Amateur milling machine.. Components

Linear Guideway

The realization of the motion along the axis of the machine allow the guides that restrict freedom of movement in all directions except one, which runs along the axis. This solution may be plain, as is the case in conventional machine tools, or by using the linear guide of the rolling elements.
Browsing through the available offers in terms of their applicability to the construction of the plotter selected several solutions of linear guides and are shown below:

-Low Profile - the best solution (used in the professional machines) but also the most expensive.

- Shafts Precision with linear bearings in closed cabinets - a solution that many opportunities (used in professional machines, but not as part of implementing the major movements of the work) at an affordable price.

- Precision shafts supported with linear bearings in housings open - a solution similar to the previous but for greater rigidity same track.

Screws

Propeller is a very important element of the drive, as responsible for the implementation of feed motion. A very good solution is to screw with ball screw. The efficiency of their operation is significantly higher than the efficiency of the sliding bolt. When designing the drive ball screw should be borne in mind that the screw is not self-locking due to the high efficiency. The drives should be used vertical slide inhibitory circuits, which in the absence of voltage collapse prevent uncontrolled carriage machine. The disadvantage of this type of screw is mainly price, up to 15 times greater than in the case of trapezoidal threads.

-Ball screw

-Trapezoidal screw

Drive motors and couplings

Axis feed drives in modern CNC machines are operated by electric motors or servo motors equipped with a feedback system. The controller sends a signal to the motor while the defeated feedback on the way back to the controller to verify the correct execution of movement. This solution is very accurate and reliable, but also expensive. The amateur machines are being used stepper motors. Characterized by a high frequency step up to 16 kHz, while maintaining high accuracy angular displacements. Depending on the construction of the engine of this type, each rotation of the shaft needs to be sent from the controller the appropriate number of pulses (steps). With the increase in the number of steps per revolution increases the accuracy of the positioning. This solution is cheap, gives you the opportunity to work with great accuracy, but its disadvantage is the possibility of losing steps by engines.

-Servomotor with Inverter