What Is Meant By Tool Grinding?

sharpening blade

Manufacturing tool wears during the cutting operation, it is important to replace it as soon as it becomes dull or after its tool life. In some cases, the dull cutting tool can reuse after retaining its cutting edges. Tool grinding is the process of reshaping a tool. The tool grinding machine is designed to sharpen a variety of tools. It assures the essential accuracy of the tool geometry (angles).

Taylor Formula for Tool Life – Relationship between Cutting Speed and Tool Life with Graph

tool life graph

Taylor tool life equation

It is observed that the higher cutting speed shorter the tool life.  This relationship between cutting speed and tool life is given by Taylor formula. This formula gives fairly good results. Tylor equation is restricted to very narrow range of cutting process parameter because this equation does not take all affecting parameter into consideration.

What is tool life? What are the factors affecting the tool life?

drill tip

What is tool life?

Tool life is a most important factor in the evaluation of machinability, it is the period of time in which the tool cuts effectively and efficiently. Tool life is defined as the time period between two successive grinding of tool and two successive replacement of tool. A cutting tool should have long tool life. The cost of grinding and replacement is very high, so the short tool life will be uneconomical. Now a day’s tool material improvement increases the tool life.

What Is The Effect Of Micro Structure On Machining?

Effect Of Micro Structure On Machining


The physical properties of the material vary with the microstructure of material. The material microstructure determines the mechanical and thermal behavior of machining.  The high degree of homogeneity has closely packed small grains which results in poor finish, buildup edges, tearing of material and decreases the overall machinability of material. That is the reason for the difficulty in machining of the full solid solution, pure metals such as iron and copper. A heterogeneous material whose component is segregated into large grain (Example: wrought iron) is also had poor machinability.

Caulking and Fullering of Rivet Joint with Sketch? Difference between Caulking and Fullering

caulking and fullering image

🔗What is Riveting metal joining process?

What is Caulking and fullering

Caulking is a process employed on riveted joints of pressure vessels like tanks, steam boiler to make joint leak proof and fluid tight. The narrow blunt chisel tool used for caulking is known as caulking tool. Caulking tool about 5mm thick, 38mm breadth and edge of tool is ground to an angle of 80°. The tip of the tool is forcing down (burring down) the edges of joint as well as the edge of rivet head as shown in figure. It closes all the asperities in the contacting surfaces. Caulking is done at the edges of plates in lap joint and edges of strap plate in a butt joint. The edges of plates are first bevel at 70-80° then caulking tool is hammered either by hand, hydraulic tool, or pneumatic tool. The blow on the caulking tool is closes to the plate, so a great care would be taken during caulking to avoided injury of main plates below the tool and that may open the joint instead of sealing it.

Fullering is also a process to make a sealed joint. It is similar to the calking except the shape of tool. The tools used for this purpose is known as fullering tool. The thickness of fullering tool is equal to the thickness of plates. So the blow on the fullering tool results in simultaneous pressure on the entire edges of the plate. The fullering is more satisfactory than caulking because it gives a clean finish and less risk of damaging of plates.

Comparison between caulking and fullering

Caulking

  • An operation to make leak-proof joint; the outer edges of the rivet joint is hammered into seam.
  • The narrow blunt tool used for caulking known as caulking tool.
  • Caulking carried out at the edges of both plates and rivet.
  • The thickness of caulking tool is about 5mm
  • The risk of getting main plate damaged is high.
  • The achieved is surface finish is not good as fullering.

Fullering

  • A process to make leak-proof joint
  • The tool used known as fullering tool
  • Fullering is carried out only at edges of plates.
  • The thickness of fullering tool is same as the thickness of plate.
  • The chance to get main plate damaged is low.
  • Very good surface finish.

Types of Riveted Joints – Lap Joint, Butt Joint, Single Strap, Double Strap, Chain and Zig-Zag Riveting

riveting lap joint butt joint

🔗What is riveting? How riveting done?
🔗What is the difference between Cold Riveting and Hot Riveting

Depending on the how riveted plates are placed, the riveting classified mainly into two i) Lap joint ii) Butt joint
Lap joint: In lap joint, plates overlapped each other. The rivets are inserted in the overlapped region.
Butt joint: In this type of riveting, the plates to be joined is kept in alignment butting/ touching, without forming an overlap. Another plate known as cover plate is placed over either one side or on both side of the main plates, then it is riveted with main plates.