Laser Cutter Users
Are you familiar with laser cutters? This guide is for you! The CNC nature of the Othermill is similar to that of a laser cutter but with a few notable differences.
The main difference is the size and characteristics of the cutting tool — instead of using a very thin beam of light to vaporize material, you’re using a solid carbide cutting tool to rapidly slice off little bits as the machine moves the tool through the material. The cutting tools are anywhere between 0.005" and 0.125" thick, and designs need to account for that.
The benefits are that the Othermill can cut many materials that a laser can’t, plus it can control tolerances very tightly and create 3D shapes and contours that wouldn’t be possible with a laser. This guide is intended to allow you to apply your knowledge of laser cutters to working with the Othermill so you can get up to speed quickly.
How It Works
A laser cutter beam is very thin — generally somewhere between 0.001" and 0.005". The laser head moves above the material, and the beam vaporizes the material from the surface down. When a job is set up optimally, the laser head moves as fast as possible while still allowing the laser to continuously penetrate all the way through the material.
The Othermill’s interchangeable cutting tools have diameters between 0.005" (for an engraving tool) and 0.125" (for a 1/8" flat end mill). You can think of the Othermill’s cutting tools as really wide laser beams, which are only an inch long and remove a precise amount of material with each pass. The spindle, which has the same role as the laser head, holds the spinning cutting tool and pushes it through the material, starting at the surface. When a job is set up optimally, the spindle moves as fast as possible while still allowing the tool to cut away the material continuously. As with a laser cutter, knowing how to set up optimal cutting parameters for each material is the mark of an experienced user.
Laser cutter designs are very similar to Othermill designs. Cutting the outer perimeter of a shape, often called a cutout, is nearly identical design-wise: a thin line. The Othermill can also engrave the surface of a material, similar to laser engraving, by using a filled shape.
Here’s an example of a design and how it shows up in Otherplan Classic:
You can see that the outer ring will be cut out and the inner star will be engraved. This design would be interpreted the same way on a laser cutter. The difference is that the engraving depth is precisely controlled. In this example, it’s 0.006" deep, but you can set it to anything you want.
As with laser cutters, files for the Othermill must be prepared for cutting before you can begin. In the CNC world, this step is referred to as CAM. For 2D designs on the Othermill, we suggest VCarve and Fusion 360 for CAM. For milling 3D designs, there are many options — take a look at our CAD and CAM guide.
Laser Cutter or Othermill?
A laser cutter and the Othermill are both great tools, but they’re best suited to different types of projects. Lasers are amazing for projects like stencils, signs, gaskets, intricate designs in really thin materials, engraving surfaces without cutting into them, CNC wood furniture, and anything involving cardboard. Their work surfaces are much bigger than that of the Othermill, and they’re generally much faster. However, the Othermill really shines with projects including small parts made of wood or metal, stamp making, mold making, engraving metal, product enclosures from various materials, anything 3D, and of course circuit boards.
An Extra Axis
A laser cutter has two axes: x and y. The Othermill has three axes: x, y, and z. The z axis allows the Othermill to create 3D contours and control the engraving depth for 2D designs.
Most laser cutters are limited to materials like cardboard, thin wood, and certain plastics. Some can cut thin metal. The Othermill has its own limits, but they allow for a wider range of materials: pretty much any type and thickness of wood, most metals softer than steel, FR-1 circuit boards, modeling foam, wax, and most plastics. The limits, other than needing to fit inside the machine, are mostly governed by material heat transfer properties. The reason it can’t cut steel is because heat builds up where the material is being cut and softens the tool, which dulls it. There’s also the issue of some materials, such as ABS plastic, melting. Check out our handy list of materials to learn more.
A laser cutter cuts by vaporizing the material, leaving nothing behind but smoke. The Othermill cuts by pushing a spinning cutting tool through the material, rapidly slicing off tiny pieces as it moves. These tiny pieces are called swarf, which is a very enjoyable word. Swarf needs to be cleaned up after each milling job, ideally with a vacuum.
Raster and Vector
With laser cutters, you can choose to use either raster or vector images. With raster images, the laser head scans back and forth while pulsing the laser on and off to match the pixels in the image. With vector images, the laser head follows paths that are mathematically calculated between coordinates.
The Othermill only uses vector images. However, the Othermill can create the same effect as using a raster image. To do this, Otherplan fills any filled shapes with concentric toolpaths that cover all the area within the shape, demonstrated by both the star and stamp examples in this guide.
Cutting Parameters (Feeds and Speeds)
When you’re setting up a laser cutting job, you have to specify the power and feed rate of the laser head. With the Othermill, you have to specify the spindle speed, feed rate, and pass depth of the cutting tool. The spindle speed is how fast the cutting tool rotates, in RPM. The feed rate is how fast the tool moves through the material, in inches or millimeters per minute. The pass depth is how deep the tool cuts on each pass.
With both a laser cutter and the Othermill, it’s important to make sure your cutting parameters are optimized for the material you’ll be cutting. However, it’s even more important with the Othermill because of the negative consequences of the wrong feed rate.
With a laser cutter, if your feed rate is too low, you waste time. With the Othermill, your tool may get dull and your material may melt or have an undesirable surface finish.
With a laser cutter, if your feed rate is too high, the laser won’t be able to vaporize the material fast enough as it moves, which results in a design that isn’t cut all the way through. With the Othermill, your tool won’t be able to cut away the material fast enough as it moves, which may break your tool or dislodge your material from the bed.
Since the above outcomes are very undesirable, we recommend that you use the feeds and speeds in our materials guides to make sure everything mills smoothly.