Download the custom tool library for Delrin here.
What is Delrin?
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 a really nice finish with the right settings. It’s also self-lubricating (aka slippery), which allows it to be used for parts that slide against other parts, without wearing down or sticking.
What is Delrin used for?
From the manufacturer: Delrin is used for high-load mechanical applications, such as gears, safety restraints, door systems, conveyor belts, healthcare delivery devices, and components across a diverse range of products and industries.
A number of the the Bantam Tools Desktop PCB Milling Machine's parts are made of Delrin, notably the bearings and anti-backlash nuts used in all the carriages. Among the Bantam Tools community, Delrin is mostly used to make mechanical parts.
Is Delrin safe?
Yes! But as with all materials, we don’t recommend inhaling or eating the swarf.
Where can I get Delrin?
We sell pre-cut pieces of both black and white Delrin in our store. They’re the perfect size for many projects, and they fit nicely on our milling machine's bed.
What's the best way to fixture Delrin to the bed of the milling machine?
High-strength double-sided "Nitto" tape is a great method of attaching Delrin to the machine's bed.
To use Nitto tape, place strips evenly across the underside of the material. Then peel off the backing, and press the material firmly down onto the machining bed.
If you’re feeling ambitious, you can remove the spoilboard, attach the material with tape, drill holes in the material that align with the slots in the T-slot bed (see Dimensions and Diagrams), and then bolt the material to the bed with low-profile M5 bolts. This provides extremely strong fixturing.
What end mills should I use when milling Delrin?
In general, larger tools like 1/8" and 1/16" end mills are better because they cut through material the fastest and are least likely to break. For 3D shapes like the yo-yo project below, a 1/8" or 1/16" ball end mill produces the smoothest contours.
For best results, keep a set of end mills specifically for Delrin and other plastics, and never use them to cut metal or PCBs. This allows for increased milling speeds and a better finish.
What are some sample projects?
The OtherYo Yo-Yo
Breakfast Heroes Wearables
Sharpie Tip Adapter
Recommended Feeds and Speeds
To make it easier to use these recommended feeds and speeds, we’ve created a way for you to quickly import into our software all the settings you see listed below. To do this, first, download the Delrin Custom Tool Library, which contains all the recommended feeds and speeds for this material. Then, open our software, click File > Tool Library, click the “Import” button, and select this file. Before using these settings, it’s a good idea to read through our Feeds and Speeds Guide.
Download the Delrin Custom Tool Library here.
Note: The feeds and speeds below are optimized for the V2 Othermill. If you're using a Bantam Tools Desktop PCB Milling Machine, Othermill Pro, or Kickstarter Othermill, you may need to experiment to find optimal settings.
Tool: 1/8" flat end mill
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.008" (0.21 mm)
Tool: 1/16" flat end mill
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.020" (0.5 mm)
Tool: 1/32" flat end mill
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.020" (0.5 mm)
Tool: 1/64" flat end mill
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.003" (0.08 mm)
Tool: 1/100" flat end mill
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max pass depth: 0.003" (0.08 mm)
Tool: Engraving bit
Feed rate: 23.622 in/min (600 mm/min)
Plunge rate: 1.575 in/min (40 mm/min)
Spindle speed: 12,000 RPM
Max Pass Depth: 0.003"–0.020" (0.08 mm–0.5 mm) Keep in mind the engraving tool is V-shaped and thus has a variable width, depending on your “engraving cut depth.” The deeper the cut, the wider the tool. The shallower the cut, the narrower the tool. If you’re using an engraving tool and the generated path isn’t cutting part of your SVG file, try reducing the engraving cut depth.
Advanced Feeds and Speeds
Warning: These settings are for advanced users. Before using any of the information provided here, you must read the section above on fixturing your material. The feeds and speeds specified here are more aggressive (and thus faster), and improperly fixtured material can be knocked loose and damage itself and your machine.
Tool: 1/8" flat end mill
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max pass depth: 0.02" (0.5 mm)
Tool: 1/16" flat end mill
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max pass depth: 0.02" (0.5 mm)
Tool: 1/32" flat end mill
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max pass depth: 0.02" (0.5 mm)
Tool: 1/64" flat end mill
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max pass depth: 0.01" (0.25 mm)
Tool: 1/100" flat end mill
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max pass depth: 0.005" (0.13 mm)
Tool: Engraving bit
Feed rate: 59 in/min (1500 mm/min)
Plunge rate: 5 in/min (127 mm/min)
Spindle speed: 16,400 RPM
Max Pass Depth: 0.003"-0.020" (0.08 mm–0.5 mm) Keep in mind that the engraving tool is V-shaped and thus has a variable width, depending on your “engraving cut depth.” The deeper the cut, the wider the tool. The shallower the cut, the narrower the tool. If you’re using an engraving tool and the generated path isn’t cutting part of your SVG file, try reducing the engraving cut depth.