Computer Aided Manufacturing

3D Printing Feb 18, 2022

By Dhiren Hajare

"We have become a very white collar workforce & automation has become a necessity"

~Randy Breaux

Human beings have always tended towards research that reduces input and increases output. Introducing computers in manufacturing has proved to be a boon to a large extent. From designing products to actual manufacturing processes, computers have led to cost & time-efficient manufacturing. Before introducing designing software like AutoCAD, SketchUp, Fusion 360, it used to take numerous hours or days to prepare a product's design. But now, it is a work of just a few minutes or hours.

Earlier, manufacturing processes like turning, facing, drilling used to take place on conventional machines, which required human effort. Also, consistent precision and accuracy of products were a problem. But now, with the use of CNC and VMC machines, it consists of just a few G and M codes to get the desired outcome with precision and accuracy.

This article mainly focuses on technologies like Computer Numerical Control (CNC) in Machining & Plasma Cutting for Sheet Metal.


Computer Numerical Control (CNC) Machining

All modern manufacturing centers use different Computer Numerical Control (CNC) machines to produce engineered products. The process that uses a CNC machine to perform a specific action is called CNC machining.

To upgrade the current programming and machining processes and get the benefits of the technology advancements, it is vital to view the process as a whole instead of focusing on a specific aspect of manufacturing the part. Below are the three standard steps for generating a part using the traditional CAM CNC processes:

  • Accurately model the part in a Computer-Aided Design (CAD) system.
  • Using the G & M code manual, create a suitable code to enter the control unit. Nowadays, softwares are developed that generates codes based on the CAD model.
  • The CNC works as per the code entered manually in traditional processes.

Modern process utilizing the advanced CNC features:

  • Accurately model the part in a Computer-Aided Design (CAD) system.
  • A CAM system creates a map of the part from the CAD model as an approximated series of points and orientations around the model surfaces.
  • The modern post-processor takes a CAM-generated series of points and transforms them into G-code.
  • The CNC has Tool Center Point Control (TCP) and Tool Posture Control (TPC) that calculate how to position the physical machine axes to achieve the objective.

Plasma Cutting for Sheet Metal

In our daily life, we come across plasma while watching TV, fluorescent lamps, neon lights, etc. Plasma is an electrically conducting ionized gas in which some electrons are missing or floating around. Gasses can be transformed into plasma by excessive heating, making them ionized.

In manufacturing, plasma cutters are used for cutting metal sheets at a breakneck pace. Plasma cutting is a thermal metal cutting process in which metal is melted for cutting. Usually, nitrogen is used for making plasma for cutting. The cutting tip of the instrument creates a flow of hot plasma that is subjected to the sheet metal. As plasma is electrically conductive, the workpiece is connected to the ground through the cutting table. There are numerous ways of plasma cutting. High-Frequency Contact, Pilot Arc & Spring Load Plasma torch head are the ways of plasma cutting depending on the mode of operation and mechanism involved. The High-Frequency Contact method uses a high voltage and high-frequency spark. The spark creation takes place when the torch touches the workpiece. This creates a closed circuit and the spark, which then creates plasma. In the Pilot Arc method, the spark is created inside the torch & the cutting arc gets created when the pilot arc is brought into contact with the workpiece. Another way is using a spring-loaded plasma torch head. Pressing the torch against the workpiece makes a short circuit that flows the current. CNC Plasma cutting includes submitting CAD drawing into the control unit, which is operated automatically later on.

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