Pengencangan Sambungan Fastening Joining Jurusan Teknik Industri Universitas
Pengencangan & Sambungan (Fastening & Joining) Jurusan Teknik Industri Universitas Brawijaya
Fastening & Joining System
Screw & Nut (MUR DAN BAUT) O Sistem sambungan yang dapat dibuka tanpa merusak bagian yang disambung serta alat penyambung. O Bagian terpenting – ulir O Ulir luar : baut O Ulir dalam : mur
Advantage & Disadvantage Advantages: O Screwed joints are highly reliable in operation. O Screwed joints are convenient to assemble and disassemble. O A wide range of screwed joints may be adopted to various operating conditions. O Screws are relatively cheap to produce due to standardisation and highly efficient manufacturing process Disadvantage: Stress concentration in the threaded portions which are vulnerable points under variable load conditions
Sambungan ? Mekanisme sambungan apakah ini? Tipe sambungan permanen atau sementara?
Sambungan ? ? Tipe sambungan yang memerlukan panas dan memanfaatkan pemuaian logam dalam proses penyambungan Proses penyambungan apa?
Rivet (Keling) O Paku keling digunakan untuk menggabungkan dua pelat secara permanen O Bahan paku keling biasanya disesuaikan dengan material yang akan terpaku bersama: Paku keling baja menggabungkan pelat baja O Paku keling aluminium menggabungkan pelat aluminium. O O Bahan aluminium dan tembaga relatif lembut dan mudah dibentuk
Klasifikasi Paku Keling
Proses Keling [1] 1. Rivets are made from either aluminium, steel, copper or brass. They are supplied in different lengths and diameters and must be cut to the exact length.
Proses Keling [2] 2. The head of the rivet is set to rest in the 'dome' of a ‘dolly’. A typical 'dolly' is shown on the right. This tool is held in an engineers vice and it supports the rivet’s head.
Proses Keling [3] 3. The plates are placed over the rivet, resting on the top surface of the dolly.
Proses Keling [4] 4. The plates are pushed over the rivet and in order to ensure that there are no gaps between them a rivet set is pushed down, over the rivet's shaft. The rivet's shaft fits inside a small hole at the base of the rivet set. The rivet set is made from hardened steel as it is tapped at the top with a ball pein hammer. This closes any gap between the two plates.
Proses Keling [5] A ball pein hammer is used to tap the plates together. If this is not done, the plates may be move slightly, even after a series of rivets have been hammered in position.
Proses Keling [6] 6. The ball pein hammer is reversed and used to expand the ‘tail’ of the rivet. This may take several slight taps. At this point the rivet cannot be removed from the plates.
Proses Keling [7] 7. The ball pein side of the hammer is used to form the rivet head. This takes time and should not be rushed. The head should form a dome.
Proses Keling [8] 8. The final shaping of the rivet head is formed using the rivet snap. The plate should be permanently fixed together at this stage.
Aplikasi Keling
Blind Rivet The Installation Process of Blind Rivets 1. Blind rivets are a two-part fastener consisting of a shell and a headed stem (mandrel) assembled so the shell can be placed into the work to be fastened. 2. The rivet is ‘set’ by drawing the stem through the shell, which causes the shell to deform and clamp the material securely. 3. After the desired clamping force is achieved, the stem breaks off and is discarded. 4. A small portion of the stem remains trapped in the bottom of the shell to ensure the clamping force is retained in the joint. 5. Withdrawing the stem is done with special tools operated by hand, pneumatics or electricity.
Grip Range O Blind rivets are designed to clamp together specific thicknesses of material. The amount of deformation in the shell during setting depends upon this grip range O If the grip range is less than it should be (the rivet is too long), excessive material will be left on the blind side and more pulls will be required to break-off the mandrel. O If the grip range is too large (rivet is too short), insufficient material may be left on the blind side to secure the joint.
Remove blind rivet How to remove blind rivet in any special case : 1. Ensure the stem is well below the rivet head. If it appears the be flush, drive it below the head with a punch. 2. Select a drill bit with the same diameter as the recommended hole size for the rivet, and drill through the head until enough material is removed to separate the head from the shell. 3. Punch the remainder of the shell clear of the clamped material.
Galvanic Corrosion O When dissimilar metals come into contact in the presence of an electrolyte, a galvanic action occurs which corrodes one metal at a faster rate and the other more slowly. O The rate of corrosion depends upon: a) the difference in electrical potential b) the conductivity of the electrolyte and c) the relative sizes of the contacting areas.
Apa yang terjadi pada kasus A dan B ? ? ?
o Compatible o Incompatible. Must not be in contact with each other. o Compatible in rural and mild environments. Some corrosion may occur in marine or industrial environments. Painting both metals could reduce the reaction.
Avoid Galvanic Corrosion When galvanic corrosion becomes a threat to the serviceability of the joint, the following suggestions may be worth considering: 1. Avoid dissimilar metals by careful selection of rivet shell material 2. Build a barrier between the materials such as paint, plastic washers or gaskets. 3. Make provision for drainage to allow water or other electrolyte material to escape. 4. Consider the use of anodized rivets.
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