Linear actuators are mainly moved with belt, rack and pinion, or screw drives. Each of these systems has features that make them suitable for specific applications. Rollon, the international Group with a direct branch in Bangalore, has a broad and extremely varied range of axis solutions, which include different models of actuators for each of the drives mentioned above. Let’s look more closely at three different cases, and together, we will define the different needs and assess the correct choices for each application. The correct actuator defined by the peculiarities of the application allows us to maximize results and reduce costs.
CASE 1 – High Performance Packaging Systems
Productivity, performance and safety: in the packaging sector, speed is fundamental and reducing cycle times translates directly into an economic advantage, while component reliability translates into reduced maintenance costs and increased productivity. To obtain high performance and production rates on discreetly long strokes, choosing one of the belt solutions would be spot on. Belt solutions allow high speed accelerations on distances as long as 10-12 m strokes. At the same time, load capacities are high: an X-Y-Z portal built with a belt drive solution can manage loads in the range of 150/200 kg. The absence of lubrication on the belt, unlike the other two solutions, involves less maintenance and avoids costly “machine downtime”. The choice of a different type of actuator would not guarantee the same results: for example, a screw system would be too slow and would not be able to handle such long strokes.
For packaging applications, Rollon has created the Plus System, a high performance product family of extremely robust linear actuators in extruded aluminum with a high level of protection of sliding and drive systems; and the Smart System linear actuator product family, which features simplified construction that successfully combines performance and competitiveness. Both product families are driven with toothed belt systems, they use linear rails with recirculating balls, and they reach accelerations of up to 50 m/s2 and maximum sliding speeds of 5 m/s. Both of these product families also offer dedicated solutions for vertical applications on the Z axis.
CASE 2 – Pick & Place systems with long strokes
Our second case involves large portals for pick and place systems, such as those that move metal sheets for the appliance industry or various types of production lines. Load capacities are crucial aspects of these systems, along with the rigidity of the system and the possibility of moving several vertical axes independently along Y axes and strokes possibly longer than 30 m. A belt solution would be limited in this case. Since belts are made of polyurethane, when we assess applications, we must consider elastic deformation rates with the resulting loss of rigidity in the system, and the reduction in precision as the stroke becomes longer.
A belt system also usually has a single motor that uses a motor head to drive the belt and move the different carriages and their respective vertical axes in perfect synchronization. A Y axis moved with a rack and pinion drive would, instead, maintain its rigidity along potentially infinite strokes and offer the option of moving each carriage independently. For these reasons, a rack and pinion drive would be the best choice for these large portals, especially on the Y axis.
The series of actuators in the Tecline family by Rollon mounts induction hardened steel racks with inclined teeth, and rails with recirculating ball bearings or prismatic rails with bearings depending on the application. They also have extruded aluminum profiles with different sized sections, up to 360 mm. Able to handle loads up to 1000 kg, these systems can easily be configured with actuators from the Modline family (these are belt driven) to create portals.
CASE 3 – Assembly systems for semi-conductors
Precision is undoubtedly the main feature for a system used to assemble small parts, such as in the semi-conductor industry. Precision is necessary in terms of positioning and repeatability, to allow the assembly system to be efficient and produce high quality over time. Moreover, when speaking of precision in the semi-conductor industry, the level must be extreme (two-place decimal tolerance). The ideal choice for this solution would be the an axis with a screw drive unit.
The Precision System product family by Rollon includes several models of linear tables for translating with great precision. These systems are built with anodized extruded aluminum profiles and rails with recirculating ball bearings, and they are driven with screw units with recirculating ball bearings, which can achieve a level of precision of 10 µ with regard to positioning and ±5 µ with regard to repeatability. All mounting and reference surfaces of higher performance models are finished.
Needless to say, this level of precision is impossible to reach with any belt or rack and pinion drive system.
For more information:
ROLLON INDIA Pvt. Ltd.
1st floor, Regus Gem Business Centre
26/1 Hosur road, Bommanahalli
Bangalore 560068, INDIA
Tel: +91 80 67027066
Fax: +91 80 67027004