Source flow imprinting

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The laminar flow embossing is a development of the insert molding process for the manufacture of components made of plastic with decorated surfaces, in particular for sheets of thermoplastic polyolefins (TPO) on a foam backing. The plastic melt is injected into the opening tool as a cake. As soon as all of the plastic melt has been injected, the tool collapses and the plastic melt forms the component completely. This process enables low internal mold pressures and thus gentle decor processing.

Process flow

A decor that is optionally preformed by means of thermoforming , e.g. B. TPO foam film, which enhances the feel and appearance of the component, is inserted into the tool and fixed with pneumatic clamps. The source flow stamping tool is first completely closed. An opening stroke is carried out while the plastic is being injected. This creates a cake of mass with every plastic nozzle. Once the required amount of plastic has been injected, the nozzle needles close and the tool makes an embossing stroke. When it is closed, the plastic is distributed in the cavity and forms the component. After the cooling phase, the tool is opened and the finished component is removed from the mold.

advantages

The source flow embossing process can be used on a conventional injection molding machine (with embossing control) and offers three major economic advantages:

  1. lower investment requirement compared to a press system.
  2. The injection molding machine and its peripherals require a smaller footprint.
  3. The total cycle time is less than with back pressing.

In addition, low internal mold pressures allow a gentle decoration processing, whereby decorated plastic components can be produced with the swelling flow embossing process in a fully automated one-shot process.

Limits of source flow shaping

The process of source flow imprinting reaches its limits with large jumps in height and closed profiles.

When embossing decor foils (e.g. TPO foam foil), protrusions are necessary to fix (position) the decor, which requires post-processing.

variants

Source flow stamping can also be combined well in connection with the normal injection molding process . The decorated parts of the component are created by source flow embossing. Immediately after the stamping stroke, further areas of the component are injected and shaped. This enables great freedom of design in component development.

In the case of metal foil back-molding , thin sheet metal is back-molded with plastic.

Applications

The source flow embossing process is used in particular for components in vehicle interiors. This includes door panels, instrument panels, armrests, center consoles, parapets, etc. The most common materials are polypropylene (PP) in combination with TPO foam films.

Other applications in the furniture or household appliance sector are conceivable, but have seldom been implemented to date.

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