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Centroid Mill Operator Manual

If you’ve never used a CNC machine before, we recommend learning the basics on the X-Carve machine before using the 4×8. It is safer for both you and the machine, and the software used by the X-Carve (Easel) is much easier to use. Once you’ve made a simple project with it and learned the basics of CAD/CAM software, speeds and feeds, end mills, and toolpathing, follow the steps outlined in the training section below to get access to the 4×8 machine.


If you are new to CNC, we HIGHLY recommend you learn on the Shapeoko or X-Carve first.

To get signed off on the 4×8, attend a 1-on-1 training session with an authorized trainer. When you arrive at the training session, you will need to bring a project with a CAM design already prepared. The CAM file must have been created by you and not a third-party or downloaded file. You must be able to modify the file on site (bring a laptop, or if using VCarve Pro, you may use one of the CNC computers with VCarve Pro installed. To schedule a 1-on-1 session with a trainer, email [email protected] The certification form must be signed by you and the trainer for you to be signed off on the machine.



Machine specifications

Note that the metric numbers for the work envelope don’t quite match the Imperial units. We need to do some testing with the machine to verify which are correct.

  • 1300 x 2500 x 200mm = 51.1811” x 98.4252” x 7.87402
  • 4’ x 8’ x 0.66’ = 48” x 96” x 7.92”
Make and model Sequoyatec 1325
Controller Centroid Acorn
Work envelope 4' x 8' x 0.66’ (1300 x 2500 x 200mm)
Spindle power 3KW, water-cooled
Spindle speed 0-24000rpm
Transmission Rack and pinion for X and Y, ball screw for Z
Repeatability ±0.002“ (0.05mm)
Weight 1100kg


Tips for creating a toolpath file

Fusion 360

First, in your part file, set your model origin to what you intend.

In manufacture mode, right click on your setup definition and select Edit. In the setup dialog box, ensure the origin is what you want. F360 does not seem to always default to the model origin.

You have a few options in here. Whether you want your origin to be the material top, bottom, or something else, make sure what you select here matches how you setup the machine.

:!: An unexpected setting for your model origin will at best cause the machine to mill through air, at worst plunge your tool through your workpiece and into the machine bed!

Next, setup your NC Program settings

The most important setting is the Post Configuration. Use the following settings:

  • Vendor: CENTROID
  • Post: CENTROID / centroid

Defaults for the right-hand pane all work.

In more complex parts, it may be worth having multiple programs for a single complex part. This could be useful for example if you are concerned about crashing into your workpiece clamps. You could have one program that only cuts in a certain area, then another program that cuts elsewhere, switching clamp positions in between programs. In that case, you can use the Operations tab of the NC Programs setup to select a subset of your tooling instructions. Each NC Program can be configured to output to a different file, and you can postprocess all in one operation.

  - Discuss only the settings and procedures that are unique to the Sequoyatec machine. General CAD/CAM guidance should be provided in a separate article that is applicable to all CNC machines.
  - Would it be feasible or helpful to provide some kind of starter project file?

Operating the machine

Starting up the machine

  1. Ensure the 240VAC plug is inserted into the wall socket and twisted into the “lock” position.
  2. Twist the large E-stop button counter-clockwise until it pops up. If it doesn’t pop, it may already be up.
  3. Turn the key lock to the “on” position.
  4. Turn on the PC (if it is not already on) by pressing the power button on the front of the small Dell box.
  5. Log on to the PC using your account.
  6. Run the CNC12 software (cncm.exe) using the shortcut on your desktop. It should automatically connect to the controller electronics.
    1. If you don't have this shortcut, create a new one by right-clicking the desktop and choosing New > Shortcut, then typing in the following as the location: C:/cncm/cncm.exe
  7. Reset the machine by pressing the large red “Press to Clear” button in the bottom right.
    1. A green “Reset Cleared” message should appear in the command log.

NOTE: you should hear the machine make a noticeable “ka-chunk” noise when both the E-stop and key lock switches are engaged. This is just the high-voltage motor drivers taking control of the stepper motors!

Homing the machine

  1. Manually jog the machine so that the toolhead is close to the origin (corner closest to the controller cabinet).
    1. The homing routine is really slow, so this can save you a good amount of time.
    2. Use the on-screen jogging controls in CNC12, or press Alt + J to bring up and enable the keyboard jogging interface.
  2. Bring up the MDI console in CNC12 using the MDI button at the bottom, or by pressing F3.
  3. Type G28 into the text field, then press Enter.

Setting the Z height

  1. Move the Z axis down until the end mill is about an inch above the workpiece.
  2. Set the touch probe on top of your workpiece, directly under the end mill.
    1. Note: the touch probe is connected to ground through wiring inside the machine, so no ground clip is needed.
  3. Bring up the MDI console in CNC12 using the MDI button at the bottom, or by pressing F3.
  4. Type M55 into the text field, then press Enter.
  5. Follow the prompts that come up on the screen.
    1. Note: the “Cycle Start” button is the green “I” icon at the bottom right corner of the jog controls (right of “Feed Hold” and under “Z-”.

Securing your material with clamps

  - Where to find clamps in the shop
  - How the clamps work
  - How to know when a piece is clamp correctly.
  - Ensure the end mill won't run into the clamps during the job (not just X/Y, but also Z!).

Running a toolpath file

  - Start the electronics (link to section below).
  - Loading the file.
  - Previewing the toolpath using the visualizer. Make sure the dimensions are correct and are less than the machine size.
  - Home the machine (link to section below).
  - Set the Z height (link to section below).
    - Consider running an "air cut" by setting the Z height above the material and running the job.
  - Activate the dust collection system (link to section below).
  - Start the job

Activating the dust collection system

  - Using the remote to turn on the dust collector.
  - Installing the dust shoe on the spindle.
  - Ensuring adequate air flow by disabling the X-Carve hose.

Shutting down the machine

  1. Return the machine to the home position using the G28 command as a courtesy to the next person who uses the machine.
  2. Exit the CNC12 software.
  3. Log off the PC.
  4. Turn off the controller electronics by turning the key lock to the “off” position and press the E-stop button down.
  5. Vacuum any debris off the machine.
  6. Turn off the dust collector using the remote.
  7. Sweep up debris from the floor, if necessary.
  8. Don't forget to log your time on the timesheet!

Retrofit documentation

When the CNC machine first arrived, it came with a controller board and software that was a bit limiting and confusing. Robert Payne volunteered his time to replace this board and software using the Centroid Acorn platform, a process which he documented thoroughly here:

Controller cabinet documentation

System diagram

Use this diagram to understand the relationships between each component to help with troubleshooting. See the components section below for detailed pinouts for each component.

Cabinet photos

Front side Back side

Front side close-ups

Back side close-ups


Incoming 240VAC terminal block

Connects the wires from the 240VAC plug to the components inside the cabinet.

Make/model or part no. N/A
Manual and/or datasheet N/A
Wiring diagram

Residual current circuit breaker

Turns off all power when there is too much current (>30mA) running through the cabinet itself.

Make/model or part no. DZ47LE-32 C32
Manual and/or datasheet
Wiring diagram

Thermal overload relay

Turns off all power when the 240VAC wires get too hot.

Make/model or part no. Shern Dian RA-30
Manual and/or datasheet
Wiring diagram


Turns off all power when more than 32A of current is detected in the 240VAC lines.

Make/model or part no. RT28N-32X
Manual and/or datasheet Datasheet
Wiring diagram

240VAC distribution block

Splits the protected 240VAC lines to power other subsystems.

Make/model or part no. N/A
Manual and/or datasheet N/A
Wiring diagram

EMI filter

Helps protect the VFD by filtering out noise in the 240VAC lines.

Make/model or part no. ZONL ZJ2AC-20A
Manual and/or datasheet
Wiring diagram


Safely controls the speed of the spindle using command signals sent from the Acorn board.

Make/model or part no. Best FC300-3.0G-3S-B4CF
Manual and/or datasheet Manual
Wiring diagram

Stepper motor transformer

Converts 240VAC to 70VAC for the stepper motors.

Make/model or part no. FDK-800VA
Manual and/or datasheet N/A
Wiring diagram

Stepper motor drivers

Controls the movement of the stepper motors based on low-voltage signals supplied by the Acorn controller board.

Make/model or part no. Leadshine DMA860H
Manual and/or datasheet Datasheet
Wiring diagram

Acorn board

Interprets G-code from the PC and produces electrical signals to control various parts of the machine.

Make/model or part no. Centroid CNC Acorn
Manual and/or datasheet
Wiring diagram

Acorn power supply

Converts 240VAC into both 24VDC and 5VDC to power the Acorn board and 5V logic of the stepper drivers.

Make/model or part no. Mean Well RD-35B
Manual and/or datasheet Datasheet
Wiring diagram

Acorn relay board

Allows control of ??? through the Acorn board using G-code commands.

Make/model or part no. N/A
Manual and/or datasheet N/A
Wiring diagram

Wiring harness terminal block

Connects all of the various sub-systems to the giant cable that goes to the machine.

Make/model or part no. N/A
Manual and/or datasheet N/A
Wiring diagram
Pin mappings
  • 1 = X axis stepper driver - A+
  • 2 = X axis stepper driver - A-
  • 3 = X axis stepper driver - B+
  • 4 = X axis stepper driver - B-
  • 5 = Y axis stepper driver - A+
  • 6 = Y1 axis stepper driver - A-
  • 7 = Y1 axis stepper driver - B+
  • 8 = Y1 axis stepper driver - B-
  • 9 = Y2 axis stepper driver - A+
  • 10 = Y2 axis stepper driver - A-
  • 11 = Y2 axis stepper driver - B+
  • 12 = Y2 axis stepper driver - B-
  • 13 = Z axis stepper driver - A+
  • 14 = Z axis stepper driver - A-
  • 15 = Z axis stepper driver - B+
  • 16 = Z axis stepper driver - B-
  • 17 = Acorn board pin IN1 - X limit switch signal
  • 18 = Acorn board pin IN2 - Y limit switch signal
  • 19 = Acorn board pin IN3 - Z limit switch signal
  • 20 = Acorn board pin +24 IN
  • 21 = UNKNOWN
  • 22 = VFD - U
  • 23 = VFD - V
  • 24 = VFD - W
  • 25 = Incoming 240VAC terminal block - ground
  • 26 = Acorn board pin IN7 - touch probe signal
documentation/cnc_routers/sequoyatec1325.txt · Last modified: 2021/04/20 05:12 by robertdahlstrom