Used Positioners for Sale — 249

A positioner is an assisting tool used when working with bulky or heavy workpieces. It is used for manual work and is available in a large range of sizes. A positioner allows for a component to be swung along it's longitudinal axis. High-end positioners are equipped with a multi-axis articulated arm, which ensures a large freedom of movement. Another term used for a positioner is a “manipulator”.

Types of positioners

The term positioner cannot be specifically defined. Basically, a positioner includes every lifting device that is used to suitably position a workpiece so that it can be further processed. This includes lifting devices on presses, metal shears, punches, bending benches and even little machine jacks like those that always keep stacks at reach. Other smaller positioners are simply clamping devices that are used in automobile workshops for engine repairs. The engines are either clamped into these or screwed in, which allows for the engine to be manually turned around so that all areas can be easily reached. Mid-sized positioners are used for electronic technology and switchboard construction. These are work tables where the height can be adjusted and they can be pivoted. These devices are particularly useful for ensuring that the workers can maintain a good posture throughout the working day, especially when working for long periods of time. Most valve positioners are found in heavy-duty industry. With their help, especially large castings and welded constructions can be swung around, enabling them to be further processed. 

Small lifting tables usually have mechanical or manually operated, hydraulic power. Small aids for assembly work in workshops usually have manual mechanics. Mid-sized positioners are available as manual mechanical, pneumatic positioner, electric and hydraulic machines. This includes the turnover positioner and the rotary table. Large positioners are usually only availably as hydraulic machines. Mid-sized positioners have a control system directly on the machine. Large positioners are usually controlled via remote control or a foot pedal. The carrying capacity of large positioners can be several tonnes. 

Positioners can be combined with industrial robots. These devices can be used for loading, processing and receiving workpieces. This is particularly useful when mass producing of complex and massive components.

How positioners are applied

Cast pieces with complex forms usually have deep set cavities and a hollow space where moulding sand collects. The workpiece needs to be completely cleaned before it can be further processed. For producing individual components with different shapes, it is necessary to deliberately fire at all the component's areas that are difficult to reach. A positioner and its optionally connected sandblasters are extremely helpful for this. Complete cast pieces can be ground and deburred using positioners. Complex welded constructions can be built onto a welding positioner piece by piece, without the risk of the welding force not being able to reach certain areas. Positioners can also be used for painting jobs. 

Working with a Positioner

Positioners are very easy devices to use. The positioner is put into a horizontal position via its carrier plate and then guided towards the component by a crane. It can pivot very easily after the component and the positioner are tightly screwed to one another. There is no additional training required to operate a positioner; a basic brief should be enough. Positioners often carry components weighing several tonnes, which can develop a high momentum of force. It is important to work slowly and carefully with a positioner, to ensure that the work is safe. The qualification required for working with a pneumatic valve positioner is determined by the type of of work that will be undertaken. Sand blasting, cleaning and even painting processes that require a positioner can be undertaken by non-skilled workers. However, sand blasting is a very dangerous task and should only be undertaken after receiving a thorough security brief. The hinges of the positioner should be well protected. Blasting is very abrasive and can easily lead to wear and tear. Packing the hinges with plastic foil is usually suitable enough to prevent this from happening. Welding and drilling work on cast iron pieces and constructions should only be undertaken by specialist staff with the help of a weld postioner. 

Positioners are extremely heavy machines. They generally require a separate foundation. Due to the combined weight of the heavy positioner, and the often heavy workpieces, positioners' bearings are under a lot of stress. These bearings are generally set up to have a very long working life. However, it is still advisable to take some care. If the bearings start playing up, squeaking or moving turbulently, it is a sign that they are starting to wear down. If this is not dealt with, then it will become difficult to disassemble the machine and changing the bearings later on. Positioners can move a load in several directions, which means that different levels of force are inflicted upon the device's entire mechanical structure. It is recommended to regularly check the arms for any hair line cracks. This can prevent sudden breakages, which would be dangerous for staff and materials. Ideally, monitoring should be done regularly (in a cycle) and results should be recorded. It is generally recommended that the worker who moves the positioner is the same one that will undertake the further processing work. If the positioner is operated by two workers, then proper communication between the two must take place.

Suppliers of Positioners

Particularly interesting positioners, which were especially developed for the production of welded constructions, are available from the companies FÖRSTER and CLOOS. These machines are characterised by their high carrying capacity and precision. A wide choice of one, two and three-axes positioners are available from the industrial robot manufacturers, KUKA and ABB. These companies have a very good customer service, and can give good advice about combining robots and positioners. Large positioners, with a carrying capacity of over 100 tonnes, is part of HEITZE's product range.