Lathe Operations: Facing

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Facing Operations Facing is the process of removing metal from the end of a workpiece to produce a flat surface. Most often, the workpiece is cylindrical, but using a 4-jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes.

When a lathe cutting tool removes metal it applies considerable tangential (i.e. lateral or sideways) force to the workpiece. To safely perform a facing operation the end of the workpiece must be positioned close to the jaws of the chuck. The workpiece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end. Cutting Speeds

If you read many books on machining you will find a lot of information about the correct cutting speed for the movement of the cutting tool in relation to the workpiece. You must consider the rotational speed of the workpiece and the movement of the tool relative to the workpiece. Basically, the softer the metal the faster the cutting. D…

What are the Advantages and Limitations of Broaching Machine?

Advantages of Broaching Machine


Broaching has been adopted for mass production work. It has following features and advantages:




  • Rate of production is very high with properly applied broaches, fixtures and machines, more pieces can be turned out per hour by broaching than by any other means.

  • Little skill is required to perform a broaching operation, in most cases the operator merely loads and unloads the work piece.

  • High accuracy and high class of surface finish is possible. A tolerance of ±0.0075 mm and surface finish of about 0.8 microns can be easily obtained in broaching.

  • Both roughing and finishing cuts are completed in one pass of the tool.

  • The process can be used for either internal or external surface operation.

  • Any form that can be reproduced on a broaching can be machined.

  • Cutting fluid may be readily applied where it is most effective because a broach tends to draw the fluid into the cut.


Limitations of Broaching Machine


Following are the limitations of the broaching machine:




  • High tool cost. A broach usually does only one type of job and is expensive to make and re-sharpen.

  • Very large work pieces cannot be broached.

  • The surfaces to be broached cannot have an obstruction.

  • Broaching cannot be used for removal of large amount of stock.

  • Parts to be broached must be capable of being rigidly supported and must be able to withstand the forces that are set up during cutting.

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