Tool measureing feed rate

[Eric Montbriand]

Someone metioned to me (a boss) that the Z axis feedrate should be increased because it was going down to the sensor so slow during tool measureing. I tried to explain that it's a Thermwood setting and probably shouldn't be messed with. Is it possible or safe to change, or should those settings be left alone?

Thanks

[David Hall]

It's actually not a feed rate, but a feed increment that makes it appear so slow. Move down, check if we hit the sensor, move down, check if we hit the sensor... 1/10\" increments if I remember correctly.

I've toyed with the idea of putting one big move at the beginning of that program but I'm not sure it's worth the time or risk to my tool sensor if I mess it up. For sure one day I'll load a tool that's too long for that first big move and bam! good bye tool sensor.

But now you've got me thinking and I'll let you know if I take the time to figure it out.

Regards,
Dave

[Brad McIntosh]

Most of the time what makes the whole measuring process seem to take forever (and it really doesn't but...) is the starting location in Z.

It is possible that the variable in the M999 that tells the control where to drop down to in Z before starting its initial step down loop is 0 or other small value.

This variable is usually set so that the LONGEST TOOL still clears the sensor switch BEFORE going into the initial step-down loop. If you have a Drill Bank or measurable aggregate tooling, the LONGEST TOOL would represent whichever drops down the lowest in Z when active!

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Now before I begin - Messing with this variable and not doing it right can drive your tool/head into your sensor... possibly knocking it off.
MAKE SURE YOU FULLY UNDERSTAND WHAT YOU ARE DOING! I TAKE NO RESPONSIBILITY FOR DAMAGE.
If you don’t understand... don’t touch!!
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1. Start a measurement of your LONGEST TOOL.

2. As the head/tool moves towards the sensor in X & Y use the feedrate override knob to slow it down a bit.

3. As the tool performs its decent to the tool sensor, slow it down even more and glance at the ABSOLUTE Z readout (the column on the upper far right of the control screen) on the control when the tool is about where you would like it to begin its incremental downard stepping cycle. (You can turn the feedrate right to ZERO to \"pause\" the decent, if required.) Make a note of this absolute Z measurement. Then turn the Feedrate Override knob all the way up and let the measurement cycle complete.

** You may want to perform #3 above a couple of times to make sure of your \"future\" absolute Z starting point.

>> Make sure you will still have some clearance and that you consider any possible tools that you MAY use in the future that may be longer than what you are using for this \"calibration\". Be somewhat liberal with the clearance that you are leaving. Remember we want to reduce the measurement cycle and NOT BREAK ANYTHING!

4. Edit the M999 and look for the section that defines the \"Tool Measuring Sensor\"...

( **** TOOL LENGTH MEASURING SYSTEM VARIABLES **** )

( * FIRST SWITCH * )
:
~SET LENCLEAR=0.000 (Z ...., A.M.T.L. START POSITION)
:

Change the LENCLEAR variable to reflect the Z you determined in Step #3. (Although the value on the screen was negative, just enter the positive value. In this case the machine knows that this is an ABSOLUTE Negative Z position.)

Make sure to save your changes to the M999 and then go and test it.

Be careful and happy measuring!

[David Hall]

Thanks Brad!

Regards,
Dave

[Eric Montbriand]

Thanks guys!


Eric M