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Design and fabrication of power hammer report Download

Study of Power Hammers

Until now we have confined ourselves to study of hand tools used in smithy work. They certainly perform very well so far as the hand- forging is concerned, but their use for satisfactory production is limited to small forging only. It would not be difficult to understand that the intensity of blows, however great one may try to achieve through hand hammering, will not be sufficient enough to effect the proper plastic flow in a medium sized or heavy forging. For this, a power hammer is usually employed. The capacity of these hammers is given by the total weight of their falling parts i.e., tup or ram and die. A 200 kg hammer will be one of which the falling parts weigh 200 kg. The heavier these parts and greater the height from which they fall. The higher will be intensity of blow the hammer will provide. Power hammers in common use are of different types e.g. spring power hammers, pneumatic power hammers, Steam hammers and Drop or Forge hammers and six bar slider crank power hammers. These hammers are named partly after their construction, partly according to their way of operation. Apart from these, a large number of forging presses and machines are used in forging work. In the following articles these hammers and machines will be discussed in detail.

Mechanism

Four bar parallel linkage mechanism for toe movement

In recent research the four bar linkage mechanism is used for the humanoid robots for the free movement of their toe. Using this mechanism the major part of the force acts on the non-movable portion of this link rather then on the toe tip. Because of this it is possible to decrease the constraint on the joint. At the same time the following multiple roles of the toe are expected. One it to generate a large kicking force at the toe pad and another is to maintain multiple contact with the floor by the toe joint control.

SIX BAR SLIDER CRANK POWER HAMMER MECHANISM

Construction

As shown in above diagram it consists of 5 links, and one fixed link. The five links are crank (link 1), link 3. Connecting rod (link 4), Crank (link 5) and Ram die (link 2).Column can be considered as a fixed link. The link 1 rotates about a turning pair F, it is rotated by a pin joint axis, the link 3 and link 1 is connected by a turning pair E. The connecting rod (link 4) and link 3 are connected by a turning pair D. The crank (link 5) is fixed at a turning pair A and oscillates about the pin joint axis. Crank (link 5) and connecting rod (link 4) are connected by a turning pair B. Ram Die (link 2) and connecting rod (link 4) are connected by a sliding pair C. Ram Die and composite bush are connected by a sliding pair G. Crank (link1) is joined at turning pair F to the column and also crank (link 5) is joined at turning pair A. Column is welded to the base, vice (not shown in above fig) is fitted to the column for holding the work piece. All the links, Column, Base and Vice are made up of Mild Steel, they are rigid enough to absorb the vibrations and shocks produced during work. Composite bush is made up of two materials outer one is of Mild Steel and the liner is made up of Gun Metal to prevent from wear, tear and corrosion resistance. A handle is provided at point E, with the help of the handle the crank (link 1) is rotated.

six bar slider crack power hammer -Mechanical projects

Working Principle

The Crank (link 1) rotates at a fixed axis at F it is joined to link 3. As the link 1 is rotated the motion is transmitted to the link 3 which is connected at point E. The motion is further transmitted to the connecting rod which is joined with the link 3 at D. Finally the connecting rod transmits the motion to the Ram Die (link 2) which reciprocates at a fixed path G. The Connecting rod (link 4) and Ram Die (link 2) are connected at C, Where a slot is provided for getting a straight line motion of the ram Die. The crank (link 5) is provided for oscillating the connecting rod at a fixed path.

Manufacturing Process

Cranks (link 1 and 5)

A mild steel material of the required dimension is cut on the power hack saw machine. After cutting process is over the fillet is provided over the edges by using a hand grinder. After a drill of diameter 6 mm is made. Finally the filing was done on the bench vice.

Connecting Rod

A mild steel material of the required dimension is cut on the power hack saw machine. After cutting process is over the fillet is provided over the edges by using a hand grinder, after providing fillets drilling operation of required diameter is done after completing this process now we proceed towards milling the slot of 65 x 8 x 6 mm3 by using an end mill cutter. Finally filing was done on bench vice to remove unnecessary sharp corners.

Ram die

Mild steel material of required dimension is cut on power hack saw. The material was fixed on the chuck in a lathe machine for doing facing and turning operations. Polishing was done for good surface finish. Chamfers were made for removing sharp corners. A hole was drilled at the end of the ram of the required size for fixing the slider pin. A slot was milled on the rod to insert the connecting rod in the slot and fixing it in the slider pin. At the other end of the ram a hole of required size was made and then later it was taped at the same end to make the fixing adjustment of the punch with the help of a screw.

Column

The Column is made up of Mild Steel of required dimension. First the marking for the holes to fix the links were done on the column. The outer profile was marked and then made to cut on a gas cutter, and then it was milled to the required size and then finally chamfering was done to remove unnecessary sharp corners and edges. Drills were drilled on the column for bearings, turning pairs F and A. Then the composite bush was welded on the column. Vice was fitted on the column by the application of welded joints for holding the work piece.

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Design and fabrication of power hammer report pdf Download