Week 7: Computer-Controlled Machining

#Fusion360 #CNC #Mach 3

Assignments: (Group) 1. Test runout, alignment, speeds, feeds, and toolpaths for your machine. (Individual) 2. Make (design+mill+assemble) something big.

Published on: Mar 11, 2020
Last updated on: Jan 12, 2021

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Group Assignment: Characterize Our CNC Machine

Individual Assignment: Chair & Rotational Table CNC Milling


# Name
1 CNC Milling Machine: Recontech 1312 (Manual)
2 6mm Two-Flute Square Flat Milling Bit
3 15mm Plywood
4 12mm Fiberboard

Design Tool: Fusion 360

3D Designing with Fusion 360: Learn more from Week 2: Computer-Aided Design

Generate Bit CAM-Toolpath in Manufacture Section of Fusion 360

After finishing designing the chair and the table, I unfolded their parts and placed them within one piece of flat plywood respectively.

Chair: Chair_Assemble.png CNC_Chair_1.png

Rotational Table: Rotational-Table_Assemble_1.png CNC_Rotational-Table_1.png CNC_Rotational-Table_2.png

The bit I used for milling the rotational table (12mm fiberboard) and the chair (15mm Plywood) is 6mm thick and its shape is two-flute square flat.


I followed the steps below to generate the toolpaths:

  1. Select 2D Contour within the Manufacture section. cnc_fusion_step_1_2d_contour.png
  2. Add the bit to the Tool by typing correspondent parameters.

General: cnc_fusion_step_2_bit_setup_1.jpg

Cutter: cnc_fusion_step_2_bit_setup_2.jpg sch_bit.png

Cutting data: cnc_fusion_step_2_bit_setup_3.jpg

Cutting speed & Tool Feed Calculation: cnc_speed_calculation.jpg

Post processor: cnc_fusion_step_2_bit_setup_4.jpg

  1. Back to the 2D Contour window to finish the settings of other tabs.

Geometry: cnc_fusion_step_3_2d_contour_geometry.png

Heights: cnc_fusion_step_3_2d_contour_heights.png

Passes: cnc_fusion_step_3_2d_contour_passes.png

Linking: cnc_fusion_step_3_2d_contour_linking.png

  1. Click Generate to get the toolpath. cnc_fusion_step_4_generate.png
  2. Click Simulate to watch if the spindle moves correctly. cnc_fusion_step_5_simulate.png
  3. Click Post Process to set the correspondent post processor (Here: Mach3Mill) and export the tap file for milling. cnc_fusion_step_6_post_process.png


Fabrication: Recontech 1312 CNC Milling Machine

Following is the CNC machine I used for milling.


The fabrication steps are:

  1. Follow the manual to set up the CNC working environment. cnc_milling_step_0_setup_manual.jpg The correspondent buttons: cnc_maccnc_milling_step_0_mach3_UIhine.jpg
  2. Use foams and the built-in vacuum table to suck/fix the plywood. cnc_milling_step_1_suck_sheet.jpg
  3. Insert the bit into the spindle with 2 spanners. spanner.jpg


  1. Measure the focus of the z-axis by pressing the Terän mittaus button in Mach3 to touch the yellow magnet. cnc_milling_step_3_focus_z_axis.jpg


  1. Set the milling origin to the bottom left corner by moving the spindle with Left, Right, Up, Down Arrow and Page Up/Down keys. spancnc_milling_step_4_set_origin_1.jpg


  1. Open the tap file in Mach3. cnc_milling_step_5_mach_open_tap_file.jpg
  2. Click Regen Toolpath. cnc_milling_step_6_mach_regen_toolpath.jpg
  3. Reduce the Slow Jog Rate to 20% during the initial milling. cnc_milling_step_7_mach_show_jog_rate-.jpg
  4. Start milling by pressing the red button in the outside room.

The inital cut depth:

The max cut depth:

  1. Gradually increase the Slow Jog Rate to 100% during miiling. cnc_milling_step_7_mach_show_jog_rate+.jpg

Assembling & Sanding

After finishing milling, I followed the steps below to do the post-processing:

  1. Separate the cutting parts with the following tool manually. cnc_cutting_tool.jpg
  2. Assemble the chair with screws and an electric drill. cnc_sanding_step_1_before_1.jpg


  1. Remove the rough wooden fibres with a sanding machine. cnc_sanding_step_3.jpg
  2. Fix the chair for gluing with G clamps. cnc_sanding_step_4_add_glue.jpg
  3. Add the top sheet. cnc_sanding_step_5_add_top_sheet.jpg
  4. Remove the extra glue with tissues. cnc_sanding_step_6_dry_glue.jpg


  1. Wait for drying. cnc_sanding_step_7_waite_dry_1.jpg


  1. Finish! chair_2.jpg


End Result






Problem & Solution

The dust sometimes affected the sucking strength of the vacuum and therefore made the plywood move during milling, which was really dangerous. I needed to pause the machine to remove the dust and fix the sheet again evrey now and then before continuing milling. cnc_problem_weak_sucking.jpg

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