May 2019

48 n LINEAR MOTION May 2019 www.drivesncontrols.com LINEAR RAILS & CARRIAGES CLAMPS & BRAKING Tel : 01202 623393 sales@moore-international.com www.moore-international.com BALLSCREWS & LEADSCREWS Ball Screws from 4mm o NEW Aluminium Leadscrews Custom CNC Nuts to spec Large or Small quantities Linear & Pro led Guideways Measuring Systems Slides & Miniature Tables Gear Racks Clamps & Braking Elements for Linear Guides & Piston Rods o ering low-friction running with the ability to hold systems or brake securely Unit 6, Factory Road, Poole, BH16 5SL Tel : 01202 623393 Unit 6, Factory Road, Poole, BH16 5SL The X-axis comprises a pair of 16.16m-long aluminium beams, both fitted with two single-edge HD slides. V-slides are used on one beam and flat tracks on the other, providing allowances for the variation in parallelism between the two beams. The parallelism of ±2.5mm reduces the set-up time to assemble the system accurately. Moreover, the tolerance of misalignment ensures the system can cope with offset loads. The X-axis has been optimised to move at a steady nominal speed of 0.5m/s to ensure that the slides remain securely on the dipping module. The slides cannot be fastened to the module because this would result in them having non-blacked areas. ESR slides with a 700kg payload are used on the Z-axis, offering up to four times the load capacity of standard HDS2 slides. These slides are precision-machined from high- quality steel and are surface-hardened to provide good load capacities and wear resistance. The slides are mounted to a beam housing the motors, gearboxes and drive shafts that provide the vertical and horizontal movements. Dipping motion The Z-axis moves at a speed of 0.5m/s, with a stroke length of 1.5m, to raise and lower the slides into the dipping tank. Two heads provide stability when manoeuvring the 4m lengths. The time spent in the tank ranges from 30 to 240 seconds, depending on the tank. Between each chemical tank, the slides are submerged in a clear-water rinse tank to clean the slides and to prevent cross- contamination of the chemicals used in the process. Because the dipping module moves from one tank to the next, a smooth and repeatable movement is paramount. The system aligns the dipping module to repeatable positions along the 16m gantry to within ±0.25mm, ensuring that the slides are positioned accurately above the tanks before lowering. The gantry is programmed to move from the start position to each of the seven tanks at set intervals, and then back to the start position. Low maintenance was a key driver for the high-duty application which moves heavy loads over long distances. Any downtime in the blacking process could affect orders and delivery times, so it was key for the system to deliver continuous operation, without needing to be stopped regularly for routine maintenance such as re-lubrication. Low-maintenance cap wipers provide effective sealing and protection, while also wiping debris from the guide profile. The gantry also has an automatic lubrication system which delivers lubricant directly and constantly to the contact surfaces between the slide and the V bearings. There is no need to stop at regular intervals for re-lubrication. When maintenance is needed, it does not impinge too much on production time. All of the bearings used in the gantry carriages are removable and can be dismounted without needing to remove the carriage from the end of the axis. The process is quick and can be achieved with minimal downtime. Under lubricated conditions, there is no need to change the guide. The V-guide system uses a “unique”wiping action to expel debris, allowing it to perform particularly well in harsh industrial environments. The outer diameter of the bearing travels faster than the inner diameter. The difference in speed causes particles nearer the centre to move outwards to the periphery, and to be expelled. Due to the geometry of the slide and bearing interface, debris is expelled to the outer diameter of the bearing in a spiral motion, away from the running surface. n Components are dipped into the tanks using a Z-axis that moves at 0.5m/s and has a stroke length of 1.5m