Computer controlled machining

1. Weekly Brief Summary

This week I made a tripod table using the large CNC of FabLab Hamamatsu.
Our students at Fab Lab Kamakura originally planned to use the ShopBot of TechShop in Tokyo to create an assignment.
However, because it suddenly closed a month before the scheduled date of use, we suddenly decided to use FabBot Hamamatsu’s ShopBot.
After designing on the Fusion 360, we created a top panel decorative design using Adobe Illustrator.
It took about 6 hours to carve the top panel, 2 hours to cut the parts, and 1 hour to file.

2. Weekly Assignment Requirement

Group Assignment

  • Test runout, alignment, speeds, feeds, and toolpaths for your machine
  • Document your work (in a group or individually)

Individual Assignments

  • Make (design+mill+assemble) something big

Learning outcomes

  • Demonstrate 2D design development for CNC production
  • Describe workflows for CNC production

Have you

  • Linked to the group assignment page
  • Documented how you designed your object (something big)
  • Documented how you made something BIG (setting up the machine, using fixings, testing joints, adjusting feeds and speeds, depth of cut etc.)
  • Described problems and how you fixed them
  • Included your design files and ‘hero shot’ photos of final object

Kamakura Group Assignment Week07

4. Assignment Work Planning

  • Group Assignment
    Verifying Microcontroller Circuit Board Operation
    (a)Verification of Kerf and cutting test-cut using conifer plywood・・・Toshiki Tsuchiyama
    (b)Verification of Kerf and cutting test-cut using OSB・・・Yuki Oka

  • Individual Assignments
    (a)Design Using Fusion360
    (b)Creation of Output Data Using Adobe Illustrator
    (c)Cut & cutting with CNC Router ZN1325

5. Description of Assignment Work

Designed with Fusion360

FabLab Kamakura has a Japanese-style room but no table.
So I decided to create a low dinning table for use in this space.
In Japan, tables used in Japanese-style rooms are called “chabudai.”

First, I designed it with a parametric design using Fusion360.

Name Unit Expressionn Value
table_diameter mm 800mm 800.00
thickness mm 24mm 24.00
table_hight mm 400mm 400.00
bottom_length mm table_diameter/8 100.00
leg_angle deg 105deg 105.00
leg_number 3 3

Basic Safety Training Course for CNC Router ZN1325

Take-san from FabLab Hamatsu trained me on CNC Router ZN1325.
CNC Router ZN1325 is a large CNC machine made in China that is operated using “Vector Cut2D” and “MACH3 CNC Software.”

(1) Vectric Cut2D

For the data to be processed with [CNC Router ZN1325], vector data such as Adobe Illustrator is read with [Vectric Cut 2D] and [G-code data] is output.

Interface of Application

(2) MACH3 CNC Sofyware

Use [MACH3 CNC Sofyware] to adjust the origin position and machining speed of [CNC Router ZN1325].

Interface of Application

Clean Up

We cleaned the room before we started processing.
By cleaning the area around the machine tool, we can prevent errors on the machine side and injuries during work.
In addition, if the working range of people working indoors is sufficiently secured, it is possible to respond immediately when something happens.


⑴ Drill Set

This time, the end mill prepared by FabLab Hamamatsu is [6mm straight-through blade].
This end mill is cheaper than other end mills and seems to be able to be reground at a low cost.

⑵ Installation of Materials

We procured materials at a home improvement center near Fab Lab Hamamatsu.
The wood I purchased is [24 mm of softwood plywood].

I lay a MDF dump board on the table, put the material on it, and fix it with 6 screws.

While fixing the material, I hit the end mill and my hand and bleeded.
You need to be careful because even a little caution can lead to serious injuries.

Topboard Design

⑴ Design Using Adobe Illustrator

I created design data for the top panel using Adobe Illustrator.
I designed a Japanese garden with a motif.
(It’s not a motif for tattooing a yakuza.)

Initially, I didn’t put any design on the top plate, but I received advice from the instructor and decided to engrave.
The size of the art board is the same as the material [[W]900mm x (H)1800mm].

Vectric Cut2D

⑴ Open File

Load the vector data created from [File tab] → [Open].

I confirmed in [Material Setup] that the size is the same as the artboard created in Adobe Illustrator.
Also, the location of [Z Zero] is set to the lower left of the material.
[XY Origin Position] is also set to the lower left.

Wave cutting

First, I made settings for cutting ripples.

  • [Start Depth]・・・[0.0mm]
  • [Cut Depth]・・・[1.5mm]
  • [Tool]・・・[End Mill (6mm)(Wood)]
  • [Clear Pocket]・・・[Offset]
  • [Cut Direction]・・・[Climb]

Fish cutting

Next, I made the settings for carving the carp.
The reason for changing the depth of the ripples and carving is to create a three-dimensional effect on the top plate design.
Also, since I am planning to make the carp body and pattern with 3mm acrylic, we have taken into account the depth.

  • [Start Depth]・・・[0.0mm]
  • [Cut Depth]・・・[4.5mm]
  • [Tool]・・・[End Mill (6mm)(Wood)]
  • [Clear Pocket]・・・[Offset]
  • [Cut Direction]・・・[Climb]

Cutting of Table Outline

Finally, I set the outline processing of the table.

  • [Start Depth]・・・[0.0mm]
  • [Cut Depth]・・・[24.2mm]
    ・The purpose is to reduce the possibility of not cutting by setting it slightly deeper than the actual material thickness.
  • [Tool]・・・[End Mill (6mm)(Wood)]
  • [Machine Vectors]・・・[Outline]
  • [Direction]・・・[Conventional]
  • [Add tabs to toolpath]・・・[Length=5.0mm / Thickness=3.0mm]

Set [Toolpath Tabs] from [Edit Tabs…].
Click the mouse anywhere to display the tab icon.
This time, I created tabs in 4 places.

⑵ Confirm Preview

You can check the state during cutting from [Preview Toolpath] on the [Toolpaths tab].
Before checking, you need to set [Pocket] in [Toolpath List].

Wave cutting Preview

Fish cutting Preview

(3) Makinng G-code

G-code can be generated from [Save Toolpaths].
Select [G-code(mm)*tap] for [Files of type], name and save.

XYZ Axis Alignment

Start [MACH3 CNC Sofyware] and select [Jog ON/OFF Ctrl-Alt] in [Tool Information] to operate the XYZ axes using [←↑→↓] on the keyboard to set the origin position.

When the origin is aligned with the bottom left of the material, use thin paper such as newspaper to align the Z-axis.
By gradually lowering the Z-axis, you can set the place where the newspaper is sandwiched between the tip of the drill and the material and caught by it as the origin of the Z-axis.
You can definitely cut if it is about 2 mm from the surface of the material.

When all the origin positions of XYZ are decided, press [ZERO X][ZERO Y][ZERO Z] respectively to set all values ​​to [0].
This completes the origin position setting.

Reading G-code

Load the G-code data generated earlier from [Load Gcode] of [MACH3 CNC Sofyware].

Press [Cycle Start] to start processing.

⑴ Cutting Start

Wave cutting

Fish cutting

Table Outline Cutting

Since FabLab Hamamatsu has removed the [CNC Router ZN1325] dust collector, we were working to remove wood chips during processing.
This is a bit dangerous.
However, there is a risk that wood chips accumulated in the processed groove may be ignited by frictional heat with the end mill.

⑵ Adjusting the Speed and Rotation of the Drill

By operating the [+] and [-] buttons in [Feed Rate] and [Spindle Speed], you can freely adjust the rotation speed of the drill during machining.

Changing Feed Rate

I set [Feed Rate] to [700].

Changing Spindle Speed

I set [Spindle Speed] to [12000].

End of cutting

The cutting process took 6 hours.

Wave cutting

Fish cutting

Legs Processing

After cutting, I edited the processing data of the tripod.
I edited the data by loading the tripod vector data by overwriting the cutting data.
Import data from [Import] on the left side.

For the machining information, the same settings as for the external cutting of the table were set.
In the tab settings, I placed three tabs in a well-balanced place for each part.

Legs Cutting Preview

Legs Cutting

End of Cutting

The cutting process took 2 hours.

After finishing the process, I cut off the tab using a chisel and a mallet and took out the part from the material.

Assembly and Sanding

(1) Assembly

I noticed a serious mistake after processing.
I forgot to add Dog Born to my process data.
As a result, the parts did not mesh well during assembly.

That’s why I manually created Dog Born using Belt Thunder.
As a result, I was able to engage the parts safely.

I fixed the tripod parts with screws and nuts.
I used an electric drill to pierce the parts together.


(2) Sanding

For finishing, I sanded the wave and the carved part of the fish.
In the state of primary processing, there are many burrs on the surface and the feel is very bad.
I want to use this table when working on a PC, so I had to finish it to make it feel good.

This process took about an hour.

The Finished Table

6. Description of Important Weekly Learning Outcome

When I tried using CNC Router ZN1325, I personally felt that it was easier to use than ShopBot.
When I assembled it, I realized I had forgotten to make a dogbone.
As a result, I had to adjust it with sanding.
I don’t think this kind of problem would have occurred if the design was corrected after enough test cuts.

8. Appendix