The working area of the machine is X=450mm (approx. 17.5 inch) and Y=250mm (approx. 10 inch) and it can mill parts as high as Z=110mm (approx 5 inch). The maximum milling speed on X an Y axis is 2400mm/min. and on Z axis is 1800mm/min. The resolution of each axis is 1/50 or two hundredths of a millimeter and one motor revolution on each axis results in 4 mm of movement. The router used is a Kress 1050. The number of parts used for building this mini CNC machine is 42, excepting screws and nuts, and the total cost is $1200.19.
For this project you will need to have a set of screwdrivers and a set of hex keys or Allen keys, a drill for some extra holes, metal-cutting saw to cut some custom parts, soldering station or soldering gun to join the wires so they'll have good conductivity, and a multimeter. You should have knowledge of basic electronics, how to solder and how to use a multimeter.
All the parts used to build the machine were bought from local dealers, so I suggest you do the same if it's cheaper (parts + transport). If not you can find all the parts on eBay. The trapezoidal cylindrical nut was made in a local workshop.
The motors chosen for this project are 3Nm 8-wire stepper motors that can be wired as unipolar or bipolar, depending on the user’s choice or which driver you have. Three 3Nm stepper motors (cost: $158.20).
A unipolar stepper motor has two windings per phase, one for each direction of magnetic field. This motor has only five leads. Bipolar motors have a single winding per phase. The current in a winding needs to be reversed in order to reverse a magnetic pole. There are two leads per phase; none are common.
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