[Gary588]

Thank You

[Kerryfisher]

Give us a clue Aj cos I can't see it

Dave, Just about fell out the chair.... I just figured it out. Talk to you later..

Aj

[ajclay]

If you look at the two linear rails on the Z axis you'll notice 4 blocks that slide on the two vertical rails. The bottom two blocks are bolted solid to the plate the torch is mounted on. The lead screw that raises and lowers torch is connected to the top two blocks, and they have a loose connection to the torch mounting plate. Notice the slot for the bolts on the top blocks.

The torch is lowered down by the lead screw on the top two blocks. The torch touches the plate and stops. The top two block continue to move down till they trip the switch that stop the Z axis motor.

Gravity lowers the torch as the top two blocks are screwed down. I'm assuming....

If the bottom blocks stick, the torch would just dry fire in the air for the pierce thinking the torch hit the plate....

Fewer pieces to accomplish the same task. Got to give it to Dave on this....

If I got it wrong..... speak up!

Aj

[Kerryfisher]

Ah right I see now so the bottom block isn't connected to the lead screw at all, just suspended by the two bolts in those slots, I didn't realise the torch needed to be floating like that, thanks Aj

[ajclay]

Ah right I see now so the bottom block isn't connected to the lead screw at all, just suspended by the two bolts in those slots, I didn't realise the torch needed to be floating like that, thanks Aj

Kerry,

The torch has to be able to move independent to the lead screw. Hence the name "floating torch".

That's a good way for the machine to find the surface of the plate regardless of the plate thickness.....

More often seen is the torch mounted on it's own mini linear rail that allows it to slide/move independent to the Z axis.

A small limit switch of some type can be mounted on top or bottom to sense the torch movement..

My machine uses prosimitry sensors which is a big pain in the rear. I'm in the process of trying to work out the details of a THC system from CandCNC. Tom is linning me out on what and how to do it.

It uses the floating head design. Simple and easy to maintain......

AJ

[ajclay]

By the way... Photos isn't showing up for one reason or another.

[Kerryfisher]

By the way... Photos isn't showing up for one reason or another.

Thanks Aj, looks like I have more studying to do on the zaxis as well, not sure why the image doesn't show, chrome loads fine, explorer doesn't, it was only a copy of Daves further back.

http://www.cnczone.com/forums/attach...s-imag0544.jpg

[ajclay]

Yep that was the best photo he had of it.. It was so simple to him he never really put up the details. The ridged torch mount is a no no for sure. Been there and done that. One simple careless mistake and the machine will brake off the end of torch. A magnetic mount is easy enough to come up with so it will break away when it hits something... You should e-mail me directly and when I get my drawing worked out for my torch I'll send you a copy and it may spark an idea.... You use AutoCAD or something.... e-mail me at [email protected]. Aj

[LeeWay]

That is a very nice compact method to float the torch there. Mine takes up quite a bit of room in the X.
Here is a short clip I did the other day of my floating torch.
It has a floating grinder too for plate marking now, but that may become an air actuated plate marker if I can get the scribe cheap enough.
I have since put a foot under the grinder to keep it from going too deep. It just scribe the surface pretty well now.
Still working out a few kinks in mine.
I'll have more on it in my thread as it progresses.
A breakaway will certainly be added at some point. Look forward to what you come up with.

[eloid]

Can you explain or show use in more detail how you aligned and drill
the Mounties on the x, y axis for the linear rails
and how you referance them

Great build,

[dnelso]

On the x axis those were drilled on the mill. The y long axis was done on a surface plate after the table is welded.I used machined spacers off the plate to hold the height of the rails and used a drill jig that fit in the counter-bore of the rail to center drill the rail. Then power tapped the holes with a drill. Hope that is clear to you. If not let me know.
Dave

[Johnpo]

Hi dnelso,
my colleague and i are just starting building a plasma table. May i say that your tables in this thread look very professional :cheers: We want to use it in our workplace and at weekend for our private jobs, (so it must be fairly robust) My colleague bought all the motors, drivers and power supplies from a contact that he found on you-tube. I've seen the machine working on you-tube and it also looks quite professional, but i have a concern about the motors ( I think they might not be strong enough). The motors are all NEMA23 we have a 170oz/in motor for the z axis, a 297oz/in motor for the x axis and a 439oz/in motor for the y axis. In your experience do you think these sizes of motor will be enough? Thanks for any help or information you can give in advance.

[dnelso]

I run 3.5 to 1 gear reduction on the x and the y and use 620 oz in motors from candcnc.net.I dont know your weight of your gantry or what drives and power supply or if you are using reduction so im not sure if those motors will work or not.
'Sorry cant be of more help.
Dave

[dnelso]

Attachment 294938
A few pictures of the new table im building for a friend.