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Kundenspezifische Gehäuse und Formteile aus Polyurethan

Design and construction hints

Wall thickness
The wall thickness can vary greatly (there are no sink marks on the surface). It should be noted, however, that different wall thicknesses can lead to a delay (due to unequal moderate atrophy) of the molded parts.

Mould
When designing a molded part is to make sure that the tool can be produced economically and that nevertheless a rational and high-quality production is guaranteed. Generally, up to 30000 pieces out of a mould are possible  without special maintenance work.

Side shift and loose parts are state of the art, but make a mould  and moulded parts more expensive and may also reduce mold life too.

Especially with free-form surfaces, it is  nessecary that 3D CAD data must be available. For the mold, we prefer to use 3D IGES, Parasolid and SolidWorks data. Other data formats are possible, but must be discussed in advance. The data referes to the raw piece. If there are critical tolerances the thickness of the paint must be taken into account!

Demoulding angle
1 ° and more form slope is always welcome and greatly facilitated the removal from the molding tool. Less (possibly no)  demoulding angle  is possible, but this must be  aproved by us. The suit should be in the 3D CAD data is already taken into account. Please contact us therefore in advance.

Radii
Radii increase the breaking strength of the  parts and reduce costs of the mold. In general, the larger the radius the better. Only along the separation of the mould form  sharp edges are easier to make than rounded edges.

Ribs
With ribs having a thickness of  ± 50% of wall thickness, an optimum stability of the molded parts can be achieved without sink marks occuring on the visible sides. If possible, position the ribs match the foaming flow  to avoid air pockets.

Metal inserts
The most common thread inserts are cast in brass (various products usually proprietary).

When inserting metal parts for reinforcement is to ensure that no delays occur an intolerable form of parts and that there is no tension, leading to damage.

Connections
For detachable connections are used mostly threaded bushings, are the most reliable cast threaded inserts (see also ep-FIX), and various Spreizbuchsentypen can satisfy limited demands.

For rare to break connections can also be self-tapping screws (PT screws) are threaded into precast holes.

By gluing, good links with polyurethane moldings and polyurethane moldings and between foreign elements can be achieved. In the latter application, the differential thermal expansion of various materials must be considered. Regarding the choice of adhesive will be made by molding manufacturers, depending on the application recommendations.

Marking of the molded parts
Generally, an identification of ourselves with the Emaform form number and the production month attached to the molding. Other markings (customer name, customer item number, PUR Signet ...) can be attached if desired. It should be noted that these markings are possible only in the ejection.

Dimensional tolerances
Without special measures in pattern making and the manufacture of molded parts can be achieved following standard tolerances:  ± 0.5 mm to 250 mm from 250 mm  ± 2 ‰.

Tighter tolerances are possible, however, mean an added expense. Special tolerances are checked with the manufacturer before making the mold to most exactly on the viability. Asymmetric tolerances can die from the current 3-D data are not directly taken into account. Also in the mold, the thickness of the paint are not included (blank corresponds to 3D data).

Wherever you need to install game, is something more in the design to provide too much play, because a subsequent reduction remilling game ever at the tool does, but too little material, however game is missing on the tool!

Shrinkage of the material
The shrinkage of the material in the production process is between 5 ‰ and 8 ‰, depending on the material and molding. This shrinkage must be in the non-customer-supplied CAD data into account. The necessary corrections are introduced in the mold.

Reaction to fire
The addition of flame retardants (ammonium polyphosphate), the strict American UL 94 V0 can be achieved.

The raw material suppliers have generally plate material of 10 mm wall thickness with PUR IHS and most compact 4 mm with polyurethane material with a density of 0.6 and 1.050. Only products specifically tested objects are considered UL 94 V0 approved products.

Paintwork
Finish in a RAL color with a light structure to facilitate the production and contribute to very low-maintenance products. In most cases it is sufficient to paint the summary pages. Special finishes (smooth, high gloss and special effects paints) or coatings (eg, EMC coating with copper-silver conductive paint) can also be applied are usually more expensive. Do some jobs remain unpainted or paint mist must not have, additional masking is required. When tight tolerances must be taken into account the thickness of the paint in the design data and discussed with the manufacturer.

Thermal conductivity
The thermal conductivity of the polyurethane integral hard foam is dependent on the density. This is usually at 500kg/m3.

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Registration

Emaform AG

Zetzwilerstr. 760

CH-5728 Gontenschwil

Schweiz