Ask the CNCKing: What’s the difference between additive and subtractive production?

Ask the CNCKing: What’s the difference between additive and subtractive production? Watch the video below for the answer!

Ask the CNCKing: What’s the difference between additive and subtractive production? Transcript

Hi there, this is Jon from CNCKing.com and today’s question is, what’s the difference between additive and subtractive production?

Let’s deal with additive first. Additive is basically 3D printing where you have one layer added to another and another.

Subtractive is actually removing chunks of material from a model. So this would be like a table router or laser cutter. A laser cutter and table router, generally speaking, can only work from the top down. Cutting things out in 2D while a 3D printer, because it’s additive, constructs the project layer by layer into a 3D form.

Which one is better?

It depends on the application you want to use it for. If I want to make a shoe for instance, and I only have a three axis CNC laser or table router – I’m going to use 3D printing otherwise my foot isn’t going to fit into it as I can’t remove material without taking the top layer off first. As I’m always working from the top down, even a vase that has a slight angle wouldn’t be possible with a laser or router.

Now, if I want to make something like this Sydney Harbour Bridge here – I definitely want to use a laser or router as it would cost a fortune to make with a 3D printer and take about a week with a machine costing half a million dollars.

There is something neat with lasers and table routers, it’s called 2.5D. You can engrave with a laser or a router they work from top down while 3D printer is bottom up.