Brushless DC Motor Used For High Speed CNC Spindle

Brushless DC Motor CNC Spindle

Brushless DC motors are common place in RC Vehicles. They are small, light, fast and can be inexpensive. [Raynerd] wanted a new spindle for his CNC machine and thought that a brushless DC motor would be a great platform to build from.

[Raynerd] started with an off the shelf motor that had an 8mm shaft. This shaft size was important because the motor shaft was to be replaced with an ER16 collet arbor of the same size. A collet is a device used to hold cutting tools by collapsing a segmented ring around the tool. Collets allows for quick tool changes while providing a strong clamping force. ER16 is a designation of one of many collet standards.

The main housing was machined out of aluminum specifically for this project. This housing holds two radial load ball bearings that support the new rotating collet arbor. There’s another bearing in this assembly, a thrust washer this time, that keeps the arbor from moving axially in the housing.

The 12 volt output of a standard ATX power supply was used to power the system for testing purposes. A general RC Vehicle electronic speed control and a servo tester work in conjunction to manually regulate the spindle speed. Check out the bench test video and an exploded photo after the break.

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Building a CNC Milling Machine for less than $1300

CNC milling machine

[Mynasru] tipped us about a homemade CNC milling machine that his friend [trochilidesign] recently made. We have to admit it may be one of the best ones we’ve featured so far on Hackaday, mainly due to its elegant design (see picture above) and its all metal structure with linear guide rails. In the very well detailed write-up, we can gather that the CNC machine was designed using SolidWorks.

The main frame is built around 2 Maytec 40x80mm profiles and 2 endplates made from 10mm thick aluminum. 3 Nema 23 stepper motors and their drivers power the build, all of them bought on ebay. Finally, the Mach3 CNC software was chosen to interpret the G code and send the appropriate control signals.

Due to licensing restrictions the original author can only provide us with PDF files detailing each part of the machine, but we’re sure this should already be enough for interested persons out there.

Three Axis Position Indicator with Digital Calipers

[Malte] just finished a little project for his Wabeco F1200 milling machine: a compact external display for three digital sliding calipers (Translated from German). As you may have already guessed, [Malte] was lucky enough to be able to fit disassembled calipers onto the machine and use them for positioning. Before embarking on this adventure, he noticed that there were similar projects present on the internet, but all of the calipers used had different data interfaces and protocols. The calipers that [Malte] bought have a mini USB connector, even though the interface itself isn’t USB. As he couldn’t find any information on that interface, he turned to his oscilloscope to decode the protocol.

[Malte] then built an AVR-based platform that reads out the three calipers and shows the position data on the dot matrix LCD shown above. The AVR firmware is written in a mixture of Basic and assembler language. The source code, schematics, and other resources can be downloaded from the project’s web page. We are impressed on the professional aspect of the final result.

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