By- Aditya

Shilame

WHAT IS MILLING?Milling is the process of cutting away material by feeding a workpiece past a rotating multiple tooth cutter. The cutting action of the many teeth around the milling cutter provides a fast method of machining The machined surface may be flat,angular, or curved The surface may also be milled to any combination of shapes.The machine for holding the workpiece, rotating the cutter, feeding it is known asthe Milling machine.

Types of Milling Cutters Types of Milling Cutters Types of Milling Cutters Types of Milling Cutters Types of Milling Cutters

Types of Milling Cutters

Gears can be manufactured by most of manufacturing processes discussed so far (casting, forging,extrusion, powder metallurgy, blanking). But as a rule, machining is applied to achieve the finaldimensions, shape and surface finish in the gear. The initial operations that produce a semifinishing partready for gear machining as referred to as blanking operations; the starting product in gear machiningis called a gear blank.Two principal methods of gear manufacturing includeΠgear forming, and gear generation.

GEAR MANUFACTURING

In gear form cutting, the cutting edge of the cutting tool has a shape identical with the shape of thespace between the gear teeth.

Gear forming

Two machining operations, milling and broaching can be employed to form cut gear teeth.

Form milling-In form milling, the cutter called a form cutter travels axially along the length of the gear tooth atthe appropriate depth to produce the gear tooth. After each tooth is cut, the cutter is withdrawn, thegear blank is rotated (indexed), and the cutter proceeds to cut another tooth. The process continuesuntil all teeth are cut.

Each cutter is designed to cut a range of tooth numbers. The precision of the form-cut tooth profiledepends on the accuracy of the cutter and the machine and its stiffness.

Form cutters for finishing cutting (Left) andfor rough cuts (Right).

Dividing head (Left), and footstock (Right) used toindex the gear blank in form milling.

specifications

The demand for greener energy and concerns about climate change are making wind energy increasingly topical.Indeed, wind power is a rare bird in today’s unforgiving economic climate. While the 30 percent growth rate of recent years has diminished to 18–22 percent, long-term growth still remains strong.The main challenge in the wind power industry – how to keep pace with demand – is very different and much more positive than the challenges facing many other fields. In wind energy, the focus is on increasing productivity and fulfilling the stringentquality requirements.

Increase Productivity in Gear Milling Operations with Carbide ToolsIncrease Productivity in Gear Milling Operations with Carbide Tools

The gearbox, the link between the rotor, the main shaft and the generator, is one of the most critical components in a wind turbine. A typical gearbox contains several geared parts such as the ring gear, planetarygear, sun gear and slow gear wheel.In addition, wind turbines include various rings with gears such as slewing rings, a type ofcomponent consisting of a gear and a bearing to control the pitch angle of the blades and to orient the nacelle appropriately in relation to the wind.

New Technological Possibilities of Universal Gear Milling Machines

The calculation of the hob tooth profile requires the use of difficult mathematical formulas and graphical checks. Even with the best calculations, it will frequently be necessary to undertake numerous adjustments during the cutting process in order to achieve the desired result.The second aspect of the milling machine that we discovered in May 2005 — 100 to 120 years from the time the universal gear-milling process was introduced — involves changing the places of the cutting tool (hob) and the blank.This “reversible MLG method” will be of interest to those who already have knowledge of the hobbing process. Therefore, I will not go into detail about the actual cutting process or the techniques required for manufacturing hobs and broaches.

The hob that is created will be custom-matched to the shaft; a shaft of a different size will require its own custom hobs.First step: Instead of installing a hob on the mandrel in the gear-milling machine’s spindle, I mount a blank (usually soft tool steel) with the same O.D. and length as the actual hob. Then, I turn the blank to match the helix of the desired size of the hob. I mount a blank above the broach.Second step: The broach that is required looks like a straight-sided spline broach for splined holes (round internal, push-type.) The dimensions of the broach must match those of the desired spline shaft. The cutting rake and back angles should match those of the standard straight-sided spline broaches. Unlike a standard broach that is tapered, this broach must be made with a constant outside diameter for its full length. When producing the relief for the edges, be certain to provide enough room for chip clearance between the teeth. The completed broach is installed on the milling machine’s table, in the same manner that a workpiece would be installed.