Plasma Cutter

Post your build logs here

Re: Plasma Cutter

Postby Enraged » Fri May 25, 2012 5:09 pm

Looks good. have you thought about running two Makerslide extrusions back to back for the gantry, basically making a 40x40? Or you could always get the machine to cut it's own gantry stiffener plate, and make a "composite" steel/aluminum gantry.
Enraged
 
Posts: 438
Joined: Fri May 06, 2011 3:13 pm

Re: Plasma Cutter

Postby bdring » Fri May 25, 2012 6:01 pm

I have a couple backup plans. The rack actually adds way more stiffness than I had expected. Hopefully it will work as designed.

I'll learn a lot soon.
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Gantry Parts Fabricated

Postby bdring » Wed May 30, 2012 1:38 am

I am working about three projects at once, so I can only give a little time to each right now.

I finished fabricating all the gantry parts. I am pretty impressed with the rigidity. I would not try to route with it, but I think it is good enough for plasma. It has good stiffness and resistance to twist. I will get all the parts hardcoated after I am happy with the design.

I noticed I can flip the XZ carriage. One way will be stiffer and the other is farther from the slag. I'll see how it goes.

gantry_01.JPG


Here is a more recent rendering.

Untitled Project 90.jpg
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Frame Completed

Postby bdring » Fri Jun 01, 2012 11:47 pm

The frame is now built. It is quite strong, but not too heavy.


plasma_frame2.JPG


plasma_frame1.JPG




This detail shows how the MakerSlide is bolted to the 20x80 Misumi piece. These "sister" brackets are mounted above and below. They do not bother the wheels. The Makerslide is plenty strong at this length, but I plan to make it a lot longer and I like the way the 20x80 will shield the Makerslide from slag.

DSC00219.JPG
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

LCTHC Arrived

Postby bdring » Thu Jul 05, 2012 10:56 pm

While I was on vacation my LCTHC (Low Cost Torch Height Control) arrived. This came from CandCNC.com. Eventually I hope to make an open source simplified version of this, but I need to get a experience using a CNC plasma first.

In addition to a bunch of cables and power supplies it came with these parts. I also ordered a Gecko G540 interface board. I had a G540 left over from the original laser cutter.

This is the interface panel. you control it via a rotary/push knob.

LCTHC_front.JPG


This is the rear view of that panel. It is really quite simple. Most of what you see is simple the back of the LCD.

lcthc_back.JPG


This is the Gecko interface. It makes the wiring a lot simpler.

gecko_adapt2.JPG


Here it is attached to the G540

gecko_adapt.JPG


This is the sensor for the plasma. At one end is a voltage dividor and the other end has the trigger and a few other interfaces.

torch_intfc.JPG
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Re: Plasma Cutter

Postby bobt » Sun Jul 22, 2012 1:27 am

I know that Bart has been very busy lately but is there an update on this?

Bob Teeter
"What Box"
bobt
 
Posts: 49
Joined: Mon May 16, 2011 5:11 pm

Interface Panel

Postby bdring » Sun Jul 22, 2012 3:42 pm

I have made slow but steady progress. I have three axis motion on the machine and am now working on the final wiring. The only item I still need to buy is a bigger air compressor. I did some test cuts by hand with my little pancake compressor. It cuts but immediately cycles on and starts loosing pressure. It uses a lot of air and the air stays on for quite a while after the arc is off. This is probably to cool the tip.

Here is a shot of my interface panel. It still needs a bit of wiring.

pl_panel_front.jpg

pl_panel_rear.jpg
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Lots of progress.

Postby bdring » Wed Aug 01, 2012 1:09 pm

I have been a bad buildlogger on this project. :oops:

I have made a lot of progress, but am not documenting it well. I have been so busy, that I just try to sneak and hour here and there to work on it, but don't have time to take pictures.

My goal has been to debut it at the Mini Maker Faire in the local suburb of Evanston, which is this weekend. I have done a big push to get it cleaned up and ready to go over the past few days.

I have had full three axis motion for a while, but not in a clean well wired way. That is done. The cable leading to the plasma is quite thick and heavy because it also carries the air hose. I did not want a huge cable carrier on a machine this size so used an overhead arm similar to what Torchmate uses. Mine rotates which works well to limit the slack required.

I have two slaved motors for the Y to drive the gantry. I did that because it is an easy way to insure squareness on such a light machine. I placed two hard stops at the back to square it. If it needs to be squared you just manually push it against those stops then engage the steppers. The 2.4:1 gear down on the rack drives has a lot of detent torque, even when off so it stays pretty square. Mach3 has a feature where you can use two limit switches to automatically square it when zeroing the axis. I may try that, but the plasma controls really eat up the inputs, so I may need a second parallel port.

The speeds are quite fast. I run 1500 ipm on the X, 800 on the Y and about 200 on the Z. It will run faster, but the acceleration is the limiting factor. The whole thing is on wheels right now. Fast accelerations tend to make try to roll around. Once I find the final home for it, I will loose the wheels.

I'll try to take some pictures tonight.
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

Re: Plasma Cutter

Postby Cre8ivdsgn » Wed Aug 01, 2012 1:27 pm

Bart:

Stupid question here. What are you going to use to drive the gecko steppers? I ask because I have been looking at the Smooth Stepper stuff which has higher pulse rates than some other boards. I like the idea of an ethernet interface, too.

I am guessing you plan on using Mach3?

I know these are noob questions!

Thanks
Cre8ivdsgn
 
Posts: 52
Joined: Mon Aug 15, 2011 12:42 am

Re: Plasma Cutter

Postby bdring » Wed Aug 01, 2012 1:37 pm

What are you going to use to drive the gecko steppers?


Parallel Port

I am starting with the CandCNC LCTHC Torch Height Control. It cannot use a controller like theSmoothStepper because the latency is too slow for effective closed loop feedback on torch height control with Mach3. The Smoothstepper is fast, but it's actual communications rate with Mach3 is quite slow (40 Hz I think).
Bart
"If you didn't build it, you will never own it."
bdring
Site Admin
 
Posts: 2966
Joined: Sun Nov 22, 2009 7:33 pm
Location: Chicago, IL, USA

PreviousNext

Return to Build Logs

Who is online

Users browsing this forum: No registered users and 2 guests