Week_7 - Computer-Controlled Machining


  • group assignment:
    • test runout,
    • alignment,
    • speeds, feeds, and toolpaths for your machine
  • individual assignment:
    • make (design+mill+assemble) something big

Group Assignment

A few words about our milling machine:

  • the work area: 2500x1250 mm
  • spindle: 5.5 kw water cooled (24000rpm)
  • table with a wireframe
  • jog for remote milling machine control
  • tool changer
  • materials in which it cuts: wood, plywood, mdf, plexiglass, polystyrene, styrofoam, aluminium (with additional coolant)
  • soft to control : ucancam

    the tool wall at our cnc workshop is very useful for organizing tools

    Preparation of tools in Fusion 360

    Preparation of the tool makes it very easy to get the data sheets of the cutter from the distributor, or to check the auction or basic data in the online store.
    As a program to create files for milling I use Fusion 360 CAM module. First it adds new tools to my accounts by entering the CAM TOOL LIBERARY icon.

    In cloud TAB we add a new folder for our tools which will be available from any computer.
    On the right side we click add milling

    We name the cutter

    We provide basic data
  • Number of flutes 3
  • HSS material
  • diameter 12 mm
  • flute length 50 mm
  • shoulder length 62 mm
  • body lentgh 86 mm
  • overall length 100mm
  • shaft diamter 12 mm

    its good to preper a holder before we start to add tools

  • here we have to know what material we're gonna cut with this bit.
  • spindle speed 24000 (rotation speed of spindle)
  • cutting feedrate 4000 mm/min
  • lead-in feedrate 3000 mm/min
  • lead-out feedrate 3000 mm/min
  • ramp feedrate 2000 mm/min
  • all other date will be fixed on base of this informations

    Then we have to add the number of the tool we are using on cnc machine and whether we will use cooling and if so, what kind.

    individual assignment:

    Modeling for cnc milling

    I have to write here that I like to design for a cnc milling machine because at the end product is usually large and almost immediately ready for use.

    Below is one of the last projects I have done, a standing desk inspired by the furnitures that are in fablab. Standing desk became very much needed when fablab suddenly had a lot of people working on 3d printers, sometimes bumping into it for literally 10 minutes to prepare and start printing. I checked the anthropometric boards for the height and started designing. The result below.

    Designing 3d model in Fusion 360

    I always start the design process by collecting information on a given topic, collecting information on similar products, searching through the pinterest to find something new to apply in my project. Also very useful are anthropometric tables and drawings showing the most ergonomic position of a person at a given device. I determined the height of the table and the appearance of the project based on the collected information. I was thinking about adding shelves under the table top and a holder for the extension cord at the back but on the other hand I thought it would be better to keep it simple. Below is the design process in fusion 360.

    extruding the table top form rectencular sketch

    sketching table legs using lines, polilines and filets

    extruding table legs form sketch

    sketching apron and stratcher for making the structure more solid

    extruding apron and stratcher symetricly

    adding one thikness by adding one more leg for a site

    mirroring legs for the other site

    Remeber always to use align before going to Manufacture in fusion 360. I always save the version before that and name it xxx_before_align.

    File Preperation for milling

    It is always a good idea to start setting up a file by preparing the workspace and setting up the setup.

    With WCS (work coordinate system) we can choose several options I usually use two with the use of the Model object or without selecting objects, simply all the objects in the project. Sometimes I also create a body which is the size of the material I will use for milling. Then using Orientation =>Select With axis... I set up the axes and with the stock point it indicates the top point of the material. In stock tab I set relative size box and give offset (in case when in the first tab I didn't choose previously prepared body in model)

    All fusion basics cam machining tools can be found in the Milling 2D tab. Among the many options we will first take care of the 2d pocket. This is a tool that allows you to cut the selected pocket with the bit.

    A new 2d pocket panel appears, in which we set all parameters

    I set:
  • clearence Hight - responsible for the starting and finishing height of the tool
  • Retract Hight - the height at which the tool is raised after the next cutting phase
  • Feed hight - the height to which the tool returns when performing a task e.g. plundge after each drilling
  • Top Hight - the highest cutting moment, that is when the milling starts
  • Button Hight - the lowest cutting moment - that is to say, it will go down to such a depth as f

    Passes In this section, the important laws are:
  • Both ways - which allows the machine to work both ways when milling
  • Multiple Depths - allows us to determine multiple depressions of the pick in the material, instead of drilling to full depth you can set an interval.
  • Even stepdowns allows us to set equal distances between descents

    We can also set whether we're going to mill the climb or conventional. (depends on the bit)

    The next funk is the 2d Contur, which allows us to cut out the line. We choose contour. We can also set Tabs, which are places where the program will design bridges so that the cut out element will be still connected to the whole board. This allows us to repeatedly avoid the problem with flying parts:)

    pass settings for cutting through for plywood

    Linking - allows us to set basic milling rules
  • Allow Rapid Retract - allows us to move back quickly during milling
  • Keep tool Down - allows the machine to not lift up to a safe height on every path made
  • Lead-in and lead-out - allows us to enter and exit the material smoothly
  • Ramp gives us the opportunity to start milling on the ramp without dangerously turning back. Thanks to this, the milling cutter is less damaged and we enter the material more smoothly, giving us a nicer edge.

    Here you can see the path we i generated for contour cutting.

    Each executed function can be saved and store in Template which will allow us to speed up work on the next similar task.

    In the Action section we have a Post process where we can add our own postprocessor or use a ready-made one available on the Internet.

    Below is a video of a video showing milling emulation.


    Finaly i get all the parts milled. And now its time to assemble and i have to be honest it was so easy because every thing assmebled so easy and smooth that i was suprise. I did all the carpentery work with less than an 1h. + a day for painting with few layers.

    Finaly done!

    Now anyone who comes to the Fablab can use this table at 3d printers zone:) Enjoy!

    all files from projects