Expert Report Hydraulic Clamping System

The fact that hydraulics is generally equated with “endless power” is nothing new. What is more surprising is that hydraulic clamping technology is also very flexible and sensitive. With a force that can be reproduced and monitored, hydraulic clamping elements make processes reliable and ensure the process capability that is increasingly required in parts production - right up to full automation. An important aspect in times of a shortage of skilled labour.

Hydraulic clamping elements push and pull with precisely metered and defined forces always in the same way and in the correct sequence at defined points and handle and fix workpieces reliably. In doing so, they relieve the operating personnel of a great deal of strenuous work and ensure ergonomic and safe working conditions during cutting, assembly and welding operations which also makes them popular at the base level. However, the hydraulic support elements should not be forgotten under any circumstances. This is where some suppliers separate the wheat from the chaff. If suppliers offer a wide range of clamping technology and a deep understanding of the process, their solutions are usually more convincing.

Providers with an all-round view think in a technology-independent and solution-orientated way

Andreas Maier GmbH & Co. KG (AMF) has emerged as one such provider with an all-round view. The Fellbach-based company is known as a full-service provider in clamping technology and is one of the global market leaders. This results in expertise and consulting skills that are characterised by clamping technology-independent solutions. The fact that the family-run company can do this is also due to its large product portfolio, which covers all clamping technologies.

So let's get down to the details of hydraulic clamping technology. First of all, it is by no means rigid, only suitable for one component and in the largest possible quantities. If a supplier masters the supreme discipline of clamping technology, they will develop flexible clamping solutions - often embedded in intelligent fixtures - that can be used for different component variants and small quantities. This is also reflected in a flexible media feed, for example with tubing instead of piping, and with various combination options that provide a basis for greater modularity

Hydraulic solutions are the supreme discipline in clamping technology

If you want to make the most of these possibilities, you should consult your supplier of choice as early as possible. Ideally, as early as the component design stage. If they refuse, they may not be the right partner for the optimum clamping technology solution. After all, it should be process-capable and reliable and fulfil the customer's requirements and standards. It should also reduce the workload on employees and increase productivity. So let's summarise as an interim conclusion: hydraulic clamping technology can do it all.

First and foremost, of course, is power. Depending on the component and available pressure, even 150 kN is no problem for the power packages when 350 bar is applied. Up to 70 kN is available at a continuous 250 bar available at the factory, for example. For example, a world-renowned manufacturer clamps large axle housings and high-tech transmissions for tractors as well as construction and agricultural machinery. A diesel engine manufacturer relies on hydraulics in production, just like a Bavarian forge. All large, heavy parts.

Hydraulic clamping technology makes processes possible and safe

It is initially important that the pressure generator safely and reliably builds up and maintains the required pressure. In addition to power units, a wide range of suppliers also offer pressure and tension cylinders, swing, lever, vertical, centring and toggle-joint clamps as well as valves, pressure switches and rotary unions. If bore and pull-down clamps are also available, he can develop solutions for many situations. And not forgetting support elements. If their support force is not powerful without being bulky, the performance of the clamping elements is wasted. AMF can provide elements with a high support force in relation to their size - unique on the market.

For process capability and reliability, hydraulic elements always clamp in the correct sequence, with the same force and at the correct contact points. Incidentally, a thoughtful partner can recommend these correctly at an early stage when designing the component so that they are accessible later on. If he recommends extra clamping lugs for complex geometries of components with demanding clamping requirements, which can be removed later, he demonstrates his in-depth understanding of the process. 

Hydraulics can follow up. That makes them unique

The hydraulic system is also unrivalled in its ability to readjust if components become loose due to weight, vibrations or other reasons. This provides additional process reliability and guarantees that the required tolerances can be maintained. If the clamping elements are also as compact as possible, the component remains free of interfering contours and ideally allows 5-axis machining. Process capability and process reliability, together with adherence to ever tighter tolerances, become all the more important the fewer skilled labourers are available at the machines. It is precisely this personnel situation that also ensures ever stricter standards for customer requirements. This means that quality assurance can check component accuracy in defined processes independently of the expertise and mental knowledge of employees.

It is important that the clamping hydraulics adapt to the components and not the other way round. For example, AMF has manufactured flexible clamping fixtures for four variants of components for a customer, which are clamped and machined in pairs. A combination of hydraulic pull-down clamps and swimming support elements is used to hold large cast parts in place. This ensures perfect flatness of the parts. Turned by 180°, the zero-point clamping modules hold the screwed-in pull-studs and fix the components directly, without distortion, and accessible everywhere for five-sided machining.

Complexity remains manageable and elements available

But the highlight is the flexibility of the clamping devices. Two movable support plates are mounted on a base plate. Hydraulic support elements are inserted and bolted in a grid and can therefore be easily moved. This means that the fixtures not only seat two related side panels, which can be processed on five sides after turning. All four variants of the components can be clamped in the respective processing conditions. To ensure that the workers keep an overview despite this unimaginable complexity, the correct positions for the respective component have a coloured number. That provides security and ensures speed during advance set-up while production is ongoing. For this purpose, a clamping plan as well as a set-up plan are available for each component at the machine.

And what if the component changes, is discontinued or relocated to another supplier? - An objection frequently heard. Is the costly hydraulic clamping technology then lost? Not at all - if you have chosen the right supplier and solution partner. Hydraulic clamping fixtures can usually be adapted to component changes. And if the component is actually discontinued from the programme, the hydraulic clamping technology is by no means lost. After all, the hydraulic components of a fixture can be used for other projects or fixtures. As they are designed for very high cycle stability, they promise great sustainability. A solution-orientated partner with a correspondingly wide range of products is sure to be available again.

A positive conclusion lists the advantages of hydraulic clamping technology

Hydraulic clamping technology is not only strong, but also sensitive and flexible. Solution-orientated suppliers with a wide range of products and a great deal of application experience provide technology and product-independent advice. The result ensures process capability through to automation, process reliability and compliance with tight tolerances and standards. Those who take advantage of this can impress their customers with quality and reliability, even in times of a shortage of skilled labour.