Flat ejectors from KNARR

 Wide range of standardized options for every application

Flat ejectors prove to be extremely beneficial in constructively critical areas. Ribs on the plastic part can be demoulded without any problems, to name just one advantage. The classic, sharp-edged version belongs to the absolute standard repertoire in both, hardened and nitride-oxidized executions.

Block ejectors

A subset of the hardened flat ejector variant is of particular interest. The blade shape is decisive for the name of the so-called block ejectors. Specifically, these are less typical dimensions such as 5.5 x 5.5 mm, 8 x 8 mm or 12 x 10 mm. Compared to the ejector pin, the block ejector achieves around 25% more demoulding area on the plastic part with a similar space requirement. This not only saves ejectors in the mould, but above all pressure points on the moulded part can be minimized.
Further applications of block ejectors are, for example, the backing movement of the ejector set or a contour providing installation.

ArticleMaterialTreatmentCorner radiiRadius toleranceRadius

Flat ejectors with corner radii

For almost 15 years now, flat ejectors with fully ground corner radii have been part of the KNARR portfolio, which has been expanded continuously in the recent past. The distinction between two and four possible corner radii is still one of the main criteria, but it is no longer sufficient to distinguish the extensive range of products.

Within flat ejectors with corner radii, Knarr differentiates between two different tolerance classes. Both versions are based on a radius of R 0.2 as standard. The radius tolerance of +0.02 is suitable for all common applications. In particular, the injection of highly viscous plastics often requires an even more precise adjustment. For these cases, KNARR offers the “precision flat ejector” version. With a radius tolerance of +0.003 / +0.008, burrs on the plastic part can be avoided from the outset. Aside from that, we recommend a DLC coating for both versions, which is also available as standard.

Precision flat ejectors, in addition to the material and coating combination 1.2067 + DLC, are also available in HSS material. With a nominal hardness of ~ 60 HRC, this is a second option to minimize wear. Besides that, HSS ejectors are ideal for tools operating at higher temperatures.

If an injected part or the corresponding plastics material place even higher demands on the corner radii of a flat ejector, an HSS variant with a radius R 0.1 is also available from KNARR. Even then, the tolerance of +0.003 / +0.008 can be guaranteed.

ArticleMaterialTreatmentCorner radiiRadius toleranceRadius
325711.3343 HSShardened2+0.003/+0.008R0.2
325771.3343 HSShardened2+0.003/+0.008R0.1
325811.3343 HSShardened4+0.003/+0.008R0.2
325871.3343 HSShardened4+0.003/+0.008R0.1

Flat ejectors with extra-long blades

Flat ejectors with extra-long blades are available both with and without corner radii. In the latter version, KNARR also differentiates between the two tolerance classes +0.02 vs. +0.003 / +0.008. The high-precision version relies on HSS material and is even offered as an additional version with a DLC coating.

ArticleMaterialTreatmentCorner radiiRadius toleranceRadius
3265411.3343 HSShardened4+0.003/+0.008R0.2
326541DLC1.3343 HSShardened4+0.003/+0.008R0.2