Plasma THC being turned off on small arcs, why?

[ae_mike]

Every Masso/Sheetcam post processor I've read thru turns off the THC at the beginning of a small arc move. That appears to pause the movement of the torch causing some dross at times. Does anyone know why you should need to turn the THC off for small arcs? I've thought of just modifying my post to remove those commands but haven't and thought I would ask the forum to see if anyone knows the reason behind it.

Thanks

Michael

 

[cncnutz]

Hi AE_Mike

THC's can crash the torch into the table when they slow down to cur small arcs. The stop this the THC turns off at the start of the arc and back on once the arc is completed

This is what is causing the hesitation.

If you have a look at this thread here Ross have modified the Post Processor in sheetcam and it seems to have eliminated the issue for him.

Search results for query: sheetcam-post-processor-with-working-thc-codes-fixed/

www.masso.com.au

Also see this post

Search results for query: masso-plasma-proma-thc-150-correct-wiring/

www.masso.com.au

It may solve your issue.

Regards Peter

 

[ae_mike]

Hey Peter,

thanks for the reply, I have reviewed Ross's code in the past, his "trick" is to make the cutoff size for the radius slow down equal to 0.1mm and the slow down speed to be 100% of full speed, basically he has eliminated the THC off for all radii. From a practical point of view, if you are cutting radii at full speed and you have the THC speed set to something reasonable, there shouldn't be any reason for the THC to go crazy while going around a curve, it is just another move. Time to just update my post and remove the THC for the arc command completely and give it a try.

Thanks,

Michael

 

[cncnutz]

Hi Mike,

At present turning the THC on and off causes hesitations in movement. When Masso sees an instruction like M667 or M666 it moves to position, turns on or off, then moves again. We had a discussion on the forum about it late last year and while Masso is working as it is designed but it isn't working as maybe it should for the user and for Plasma in general.

The good news is I found out today that there is a software update coming that should fix this hesitation issue. If you are interested in testing a pre release version and offer your feedback please post your Masso serial number here and I will add it to the list. I'm not sure when the test version will be ready but I'm just collecting a few names at the moment. In the meantime Ross's solution is probably the best option and it seems to work well for him.

Cheers Peter

 

[ae_mike]

5A-3110

thanks Peter

I'm going to use Ross's method this weekend and recut a part that had some cut/dross issues at a corner to see if there is any improvement

Michael

 

[Ross]

Michael let me know how the cutting goes and what you think of my work around.

eg; happy or not with the holes and sharp turns?

Post some photos!

Ross

 

[cncnutz]

Hi Michael @ae_mike

I have attached the test file for you to try. You should find the pausing with the Plasma turning on and off have stopped but you will have to go back to the original post processor to generate the code that turns on and off the THC or you won't see any difference. There is one other change that may or may not affect you and I wrote a little readme file to explain it.

Out of curiosity do you use metric or imperial for your Gcode?

Cheers Peter

 

[ae_mike]

Ross & Peter,

I tried Ross's trick on some house numbers for a friend, 12" tall and full of small arcs and line segments. None were smaller in radius than my 1mm cutoff in the post so the torch cut all the way around with no pauses. Probably the nicest surface finish I've seen in a while though I had just changed the nozzle and electrode. Below are some pics of one of the parts. What little dross is left chipped off easily. I've changed my default post to use this routine, mine has a 1mm min radius but still has a 70% slow down. I don't normally use any radii below 1.5mm

Peter,

I'll download the zip and look thru it. Not sure when I'll be able to test it, buried with work and tomorrow's Mother's Day so have family stuff most of the day. I design in both inch and mm but I have my Sheetcam and Masso setup in inches, more out of habit than need.

thanks for the assistance,

Michael

 

[Ross]

Michael the update from the 7th May, makes the plasma bounce along like a kangaroo!

Peter sent me a new test yesterday so i will see if it works, maybe tomorrow.

Ross.

wire cup brush for grinder will rip the dross off quick!

 

[cncnutz]

Hi Michael,

My apologies. Please ignore the previous version of software. As Ross mentioned it has a bug in it that causes the torch to bounce like a Kangaroo.

Must be the Australian version. ;-)

I haven't got a new software version to pass on to you for testing but it looks like you have it cutting well at present with your current settings

Cheers Peter

 

[cncnutz]

Hi Michael

I have attached a new test version of the Plasma software for you to try. This one should not bounce around the table like the one Ross tested and should not give you the pauses you were experiencing initially.

Please let me know how it goes for you.

Cheers Peter

 

[lilow]

You do not need to slow down the cutting speed on small arcs.

You do not need a slow down into corners.

When the parameters are set, there is continual cutting.

Where did this idea come from that everything needs to be slowed down for corners or arcs ??

 

[Ross]

Hi Lilow,

This will set your ignorance straight. How about you engage your brain before making comments, You all ways seem to put people offside on this forum but they are to polite to tell you.

Just try to change your attitude,

I myself don't need to be working with others from Masso to try to get the best out of their machine. I do it so it can benefit other plasma users.

This comes from the Guru himself "JIM COLT from Hypertherm" and has been the standard for 20 odd years!

https://www.hypertherm.com/support/system-support/maintenance-and-use/cut-quality/hole-quality/

 

[cncnutz]

Hi Michael @ae_mike

Just wondering if you had a chance to try out the test software version, (post 11), and if you have did it solve the pause issue you originally noticed when the THC turned off?

Cheers Peter

 

[lilow]

Yes, it does.

I found that the bounce comes from the Masso.

Cheers.

 

[ae_mike]

hi Peter,

Sorry I haven't gotten anytime on the fun projects over the last few weeks, paying jobs have kept me fully loaded. I'm hoping to get to this over the coming weekend.

thanks,

Michael

 

[segoman-designs]

Quote from Ross on May 22, 2020, 10:37 pm

Hi Lilow,

This will set your ignorance straight. How about you engage your brain before making comments, You all ways seem to put people offside on this forum but they are to polite to tell you.

Just try to change your attitude,

I myself don't need to be working with others from Masso to try to get the best out of their machine. I do it so it can benefit other plasma users.

This comes from the Guru himself "JIM COLT from Hypertherm" and has been the standard for 20 odd years!

https://www.hypertherm.com/support/system-support/maintenance-and-use/cut-quality/hole-quality/

Ross,

Where the hell did that comment come from?? With a little searching on the forum it is easy to find your posts when you were having the same problems as everyone else and fried a controller as I recall. I appreciate the fact your helping others now that you have your system running but posts like the above is childish.

Perhaps it is you that needs to engage your brain prior to posting, all I have seen you produce with your table is some nifty garden art, Lilow took on the THC problem that Masso promised us over 2 years ago (I quoted their original comment in another thread) yet it STILL has not appeared. Features like on the fly height / speed adjustments, rip cuts and a basic shape library are on cheep Chinese made units that cost 1/2 of what Masso does

Lilow has posted pics of some very exotic machinery he is assembling and custom rod frames he build, I guess those of us that make a living off of their endeavors see things from a different perspective. Take your build thread and know it all attitude over to P Spider or CNC Zone. Be sure to give us a link as I want some frosty's and popcorn on hand when they pound your ego back into the little frog pond it come from.

 

[cncnutz]

Quote from AE_Mike on May 28, 2020, 8:55 am

hi Peter,

Sorry I haven't gotten anytime on the fun projects over the last few weeks, paying jobs have kept me fully loaded. I'm hoping to get to this over the coming weekend.

thanks,

Michael

Thanks Michael, good that you are busy.

Cheers Peter

 

[Ross]

Fine tuned the on/off and slow down on corners.

Plus Modified a few more settings in Masso and SheetCam and have come up these cut results.

Very happy with the cut quality NOW!

Will paint tomorrow, then post them to a friend that lives in Thailand as a gift.

 

[cncnutz]

That came up really good Ross. Nice clean cuts from the looks of it.

Cheers Peter