What is Computer Aided Manufacturing (CAM) ?

Computer Aided Manufacturing (CAM): The Complete Introduction for the Beginner’s Mind

In a world full of physical stuff – whether that’s products, parts, or places – Computer Aided Manufacturing (CAM) makes it all possible. We’re the ones that give the power of flight to airplanes, or the rumble of horsepower to automobiles. When you need something made, not just designed, CAM is your answer. 

Computer Aided Manufacturing (CAM) is the use of software and computer-controlled machinery to automate a manufacturing process.

Based on that definition, you need three components for a CAM system to function:

  • Software that tells a machine how to make a product by generating toolpaths.
  • Machinery that can turn raw material into a finished product.
  • Post Processing that converts toolpaths into a language machines can understand.
These three components are glued together with tons of human labor and skill. As an industry we’ve spent years building and refining the best manufacturing machinery around. Today, there’s no design too tough for any capable machinist shop to handle.

CAD to CAM Process

Without CAM, there is no CAD. CAD focuses on the design of a product or part. CAM focuses on how to make it. You can design the most elegant part in your CAD tool, but if you can’t efficiently make it with a CAM system then you’re better off kicking rocks.

The start of every engineering process begins in the world of CAD. Engineers will make either a 2D or 3D drawing, whether that’s a crankshaft for an automobile, the inner skeleton of a kitchen faucet, or the hidden electronics in a circuit board. In the world of CAD, any design is called a model and contains a set of physical properties that will be used by a CAM system.

CNC toolpaths created in CAM for Fuison 360

When a design is complete in CAD, it can then be loaded into CAM. This is traditionally done by exporting a CAD file and then importing it into CAM software. If you’re using a tool like Fusion 360, both CAD and CAM exist in the same world, so there’s no import/export required.

Once your CAD model is imported into CAM, the software starts preparing the model for machining. Machining is the controlled process of transforming raw material into a defined shape through actions like cutting, drilling, or boring.

CAM software prepares a model for machining by working through several actions, including:

  • Checking if the model has any geometry errors that will impact the manufacturing process.
  • Creating a toolpath for the model, which is a set of coordinates the machine will follow during the machining process.
  • Setting any required machine parameters including cutting speed, voltage, cut/pierce height, etc…
  • Configuring nesting where the CAM system will decide the best orientation for a part to maximize machining efficiency.

Once the model is prepared for machining, all of that information gets sent to a machine to physically produce the part. However, we can’t just give a machine a bunch of instructions in English, we need to speak the machine’s language. To do this we convert all of our machining information to a language called G-code. This is the set of instructions that controls a machine’s actions including speed, feed rate, coolants, etc.

G-code is easy to read once you understand the format. An example looks like this:

G01 X1 Y1 F20 T01 S500

This breaks down from left to right as:

  • G01 indicates a linear move, based on coordinates X1 and Y1.
  • F20 sets a feed rate, which is the distance the machine travels in one spindle revolution.
  • T01 tells the machine to use Tool 1, and S500 sets the spindle speed.

G Code Example

Once the G-code is loaded into the machine and an operator hits start, our job is done. Now it’s time to let the machine do the job of executing G-code to transform a raw material block into a finished product.

CNC Machines at a Glance

Up until this point we’ve talked about the machinery in a CAM system as simply machines, but that really doesn’t do them justice. Watching a Haas milling machine slide through a block of metal like it’s butter puts a smile on my face every time. Without these machines, my job would be impossible.

Haas mill machining metal block with CAM

All modern manufacturing centers will be running a variety of Computer Numerical Control (CNC) machines to produce engineered parts. The process of programming a CNC machine to perform specific actions is called CNC machining.

Before CNC machines came to be, manufacturing centers were operated manually by Machinist veterans. Of course, like all things that computers touch, automation soon followed. These days the only human intervention required for running a CNC machine is loading a program, inserting raw material, and then unloading a finished product.

Over at the Autodesk Pier 9 workshop we have a decent sample of CNC machines, including:

CNC Routers

These machines cut parts and carve out a variety of shapes with high speed spinning components. For example, a CNC router used for woodworking can make easy work of cutting plywood into cabinet parts. It can also easily tackle complex decorative engraving on a door panel. CNC routers have 3-axis cutting capabilities, which allows them to move along the X, Y, and Z axes.

DMS CNC router programmed at Pier 9

Water, Plasma & Laser Cutters

These machines use precise lasers, high pressure water, or a plasma torch to perform a controlled cut or engraved finished. Manual engraving techniques can take months to complete by hand, but one of these machines can complete the same work in hours or days. Plasma cutters are especially useful for cutting through electrically conductive materials like metals.

CNC water jet laser plasma contouring CAM


Milling Machines

These machines chip away at a variety of materials like metal, wood, composites, etc. Milling machines have enormous versatility with a variety of tools that can accomplish specific material and shape requirements. The overall goal of a milling machine is to remove mass from a raw block of material as efficiently as possible.

CNC mill machining metal

Lathes

These machines also chip away at raw materials like a milling machine, they just do it differently. A milling machine has a spinning tool and stationary material, where a lathe spins the material and cuts with a stationary tool.

CNC lathe turning metal CAM

Electrical Discharge Machines (EDM)

These machines cut a desired shape out of raw material through an electrical discharge. An electrical spark is created between an electrode and raw material, with the spark’s temperature reaching 8,000 to 12,000 degrees Celsius. This allows an EDM to melt through nearly anything in a controlled and ultra precise process.

CNC wire EDM cutting metal CAM

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