Sheetcam and THC

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Re: Sheetcam and THC

Post by djreiswig »

Is your work clamp directly attached to the material? If it's on the slats that could throw off your cut.

To check if you have the correct volts, cut a straight line with the thc off and stop and measure the torch to material gap with a feeler gauge and see if it matches book specs.
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Re: Sheetcam and THC

Post by acourtjester »

Here is a video I created to show how to setup up the THC voltages for the different metal thicknesses. https://youtu.be/EyZJVMtzKzY
Now just so you know the first thing when starting a cut is to find the metal surface to have the correct pierce height for each cut. The THC only is active after the pierce is made and the torch starts to move doing the cut, not at the start of the cut operation.
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Re: Sheetcam and THC

Post by weldguy »

When I see heavy dross I speed up the cut feedrate, moving the torch faster will put less heat into the plate and help to prevent the arc from "wandering" and removing more material which equates to more dross. Proper speed should have very little dross or none if all your moons are aligned.

Keep it simple. Looks like you have multiple issues here so simplify and go one thing at a time. Don't bother to dial in the THC until you have your machine making awesome cuts without the THC and you have confidence in that.

Find the cut feedrate that works well for the material your cutting first. Do straight line cuts at manufacturer specified cutting height with the THC off and with each line you cut you want to speed up the feedrate up a little and find the speed that is too fast and can no longer cut through and then back it off a bit, should be very little dross on your cuts. This will be a good cut speed.

Now do some small test circles using 60% of the speed you just determined to be good on the straight lines. Again keep THC off but be sure your cutting at the proper height. I use feeler gauges to measure the cut height, just pause the machine mid-cut and measure. Just because your software says .060" doesn't necessarily mean that it is so be sure to check. There will be more dross on the these holes than the straight lines but thats because were traveling slower at 60% of the best feedrate, should still look good though.

Once you have all this mastered turn the THC on and go back to your straight lines and begin cutting those until you find a THC voltage that will maintain the proper cutting height. If it all goes to sh@# wen you turn the THC on and you just can't get it right you know what the problem is. I have no experience with the THC your using so can be of no help there but these other guys seem to be in touch with it.

Best of luck!
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Re: Sheetcam and THC

Post by mkingaz »

So pretty frustrating night. Worked on the table (tuning) for over 7 hours. I finally disconnected the SD promo and was just getting the table to cut at .06 on my setting and manually measuring it many time's across a sheet of steel before cutting. Tested it 5 times with NO arc. All looked good so I decided to try to cut the welding table with multi holes and small squares, 7 peirces in it screwed up and looks like it did not have the right eight, did not piece through, molton steel in the cut and I killed it. So freaking frustrating, many lesions learned today. I wired the promo back up to see if I could cut small steel 16 ga, and I can get away from it but the table simply is not right.

I''m cutting hot rolled sheet metal at 1/4 inch, do I need to have the shielded cap for beginners to keep the slag off the tip? It seemed like that's what screwed me the most. The .60 cutting height is tight with no THC. I tested several straight and circle cuts prior to making the cut. I felt like I did get a good cut but my circles still where no perfect round, seemed almost oblong. I measured with a caliper and I was from 4.3 to 4.7 in cuts on a .50 round cut. Considering the Kerf I would have expected the circle to be bigger. I tried speeds from 20-48 imp.

Its damn hard for a new guy that purchases a table like this to understand it all and put all the pieces together for a smooth machine when I can't even get it to par. Sucks, I don't know anyone local to ask for help.

Ok, enough crying, I need to figure out my next step. I realize I should be able to get the machine to work consistantly without the THC and will work on that first. Smaller gauge material I think it just cuts through the issues, the thinker stuff and it magnifies. However, I'm thinking throw this SD Promo in the garbage and order the CNC PRICE AVHC10. Is this the best THC for the price range to put on my Premier Plasma table? I watched all the video's on this unit today and it seems like it works with Mach 3 (I'm using) and you have some adjustments that the SD Promo simply does not have.

Any advice would greatly be appreciated. If anyone is local in Phoenix, I'd be happy to pay for some help onsite?
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Re: Sheetcam and THC

Post by acourtjester »

Do not feel bad many have complained about the Proma SD, I am using the Price AVHC 10 on my table and it works great. You will need to rewire your setup, the wiring is shown in their manual. The wiring diagram is shown in his ad for the unit. the video I posted above is using the Price unit.
You may need to get a wall wart for powering the Price. I have a Hypertherm 65 and use 45 amps with a shielded 45 amp nozzle at 48 IPM, I would think the 45 XP would be the same. If you feel you have mechanical problems with the circles out of round you may want to mount a ink pen and run your g-code and see what they look like. Just use a standard Mach 3 post processor with no plasma to mark you parts on paper. There are posts here about doing that to check the table movements.
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Re: Sheetcam and THC

Post by weldguy »

Man that sucks but don't let the frustration compound the problems.

Should be able down to cut 1/8" material without THC with no issues, wouldn't go thinner without THC as the warpage will create even more issues for you right now. Your 1/4" should be easy to cut.

Shielded caps are helpful but really shouldn't prevent success with what your doing, I would't run out and get one in hopes of getting back to the shop and having better luck.

Bad cuts and oblong holes are 2 different things. Which one do you want to solve first? I would fix the oblong hole issue as it may be an indication of something loose on your machine like a pinion gear.

A plasma cut hole can look oblong despite the machine moving in a perfectly circular motion. To determine if its something loose get a sharpie marker and some electrical tape and tape the marker to your machine torch and have the machine draw various size circles small to large and measure them to confirm machine motion is OK. Be sure the tape is stretched tight and the marker isn't wobbling during this procedure. If you have an Easyscriber use that for this exercise instead of the Sharpie.

If you find something is loose fix that first and then move to the next step of cutting holes and we can work through those issues. Don't even bother trying to cut something useful at this point, just focus on getting everything correct first and you will learn a lot while doing that.
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Re: Sheetcam and THC

Post by mkingaz »

Weldguy much appreciated. Headed home to get a sharpie on the table.
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Re: Sheetcam and THC

Post by mkingaz »

So I decided to check everything on the table since I put it together. I was actually surprised, I did have my Y motors were slightly lose, some play. I went through the entire table to make sure everything was tight and clean. I unplugged the - + wire on front of my SD Promo and cut these holes. I measured them with the caliper and right on the money.

Now I'm not sure what's next. I already screwed up a half sheet of 1/4 that I was going to use for a welding table so now I'm thinking go ahead and cut same holes in this 1/4 and see what it looks like no THC.
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Re: Sheetcam and THC

Post by mkingaz »

Wow, making progress. Holes look excellent in my opinion. Be nice to get another opinion on them? I put a caliper on them and they are all very close.

So I feel I have the table working again but not sure what to do with the THC. I'd like to get a nicer one that work with this Premier Plasma table. My biggest issue is I have no idea on the electronics in the box. I will try to txt Jake the builder but not so sure I get the answers back, he's seems to be extremely busy in his own life. I was thinking of the Price AVHC10.

Now to figure out my next move. Any suggestions?
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Re: Sheetcam and THC

Post by mkingaz »

ok, so cut same file with SD Promo on at 90 volts, all other settings the dame. Looked ok but I could clearly see the Promo diving into circles after start. I believe this is because they are simply too small. Bad thing is I cannot turn off the promo. Cut got worse as you left the first large hole.

So I'm back to, I need a NEW THC.
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Re: Sheetcam and THC

Post by acourtjester »

There needs to be a slight delay between the pierce and the cutting operation, this is not the pierce delay, that is for the time to finished the pierce. This other delay is for the arc voltage to become stable before the THC start controlling the cut height, to soon and you get the dive of the torch, I think .5 seconds is good.
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Re: Sheetcam and THC

Post by weldguy »

Awesome, glad you checked over the machine, got everything tight and had better success!

Holes look mint, I wouldn't think you could expect much better that what your getting with the THC off :Like

I wouldn't give up on your THC just yet, it sounds like your not too far out from success and just need some more time, I believe that since everything is working well now the next step is to give the THC another go.

Don't cut circles when testing the THC, cut straight lines. Small circles require a slower cut speed which will change the arc voltage and cause your torch to dive towards the material. Ultimately we want the THC off when cutting small diameter circles and anytime the cut speed is slowed down. Some machines will do this automatically, some will not, maybe yours will but lets worry about that later. Cut straight lines for accurate and consistent THC testing and to save on material as you can cut these lines very close together and waste less of your material.

Start with 24" straight line and set your voltage to what the cut chart says or slightly higher, be sure to use a good known cut speed, shoud be very close to the cut charts suggested sped. The purpose of the THC is to maintain a consistent cutting height and thats all we want to see at this point.

If your using Hypertherm you will want a .060" cut height, stack up some feeler gauges so you can measure this. Begin cutting a couple inches of your first line and pause the machine mid-cut. Measure with the feeler gauges. If your too low increase your arc voltage 2-5 volts, if your too high off the material decrease the arc voltage 2-5 volts. Resume cutting a couple more inchs and pause again to recheck. Find the arc voltage that allows you to maintain the .060" cut height and write this down as the known good voltage for .250" material on your setup. If you change the material thickness or cut speed you will need to do this check again, one voltage value does not work for everything, you need to find what voltage works for all the materials you plan to cut and build your own chart for future reference.

As for diving at the beginning you may simply be seeing the torch go from the pierce height to cut height. Typically we pierce higher than we cut so once the pierce delay has elapsed and the torch begins XY motion the THC takes over and lowers the torch to the correct cutting height indicated by the voltage we just figured out.

Play with this for a while and see what happens. Maybe your THC is junk but at least take another stab at it. Good luck.
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Re: Sheetcam and THC

Post by mkingaz »

Excellent help here guys thanks again. I'll try a few straight line cuts this morning.

I did cut a 5" by 31" art project on 16 ga last night with the THC on. It cut the project but it really pushed through it. For the first time I used the book setting and that was about twice as fast as I have been cutting. Seemed really fast but no dross on project except in tight turns and super small spots. I notice the torch would not raise fast enough between cuts and I had to manually lift it twice or it would have snagged the project. I also measures the cut height prior to fire and after and I feel I have the piece and cut height correct. The issue was the THC would lower into the project as it was cutting and on the bigger cuts actually dragged. I tried to increase volts and see what happens.

I'm really still thinking I would like a THC that has adjustments and some basic instruction that are much better than the SD PROMO. I watched all the videos on the Price CNC THC but I'm not a computer guy and have no idea brand, make or model of mother board and electronics. I was going to try to reach out to Price and see if they can help. Just seems like this THC has does several major things, communicates with Mach 3 and has adjustability. I'm just not use if it is compatible with the Premier Plasma electronics. I thought I would add a few pictures here of what I can see? If anyone has an idea if the Price would work that would be great.

I do feel like I'm making progress with all your expert help. Thanks again.
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Re: Sheetcam and THC

Post by acourtjester »

The board with the red leds is BOB board and is a common one you would rewire the connections from the BOB to the Z driver by removing the wire to the SD. they would be hook up like the ones for the X and Y BOB to drivers. The Price would get the arc voltage signal from the Plasma unit and would send 3 signals to the BOB. Arc Ok, torch up and torch down these would go to the BOB board inputs and the software will direct then to the Z axis to move the torch as needed. this is not the same but similar BOB.
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Re: Sheetcam and THC

Post by robertspark »

mkingaz wrote: Fri Dec 20, 2019 11:16 am, communicates with Mach 3
The price CNC avhc does not communicate with mach3
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Re: Sheetcam and THC

Post by mkingaz »

Great to know, I think that's an important part of cutting nice parts, yes? Or, an I getting confused as to wanting this unit to communicate with sheetcam to set path rules and such. Control the THC for better quality cuts.

The SD Promo is a pain. I'm actually sitting on the table now making 24" cuts trying to get the volts correct.

Do you recommend a good THC without breaking the bank?

Thanks Robert
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Re: Sheetcam and THC

Post by mkingaz »

I also just scanned your old thread list of THC, wow way over my head on tech. I'm very new to CNC Plasma world and just trying to get some quality cutting and learning completed. I still think the SD is the most basic THC possible. I would not investing a little money for a better unit but I guess would I really get my money's worth?
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Re: Sheetcam and THC

Post by mkingaz »

Did several cuts today. working on 16 ga right now. I used the same part over and over, changed the pierce delay and got that very close to book setting. Speed seems way to fast, smaller part. Went from 80 volts to the 128 volts per book on the SD Promo. 80 being to slow and torch slowly drops into sheet of metal, 128 being entirely too fast. At about 90 it was close but I don't think the SD Promo can really hold the right .06 cut height as the torch is making moves, curves, bends etc.

The good news is I'm cutting again and can make it work. I think getting it to cut like it should and tuned in will just take time. Thank you everyone for the help. I'm still going to research a better THC.
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Re: Sheetcam and THC

Post by acourtjester »

The price CNC avhc does not communicate with mach3 OH really! now SheetCam I agree
this is from their manual
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Re: Sheetcam and THC

Post by robertspark »

acourtjester wrote: Fri Dec 20, 2019 4:51 pm The price CNC avhc does not communicate with mach3 OH really! now SheetCam I agree
this is from their manual
mach.JPG
Sorry but up, down and arc ok does not clarify as communication with me...

If you are running mach3 via parallel port then ok... It sends signals to the pc which the parallel port mach3 driver responds to directly..... If you are using a motion controller then THC is handled directly within the motion controller and has zero communication with mach3 because of latency handling the signals.

If you want a THC which is of similar cost that does do communication with mach3, mach4, uccnc.... Or any other plasma controller compatible software then the miniTHC does RECIEVE communication from mach3 etc.

It uses what Denis called "c-axis protocol" in the manual.
Basically it uses one of the spare axis that you don't need to use to send a series of pulses which allow you to set the THC signal delay (if you wish to use it) but more importantly it allows you to SET the THC voltage on the torch height controller from within the CNC software or even directly from sheetcam so you can save your THC with the material in sheetcam and send it with gcode to the machine.... That you cannot do with the priceCNC.

And it is so simple it can be done with any motion controller software
Have a look at pdf page 29/38 of the manual below.

https://minithc.com/pub/MiniTHC2_EN.pdf

That is "Communication" as it is bi-directional and you send the relevant signals to the THC (voltage and THC delay) to the THC to act upon.... You don't have to fiddle with it and remember your settings from last time on a bit of paper when you change material thicknesses .... Issuing thcup/DN and arcok is not communication.... It is just issuing digital signals... I would say it is the MOST basic form of communication for any THC

I'm a hobby user... I don't use it every day week or even month.... Same with my welders, the best welder I have is a synergic mig welder (ESAB Caddy c200i. https://mam.esab.com/assets/1/3B26C7364 ... ain-01.pdf) where all I have to do is set the thickness and pull the trigger and it gives me good welds every time, and I may not use it for months, but within a few minutes on a bit of scrap I can get good clean welds before I have to do the weld job I need to do which for me is what it's all about.... Using the software to store the settings and share them with the device and all indeed to do is tell it the material thickness and press the start button.... No need to remember or check the THC voltage setting
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Re: Sheetcam and THC

Post by robertspark »

mkingaz

What is the acceleration setting for your X and Y axis within mach3?

What are your steps per unit setting for the X and Y axis within mach3?

Do you have a motion controller?
How are you interfacing the pc with the breakout board?
(Does it use the printer port or ethernet cable??? Very important before buying a THC... As not all motion controllers do THC!)

(I may have asked these questions before, sorry i speak with so many users I loose track of who or how many i may be trying to help at once.... )
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Re: Sheetcam and THC

Post by acourtjester »

Communication
Description Communication is the act of conveying meanings from one entity or group to another through the use of mutually understood signs, symbols, and semiotic rules. The main steps inherent to all communication are: The formation of communicative motivation or reason. Message composition. Message encoding.
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Re: Sheetcam and THC

Post by Steviem077 »

Hi there could anyone help me im running an hypertherm HPR130 wit a soitaab interface it works on .ISO files instead of .Tap what should i be putting in the post productions instead of mach 3 as i cannot find my brand of table or controller in sheetcam is there any way i can over come this it was working fine using lantek but its very pricey was wondering if i could achieve the same with sheetcam
Thanks for taking the time to read
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Re: Sheetcam and THC

Post by plasmanewbie »

Thats a tough one. Your likely best to contact Les at Sheetcam and see if he has a post for you. Good luck
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Re: Sheetcam and THC

Post by djreiswig »

Can you post a sample code for us to look at?
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