Hattori:en

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General

Hattori[1] is a small (desktop sized) CNC milling machine. It is available for general use. You need to take a course before you are allowed to use the machine. Relevant courses are announced at Bitraf's meetup page. These instructions are (mostly) copied from the Hattori1 How to use wiki page.

Location

Hattori has its own place in the workshop.

Safety

Safety is a way of thinking to prevent humans from getting physically hurt.

  • Never leave the machine while it is running
  • Never open the safety door while the machine is running
  • Don't hesitate to hit the red emergency button if something goes wrong (it wont harm the machine to hit the e-stop)
  • You can both pause and stop a job from the interface
  • Always make sure the machine is off when changing bits

Preparing the machine

  • Make sure the machine is off by pressing the red off button on the left side of the machine
  • Insert your bit in the spindle (collets and wrenches are in the door)
  • Pull the bed out of the machine
  • Drill a hole in each corner of you material and mount it on the bed with screws
  • Vacuum clean the machine if it is dusty
  • Turn on the machine green on button on the left side of the machine
  • Start the Hattori-control program on the small laptop next to Hattori (shortcut on the desktop)
  • Press the connect icon in top middle of the screen
  • Start the spindle warmup routine (desktop/hattori_config/warmup_routine.gcode)

Software

Setting up a job in V-Carve

  • Start the desktop computer to the left of Hattori
  • Start V-Carve
  • Create a new file
  • Set the X and Y job dimensions to the size of Hattoris bed. Width: 150mm Height: 220mm
  • Set the the material thickness to the thickness of the material you are cutting
  • Set Z zero to above your material
  • Set XY datum position to bottom left
  • Hit OK

Creating toolpaths in V-Carve

  • Vectric has good tutorials on creating toolpaths with V-Carve here[2]. There are also regular courses in V-Carve at Bitraf[3].
  • On Hattori we always work with X and Y zero at the bottom left corner off the bed. The white canvas in V-Carve is the same size as Hattoris bed (150mm x 220mm). Use the canvas and measurement tape to place the parts in the correct position in V-Carve.
  • There is a tool library set up with recommended bit settings for Hattori
  • In general you feedrates should be 33% faster than what you would use on a shopbot. (Because Hattori's spindle can run at 24000rpm. That is 6000rpms faster than the shopbots max 18000rpm.)
  • Your pass depth should be about 40% less than you would set up on a shopbot. (Because the motors and spindle is not as powerful as on the shopbot)
  • When cutting out parts you should add 0.5mm extra cut depth. (no need for more than 0.5mm because the autohoming is very precise)

Exporting toolpaths from V-Carve

After creating one or more toolpaths in V-Carve, they must be exported.

  • Double check that you have entered the correct material thickness in the job setup
  • Click the floppy disk icon to enter the toolpath export menu (on the right hand panel)
  • Make sure the Hattori post processor is selected from the drop down menu
  • Hit the Save toolpath(s) button and save the job in your personal dropbox folder at bitraf

Using other CAM software

It is possible to use a different CAM program, but there are some things you must know and do.

  • You can, but you have to run the home_all_axes.gcode job in the Hattori config folder before running a job.
  • Running the home all axes job will set Z zero beneath your material and in the bottom left corner off the bed
  • If you have to you can jog the machine around like a peasant and set manual zero positions as needed

Materials - settings

This section should contain verified, safe settings for various materials. For now, see the section about creating toolpaths in V-Carve.

safe settings

wood 
example, copied from ShopBot page
tool feed rate (mm/s) plunge rate (mm/s) spindle RPM pass depth (mm) ramp angle (degrees) comment
6mm Up-Cut single-flute 30 30 24000 19.6 45 check cutting part length
6mm Up-Cut single-flute 40 30 24000 10 45 -
3mm Up-Cut single-flute 15 10 24000 5 45 -
- - - - - - -
POM 
tool feed rate (mm/s) plunge rate (mm/s) spindle RPM pass depth (mm) ramp angle (degrees) comment
- - - - - - -
aluminum 
tool feed rate (mm/s) plunge rate (mm/s) spindle RPM pass depth (mm) ramp angle (degrees) comment
- - - - - - -
steel 
tool feed rate (mm/s) plunge rate (mm/s) spindle RPM pass depth (mm) ramp angle (degrees) comment
- - - - - - -

Running your job

Revied the Safety section first.

  • Turn off the machine
  • Insert the bed
  • Close the safety door
  • Turn the machine back on again
  • In the Hattori control software click the browse button in the top right corner the screen
  • Navigate to your .gcode file and select it
  • Have a look at the preview on the screen to verify that you have loaded the correct job
  • Double check the the correct bit and material is in the machine
  • Press the magic green play button in the top right corner off the screen

Finishing and cleaning

After you are done with the machine, you must do this. This is NOT optional.

  • Vacuum clean the machine thoroughly
  • Remove your material from the bed and your bit from the spindle
  • If you did a commercial job you pay for the cutting time in the iZettle downstairs (commercial is when someone pays you to fabricate something for them or you are planning to sell what you are fabricating)

Troubleshooting

Troubleshooting hints.

  • You forgot to turn on the machine before starting a job (the control software goes in alarm mode, disconnect and connect again for a fresh start)
  • You specified the wrong material thickness in the v-carve job setup
  • You use the wrong post processor when exporting a job
  • You used the wrong milling bit or settings
  • The cable to the autohoming plate is disconnected
  • Bitrafs Slack CNC channel is a great place to get help
  • The Issues forum of the Github repo is also a good place to get help and suggest improvements

Happy cnc milling!

Don't forget to share pictures of your projects in the Bitraf communication channels.

References