Welcome to our Material pages. Below is a list of guides for materials that work with the Othermill. These guides provide info on attaching the materials to the Othermill bed, tips on milling, and suggested feeds and speeds. The list of material guides can also be found in the left sidebar.
ABS, or acrylonitrile butadiene styrene, is a terpolymer, meaning a combination of three polymers. ABS is a versatile, impact-resistant material that is easy to add color to and construct things with. It’s a little finicky to mill because it can melt and gum up your tool, but it’s also less expensive than some other plastics.
Acrylic is a transparent thermoplastic derived from natural gas. It’s more brittle and has a lower melting point than polycarbonate but has better scratch resistance and comes in a variety of colors and textures. It can be tricky to mill because of its lower melting point, but its clarity is very desirable. It’s known commercially by such names as Acrylite, Lucite, and Perspex.
Aluminum is a lightweight, durable, and corrosion-resistant metal that is electrically conductive. It comes in a vast number of different alloys, each with different physical and thermal properties. The most commonly used, general-purpose alloy is 6061 aluminum, which has a great blend of strength and machinability.
Brass is an alloy of primarily copper and zinc. It’s desirable because it has a gold-like luster and color, a low enough melting point to be easily cast, and low friction. There are many kinds of brass alloys, each with different properties that make it suitable for different uses. For milling, we recommend 360 Brass.
Delrin is the brand name for acetal homopolymer resin, which is a very hard, high-strength engineering plastic. It can withstand temperatures from -40°C to 120°C (-40°F to 248°F), and it holds its shape well over time. Despite being hard, it mills easily and gives an excellent surface finish with the right settings. It’s also self-lubricating, which allows it to be used for parts that slide against each other without wearing down or sticking.
FR-1 is a hard, flat material that consists of a thin layer of copper over a non-conductive phenolic resin. It’s usually about the thickness of two or three credit cards.FR-1 is primarily used for making circuit boards. The thin copper layer can be milled or etched away, leaving traces to which electronic components can be soldered. Dust generated by milling FR-1 is considerably less dangerous than dust from milling FR-4 (fiberglass).
HDPE stands for high-density polyethylene. It’s an inexpensive, lightweight, chemical-resistant, food-safe plastic that has a high strength-to-density ratio, which makes it well suited for a vast number of applications. It can be blow molded, injection molded, extruded, and milled. You may recognize it as “#2 plastic” by its recycling symbol.
Machinable foam is a hard, rigid foam that retains high detail, is very durable, and can be machined at high speeds, similar to machining wax. But unlike wax, it’s mostly air, so the amount of swarf generated during milling is significantly less.
Machining wax, or machinable wax, is wax that has been mixed with plastic to make it very hard, tolerant of high temperatures, and able to retain extremely fine details. This means that it won’t melt when you mill it, and it also won’t droop, sag, or deform like many other soft materials, so you can mill very thin surfaces and tiny features.
Polycarbonate is a set of durable, impact-resistant thermoplastic resins that have relatively high heat resistance and color stability. It’s naturally clear and can transmit light almost as well as glass. It’s commercially known under trademarked names such as Makrolon or Lexan. It has excellent milling properties.
There are many kinds of wood, with many different uses. The Othermill can mill all of them. Softer woods like plywood or balsa are useful for jigs or quick models, but may not give a great surface finish due to their long grains and low density. Hardwoods like mahogany, purpleheart, or cherry mill more slowly, but can be given a beautiful surface finish.