Task

  1. Group Assignment:test runout, alignment, speeds, feeds, and toolpaths for your machine
  2. Individual Assignment:make something big

This week is about Computer controlled machining,in this week I have to test cnc machine and make someting big

What is CNC machining?

CNC Machining is a process used in the manufacturing sector that involves the use of computers to control machine tools. Tools that can be controlled in this manner include lathes, mills, routers and grinders. The CNC in CNC Machining stands for Computer Numerical Control.

TYPES OF CNC MACHINES
  • CNC Mills:The programming employed for a mill machine could be based on either G-code or some unique language developed by a manufacturing team. Basic mills consist of a three-axis system (X, Y and Z), though most newer mills can accommodate three additional axes.
  • Lathes:In lathe machines, pieces are cut in a circular direction with indexable tools. With CNC technology, the cuts employed by lathes are carried out with precision and high velocity. CNC lathes are used to produce complex designs that wouldn’t be possible on manually run versions of the machine. Overall, the control functions of CNC-run mills and lathes are similar. As with the former, lathes can be directed by G-code or unique proprietary code. However, most CNC lathes consist of two axes — X and Z.
  • Plasma Cutters:In a plasma cutter, material is cut with a plasma torch. The process is foremost applied to metal materials but can also be employed on other surfaces. In order to produce the speed and heat necessary to cut metal, plasma is generated through a combination of compressed-air gas and electrical arcs.
  • Electric Discharge Machines:Electric-discharge machining (EDM) — alternately referred to as die sinking and spark machining — is a process that molds work pieces into particular shapes with electrical sparks. With EDM, current discharges occur between two electrodes, and this removes sections of a given work piece.
  • Water Jet Cutters:In CNC machining, water jets are tools that cut hard materials, such as granite and metal, with high-pressure applications of water. In some cases, the water is mixed with sand or some other strong substance. Factory machine parts are often shaped through this process.

At Vigyan Ashram we have plasma cutter and laythe machine but for making somthing big we need cnc milling machine so we went to COEP college ,Puneand Muktangan Science labon Thursday.here we understand the shopboat cnc machine In COEP college.Mr.Sandip Sir gave us basic introduction about their shopboat machine ,their software,etc.

In Muktangan they have Indian manufactured cnc machine Miss Arundhati mam gave info about it so let's start what I did in this week

Group Assignment

Group Assignment

Group Assignment

Shopbot

Shopbot

The ShopBot PRS Alpha is a CNC machine that allows users to cut, drill, carve and machine wood, plastic, aluminum and other materials along 3 axes, X, Y, & Z.

Why Shopboat?

Easy to configure and re-configure, learn and use, the PRSalpha CNC delivers affordable, full-production performance in digital fabrication of wood, plastic, aluminum, and other materials.

With enough production capability of manufacturing, ShopBot PRSalpha tools are our toughest, most sophisticated, gantry-based CNC routers.


Specification

Table Cutting Dimensions: 69 inches x 96 inches; Table Area: 6624 square inches = 46 square feet; Table Thickness: 0.75" Plywood Bottom Layer, 0.75" MDF Top Layer

Z Positioning Speed Variable, max. 15”/sec (380mm/sec) 900”/min. (22.8m/min.

Step Resolution .0004” (0.010mm)

Positional Repeatability +/- 0.002” (0.051mm)

Linear Cutting Force Approximately 150 lbs. (68Kg)

X and Y Axis Drive System Rack and Pinion

z-axis which is capable to spin 12000 rpm.

Jog Spindle : 30”(760mm) per second

Toolpath: : 220V 20A for Controls/ Router (Spindle amperage requirements vary on horsepower and voltage)

Software Basic : PartWorks for making toolpaths and sending Gcode machine used Shopbot

Scarificial Layer : Shopbot machines bed made up of metal and to protect this bed we place flat layer of the plywood on the metal bed which is the sacrificial layer. In case the endmills plunges more than the thickness of the material it will cut into the sacrificial layer, so for this Sacrificial layer is important. While cutting our main part is placed over the sacrificial layer and clamp it.

-

Shopbot test part

Now for group assignment we tried some small shapes as test part for that we used

Key Parameters for shopbot

  • Plunge rate:t is also known as stepdown, it is the distance in the z direction per pass that a cutting tool is plunged into the material
  • Spindle Speed :rotational speed of the cutting tool in revolutions per min
  • Step Over - the maximum distance in the x/y direction that a cutting tool will engage with uncut material
  • Feed Rate - Surface speed at the center of the rotating tool

    • open the "shopbot3 editor" then on the keypad option so you can adjust x,y,z axis using keyboard keys

    then we adjust the x,y,z axis for that we must understand some bed setting like collet ,endmill,clamping

    Bed allignment

    For proper cutting and engraving of material we have to fix material properly on sacrificial layer

    then we understand about endmill for our cutting we are using 1/4"bit

    Collet and endmill

    Tools

    Partwork

    software,it's user interface is easy,for part testing we opened Partwork,then chose the bed size as 2400 x1200mm,then draw test part tthen for generation of toolpath click toolpath option then select edit option and we will set parameter.

    Shopbot parameter

    Test parts

    after bed setting we load file in Shopbot editor,then print it setting for partwork,the detail of setting of partwork I am explainig in indivisual assignment

    Testpart

    Measure

    here we observe the kerf

    Indivisual Assignment (make Something big)

    Designning

    For this assignment I decided to make something that be useful ,In our Fablab we don't have any desk where we can work by seating so I visited some furniture shop to see their design,then I choose very much simple design for my desk I draw it in Fusion 360

    Tabletop

    I draw the hexagon of 1000X1000mm

    Base