New Machine Build- Started 4x4 plasma table

[karpro]

Been a member on this board for over a year. Have seen a lot of beautiful builds. Finally decided to start my own. Table size is 5' X 5'. Used 2" X 4" X 3/16" for the main frame, with 3" X 3" X 3/16" for the legs and gantry crossbar. Gantry side plates are 1/4" inch. Plan on making the table a water bed. Going to try the gecko 251 drives with nema 23, 381 oz-in stepper motors. I know i'll get alot of flack for this but I decided to make the X & Y axis chain driven. I am keeping the chain stationary similar to how fiero addiction built his table using belts. I will however be using a 2.5 to 1 reduction on both axis. Few pictures so far, (cell phone quality is rather poor, sorry) let me know what you think.

[DanOSB]

very nice build..

speaking of chain.. i have one cnc machine with chain and im very happy with it...

the repeat/tolerance is very impressed.. dont listen to others about the chain..

[karpro]

Thanks for the support!

[millman52]

Craftsmanship looks good. Keep us posted, & welcome aboard.

[karpro]

Its been real hard to find time to work on the table but I thought I would post up a few pics of the progress so far. Have managed to complete building all the axis and am currently wiring the table and control box. Did some getto wiring to test the table and it worked great, perfect 90s and perfect circles. It runs very smoothly however the chains are noisier than I would have expected. All in all I am very happy so far. Still need to finish the water tank, monitor / keyboard mount, and then paint it. Hoping to finish by November.

[karpro]

Today was a very productive day. First thing finished was getting all the small round bar that hold the slats, cut and tacked in. Can not take credit for that though, my 16 year old son came to the shop and tackled that project. Second was to get the CandCNC LCTHC card installed in the plasma machine. Lastly we got started on the monitor / keyboard tower. Snapped a few pics before we left.

[outofoperation]

Originally Posted by karpro Second was to get the CandCNC LCTHC card installed in the plasma machine.

Sir,

I´m in the planning stage of a table similar to yours, also with the LCTHC. But I´m not familiar with the electronics- I have studied the manual of the LCTHC - Installing the sensor card inside the plasmacutter is clear to me, but I have problems how to wire the four leads (which controls the ARC) to the BOB.
For this I will use the limit switch inputs- but every screw terminal for the limit switches at the BOB has two inputs- "signal in" and "24v out". Is there only the "signal in" needed and the other terminal left blank?

A little sketch or a close-up from your wiring BOB-->LCTHC would be great

friendly regards,
Steff

[karpro]

Originally Posted by outofoperation Is there only the "signal in" needed and the other terminal left blank?

Steff,

Yes, you are correct, you will not use the 24V terminals. Three of the inputs on the BOB will be used for THC DOWN, THC UP, and ARC OK. The fourth connection on the BOB will be an output for the TORCH ON. The fifth will be to connect a BOB isolated common to the PC COM terminal of the LCTHC. Lastly connect the supplied 12V power supply to the POS and NEG terminals. The question that I have about your set up is the 24V breakout board. Does it require 24V signals on the input terminals or will it work with 0V to 5V. I do not believe there is a way to get the LCTHC to export a 24V signal.
I will be happy to post up picks of the LCTHC wiring however I have not completed it yet, only the m/c card inside the plasma. On a side note, I had a problem with CandCNC not shipping a order to me at all, they really dropped the ball. When I contacted them they bent over backwards to rectify the problem and I had my order the next day! Great customer service and really good people to deal with.

Jon

[outofoperation]

Hello Jon,

thank you for your explanation.

Originally Posted by karpro The question that I have about your set up is the 24V breakout board. Does it require 24V signals on the input terminals or will it work with 0V to 5V. I do not believe there is a way to get the LCTHC to export a 24V signal.

I think it will work from 0 to 5V, about this I can also ask the vendor of the BOB, it comes not from China . Vendor and BOB have excellent reputations here in the german CNC community. If there will be problems with this BOB I will install a second LPT port and run the THC with it´s own little BOB- maybe it´s an easier solution for a Goofy like me .

regards, Steff

[Torchhead]

Originally Posted by outofoperation Hello Jon, thank you for your explanation. I think it will work from 0 to 5V, about this I can also ask the vendor of the BOB, it comes not from China . Vendor and BOB have excellent reputations here in the german CNC community. If there will be problems with this BOB I will install a second LPT port and run the THC with it´s own little BOB- maybe it´s an easier solution for a Goofy like me . regards, Steff

All of the outputs of the LCTHC are opto isolated with open collector outputs. They turn on by taking the output (THC UP, THC DOWN, etc) to the COM rail (PCGND/COM on the connector). If you BOB will supply the 24V to it's opto inputs There is a +5 (PC+5) for an external pull-up voltage for inputs that do not have their own pullup. That voltage connects to each collector of the outputs but it has diode blocking so that if a higher DC voltage appears on one or all of the outputs no harm is done to the +5 bios supply (if you have one hooked up).

It's important to note here that the PC+5 connector is an INPUT (for supplying an external +5 bios).

The G540 Interface card (for use with the Gecko 540 as a motor drive has screw terminals for an external aux 12VDC supply that provides the +5 voltage for PC+5 input and also the 12VDC coil voltage for the a AUX relay on that card.

So if you can read +24 from the two input terminals on your BOB and shorting them together activates the input then connect the outputs of the LCTHC (Output & PCGND (com)) to the inputs. The 24VDC on the outputs of the LCTHC will not hurt it.

The input (TORCH ON) cannot take 24VDC. it needs to be 5 to 12VDC

The PC+5 is the current source for the TORCH ON too so never use more than 12VDC on the PC+5 input

TOM Caudle
www.CandCNC.com

.

[outofoperation]

Thank you Tom too, I´m sure I can bring this to work. The manual is so far as easy understandable, and further there is a very detailed thread written by a user named Creepy how to mount the sensor card into the PMX45- seems like there is no witchcraft necessary.

Steff

[karpro]

Got the mount made today for the LCTHC. Should work out pretty well.