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CandCNC torch height control compared to Plasmacam

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Dakotafig
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CandCNC torch height control compared to Plasmacam

Post by Dakotafig » Wed Nov 28, 2018 6:11 pm

Long time board troll, first post.

So, I’m building a table that will act as my cutting table now with the long term plan to be able to convert it to a CNC table down the road. I’m using the plans posted at precision plasma as a starting point but making some modifications to suit my needs a little bit better. I’m in the process of purchasing a plasma cutter so I don’t have to continue borrowing the thermal dynamics one I’m currently using.

So, I gave all of that not so relevant background to preface my actual question. I was originally sold on getting a gotorch setup and expanding it to fit my table. The selling point there was the absolutely marvelous THC, and dead simple software. I guess one other piece of information I need to throw out there is the fact that I grew up with AutoCAD and currently use draftsight (which is free). So I don’t need drawing capability in my CNC.

However, my qualm is I believe I have to spend $2000 for the advanced torch height control. I would also have to purchase the custom table size option, another $1000. So, I’m up to $7000 with the gotorch and software, and I haven’t even bought the rails etc.

So, I was looking into CandCNC servo drive systems, and it looks like THC is built into their Linux software. From a software perspective I believe I only need a few hundred dollars of stuff to have basically the same capabilities as the Plasmacam software. So, the real question, does the CandCNC Linux THC work as good as Plasmacam’s system?

If I’m understanding everything correctly I would be several thousand dollars ahead with CandCNC vs gotorch.

I will be using a Hypertherm 65 or 85.

Thanks everyone.

BTA Plasma
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Re: CandCNC torch height control compared to Plasmacam

Post by BTA Plasma » Thu Nov 29, 2018 10:39 am

CandCNC THC and integration works only as good as the code you send it. Most code is made in Sheetcam however there are other sources for good code. Plasmacam does not have a poor THC but they do lock out most parameters. CandCNC's THC allows you to tweak any and all parameters to obtain the best cut per material, consumable life and amperage. However having access to those parameters can send you down a rabbit hole and cause frustrations if you do not fully comprehend the dynamics of THC. It is the navigators system while Plasmacam does the driving for you. Depending on your level of commitment you should know this before deciding on one or the other.

tcaudle
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Re: CandCNC torch height control compared to Plasmacam

Post by tcaudle » Thu Nov 29, 2018 8:31 pm

Actually the DTHC, Now in the 5th generation, is a 48MHZ embedded processor based hardware THC. It is tightly integrated with the other control electronics and supports a lot of automation (like an Electronic Cut Chart) PID (loop feedback, and one of the fastest vertical speed THCs on the market. It handles the control of the Z in real time outside the Main control software but it communicates and takes settings from CommandCNC.

Having a software only THC has advantages and disadvantages. It's cheap but not as fast and has to share main processor cycles with the OS and CNC control software. We have been designing and building board level THC's since 2004 and worked with Art at MACH to put in the first THC logic. For years we supplied builders and table manufacturers with first a digital THC (MP1000 circa 2005 ) using MACH's parallel port engine . We introduced the DTHC IV (there was no III ) after the DTHC II . It was prompted by two things: The advent of the Ethernet based MACH controls and the need for more speed and a closed loop tunable response independent of the internal MACH THC logic.

In 2015 faced with MACH3 being obsoleted and MACH4 lacking any support for THC, and a total rewrite of thousands of lines of plugin code, we started development on a LINUX based system. We introduced CommandCNC in 2016 and are approaching over 1000 units shipped. We continue to add features and do development. We recently introduced an FPGA based BoB with expanded inputs and up to 8 channels of motor logic (step & dir) We are only one of two vendors that support the Hypertherm RS485 Serial port (Option on all the new PowerMax units) that adds even more automation to plasma cutting.

I would suggest you look at a stepper based controller (Like Our Most Popular Bundle ) with everything you need While we sell both types the servos do not offer a major advantage on a table with a gantry weigh of 100 lbs or less. All Precision Plasma tables are designed for stepper systems. Modern stepper motors and drivers have closed the gap in smooth operation and available torque. A plasma table is not a precision cutting machine and its only as accurate as the linear guide and mechanical tightness allow, no matter how much resolution the motors can provide. That being said you don't want to squander accuracy for speed . There are optimum ratios for the linear mechanical parts of a table . For roughly $7000.00 (elctonics, software, PC and a mechanical ganty kit) you can have a 4 X 8 fully capable (plasma , routing, and options for plate marking and even rotary pipe cutting) machine. That includes a heavy duty Super Z axis with floating torch holder , built in sensors and Ohmic Touch off with switch backup . We have watched table vendors come and go. We just completed our 4th facilities and staff expansion on the last 8 years.

Just like a Harley with training wheels, some systems push how "Easy" they are to use (mostly in the file creation part which intimidates a lot of shop guys) . What you find is easy comes with a price of being non-flexible.

You are welcome to contact us for a non-pressure introduction and explanation. We can get as technical or as pragmatic as you want. it's typically not cost effective to take a low end ,entry level , hobby type machine and upgrade it to be a shop grade light industrial table.

Dakotafig
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Re: CandCNC torch height control compared to Plasmacam

Post by Dakotafig » Fri Nov 30, 2018 2:47 pm

Gentlemen, I appreciate your responses. Everything makes sense. I hate to say it, but I really am looking for the “easy” system where I can load the DXF file, tell the machine the material and thickness, set the torch and go.

It sounds like CommandCNC can do this, with the possibility of going deeper if needed.

As for the stepper vs servo, that has been an interesting read searching around on that topic. Folks with servos want to say they are the best that is for sure. I guess the question that comes to mind is if there is a torque concern with steppers, does it hurt to put on slightly bigger stepper motors (besides cost obviously)?

Dakotafig
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Re: CandCNC torch height control compared to Plasmacam

Post by Dakotafig » Mon Dec 03, 2018 4:27 am

Ok, I figured out the easy answer to the stepper question. As long as the gantry is between a certain minimum and maximum weight for a given size stepper motor, they should be fine. That is why you should purchase motors after the gantry is built. 😬

One thing I can’t figure out however from precision plasma’s website, what if I want the table 6 foot wide instead of 5 foot? I know it says on there the don’t do any customization to the gantry, but is that really customization? The worst case is I believe I could buy a longer v rail for the gantry. Is that a correct assessment?

motoguy
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Re: CandCNC torch height control compared to Plasmacam

Post by motoguy » Tue Dec 04, 2018 2:54 pm

Dakotafig wrote:
Mon Dec 03, 2018 4:27 am
Ok, I figured out the easy answer to the stepper question. As long as the gantry is between a certain minimum and maximum weight for a given size stepper motor, they should be fine. That is why you should purchase motors after the gantry is built. 😬

One thing I can’t figure out however from precision plasma’s website, what if I want the table 6 foot wide instead of 5 foot? I know it says on there the don’t do any customization to the gantry, but is that really customization? The worst case is I believe I could buy a longer v rail for the gantry. Is that a correct assessment?
No. A longer gantry is going to require more support/"beefing up" to have the same rigidity as a smaller one. It's also going to add a bit more weight, though that shouldn't be an issue if it still falls within the window for the motors.

Not sure if 6' vs 5' will make an difference. However, my 6' gantry exposed some rigidity issues in the gantry that didn't exist for the 4' version. The manufacturer send some reinforcing brackets to brace up the gantry, and their new 6' versions are redesigned...
Bulltear 6x12 w/ Proton Z axis & watertable
CommandCNC/Linux w/ Ohmic & HyT options
Hypertherm Powermax 85 w/ machine torch
Solidworks, Coreldraw X7, Inkscape, Sheetcam

Dakotafig
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Joined: Wed Nov 21, 2018 3:58 pm

Re: CandCNC torch height control compared to Plasmacam

Post by Dakotafig » Fri Dec 07, 2018 1:26 am

I actually emailed Ron at Precision Plasma and he can sell a setup for a 6 foot gantry. At 6 feet it will be fine, but he doesn’t recommend going wider than that because of resenance.

Desertdog
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Re: CandCNC torch height control compared to Plasmacam

Post by Desertdog » Sun Dec 09, 2018 1:07 pm

You want to look at Flashcut for your software. PM sent.

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