Unscrewing units
Units for unscrewing threads in injection moulds
The smooth, fast, and clean unscrewing of moulded parts requires powerful unscrewing units that can be compactly integrated into the tool. Depending on the application, our servo unscrewing units are grouped in different versions. A special feature of the Servomold unscrewing systems lies in decoupling the threaded cores from radial forces from the drive train. Here, the interaction of pinion, thin-section bearing, lead screw, and spline profile ensures smooth, low-disturbance operation with high efficiency.
- Repeatable and micron-accurate: full servo-electric control
- Space-saving and flexible: in various sizes and performance classes
- Completely ready to install: plug & play instead of design effort
:quality(90) "SAD Main")
Unscrewing units demould internal threads by controlled rotation
An unscrewing unit demoulds internal threads in injection moulds by rotating the threaded core out of the solidified plastic part in a controlled manner instead of pulling it. This process is also referred to as thread demoulding – both terms describe the same operation.
Servo-electric unscrewing units from Servomold operate oil-free, with storable motion profiles and micron-accurate repeatability. The alternative to unscrewing is the collapsible core:
it folds mechanically inward and releases the thread.However, collapsible cores require installation space for the collapsing mechanism and reach their limits with fine, contour-accurate thread profiles and high cavity counts.
Servo-electric unscrewing demoulds the thread contour completely and scales up to 96 cavities.
The right design for every installation situation
Which design is right is determined by cavity count, installation space and torque requirement.The spur gear transmits the force axis-parallel and delivers high torques – the unscrewing unit with spur gear (1-cavity) is the standard solution for single cavities and large thread diameters.
The worm gear offsets the drive by 90° and saves space in the mould axis – the unscrewing unit with worm gear (4-cavity) unscrews four cavities in a confined space.For high-cavity moulds, multi-cavity systems for unscrewing up to 96 cavities are used.
The SDD/SDG threaded core cooling supplements every design with temperature control of the threaded cores.
Advantages of servo-electric unscrewing units
Designed and configured according to individual customer requirements
Reproducible positioning without an end stop
High torques and high speeds
Durable, robust and cleanroom-capable
Compact and versatile to integrate
Can be supplemented with SDD/SDG threaded core cooling
Unscrewing units with spur gear
:quality(90) "SAE 50 Main")
Unscrewing units with worm gear
:quality(90) "SSE")
Unscrewing units for multi-cavity moulds
:quality(90) "SAM LM")
Unscrewing unit with synchronized linear movement
:quality(90) "SLU Main")
Application example: thread demoulding with the SAD servo unscrewing unit
A typical application is a closure part with an internal thread. After injection, the SAD servo unscrewing unit rotates the threaded core out of the solidified thread in a controlled manner before the part is ejected.
Motion profile, rotation angle and speed are stored in the control system and retrieved identically in every cycle. Because no mechanical end stop is required, the position remains reproducible even after mould changes.
The thread is demoulded true to contour – without forced demoulding and without damage to the thread flanks.
Efficient turning out - single, multiple or up to 96 cavities
Servomold offers suitable solutions ranging from standard single unscrewing units to space-saving units with worm gear, up to complex, high-cavity applications such as the unscrewing of up to 96 cavities.
In order to ensure the balance between easy integration and efficient power transmission, each gear assembly is designed as compact as possible.
:quality(90) "SAE 50 Open")
More power, less friction
A special feature of the Servomold unscrewing systems is the decoupling of the thread cores from radial forces in the drive train. The interaction of pinion, thin-section bearing, lead screw, and spline profile ensures smooth, low-disturbance operation with high efficiency.
FAQ – frequently asked questions about unscrewing units
An unscrewing unit demoulds internal threads in injection moulds. The process is also known as 'thread demoulding' – both terms refer to the same operation. The threaded core is demoulded by controlled unscrewing instead of being pulled. The unit converts the rotary motion into the appropriate screwing motion via pinions, lead threads and spline profiles.
:quality(90) "Team Richard Gane")