Groche Technik GmbH Plastifiziereinheiten

We manufacture screw conveyors as individually as plastics.
They are performance optimised, highly resistant to wear and tear and corrosion-proof. Our screw production can fulfil your requirements from 12 mm to 140 mm in diameter up to a length of 5000 mm. The manufacture of screws for plastic injection moulding machines sets increased demands on the production process as far as finishing precision and surface consistency is concerned, in order to minimise friction.

The screw conveyor has the task of drawing in the granular plastic, to consistently convey, to compress and to perfectly homogenise in the output area.

We manufacture barrels in high wear and corrosion resistance designs from 12 mm to 200 mm in diameter, up to a length of 5000 mm.

The barrels tasks are static. It undergoes high levels of pressure and tension when thermally loaded. Drill hole surfaces must withstand wear and corrosion caused by the plastics.

The barrel input can be optimised for each individual application.

Our product range comprises of thermoplastic, thermoset plastics, silicone and elastomer processing in the appropriate optimum qualities.

The screw-tip-set is the heart of the plasticizing unit.

Screw-tip-sets must shut off safely and should allow a constant mass cushion, in order to guarantee reliable and even dosing.

There are no good or bad nscrew-tip-sets, but only suitable and unsuitable ones as far as manufacturing quality is concerned.

Groche Technik manufactures the central components for your plasticizing unit.
We produce various nozzles, end caps, mixing elements and specialised nozzles for you and the special demands of processing plastics.
We adapt our products individually to the desired product processes as specified by you.

GSM mixing nozzles
The GSM mixing nozzle is used for processing thermoplasts in injection moulding processes. The design principle of the GSM mixer is unique. Each element divides the diameter into two channels, which come together at half of the diameter and then expand again.

Spring activated needle type shut-off nozzles
The needle type shut-off nozzle (NVD) is used to process thermoplastics and liquid media. The choice of nozzle size depends on the flow of injection volume (cm3/s). The NVD (shut-off nozzle) is responsible for the clean separation of the molten mass and reliable shut-off during dosing and is the prerequisite for fault free, economic production.

Nozzle with tubular coil cartridge (heated internally)
The internally heated machine nozzle is specially designed for use with narrow tool dimensions. The extremely small outer diameter offers optimum heat distribution up to the nozzle tip.

The HVOF method is a process for refinement of screw conveyors. The screw conveyors made of tool steel are roughened to start. A gas mix is now ignited with a special gun, which causes the metallic powder particles to melt, and they are shot onto the screw conveyor at a speed of 750m/s. The kinetic energy of the impact produces additional heat, supports the bond and increases the density; the required hardness levels are achieved.

The screw conveyor is fully encapsulated with this method.

A layer thickness of up to 0.25 mm is possible. The screw conveyor has the character of a carbide screw conveyor combined with the benefit of toughness in the core. Extreme torsion stress on small screw conveyors should however be avoided.

Groche Technik carries out the following repair work in screw conveyor regeneration:

Screw conveyor cleaning and crack inspection
Pre-grinding screw conveyors
Screw conveyor PTA welding, application of buffer layer if necessary
Alignment
Flank grinding
Core band grinding and polishing
Cylindrical grinding to finished size
Nitrating
Concentricity check
Leak test on screw conveyors with internal cooling
Final inspection with measurement record
The processing parameters