Halftone Engraving on a CNC Machine

When you get to work with a DATRON every day, you get to see some pretty cool things. There are so many cool things to observe, or be involved in, that you can become a little numb to just how cool these things are. So, every once in a while, it’s good to stop and look back at what you’ve been doing and take a second to appreciate it. In this case, it’s halftone engraving.

I thought this might be a unique topic to share with you, the reader, so you too can enjoy the cool things you can do with your CNC machine (hopefully a DATRON!).

What is a Halftone?

First, a little background on our subject. A halftone image, according to Wikipedia, is “the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient like effect.”

Halftone engraving is a reprographic technique simulating a continuous tone image.

Essentially, the trick behind a halftone image is to use varying size dots to create a grey scale image. It’s comparable to some comic book printing or pointillism, but is a bit unique.

Halftone engraving on blue sheet material with a silver surface finish requires milling varying size dots to create a grayscale image.

Halftone Engraving Software (Free)

Now, let me introduce you to Halftoner, a free application created by Jason Dorie. It allows you to easily import any image and not only convert to a halftone image, but also apply a tool path to it at the same time. The elegance of this software comes from its simplicity; first, import an image and choose your values for minimum and maximum dot size, dot spacing, dot offset, etc… Then determine your milling values; retract height, minimum depth, feed rate, RPM, and so on. One of the most important values for Halftoner is the tool angle, since it will take the included angle of your tool to determine the necessary depth to make a certain size of dot. It’s really quite intuitive.

Once that’s all done, click “Write GCode” and voila, you’ve got a program ready to go.

Engraving halftone images with a high speed CNC milling machine can be done easily with a free application called Halftoner.

I was fortunate enough to get to play with this for a while on a recent project, and the outcome you get for a minimal amount of effort can be very impressive.