# CNC Plasma Assembly



## MtnBiker (Dec 10, 2021)

Began assembly of our CNC plasma table today. Looked at the usual suspects (Lincoln Torchmate, ShopSaber, STV). Lots of options and all pretty expensive for what you get I think. We're months away from making money given the learning curve so I didn't want to break the bank by financing and paying interest. But I do want to make money and work envelope was a consideration. Langmuir Systems has a new model (the XR). A 4x8 table with driven ball-nut on ball screws (no whipping at higher speeds). Really good cost for performance from what we can tell. Parts quality seems excellent overall.








Frame is 12 gauge C-channel and nicely made. Where heavy brackets are attached, Langmuire includes equally heavy reinforcing brackets on the back side. Engineered to a price point but smart about it. Looks pretty rugged for a prosumer-grade tool.






Parts packaging and organization is excellent. The assembly manual is the best I've ever seen...120 pages, color pictures and very very thorough.

By contrast, professional grade stuff is welded and shipped as a finished or nearly finished assembly (and ruinously expensive to get it to your loading dock).




Assembling the gantry. 1/2" aluminum construction. For about 1/3 the price of a Torchmate 4xxx series, this seems a lot more than 1/3 as good.

More to come.


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## koenbro (Dec 10, 2021)

What was the total cost of the Langmuir system, excluding the generator and the torch?


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## NCjeeper (Dec 10, 2021)

I have been in the market for a plasma table. Interesting to hear your feedback on this brand.


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## DavidR8 (Dec 10, 2021)

Looks slick!


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## MtnBiker (Dec 11, 2021)

koenbro said:


> What was the total cost of the Langmuir system, excluding the generator and the torch?
> 
> 
> Sent from my iPhone using Tapatalk Pro


$6,250 plus shipping (and the shipping was quite reasonable). But that includes everything - automatic torch height control, Windows computer, touch screen monitor, mature CNC control software with continuous support/updates, water table with welded structural (1x1 tube) edges. So you are up and running at that price (excluding generator and torch).

Update 12/15: measured the top of the table at 52" x 100" with just a little more under the gantry, so oversized sheets will fit fine. Work area is still just a smidge over 4' x 8' but you can cut on a full, oversized sheet with rounded edges.


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## koenbro (Dec 15, 2021)

MtnBiker said:


> $6,250 plus shipping (and the shipping was quite reasonable). But that includes everything - automatic torch height control, Windows computer, touch screen monitor, mature CNC control software with continuous support/updates, water table with welded structural (1x1 tube) edges. So you are up and running at that price (excluding generator and torch).



This sounds like an excellent value. I do think THC is a must, and with other systems the computer is not included etc. 


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## MtnBiker (Dec 16, 2021)

Finished the build.




With two of us working on it, the build took about 20 hours. Not too bad given the shipping cost alone on a fully assembled/welded turn-key.

Only one issue cropped up - for those not familiar, a nut driven ball screw does what you'd think. Turns the nut on a stationary ball screw. On the more common solution with a driven ball screw, particularly at longer lengths, you tend to get a "whipping" problem at higher speeds. At almost 9' for these ball screws that would be a no-go.




You can see the stepper connected to the ball nut via a belt drive. This is cheaper than a high quality rack & pinion drive but delivers most of the performance.




During the break-in program I was getting a lot of whipping. No bueno. After running through a list of possibilities I indexed the ball nut which was fine. Indexed the ball nut holder/hub (the part to the right that the ball nut is inserted into) and had .075" of TIR. The runout caused a vibration that hit all sorts of harmonic goodness . Worked with Langmuir and getting new part on Saturday. Pretty short punch list for a new product launch.

And for those who might be interested, Langmuir is launching a "garage shop" CNC mill next (that is a secret, but we're all friends here).


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## brino (Dec 16, 2021)

MtnBiker said:


> And for those who might be interested, Langmuir is launching a "garage shop" CNC mill next (that is a secret, but we're all friends here).



Don't worry, we will keep it a secret here!  
-brino


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## koenbro (Dec 16, 2021)

Very curious about that which cannot be named. Work envelope, weight, type of motors, controls and software. 


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## MtnBiker (Dec 22, 2021)

Langmuir sent a replacement part. Took about 20 minutes to install and we're in business. No more harmonics. Can run at full speed without issues. First cuts yesterday. Lots to learn but my son, the engineer, is dialing things in pretty well. 

Happy with the table. Now to managing the water bed. To use chemicals or to just use water and empty after using. That is the question.


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## DavidR8 (Dec 22, 2021)

MtnBiker said:


> Now to managing the water bed. To use chemicals or to just use water and empty after using. That is the question.



I believe the internet will provide 41,821 opinions on the matter. 
Were it me I think I’d use straight water and drain it every so often. 
There, 41,822 opinions 


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