Nozzle tips for hot runner nozzles
Plastic injection molding is a process used to manufacture plastic products. This is done by transporting the liquid plastic through a hot runner and then injecting it into a mold via a hot runner nozzle. We have optimized the material of our nozzle tips for the special requirements of this process.
Your advantages at a glance:
High thermal conductivity of 140 W/mK
Extremely temperature- and corrosion-resistant
High product service life due to special surface hardening
Good mechanical workability
Our product specification available for download:
Many plastics have a very narrow range when it comes to processing temperature. If the temperature is slightly too warm, the material may be damaged. If the temperature falls too sharply, the plastic hardens and no longer flows optimally into the mold. This is why the heat transfer in the hot runner nozzle is essential.
To keep the plastic at the right temperature, the nozzle is heated externally using heating coils. Only at the very end – in the nozzle tip – is no further heating equipment used. This means that the heated nozzle itself must transfer the heat to the plastic.
The thermal conductivity of the material is crucial here. For common metals like steel, this is insufficient. Although copper has a very high level of thermal conductivity, it is not able to withstand the abrasive plastic and the mechanical loads.
That is why we developed titanium-zirconium-molybdenum (TZM). TZM has a particularly high thermal conductivity of 140 W/mK and it also has a very high temperature- and corrosion resistance. If a particularly high level of material hardness is required, we can further harden TZM by subjecting it to our SHN process after machining. Compared to carbides (tungsten carbide), TZM is easier to machine.
SHN process for surface hardening
Glass fiber reinforced plastics are particularly challenging for manufacturers because the tools are subjected to a very high abrasive load. During the production process this can place considerable strain on hot runner systems – and the hot runner nozzles in particular. An optimum combination of thermal conductivity and material hardness is required. That is why we have developed the SHN surface hardening process for our TZM nozzle tips to make them particularly resistant.
Using SHN surface hardening , we can strengthen the surface and entire TZM components through the addition of a permanent, adherent diffusion layer. As a result, our customers benefit from a wear-resistant surface and a material that is also easy to machine. The hardening takes place in the gas phase. Coatings that we produce using the SHN process adhere better than conventional PVD- or CVD layers. They perfectly replicate the surface contour of the TZM component.
Microsections of a SHN-hardened hot runner tip