Help with Peck Pierce

[cdindustries]

Trying to set up peck pierce for marking hole centers for drilling later.
Problem I am having is, torch moves to first point, raises to 1.0 and dry fires, then moves to .120 height but does not fire again, moves to second point and fires at .120 (perfect dimple), moves to third point torch goes to .120 and does not fire, moves to fourth point and fires at .120 (perfect dimple).
I can't figure out why it is skipping the first and third peck. Any help would be greatly appreciated.
Post proccessor is 27E.
Running Command cnc.
I have attached a copy of the code for this part below.
Thanks in advance. I also have this posted on the candcnc forum, but no replies as of yet.

railvac post.pdf

[cdindustries]

So I did some further testing today, and have determined that the torch is not firing so long as post flow air is flowing. Seems strange because this is not a problem with regular cutting. If I manually pause the code in between pecks, until post flow stops, and then resume, it will hit all the pecks. Would like to find a way around having to pause the machine after every peck.
Power source is a Hypertherm Powermax 85 if it makes a difference.

[TJS]

I could not get this to work for the life of me. I even posted like you did over at CandCNC form. Then I found a vid on this from ArcLight Dynamics. I followed the exact steps in the vid and mine did work.

https://youtu.be/9tVllW1Yu1I

[acourtjester]

I have created a tool in SheetCam for center punching where I want holes to
be drilled. This is run as the first part of a cut to make where I want
holes then it cuts the parts. SheetCam will identify all center punches and
do them first then pause for me to change the plasma amps and make all the
part cutouts Here is what it looks like doing center punches before cutting.
https://drive.google.com/file/d/1-itiRk ... sp=sharing
attached is an image of a center punch temple I made for drilling holes for
the linear slide bearing I plasma marked the plate and use it for center
punching the aluminum plate for drilling.

DSCN3469.JPG

DSCN3181.JPG

In SheetCam you do the cut plan as normal setting all center punch location
as a layer (center punch name) with a no offset as the first part of that part’s cut operation. Then with
the last part to have center punches planned then you enter the “table
Pause” snippet then the cut operation for rest of that part. And any other
types of cutting you want to do for the whole operation plan. SheetCam will
automatically separate all the center punch locations and set the G-code to
do that operation first the pause the table for you to change the plasma amp
setting to the cut amps. You hit cycle start and it will then complete all
finishing cut operations.

centerunch tool.JPG

center punch2.JPG

When doing the DFX I mark all the center punch locations on the drawing as a 0.001" circle the show up in SheetCam as a +
in conture change them to another layer first when planning each part to be cut, and that being the first operation of that part.

[plasmanewbie]

AC's the best

[cdindustries]

Thanks for the replies TJS, and acourtjester. I found the video from arclight dynamics last night. That setup is working well. The divots for that method are a little deeper than i would like ,but it will work. Thanks again for the info.
Chris.

[robertspark]

Thanks for the replies TJS, and acourtjester. I found the video from arclight dynamics last night. That setup is working well. The divots for that method are a little deeper than i would like ,but it will work. Thanks again for the info.
Chris.

you could raise the torch above pierce height.... that will lessen the dimple

disable thc and arc ok so the torch fires as fast as possible and does not wait for arc transfer... then add a delay to increase the dimple via G04

although not your plasma cutter, page 138 is useful as it gives a pierce height of 1/4" and 50 msec delay.... very fast 0.05 sec

https://www.google.com/url?sa=t&source= ... fXUFBZFeKl

the dimple / marking consumables are a little different than the standard consumables as they have a slightly larger orifice and some air bleed ports on the side of the retaining ring indicating the airflow velocity out of the the nozzle will be slightly less given the air pressure is unchanged as it would be needed for blowback start which. lessens the effect of the plasma arc I guess and gives it the dimple effect

[cdindustries]

robertspark, Thanks for the link, and the information. It is very helpful. Since I am not the type of person to leave well enough alone, I had planned on doing some testing with different heights and times as well. I will get it dialed in and post the results that work the best for me.

[robertspark]

one thing to watch is most plasma users report the first pierce is always larger than all others.... I suspect (but do not know!) this may be because the electrode and shield are cold also the blowback spring may also be "hard" and once the first pierce and cut is out of the way then there is a bit of heat in the parts plus the electrode will be unseated (broken the seal)...and some thermal expansion of electrode, orifice and swirl ring plus the hafnium

something to just be aware that you probably want to do some cutting before testing pierce and dimple functions

[acourtjester]

I do my center punch at 20 amps lowest setting to the PM 65 I have and as robert said I place a first punch outside of the first part, or in the middle of a dropout. I use a standard post processor with THC active to have the torch at the correct height in case of warped metal.

[cdindustries]

I am doing the drill marks at 25amps, stadard post processor just like acourtjester mentioned above. I have not noticed any difference in quality between any of the marks. They are all nice round dimples just a little deper than expected. I may just stay at the settings I have now. It should work out just fine for what i need.

[Jason@bc]

I can't get my peck pierce to work at all, only with finecut consumables, it used to work not bad a year ago or so, but now it pierces all the way through, not even close to a peck, have tried everything but no success, any suggestions.