FEATURE PRODUCTION & ASSEMBLY
USING EDGE BONDED SHIMS to cut machining and assembly time
Shims are used in industry as compensators to absorb tolerances between mating components. Christie Jones of SPIROL explains the advantages of edge bonded shims
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recision shims are used as compensators to absorb tolerances
between mating components. They significantly reduce manufacturing costs by eliminating the need for each component to be precision machined in order to achieve the proper fit and function of the total assembly. During assembly shims provide adjustment to compensate for accumulated tolerances that significantly reduces the need for re-machining and assembly time. They are commonly used to preserve the faces between mating components, cutting down the required machining time during rebuilds/retrofit. Laminated shims have peelable layers
of metal which are removed until the shim has the proper thickness. They are built up from layers of precision gauge metal foil. Layers are bonded into a rigid structure that appear and function as a solid sheet or plate. Adjusting them is as easy as peeling off laminations with a knife or in the case of some materials no tool. Rather than having to stack a number of individual shims a single set can be adjusted to desired thickness and slipped into position. In this way variable close tolerances can be achieved, saving considerable time required to pick various different thicknesses of loose shims. This provides cost savings by reducing assembly time and minimises lineside SKUs and related inventory storage space. The finished
SURFACE BONDED LAMINATED SHIMS Surface bonded laminated shim packs (laminated shims) are adhered throughout the entire surface between each layer of material and the layers are pressed together to cure similar to the way plywood is manufactured. The unwanted layers must be discarded due to their deformation during peeling.
laminated shims withstand reasonable handling including shearing and machining. In addition, laminated hims can be partially solid, partially laminated. This type of shim is either half-solid or three-quarter solid depending on the ratio of solid section to total thickness. Semi-solid shims add rigidity to a design by meeting performance requirements of a thicker, solid shim as they provide a bearing surface on one side yet allow adjustments to the overall thickness of the shim by enabling the user to peel off unwanted layers from the other side.
Surface bonded laminated shims must be adjusted using a tool
Semi-solid edge bonded shims allow course and fine adjustments to thickness
EDGE BONDED SHIMS The layers of an edge bonded shim set are pressed together and then adhered by only the edges of the shim’s profile. This allows for a much easier separation of the layers in the field. Since edge bonded shim sets are easy to peel the layers that are not needed are preserved and can be used for a later application. Edge bonded shim sets have all the performance and cost advantages of solid and loose shims yet provide a solution for companies seeking a better point-of- use adjustable shim set. Furthermore, multiple lamination thicknesses can be combined in the same stack giving the customer more flexibility for adjustment. This is not an option for traditional
PLASMA WELDING APPLIED TO GEAR MANUFACTURE
By using plasma welding IMI is able to weld forged metals to sheet metal gears with a diameter of up to 4 m and a weight of up to 19 tons. This technique allows a full penetration butt weld to be performed in those cases where the geometries of the components make the use of traditional welding techniques almost impossible. Two factors play a pivotal role in choosing this type of welding over the traditional technique of back-gouging: the temperatures at which the welding is to be performed and the space in which the butt joint must be created. The use of quenched steels means that very high temperatures are necessary which are extremely difficult for a welder to tolerate using traditional welding techniques; he would need frequent breaks and subsequently reheat the metal each time, prolonging the time it takes to
26 FEBRUARY 2016 | FACTORY EQUIPMENT
carry out the weld. In terms of geometries, working with a technique that is only performed on one side of the joint simplifies the welding process: there is no need to intervene on the opposite side. This is especially important when considering that work is being carried out in an extremely restricted space where more complicated welding operations could result in a lower quality finish and requiring a considerable effort on the part of the welder. IMI is able to manage the manufacturing process as it sees fit, diversifying the application of its techniques in order to achieve superior quality and give added value to the component. The company is currently testing different materials to further expand the applications of plasma welding.
IMI
www.imisrl.eu
laminated shims. Edge bonded shims provide cost saving advantages over conventional laminated shims because the materials are less expensive. They offer safe adjustment in seconds and are much easier to peel than surface bonded laminates. Safety is improved because a knife is not required to remove the edge bonded layers. Cost savings can be realised because the layers that are removed from the edge bonded shim pack are reusable, functional parts since no deformation of the layers occur during adjustment. Both surface bonded and edge bonded shims offer the advantages of reducing assembly time, taking up less inventory storage space and reducing the number of lineside SKUs. However, when speed of adjustment, operator safety and minimising your overall cost of assembly are your primary objectives, edge bonded shims provide the best solution.
SPIROL T: 01536 444800
www.SPIROLShims.com
/ FACTORYEQUIPMENT
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