connections without component distortion and without the formation of gaps.


We form strong connections.

  • Back-injection
  • Integration of electronics
  • Anodising of back-moulded components
  • Plastic injection moulding

Manufacturer of metal and plastic components joined together via back molding

Back-injection of metal and metal foils

We back-inject metals and metal foils with specific plastics and integrate electronics, lighting elements and/or sensors as desired. Even the anodising of previously back-moulded components is possible. The optimal design of our tools avoids distortion caused by shrinkage and different linear expansions.

  • Decorative and functional elements with injected support elements
  • Door sill trims in the automotive sector

Manufacturer of smart metal surfaces controlled by sensors as well as integrating other elements such as light.

Perforated surfaces that enable the metal to communicate through integrated light controls or sensor technology.
When switched off, both the elements and the perforated surface are invisible. Integrated effects such as illuminated icons, logos, symbols or lettering, only become visible in the ‘on’ mode.

Details on smart surfaces

Supplier, manufacturer of back-injected components, metal parts and metal foils with plastics.

We anodise the surfaces of previously back-moulded metal components in the highest optical and haptic quality, in accordance with your design concepts. To best support you, we have our own anodising plant complete with the following finishing processes:

  • Organic or electrolytic anodisation
  • Partial / selective anodising
  • Anodising of already back-moulded components

In addition, various forms of pre- and post-treatment are possible, for example brushing, grinding, blasting, polishing, special pickling and lasering.

Anodising details

Supplier, manufacturer plastic injection molded fan impellers, fans

Equipment in our injection moulding department:

  • Injection moulding machines with up to 250 t clamping force
  • Presses with up to 500 t pressing force
  • Servo eccentric presses for complex forming operations
  • Machinery for turning and milling tasks
  • Plant for welding and bonding plastic components

We design and manufacture the composite tools ourselves.

  • Complex injection moulding tools based on Moldflow analyses and numerical simulation methods
  • Sheet metal tools for bending, punching and deep drawing of visible components in form and design
  • Progressive composite tools and jigs


Advantages of the technology.


No component distortion, no bending.
Durable and seamless connections of the component parts.


Unique components for your customers and products.
Realisation of cool touch effects.


Ability to integrate electronic components, light, etc.
Possibility of anodising previously back-moulded components.


In-house toolmaking for injection moulds.

Download brochure (PDF)


Cross-functional performance spectrum.

  • Metal processing
  • Metal finishing
  • Bonding
  • Toolmaking
  • Appliances & components

Supplier, manufacturer of metal components and metal moldings

Industrial metal processing

Aluminium, sheet metal, stainless steel and steel:

  • Bending and forming
  • Turning (CNC), milling (CNC), sawing
  • Punching and pressing with up to 500 t
  • Grinding and polishing
  • Welding

Further informations

In metal processing, we design and manufacture your required metal mould from sheet material or extruded profiles in medium to large series, finishing them as desired. Our service portfolio ranges from mechanical pre-treatment to anodising and powder coating to various laser, etching and printing technologies.


Joining and bonding technologies

We join components using a wide variety of methods. In bonding, we use liquid adhesives, adhesive tapes and also adhesive die-cuts, which we apply manually or robotically. Optionally, different types of pre-treatment are possible, including plasma, primer, scarfing or pyrosil as well as different rapid curing methods (UV light, infrared, heat radiation).

  • 1C adhesives with manual and robot-assisted application
  • 2C adhesives in robot systems with high-end dispensing technology
  • Adhesive tapes with manual or robot-assisted application
  • Punched adhesive substrates with special systems for perfect positioning and pressing

Supplier toolmaking, toolmaker Bavaria

  • Embossing tools
  • Punching tools
  • Multi-cavity tools
  • Progressive dies
  • Injection moulds
  • Transfer tools
  • Forming tools for visible components
  • Devices for handling
  • Testing and measuring devices

Assembly and automation
  • Manual assembly
  • Partially automated assembly of small to medium quantities
  • Fully automated production of large quantities
  • Complete assembly lines incl. safety and function tests
  • Customised assembly lines


Development and series production of (OEM) appliances

In accordance with the individual requirements of our customers, we develop and manufacture complete products in series as an ODM and OEM device manufacturer and also manage the processes of certification, packaging design and logistics.



Assemblies combine individual components, which have different shapes and are made from different materials. These are permanently joined together using appropriate technologies such as laser welding or bonding. Depending on the components and the required joint, this is done manually or using robot-assisted semi- or fully-automatic systems in our plants.



Our pull-out rails and mechanical and electromechanical hinges bring movement to numerous application areas, for example for the convenient sensor-controlled opening and closing of (oven) doors or refrigerators.


Your contact partner for plastic technologies.

Sales Management

Eva Angerer


+49 8071 9150


Wilhelm Gronbach GmbH
Division Surfaces

Am Burgfrieden 2
D-83512 Wasserburg/Inn


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      • Order volumes
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      • Requests from private individuals
      Order volumes

      Please take into account that our production is geared towards medium to large series production. We are therefore unable to process requests for very small quantities for economic reasons.

      Requests from private individuals

      We ask for your understanding that we cannot consider requests from private individuals of any kind.