Service Home How To Procedures Vibration Analysis - RS-232 Interface
Last updated: 09/19/2023

Vibration Analysis - RS-232 Interface

Applies to machines built from November 2005

Introduction

This procedure applies to the vibration analyzer with the RS-232 interface. This vibration analyzer uses an RS-232 connection to send the measured data to the computer.

If you have the vibration analyzer with the ethernet interface, do the Vibration Analysis - Ethernet Interface procedure.

Make sure that the drive belt has the correct tension.

For mills refer to Spindle Drive Belt - Tension Adjustment - Gates Sonic - Mill Procedure.

For lathes refer to Spindle Drive Belt - Tension Adjustment - Gates Sonic - Lathe Procedure.

Setup the Vibration Sensor

1

Warm up the Spindle:

Insert a tool into the spindle.

For spindles that are 10,000 RPM or higher, ensure the tooling is balanced to at least balance grade G2.5

If necessary, select the [MEMORY] tab and operate the warm up program for the spindle:

Classic Haas Control O02020.

Next Generation Control O09220.

 

3

Setup the hardware for Vibration Analysis:

Connect the signal cable [2] from the sensor [1] to the RS-232 serial port [3] of the computer [4]

Connect the power cable [6] to an AC power source [5].

Note: If your computer does not have an RS-232 port you will need to get a USB to RS-232 converter.

Make sure to install the driver software for the converter if needed.

4

Place the accelerometer on the spindle:

Remove the protective magnet from the vibration sensor.

Put the vibration sensor (accelerometer) on the right side of the spindle in the X Axis direction.

Place the parallel magnets that are on the sensor parallel with the spindle.

For lathe spindles, you can either place the accelerometer on the side of the spindle casting or you can place it on one of the motor mounts near the hydraulic actuator.

Note: We measure vibration in the X Axis because the machine is weakest in this axis and thus will produce the highest vibration in this direction.

Setup Octavis

 Note: The Software can be downloaded from the HBC site.  Service > Documents and Software > 10_Service Tools.

1

Open and Setup the Octavis Program:

Select Monitoring on the left bar [1].

A window will prompt you to Create Connection. Click Yes.

Click Monitoring on the top bar, then select Spectrum Monitoring [2] .

  • Or you can select the graph button in the upper left to select Spectrum Monitoring.

Right click anywhere in the graph and select the following:

 

  • Y Axis>
    •  >Unit>Vibration Displacement. Unit is millionths of an inch (mil) [3]
    • >Scaling>0.1 mil
    • >Amplitude>Peak
  • X Axis>
    •  >CPM (Cycles per Minute) [4]
  • Averages>
    • Averages are best set to 1.  This is so you can instantaneously see what's happening with the machine in the moment.
    • If averages are set to 16 or any other number than 1, then it makes it appear that the vibration is better than it is.  This is because it takes the highest values and smooths them out with the lowest values.  It also makes it hard to see distinctive spikes that can give you valuable information about the health of the bearings.
  • Spectrum Range [5]
    •  Set to 0 - 33000 CPM
    • This is a frequency range.  The program converts frequency (Hz) to cycles per minute (CPM).

2

Select a speed to analyze the spindle vibration:

You can view vibration measurements at any speed, it doesn't just have to be max speed.

  • If the customer is having vibration issues at the speed they use in their program, it's probably best to check the vibration plots at that speed.
  • If you're not sure if there's a specific speed where vibration is happening with your machine, with the vibration analyzer connected, run the machine starting at 1000 RPM and go up in 1000 RPM increments seeing if you find an area where there is a high vibration displacement spike or lots of noise/spikes on the vibration velocity plot.

For troubleshooting purposes, it is best to get a baseline of spindle health at max speed so the factory can compare it to the expected health of the spindle.

If you're not sure the max speed of the machine, you can check Parameter 131 for your maximum spindle speed.

Run the spindle at any given speed using the below example code:

For example, for a 12K spindle enter this program in MDI mode:

M03 S12000;

Press [CYCLE START].

3

How to take Vibration Displacement plots:

When taking measurements you can select the range of Cycles Per Minute (CPM) that you can see on the graph.

When viewing the Displacement Plot you want the range to include the spindle speed in which you are running the spindle, since that is where you will see the spike of vibration at.

For most Displacement measurements this will be in the range of 0-33000 CPM.  However if you're testing a Compact Mill or Office Mill, you may need to switch to 30000-93000 CPM since the max speed of some of those spindles can be as high as 50,000 RPM depending on the spindle option.

Select the CPM range you need.

Run the spindle at the desired speed.

Let the vibration spike settle once the spindle reaches the speed you commanded (about 5-10 seconds).

Capture a screenshot.

 

4

How to take Vibration Velocty plots:

For the velocity plots you will need to take multiple screenshots at different CPM ranges.

You will need to change scaling and unit settings:

  • Y Axis>
    • >Unit>Velocity
    • >Scaling>Automatic

Take plots at the following ranges:

  • 0-33,000 CPM
  • 30,000-93-000 CPM
  • 90,000-153,000 CPM
  • 153,000-213,000 CPM

Compare results to provided tolerances for Mills and Lathes below:

If your results do not look like they are passing please view the following troubleshooting guides: