Ariel and Diana's CNC Router Springs to Life

posted Dec 3, 2009, 9:05 AM by Karl Wendt

 

Our project is about 90% complete. This week we are installing the limit switches, organizing the wiring, designing building and installing the setup platform (for holding parts in place) and programming our first cut paths. Please see our white paper about the project or go to MAE CNC Router
 
CNC Router White Paper
Abstract:
The purpose of this paper is to explain the function of a Computer Numerical Controlled Router Milling Machine (CNC Router). The CNC Router is a computer controlled 3 axis power tool that accurately cuts out pre-programmed designs from wood or plastic. Media Arts Engineering (MAE) students don't have a reliable and precise way of cutting out pieces that are hard to make by hand. The CNC Router's ability to reliably make those precise cuts eases the building process. 
 
Problem Statement:
When building and constructing parts, human error inhibits the process, there is no absolute and reliable way to get precise cuts every time. However, with a CNC Router, a higher level of accuracy is possible. CNC Routers make cuts and drill holes that are difficult for human beings to reproduce.

Understanding the Product (design):
The CNC router is able to cut out parts designed on a computer because the cutting router is steered by a motion control system and cuts on a level surface. The CNC router is located in the MAE shop and the motion control system and computer are located in the MAE computer lab
 
Parts to be cut on a CNC must first be designed with AutoCad, converted to G Code format and loaded into the CNC control software, Mach3. The computer is attached to a motion control board is a wooden plank, called the mounting board, bolted to a wall. Attached to the mounting board is a breakout board, four motor drivers, eight fans and a power supply. The breakout board is attached to the computer’s parallel printer port and an extension of the port's pins. The breakout board sends information from the computer to the four motor drivers. The motor drivers receive data from the breakout board, and relays that information through the wall to the stepper motors on the CNC, located in the other room. Each motor driver is raised off the mounting board on machine screws. Two fans are attached to one side of each raised motor driver to create a convection cooling system. The power supply is connected to each driver to power the stepper motors.

The CNC router is a three axis cutting tool mounted on a four by two foot gantry system on top of a four by eight table. The gantry is moved by rails, chains and bi-polar stepper motors, allowing the router to move on the x, y and z-axis. The router moves up and down the z-axis on a lead screw connected to a stepper motor. The router slides across the y-axis by v-groove bearings attached to a rail and controlled by a stepper motor connected to a chain drive. The router moves across the x-axis because the y and z-axis gantry are attached with v-groove bearings to rails on both sides of a four by eight table. Two stepper motors control the router’s movement on x-axis, one motor on each side of the table. The four stepper motors that drive the router’s x, y and z-axis movement are controlled by the motion control system and computer.

The precision of the CNC is aided by the rigid, stable and level four by eight table. The table is rigid because it has an eight inch high interlocking, cross-section frame supporting the tabletop. The table is stable because it has six specially made legs with four by four cross leg supports, bolted to the cross-section frame. The table is level because it have adjustable feet that allow it to be level on any surface.

Application:
Application the CNC are used for are making parts for student projects and creating signs. The CNC can be used to cut out parts for projects such as the AUVSI sub, which requires precise pieces for optimal functionality. The CNC can also be used to make signs such as a Media Arts Engineering sign to be mounted on the building.

Please Note: Thanks to Patrick Hood-Daniel from buildyourcnc.com who designed the gantry and motion control system, provided detailed assembly instructions and shipped many of the key parts required to make this project work. This project would not have been possible without Patrick!

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