January 5, 2022

Difference between Milling and Welding

What is milling

Milling is a process that involves the use of milling or cutting tools to remove material from the surface of a workpiece. The process uses cutting tools rotating at set speeds. Bring the cutting tools with the workpiece to start removing materials when they come with the workpiece.

Milling removes crevices from the surfaces of metals that cause corrosion. It gets rid of excess material off the surface of a workpiece. The process prepares metals for the application of corrosion-resistant coating.

Many milling machines in the industry feature horizontal milling with a horizontal spindle. Like the name, the cutting tool is on this horizontal spindle. Feed the cable in a vertical, cross, or horizontal direction.

Vertical milling machines have the spindle perpendicular to the table. The spindle head is fixed to a vertical column that rotates at an angle, and the cutting head is on the spindle. Vertical milling machines allow the adjustment of the spindle either upwards or downwards. These machines are for precision work.

Universal milling machines are milling machines that perform all kinds of milling operations. They feature a table fitted with all motions and a dividing head with change gears.

The table can pivot at any angle up to 45 degrees in both directions. Simplex milling machines feature a spindle that only travels in one direction. Most of these machines only travel in a vertical direction.

Duplex milling machines are two milling machines positioned opposite each other. These either work independently as or as one machine with two simultaneous spindles. They travel both horizontally and vertically. Triplex milling machines have a spindle that can travel in all three axes, such as XY and Z.

Up milling process

Up milling process is also known as conventional milling. It refers to the milling process when the milling cutter cuts the workpiece. The direction of cutting speed is opposite to that of the CNC milling part feeding towards the milling machine.

What is face milling?

Face milling is the process of milling flat surfaces at right angles to the axis of rotation of the cutter (Source). It removes the material by rotating the facing tool in a counterclockwise direction. At the same time, the table feeds the workpiece across the cutter.

What is down milling?

Down milling is known as climb milling. It refers to the milling process in which the rotating direction of the milling cutter is the same as the feed direction of the workpiece. That means the force produced by the milling cutter on the workpiece in the feed direction is the same as the feed direction of the workpiece.

Pros of Milling machine

  • Multi-tool
  • Produce a wider range of products
  • Mass production.
  • Quick
  • Repeatability
  • Accuracy and precision
  • Reduces the number of operators and labor costs
  • Good adaptability and flexibility

Cons of milling machine

  • Requires experienced users
  • Not affordable

What is welding?

Welding is a manufacturing process that joins materials. These include metals, thermoplastics. Joining these materials is done using high heat to melt the parts together and allow them to cool, causing fusion.

Welding is from lower-temperature metal-joining techniques such as brazing and soldering. These do not melt the base metal. Some materials need specific processes since some materials cannot be welded.

The parts joined are known as parent material and the material added to help form the join is called filler or consumable. These materials are parent plates or pipes, filler wire, and consumable electrodes.

Consumables are similar in composition to the parent material. They will be forming a homogenous weld. There are occasions, such as when welding brittle cast irons, when a filler with a different composition, properties. These are called heterogeneous. A completed welded joint is also known as a weldment.

What are the different types of welding?

  • MIG Welding – Gas Metal Arc Welding
  • TIG Welding – Gas Tungsten Arc Welding
  • Stick Welding – Shielded Metal Arc Welding
  • Flux Welding – Cored Arc Welding
  • Energy Beam Welding
  • Atomic Hydrogen Welding
  • Gas Tungsten-Arc Welding
  • Plasma Arc Welding

Types of welding joints

  • Butt joint.
  • Tee joint.
  • Corner joint.
  • Lap joint.
  • Edge joint.

Similarities between milling and welding.

  • Both are joining or manufacturing processes.
  • They are both used for metalwork.
  • Heat production.

Difference between milling and welding.

Welding is the joining of two pieces of metal by applying high heat, while milling involves cutting the metal with a rotating blade. The tool types are different. Milling involves a rotating cutting tool whereas, welding features a joining tool. The working process of milling includes cutting and shaping material. Welding features thermoplastics and joining metals.

Use Comparison

Milling features single or multiple rotating cutters. They shape metal, unlike the welding process that uses high heats to melt the workpieces together. The heat is low when milling and high when welding. Fire hazards are low when milling, but there is a high risk when welding. There is a high expectancy of material wastage when milling in chip generation and no wastage when welding. High skills are required when milling, and inexperienced users can still weld.

Cost Comparison

When it comes to the setup cost, it is affordable when welding transfers milling. Milling comes with a lower running cost as compared to welding.

Difference between up milling and down milling

The difference between Up Milling and Down Milling comes in direction. In Up Milling, the cutter rotates against the direction of travel of the workpiece. In Down Milling, the cutter rotates in the same direction of travel of the workpiece. Up Milling has a cutting force of zero. At the beginning of the cut and largest at the end of the cut, but when Down Milling, the cutting force is greatest when the cut begins. It reduces to a least when the tooth leaves the work.

The cutting force in Up Milling is upward. That lifts the workpiece from the fixture. The cutting force in Down Milling is downwards. That places the workpiece firmly in the fixture. Up Milling comes with difficulties in pouring the coolant on the cutting edge, due to the type of cut. The coolant in Down Milling is poured directly at the cutting zone where cutting force is greatest.

David D. Hughes
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