Coming straight to the (zero) point
Safe and secure workpiece clamping is paramount to a precise machining process. “While there are conventional systems that deliver just that, they usually require long set-up times during every workpiece change arising from the need to centre, align and clamp the workpieces. When opting for our zero-point clamping systems, users can shorten these times to a significant degree. It only takes a few seconds to centre and clamp the workpiece at the zero point. Better still, you only have to set the zero point once and can achieve a repeatability of 0.01 mm. This ability is of tremendous benefit, especially when handling workpieces in several work steps across different machines”, explains Bernd Janner, Sales Manager at Erwin Halder KG.
All models of the zero-clamping system – i.e. both the hydraulic installation version with integrated lifting of the fixtures and the mechanical, pneumatic or hydraulic models with a modular design – are made up of connecting elements and connecting rings that are interlinked by balls housed in the thrust point. Contrary to other systems, the connecting elements (with thrust point) are mounted on the machine table inside the base plates or on pallets, while the connecting rings (with locating hole) are installed at the opposite side that needs to clamped, e.g. the underside of fixtures and supporting plates. Bernd Janner: “The configuration provides an unrivalled level of flexibility as well as production reliability delivers long-term accuracy and keeps the reference point clean.”
Different models available
The modular connecting elements are permanently tensioned and centred by spring force. The balls inside the thrust points are released by the control module. “Users can choose between a mechanical, a pneumatic and a hydraulic model. Replacing the parts is quick and easy, making the conversion of the zero-point clamping system a cinch”, Bernd Janner declares. They can be integrated into base plates, brackets, cubes, etc. and screwed into tables and plates. All three models offer a retention force of up to 10 kN. As an added option, these modular models are also available with an anti-turn locking device.
The - single-acting or double-acting- hydraulic connecting elements designed for incorporation are an ideal match for any automated production process. They can be integrated into base plates, brackets, cubes, etc. Just as its modular siblings, the single-acting connecting element is permanently tensioned and centred by spring force and delivers a retention force of 20 kN. It is released by an integrated hydraulic lifting cylinder. Its double-acting counterpart generates a retention force of up to 30 kN and is tensioned, centred and released by hydraulic power. Both of these models boast a feature that sets them apart from modular connecting elements: “An integrated lift-off bolt pushes the connecting ring up while being released, allowing for more effortless removal. When the ring is being tensioned and centred, the pin retracts again. Another benefit lies in the pneumatic blow-off device that is built into the double-acting connecting element and makes it possible to clean the contact surface”, Bernd Janner adds.
Matching connecting rings
The connecting rings are designed as a perfect complement to all connecting elements. They can be screwed to and integrated into fixtures or mounted directly to the workpiece. To allow for the positioning and simultaneous clamping of fixture elements, the connecting rings are available in three models: as a centric version for aligning and clamping at the zero point, as a sword-shaped version for alignment in one axis direction and as a floating version without centring function for additional, over-determined clamping.
All connecting elements and connecting rings are made of case-hardened, ground steel, while the base and supporting plates are made of aluminium. The plates are also available as a set for two and four connecting elements/rings. Other models are available on request.
Bernd Janner: “Our zero-point clamping systems are a no-brainer for anyone who wants to cut down their set-up times and minimise their downtimes. It is fair to say that the zero point simply wanders from one machine to the next across all the steps necessary to change the workpieces, making the need for repeated and laborious aligning and centring a thing of the past – simply use the connecting rings to position and clamp the fixture of the workpiece on top of the prepared connecting elements at the machine, and you are good to go.”