Clever approach to zeroing flexible fixtures

A mid-sized Hungarian company manufactures aluminium die-cast parts and then processes them into highly relevant components for the who’s who of the automotive and large-scale industries. A multi-purpose system for workpiece clamping on the machine table is created from a clever fixture construction and efficient zero-point clamping technology from AMF. It is so flexible that the machines can be set up quickly for both mass production and small-series production. Even the most prestigious customers are impressed.

A state-of-the-art Hungarian manufacturer and processor of aluminium die-cast blanks uses flexible AMF zero-point clamping technology to clamp castings weighing between 30 g and 5500 g. Thanks to consistent further development, what began with individual pilot projects and simple hydraulic clamping elements from AMF has been expanded into effective clamping technology with automation and zero-point clamping technology. This has reduced set-up times so significantly that machine utilisation has soared. These days, the clamping technology is so flexible, as well as partly automated, that the machines can be set up just as efficiently for small quantities, such as for a Bentley, as for the mass-produced vehicles from VW.

Wide product range from AMF simplifies procurement and logistics

Today, 15 processing plants have been equipped with the latest zero-point clamping technology from AMF. But this was not always the case. It started in 2015 with some simple angle clamps, but a clever fixture design engineer was not satisfied; he wanted to further optimise the clamping technology and make it even more flexible. And so, over the course of extensive consultations, the possibilities of AMF’s zero-point clamping technology were discussed and ultimately implemented.

The number of fixtures has now grown to over 200. They are all equipped with bolts for mounting in the zero-point clamping interface. The fixtures, developed by the Hungarian company, include a base plate for each machine, which is held by the zero-point clamping modules via the pull-studs. AMF was able to provide efficient support with many tips and a wide range of products. The products the company uses include swing clamps, clamp arms, stop valves and pressure accumulators, in addition to quick-release couplings, pressure gauges, vertical clamps or support elements and lines, as well as coupling nipples for media ducts. The fact that AMF has such a wide product range has been a great help for customers, and has greatly simplified procurement and logistics.

Time-delayed control as a special additional function

Four fixture variants with pressure-regulating valves and multiple media ducts on the base plates ensure maximum flexibility. This means, for example, that all consumer circuits can be controlled with different pressure levels. And a particular highlight: they can also be controlled with a delay – i.e. consecutively. This feature means that workpieces with complex geometries can also be clamped securely and automatically. For example, the support element can first be extended to hold a workpiece and then the clamping fixtures can be closed.

The K 10 zero-point clamping modules provide the required force for secure fixing. The four modules pull in the pull-studs on the base plate with a force of ten kilonewtons each. With a tolerance of just five micrometres (5 µm), this is extremely reliable and has excellent repetition accuracy. The small power packs then hydraulically lock the pull-studs, and hold them in place with a high 25 kN spring force. Because the bolts are mechanically locked after clamping, the pressure lines can be disconnected at any time after the clamping operation. An operating pressure between 50 and 60 bar is sufficient for hydraulic opening.

Customers around the globe praise Hungarian reliability

Due to the use of an additional pressure accumulator, the fixtures can be loaded outside the machine while production continues. This allows for ideal preparation, because the components are clamped on the fixture before being transferred into the machine, meaning that set-up times are independent of machine running times, ensuring maximum efficiency. The components, made of more than 4,000 tonnes of aluminium per year, are then sent at high cycle rates from the 42 mainly fully automated die-casting machines for further processing; with unit quantities of between ten and 15,000 per week, this processing has to manage both small and large series. These parts are then processed into a range of products including chassis parts, engine and gear bearings, and electrical circuit housing, as well as complex air-conditioning compressor parts and headlight or thermostat housings. The Hungarians deliver these mostly as 1st-tier suppliers to OEM plants around the world, including BMW, Bentley and Porsche, as well as VW, BASF and Boge. All of these customers praise the creativity, innovation and reliable deliveries of the Hungarian team. And thanks in no small part to AMF zero-point clamping technology, it all works reliably.