TPT September 2014

Technology News

Centreless grind faster with coated abrasive belts By Bob Manetz

lift-truck or return conveyor, increasing the chance for damage to the tube or pipe. Hard wheel grinding gets the job done, but it is slow. With the proper set-up of a multiple head abrasive belt centreless grinder and the careful selection of a coated abrasive belt grit sequence, the end-user is able to achieve high stock removal rates, close tolerances and final surface finish in a “single pass operation” at much higher throughput rates than are obtainable with a hard wheel grinder. Many large cylinder manufacturers, after careful review, have opted for a heavy duty multiple head coated abrasive belt centreless grinding system to provide an efficient 24-hour/7 days a week finishing system. For a coated abrasive belt centreless grinder, the coated abrasive belt is the cutting tool that provides the surface finishing capabilities. Coated abrasive belts use engineered mineral grains that are orientated on the belt backing in such a way as to remain sharp for consistent stock removal and heat reduction throughout the life of the belt. However, the abrasive belt cannot do its work without the support of other major system components to meet the end- user’s finishing requirements. Acme Manufacturing Company – USA Email: acme@acmemfg.com Website: www.acmemfg.com

peeling, turning, grinding and polishing. Coated abrasive belt centreless grinders excel at grinding and polishing tube and pipe, and with a multiple head system can do both processes at the same time. Centreless grinders utilising coated abrasive belts are used worldwide in a large number of industries, including steel mills, hydraulic cylinder manufacturers, nuclear fuel, solar and energy producers, glass, plastic and acrylic manufacturers, and speciality metal producers. The hydraulic cylinder industry was one of the early adopters of coated abrasive belt centreless grinding technology. Finishing requirements for this industry usually demand from 1mm to 1.5mm OD stock removal, OD tolerances equivalent to ISO h7, surface roughness measurement of ≥0.2 Ra µm, and fast throughput speeds. If you are a product planner faced with similar production requirements, you have a decision to make. Do you select an abrasive belt or hard wheel centreless grinder for your process? For a hard wheel centreless grinder to meet the finishing requirements listed above for hydraulic cylinder tubes, you are looking at multiple set-ups and machine passes of the tube in order to obtain the necessary stock removal and surface roughness specification. Furthermore, between machine passes you will be handling the part by crane,

COATED abrasive belt centreless grinding deserves strong consideration when evaluating cylindrical tube and pipe OD (outside diameter) finishing applications. This grinding and polishing process makes use of coated abrasive belts, known by many as “sandpaper”, and they are very good at what they do when combined with the right grinding system and know-how. In today’s global marketplace, pro- ducing the best product at the lowest price is the goal for most manufacturing companies. With proper understanding, product planners, design engineers and manufacturing personnel can make the best determination in how to meet their products OD finishing requirements. For tube and pipe OD finishing applications that require stock removal, tolerance and surface roughness control, coated abrasive belt centreless grinders are often the best choice. The OD finishing requirements for tube and pipe are typically provided by the end-user in the form of an engineering drawing with geometric dimensioning and tolerancing specifications along with an expected production rate. One can then determine what processes are required to meet the specifications. With tube and pipe, the OD processes most often considered include heat treatment, straightening,

Lump-free production FOR continuous quality control in hose and tube extrusion lines, lump detectors are as essential as diameter measuring devices. The 2- and 3-axis lump detectors, Lump 2000 XY and Lump 2000 T, from Sikora quickly and precisely detect the smallest lumps and neckdowns on the product surface. or extreme vibration. The lump detector is sturdy, and due to its small dimensions easily can be integrated in any extrusion line. The settingof tolerances and the numerical

display of lumps and neckdowns are realised with the Remote 2000 or a processor system

By the use of a powerful signal processor, the height, depth and length of the fault location are evaluated. The combination of double sensor technology (differential measuring principle) with infrared light sources ensures reliable fault detection, even under difficult conditions such as dirt

Two-and 3-axis lump detectors from Sikora

Sikora AG – Germany Fax: +49 421 48900 90 Email: sales@sikora.net Website: www.sikora.net

of the Ecocontrol series. Alternatively, the Lump 2000 devices can be directly integrated in the line control via a universal interface module.

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S eptember 2014