Tuesday, June 15, 2010

Hepcomotion Develops Actuators For X-Y-Z Systems

Hepcomotion has developed a range of actuators, enabling it to supply X-Y-Z systems for industrial and scientific tasks such as pick and place, automated assembly, inspection and product labelling. According to the company, X-Y-Z linear motion systems are widely used throughout industry. For many applications, using the same type of linear actuator in each of the axes is an adequate solution. However, with manufacturing economics focusing on greater productivity, X-Y-Z systems are increasingly being specified to automate vital processes.

Their speed of operation is often greater and their duty cycle much longer. The new actuators have been developed to address these different needs so that each axis operates optimally and contributes to the overall efficiency and longevity of the system. This concept still allows X-Y-Z systems to be constructed using standard, off-the-shelf components but accommodates the specific characteristics of the application. The Hepcomotion method is to recommend the most appropriate actuator to meet the criteria of a given application.

However, to illustrate the point, a typical configuration for a low-weight payload system would start with the company's PDU2 linear actuator as the foundation of the X axis. The Hepcomotion PDU2 is a cost-effective and compact actuator. It comprises a slotted profile into which fits a toothed belt drive and a carriage - an arrangement that effectively seals the unit. The actuator's Herculane wheels run virtually friction free on the inside surface of the profile, providing stable support for the carriage plate; felt wipers sweep debris from their path.

This also means that the wheels operate well without the need for lubrication. The Y axis of a typical X-Y-Z system is often required to have a particularly high load capacity and stiffness against twisting loads. The new Hepcomotion PDU2M is said to address this need. It shares the same technology and format as the PDU2 but with moment load capacity improved by 200 per cent and stiffness by 1,000 per cent. The direct load capacity is also 50 per cent greater. In practice, this means, for example, that designers can use a single PDU2M unit as a horizontal axis in an X-Z system, where previously two PDU2 units working in parallel would have been required to provide the necessary rigidity and strength.

The needs of the Z axis are different again, with enhanced linear force and higher gearing often required. The new PSD80 linear actuator is suitable for this duty, with drive from a smooth stainless-steel lead screw operating with a bearing polymer nut. Again, it uses the same Herculane wheel technology in a unit that is matched to the other axes in terms of performance, size and cost. A choice of motors and gearboxes is provided with all Hepcomotion driven actuators, for which flanges are provided to facilitate connection. A Smart Drive Taranis stepper motor drive and control package is also available.

Left, right or double drive shafts can be supplied as well as other options such as different carriage designs, holding brakes, positioning encoders, limit switches and cable carriers. The development of the company's Heavy Duty HDS2 product has introduced larger bearings, slides and racks, additional mounting elements and automatic lubrication systems. For instance, the largest vee bearing now measures 150mm in diameter and has a radial capacity of 100,000N (10 tonnes); these developments have opened up application possibilities in the heavy handling markets.

The largest aluminium beam now offered is a 300 x 200mm section and is strong enough to be used as a standalone X axis. With slides complete with rack drive fitted, the solution is often more cost effective than machining a steel beam with slides attached, according to Hepcomotion. The necessary rack lubrication facility is provided in the X-axis carriage, which typically forms the mounting structure for the Z axis. All Hepcomotion actuators fit together using standard components to create multi-axis systems that are guaranteed to perform better than similar units where 'general-purpose' actuators are used for all axes.

Lightweight aluminium T-slotted profiles allow the axes to be incorporated into frames, such as the Hepcomotion MCS Aluminium Frame and Machine Construction System or more complex machines. The company supplies its X-Y-Z systems as individual parts, in kit form or fully assembled multi-axis units. Its approach to X-Y-Z system design can be applied to configurations with a working envelope of just a few centimetres right up to those with dimensions of several metres.

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