V-Core 4.0 - IDEX
calibration
| set-up
RatOS provides fully automated Beacon Contact model calibration and temperature offset adjustment. Learn more here.
Warning!
The extruder and hotend must be free of filament. Make sure to unload it first, otherwise the machine will not be able to perform this calibration accurately.
- Heat the nozzles to 280 °C and tighten them if you haven’t already.
Caution.
Be careful, as the hotend will be extremely hot and can easily cause burns. Avoid overtightening, as this may cause permanent damage. Phaetus recommends applying 2.5 Nm of torque when hot-tightening the Rapido 2 nozzle.
- Install the flex plate.
- Run the following command in your console:
BEACON_RATOS_CALIBRATEERROR. "Probe sample exceed sample_tolerance"
If you encounter the message ‘probe sample exceeded sample_tolerance’ during Beacon calibration, don’t worry! Here are a few potential fixes for the issue:
- Loose noozle. Hot tighten the noozle as mentioned here.
- Ensure the toolhead has no excessive play. Try gently rotating it to check for any loose screws on the rail or carriage plate.
- Verify that the beacon is securely attached.
- Verify that the Z arm screws are secure and sturdy.
- Ensure that the Z stepper motor couplers are tightly secured.
This issue usually comes down to assembly problems. If none of the above suggestions resolved it, triple-check your machine, something might be loose.
02. Gantry twist
Gantry twist significantly reduces V-Core 4 performance by introducing unwanted drag into the system. This results in poor belt tensioning and Input Shaper graphs, ultimately leading to a prolonged and frustrating process of identifying the underlying causes of the machine's suboptimal performance.
In most cases, this issue is too subtle to be detected by the naked eye. Please follow the steps below to ensure your machine is properly prepared for printing.
Warning!
Before beginning this chapter, it is crucial to ensure that the gantry moves smoothly without the belts, and that both joiners on the gantry make contact with the stepper motor cages simultaneously. If this step is not properly completed, this chapter will not be effective. If you are uncertain, take your time to remove the belts from the machine and square the gantry as outlined in the assembly guide (check here).
- Run the following command in your console:
M18 - Remove the top Y belts. This is required for proper calibration and performance.
- Slowly move the toolhead to the center of the machine, then slide the gantry fully to the back until the joiners make contact with the stepper motor cages.
- Using your hands, press the gantry joiners against the stepper motor cages. There should be no play between them, and the goal is to ensure you cannot squeeze the joiners further. Often, one of the joiners will be tightly compressed, while the other may have some play. Gently press both joiners against the stepper motor cages and feel for any movement. It is important to identify which joiner has play against the stepper motor cage.
The idlers will make contact before the plates collide, and this is perfectly fine. The idlers provide enough support and accuracy to correctly align the gantry.
- Identify the joiner that is not making contact with the stepper motor plate.
- Loosen the set screw on the tensioner blocks before adjusting the belt tension.
- Loosen the belt tensioner slightly until the joiner makes contact. Loosening the tensioner moves the joiner toward the back of the machine. Tightening the tensioner moves the joiner toward the front of the machine.
- Make small adjustments until the joiner is properly aligned.
- This calibration process involves some trial and error. Adjust the belt tension as needed to ensure that both joiners make contact with the stepper motor plates simultaneously.
- Reinstall the top Y belts and repeat steps 3 to 9, this time ensuring that the top Y belts are properly tensioned to maintain correct gantry alignment. To achieve this, repeat the steps above for the two top Y belt tensioners.
03. Belt tension
Note!
If you are building an IDEX, the Y belts were already reinstalled in step 10 (Gantry Twist). Since the IDEX toolheads only move with the Y belts installed, the graph-based belt tensioning method can only be performed with them in place. This makes the process more complex, and a dedicated guide is not yet available. If unsure, skip the belt tensioning step.
The belt tension graphs are meant to help diagnose your machine assembly rather than serve as a tuning tool. It’s easy to over-focus on them, but they should be seen as a guide for spotting issues rather than a perfect benchmark. Belt tension analysis is a nuanced and evolving subject; for deeper exploration, check out the excellent work by the Klippain Shaketune team.
Warning!
Ensure your machine build is complete, wiring is clean, no parts are loose, and the printer is placed on a sturdy surface with nothing resting on or against it. Do not touch the machine during vibration analysis.
This procedure focuses on relative belt tension—verifying that both belts are equally tensioned, which is crucial for smooth motion. Ideally, the belt graph for a V-Core 4.0 will show smooth lines with two peaks, as illustrated below.
To perform a belt tensions graph, just click on the designated button inside the "SCRIPTS" window.
You must now analyse your graph and identify potential issues. This is a very complex and involved process, but here are a few generic most found issues:
- The two peaks (blue and orange) must be aligned on the same frequency, if they are not vertically aligned, then you need to tension or loosen the belts, and your gantry is most likely twisted. Refer to this guide to help you troubleshoot.
- Toolhead vibrations typically appear in the 100–150 Hz range and can result from loose screws, damaged printed parts, unsecured wires, or insufficient cable management (e.g., missing zip ties).
- There is an issue with the belt path: If your graph lacks one or two peaks. It likely means a belt is rubbing against something along its path, such as an idler, motor pulley, or the frame.3.1. In the example below, only one belt path is affected.
3.2. In the example below, both belt paths are affected.
- Lastly, it’s important to distinguish between vibrations and swinging.4.1. Vibrations appear as zig-zag patterns on the graph and are usually caused by loose screws on the toolhead or gantry. Loose idler stacks or missing shims can produce the same effect. Carefully inspect the assembly to identify and correct the source.
4.2. Swinging appears as smooth curves on the graph and is often caused by the printer resting on an unstable table or uneven floor. Ensure your machine is on a solid, level surface to prevent it from shaking.
04. Input ShapER
This calibration follows the Klipper documentation steps but they are simplified for the V-Core 4.0
- Click on the designated button "GENERATE SHAPER GRAPHS" inside the "SCRIPTS" window.
- The printer will start moving the gantry in X and Y to determine the ringing frequencies. After this, the input shaper graphs will be available under the “machine” tab (1) , inside the “input_shaper” folder (2).
- There will be four files, the names should be intuitive, first you can see the toolhead designation, T0 or T1, then you can see the axis designation. T0_resonances_y_2025-02-17-163419 is a T0 Y axis input shaper graph made at 16:34 and 19 seconds at 17 of february 2025.
- Please open each of the graphs and record the values for the T0 X resonance ,T0 Y resonance and T1 X resonance and T1 Y resonance.
- Activate the Copy mode by clicking the "IDEX COPY" option on the "IDEX" window.
- Click GENERATE SHAPER GRAPHS, as in Step 1. The V-Core 4 will now measure shaper resonances in Copy mode, for both X and Y axes, on both toolheads. This procedure may take several minutes.
- Activate the Mirror mode by clicking the "IDEX MIRROR" option on the "IDEX" window.
- Click GENERATE SHAPER GRAPHS, as in Step 1. The V-Core 4 will now measure shaper resonances in Mirror mode, for both X and Y axes, on both toolheads. This procedure may take several minutes.
- Inside the Input shapperfolder you will find 12 Graphs, T0X, T0Y, T1X and T1Y, then you will have the copy mode graphs T0X_COPY, T0Y_COPY, T1X_COPY and T1Y_COPY, lastly you will have the Mirror mode graphs T0X_MIRROR, T0Y_MIRROR, T1X_MIRROR and T1Y_MIRROR.
- All the results must be included in the Input shapper configuration, to do this, you will need to do an average of the T0X_COPY and T1X_COPY, this new value will be the COPY_X_AVERAGE frequency.
[gcode_macro RatOS] variable_shaper_x_freq: [T0_X, T1_X, COPY_X_AVERAGE, MIRROR_X_AVERAGE] variable_shaper_y_freq: [T0_Y, T1_Y, COPY_Y_AVERAGE, MIRROR_Y_AVERAGE] variable_shaper_x_type: ["mzv", "mzv", "mzv", "mzv"] variable_shaper_y_type: ["mzv", "mzv", "mzv", "mzv"]
06. Ressonance analysis
The real-time analysis tool enables real-time resonance analysis of your printer. This functionality allows you to set the printer to resonate at a specific frequency and direction, facilitating a detailed mechanical assessment. With this tool, you can more effectively diagnose potential mechanical issues within the machine. Find more detailed information about this tool here.
The following chapters cover belt tension calibration and Input Shaper. During these steps, you can use the resonance analysis tool to help troubleshoot and diagnose any mechanical issues with your machine.
- Click on the Real-Time Analysis button (1) in the left menu.
- Select the Accelerometer (2).
- Click Start (3) to activate the accelerometer readings.
- Select the resonance direction (4):
5.1. Use ‘Oscillate X’ to debug an X-axis Input Shaper spike or noise.5.2. Use ‘Oscillate Y’ to debug Y-axis Input Shaper spikes or noise.5.3. Use ‘Oscillate X-Y’ to diagnose resonance in the lower belt line within the belt graph.5.4. "Use ‘Oscillate X+Y’ to analyse resonance in the top belt line within the belt graph. - Choose the Oscillation Frequency (5) at which you want the machine to resonate.
07. Skew Calibration
Skew correction is meant to compensate for a 3D printer assembly which is not perfectly square, the software makes small changes to the toolhead movement, maintaining a perfectly square trajectory. Every detail during the frame assembly may cause a slightly twisted frame, even the screws tightness. Making sure the machine is as square as one can get by hand is very important before advancing to software skew calibration.
The V-Core 4 has a 3-point kinematic bed levelling system that helps to mask XZ and YZ skew problems. If the build was successful and all Z rails are properly aligned, the Z squareness shouldn’t be a problem, otherwise, a skew calibration should be done for all planes. In this guide we’ll only focus on the XY plane, the procedure is the same for the other axis, more information here.
- Start by downloading the Skew_correction_tool.stl. Then open it inside your slicer. If this is your first time following this guide, please follow the Slicer installation first, then get back to this step.
Caution.
- Guarantee that no skew correction is running on your machine, check that variable_skew_profile is commented out in the macro configuration section. or type the command below in the terminal. For more information, click here.
SET_SKEW CLEAR=1The [skew_correcton] module requires 3 measurements; the length from Corner A to Corner C, the length from Corner B to Corner D, and the length from Corner A to Corner D.
Let's take the following measurements as an example:
AC= 141.15mm
BD= 140.9mm
AD= 99.65mm - Go into the printer.cfg and add the following lines:
[gcode_macro RatOS] variable_skew_profile: "my_skew" - Click “SAVE AND RESTART” at the top right of the printer.cfg window, then paste into the console:NOTE: Replace the "AC, BD, AD" text with your values.
SET_SKEW XY=AC,BD,ADWith the previous example, we have:
SET_SKEW XY=141.15,140.9,99.65Followed by:SKEW_PROFILE SAVE="my_skew" - Type:
SAVE_CONFIGType: - and re-print the test, make sure AC=BD. If not, double check all measurements and start this calibration again.