Tag Archives: cnc electronics

Powering ON / OFF Your CNC — The RIGHT WAY !!

Believe it or not … there is a RIGHT and WRONG way to turn the power on and off to your CNC equipment at the start and end of the day. And the difference can mean increased life for a lot of the electrical components at the heart of your equipment.

During my 20+ years as a field service engineer for Mori Seiki and Yamazen USA … the first thing I taught clients when they received their new CNC machine was the correct way to power up and power off. I knew from my experience that even this little lesson would bring big dividends over the long haul.

The main idea is to dissipate power or bring power on line in an orderly and limited manner. Big power boosts or cuts can damage delicate electrical components over the long haul and can even mean damage in the short run that will eventually lead to big failure.

Let’s start with the power OFF routine …

We’ll start with the power OFF because power on is the exact opposite. So we want to get this done right first off.

The WORST thing to do is to simply cut the power using the breaker on the machine. This creates a huge power vacuum all at once … not a good thing for delicate CNC electrical components. That breaker or switch  usually look something like this …

At POWER OFF … my recommended process is :

  1. Hit the big RED button … E-STOP is #1. This will kill the power to the motors and lock the axis movement preventing any axis jumps due to a bigger power cut. The E-STOP circuit is designed specifically for this type of power cut.
  2. #2 — CONTROL POWER OFF. Next up press the power off button for the CNC control. This will now kill the power to the CNC control components and control panel in an orderly manner. Again … that’s what the control off circuit is designed for.
  3. LAST — turn off the circuit breaker on the machine. Not the panel on the power box at the wall of the shop … the one at the machine. This will be the final power kill but at this point on limited items are still powered up and running.
(1) E-Stop
(2) Power Off
(3) Main Breaker

This is an orderly process that will turn the power off and dissipate power from the components in an orderly and minimum manner.

 POWER ON … the exact opposite :

  1. MAIN BREAKER ON
  2. CONTROL POWER ON
  3. UNLOCK the E-STOP (which was depressed at power off) … once that is unlocked the power will automatically return … although on some circuits you may need to  press the CONTROL POWER ON again once the E-STOP is released.

Should I Even Bother To Power Off My Machine ?

I know a lot users don’t even bother to turn the machine off … they just keep it powered on continuously.  I also know a lot of thinking here is that the power surge to the components is worse. Yes … that’s true if you just kill the BREAKER as your power off routine … but if you use the process I outlined here you will not adversely effect your electronics with power off … and you’ll save a TON on your electricity bill !!

Hope you found this article useful …
Happy LONG and PROSPEROUS Chipmaking !!

Kenney Skonieczny – President
Kentech Inc.

Deciphering M CODES for Your CNC Machine

Recently we have been working with some Kipware® conversational clients assisting them in setting up their Kipware® post processor blocks for their G code output. With the addition of our EIA MENU option … users now have greater flexibility in using machine functions ( M ) functions in their G code to accomplish specific tasks. One example might be … parts catcher UP or DOWN to catch a part being parted-off … or chuck OPEN and CLOSE during a bar feed operation … or 4th axis CLAMP and UNCLAMP for CNC mill.

During these sessions we are coming across the situation where the end user doesn’t know the specific M for their machine to accomplish some of these tasks. And for whatever reason … manuals lost or misplaced … machine was purchased used and no manuals were included … or whatever … the end user does not have any Operator or Programmer manuals for their machine which would normally outline the M codes and their function. Without the manuals … they have no way of finding out what M functions control what. OR DO THEY ??

Let’s start this journey with a brief explanation of the HOW’s and WHY’s of CNC M functions. 

  1. First … there is no “industry” standard for M functions. Although you might find that M08 and M09 or M03 and M04 work for most CNC machines … there is not an industry standard that says they must meet a certain criteria.
  2. M functions are designed by the machine tool builder … not the control manufacturer. So you may have (5) Fanuc controlled machines in your shop … some Mori Seiki’s some Hitachi some Leadwell … all with different M functions. Because the M function circuits are designed by the machine tool builder and not Fanuc.

With those basic facts … when you ask your buddy “What’s the M function to open the chuck?” … and he says “M11” … and it doesn’t work on your machine … now you know why.

So how can you find out the M functions for your machine WITHOUT an Operators or Programming manual?

One of the best ways is to use either the electrical or ladder diagram for the machine. Although most Operator or Programming manuals get lost along the way … mostly because they are not kept with the machine but rather float around the office or shop … electrical diagrams ( which outline the electrical circuitry of the machine ) and ladder diagrams ( which outline the logic of the machine ) are most often kept inside the machines electrical cabinet. Open up the doors and you will usually find one or the other or both.

Even if you’re not electrical savvy … the circuits are pretty clearly labelled and you can find say the CHUCK OPEN circuit and trace things back to find the appropriate M function. Again … because they are built and designed by the machine tool builder and their electrical outline is outside the realm of the control … these circuits are contained in the machines electrical documentation … not the docs for the control.

electrical_circuit_pic

electrical_circuit_zoom_pic

Above is a pic of an electrical diagram for a Shizuoka CNC vertical mill … with an exploded view on the bottom. You can see fairly easily even without any electrical savvy that the M10 command will control the 4th axis clamping function. 

With today’s more sophisticated controls … oftentimes the ladder diagram is available directly on the machine controls CRT. You can pull up the ladder and even search for the appropriate function command … but in other cases the “old fashioned” printed ladder can also usually be found in the machines electrical cabinet.

Taking a look at either the electrical diagram or ladder will usually result in some additional road or path to travel to find the appropriate M function on your machine. A simple execution of an MDI command is a good test to see what happens. The old Trial and Error method will open up additional doors or produce the desired results.

M functions are powerful options on your CNC machine that can help automate many tasks and make your manufacturing more efficient. Know that you know the trick to discovering the M functions on your CNC machine … why not peruse your electrical or ladder diagram and see if there are any you might be missing in your programming?

Like what you see?
Please visit us at www.KentechInc.com

Kenney Skonieczny – President
Kentech Inc.