The new Rite-Link product from DE-STA-CO is a ready-made solution for users looking for precision positioning in a conveyor system, says the company
For companies making relatively lightweight components or assemblies – particularly in highly-automated environments – a new precision link system, introduced in June this year, could prove of great interest. The product involved is the Rite-Link conveyor from the CAMCO division of US-based supplier of robotic tooling, workholding and flexible automation systems, DE-STA-CO.
According to Lou Wozniak, Director of New Products for CAMCO, who is based at the company’s head office in Wheeling, Illinois, the product offers a high-precision and low-maintenance solution that makes it an attractive option for automotive manufacturers, whether they are involved as end-users or system builders, that might otherwise try to custom build less accurate chain link conveyors for shopfloor product movement and positioning operations.
The capabilities of the Rite-Link system can be traced back to the use of aluminium as its basic construction material. As Wozniak points out, this not just standardgrade alumimium, but the material used to create the links in the drive system is of an ‘aerospace quality’. Extruded aluminium parts also make up a large part of the conveyor’s “backbone”, comprising its internal load-bearing structure.
Elsewhere, the guides for the links are made from ultrahigh strength, molecular weight polyethylene, which is completely impervious to both oil and water. Another interesting feature is the use of a hard coating for the rails. Coupled with the use of sealed or shielded bearings across the rest of the structure, this feature contributes to one of the most obvious overall performance benefits of the product; that when used in intensive manufacturing environments, where there is little tolerance for interruptions to production schedules, the system requires absolutely no lubrication.
Wozniak explains that, in terms of price and load capacity, the new product is intended to provide added performance when compared to the company’s standard product line of heavy-duty conveyors. While such heavy-duty models generally have an ability to transport workpieces or assemblies of up to 12kg per link, maximum loading for the Rite-Link system is approximately a quarter of that, at 3kg per link.
But the advantage is that while the system can be used in continuous motion mode, the degree of precision with which it can be used benefits indexing; in other words, intermittent stop-start operations, which is likely to prove of interest to many potential users. Wozniak says that the level of accuracy achievable can be of the order of +/-0.25mm. In contrast, he says that standard chain link counterparts can usually achieve only around 0.6mm. In practical terms this means that in use on a shopfloor, the conveyor itself provides the positioning capability necessary for such robotic operations as pick-and-place, or even assembly operations. He is emphatic that there would be no need for any supplementary positioning capability – for instance, a retractable shotpin system that can physically lock a conveyor in place at stations where high positioning accuracy is required.
The system further aims to deliver full operational needs through its standard configurations rather than by a system of customisation. Of course, says Wozniak, customisation is possible, but he says it is not how the system is primarily intended for use. Instead, the emphasis is on achieving flexibility of installation through the provision of a wide range of standard options from which appropriate choices can be made.
The most basic of these is the provision for three different pitch sizes, which relates to the distance between the connecting pins of the links in the drive mechanism.
Respectively, these are 75mm, 115mm and 150mm, though the links themselves have a uniform width of 30.4mm. In turn, this provides for a wide range of centre distances – the main dimension of the conveyor, or effectively the distance between the centre of the drive sprocket, where the conveyor is propelled, and the theoretical location of the centre of the compensation cam at the other end of the installation.
Wozniak says that there are five standard centre distances for each pitch size, with the first two available from stock on short lead-times, and the others are readily configurable.
Allowing for some repetition in the centre distances, achievable through the use of different pitch sizes, the fact sheet for the system lists ten in all; 1.20m, 1.38m. 2.10m, 2.30m, 3.00m, 3.22m, 3.90m, 4.14m, 4.80m and 5.16m. As a further aspect of its flexibility, the product can also be configured for endless carousel as well as over-under, pointto- point operation.
Another significant option in terms of operation relates to the customer’s choice of either a standard indexing drive or a servo, with a related gearbox connected to the driveshaft. Wozniak says that the latter option provides for even greater flexibility through its own inherent programmability. This system effectively adds another layer of precision-related accuracy over and above that provided the product’s basic mechanical operation.
The final element in the package is the Rite-Link’s extended service life. Wozniak says that apart from the normal warranty period, the system is guaranteed to run continuously for a period of up to 8,000 hours between maintenance sessions. As he points out, on the basis of 24-hour continuous operation, that is equivalent to a year of operation. Moreover, he stresses that guarantees only take into account the time over which the system is actually moving. Hence, if the process involved is one that requires indexing rather than continuous motion, then the effective calendar period covered might be much longer; one second of movement in every five seconds, for instance, would increase coverage five-fold.
Wozniak says that the product has already gained its first customers in the United States. A servo-driven example will be introduced to a European audience at this year’s Motek trade show. Understandably, he feels that CAMCO has introduced a product that - if not revolutionary - is nevertheless highly distinctive, both in material usage and in the related performance levels it can provide. He goes so far as to claim a price/performance level for appropriate applications that not only represents an advance on what has been previously available from the company, but on what is available across the market.