How to stop the machine when tool breaks

[Deepukj90]

Hello, 

I am doing a project about Process Monitoring in Milling Machine.  I could able to get the signals and process them using the DAQ Assistant.  But Now i want to stop the machine once it has detected any tool wear in the machine.  Could you please give me some ideas how to control the machine using Labview or some other ideas.

Thank you

Deepu

[Hooovahh]

• Try giving as much information about the conditions of your question.  Things like: What version of LabVIEW are you using? What operating system are you using? What hardware are you using? and What sensors are you using? are a few common ones.

Source

You give us far too little to go on.  There are many solutions to your question, they might all be right, none might be right.  My initial reaction is to suggest a producer consumer loop where one loop is polling DAQ hardware and then have some post processing to see if the tool broke, and if it did then send a message to the other loop to perform clean-up and shutdown properly.

[Deepukj90]

Dear Sir,

Please find the information below.

Labview Version : 14

Windows OS

Sensor: Accelorometer Sensor

Procedure which I am Following:  

1) Sensor is connected to the Tool --> DAQ --> Filter --> Mask and limit Testing --> If the frequency exceeds from the normal Cutting Tool Frequency the Milling 

machine should be stopped automatically.

Please advice me what can be done to stop the machine automatically using LabView.

Thanks

Deepu K J

[Dennis_Knutson]

How are you communicating to the machine itself? Please describe the physical connection and the protocol. You say you have working code for the high frequency detection so the shutdown could just be inside a case statement.

[natasftw]

Is there any reason you can't share what code you have so far so we can see if there's an easy way to implement the change to your code?  Depending on your architecture, it SHOULD be easy to use a failed test to trigger a shutdown.

[Henrik_Volkers]

All milling MC I know, have an emergency STOP button that run a current loop. Open the loop and the MC stops. (Usually the hard way, like stopping a car by putting a tree over the street , or hitting the red STOP button in the menue of a running LV program 😉 )

So all it will need is a relay with a NC contact in the current loop.

Draw back: Your car might be broken after a emergency-tree stop....  so talk with the owner of the milling MC how he want's the MC to be stopped.

The best way would be to detect a wear before you need to stop the MC and alarm the user that a change is needed in the close future!

[Deepukj90]

Hello,

Right now, I dont have architecture.  Sorry for that. Please find the method which I am following.

Acceleration Sensor is connected to the Tool of Milling Machine.

We will take the frequency using the DAQ Driver

Then Filtering it.

Then Mask and Limit Testing.

In this, i set up an frequency as a limit. If the frequency is higher than the normal, the machine should stop.  This is my requirement.

Still Mask and Limit Testing, I am pretty much clear.  

When I have the frequecy which is not normal, How to use Labview to control the Milling Machine.

Is there any Physical connection need to be established.

or Any driver need to be installed.

Thanks

Deepu 

[Dennis_Knutson]

Of course you need some sort of physical connection. How else would you control the machine? Have you read Henrik's answer for a crude way to stop it? Are you at all familiar with the equipment? It doesn't really sound like you are.

[johnsold]

I worked on similar projecst in the early 1980s (before LabVIEW).

The first thing you need to do is to characterize the accelerations you measure. Learn how they vary with tool speed, feed rate, type of tool (single or mutliple cutting surfaces, inserts, ...), rough cutting passes or finish passes, different materials, voids or cracks in the material, tool lubricant, and probably a dozen more. Decide what kind of tool wear or breakage is to be detected. Then characterize the accelerations in the presence of those broken or worn tools over all the other variations.  It might be easier to use a vibration analyzer instrument for this part than to try to do it with LV, particularly since you seem to have limited familiarity with this kind of measurements.

With that information you design or select an algorithm which (you hope) will allow you to detect the worn or broken tool.  If you are successful at the detection process, then you can decide how to respond.  A worn tool may just require a notification to the operator to change the tool at the next convenient time while some kinds of breakage may require a shutdown within a few seconds or even less. Is disabling the spindle drive sufficient or does it need to be actively braked? What about the feed and lubricant pump? Will the part being machined be salvageable or scrap? Does the machine tool program need to be restarted after a tool change or does the operator have to do a new setup?

Lynn