CNC Construction Guide

 

In this post you will find information about CNC (computer numerical control) machine, it means: construction, operation modes and more generally across a philosophy of CNC.

CNCs consists of axis with a suitable combination of movement and basis of predefined coordinates move some point, this point create 3d objects.

At this point there can be customized:

  • Milling engraving machine, cutting various materials such as wood, metal, carbon fiber, pcb boards etc. (CNC freesia "MILLING CNC").

  • Rotation head with knife (drag knife), for cutting paper, cardboard, leather, cutting stickers (labels), etc...

  • The above head mounted in the chuck of milling machine and rotates freely depending on the traffic on the axes X, Y of the CNC.

  • Head laser, for cutting various materials such as paper, cloth, plexiglass etc., For printing eidolon in materials such as glass, plastic etc.

  • Rainfall "plasma" (by means of inert gas, usually carbon dioxide, "compressed air" for metal cutting).

  • Heated head consist of ceramic resistor which melt plastic (pla, abs) for generating three-dimensional objects.

  • Special knife with hardware configuration, which is mounted on a lathe and rotated cyclically (CNC LATHE "LATHE CNC").

Construction Methods of CNC:

For the axis construction of CNC can be used:

  • Linear rail rod bar on which they operate linear ball bearings.

  • For best rigidity usually fixed rails used linear slide guide shaft with open linear ball bearing , which are fitted on the Pillow block Bearing.

To move the axes (moving parts) placed interminable who anchored in manufacturing, which moves the nut is placed in the part we want to move.

The endless self, can be:

  • Bolts with grooves (ballscrew) with nut bearing (ballscrew nut) for greater accuracy without backlash.

  • (Leadscrew) Trapezoidal less precise but more economical, backlash can be reduced by putting the appropriate (usually constructed by lathe) nut.

  • In case you do not want to have absolute accuracy and high speed we can use simple screws M6 - M20 etc. With suitable nut.

  • In large cnc for moving the movable parts used rack (gear rack) in which "run" on gear (pinion).


For the movement of the endless mounted engines are divided into two categories:

  • The stepper motors (stepper motor) that are economical solution.

  • The servomotors (servo motor) that have the greatest accuracy.

  • For the connection about motor and ballscrew (leadscrew,simple screw) used coupler.

Motor control by drivers which connected to master control board.

  • Other control need the stepper motors.

  • Other servomotors (cables for servomotors differ is "shielded" why should the signal is transferred without loss, this means that the costs are higher than the cost of the cable for stepping motors), this means how the drivers and The controllers differ depending on what engine is selected with the exception of some controllers that control and stepper motors and servomotors.

  • The most classic controllers connected to the parallel port (dp25 port) of the computer to achieve optimum speed and optimal control of the motors ( Step-Pulse frequency) with the control program *.

  • Newest controllers connected to usb port of the computer and can control fairly efficient engines, and great driving pulse frequency is achieved ( Step-Pulse frequency).


For the overall control and programming of CNCs programs vary.

  • The cnc programming language is the code g (G CODE "repertoire '' command that determines the position of the axis, the coordinate basis set).

  • There are numerous options and parameters to these control programs.

  • Noteworthy feature is that we can scan any object you want to create and program automatically transform object into G CODE.