New member

[Creative25]

I am new to plasma cnc.
I Just built my table and have lots of fun learning.
Eager to learn from others.
The first plasma table I saw live in action is my home built one. So I have no idea what’s possible and what not.
I also don’t know how well it performs but so far I am happy with what it can do with it.

[adbuch]

Welcome aboard Creative25! Perhaps post some photos of your table setup so we can see what you have built.

David

[acourtjester]

Great another DIYer, great for the learning, fun project too, great addition to your shop. Remember you can add optional attachments to your table too, like a router, diamond scribe, and drag knife. You can find these things with the search function in the upper right for a look around. Are you a craftsman/hobbyist or is it for expanding a business? Projects can include custom parts, neat gifts, other tools let you mind wander. have fun
https://drive.google.com/file/d/14hig0J ... sp=sharing
https://drive.google.com/file/d/1JHoosd ... sp=sharing

[adbuch]

Tom shows some excellent examples of creative projects using optional attachments to his cnc plasma table. Nice work Tom!!

David

[Creative25]

Some pictures of my machine.
I am still planning to add a rotational axle etc.

IMG_0261.jpeg

IMG_0260.jpeg

IMG_0401.jpeg

IMG_0262.jpeg

[Creative25]

These are some of my latest photos.
This machine has zero backlash also hardly any noise from
Chains.

Most of the gantry parts are experimental.
But I must admit it already works better than I expected.

I plan to redesign the whole gantry to make it lighter and more rigid. Which now will be easy with a working machine.
First thing will be the Z axis.

Machine works with an old MacBook Pro. And Linuxcnc with a mesa board.

IMG_0450.jpeg

IMG_0448.jpeg

[SegoMan DeSigns]

These are some of my latest photos.
This machine has zero backlash also hardly any noise from
Chains.

Most of the gantry parts are experimental.
But I must admit it already works better than I expected.

I plan to redesign the whole gantry to make it lighter and more rigid. Which now will be easy with a working machine.
First thing will be the Z axis.

Machine works with an old MacBook Pro. And Linuxcnc with a mesa board.


IMG_0450.jpeg
IMG_0448.jpeg

Welcome to the site,

Tom and I are fellow sprocket heads

Chain drives are an economical and precise moving option. I have a rear drive line with one motor so no programing arguments there. I can appreciate the comment about have a CNC table on hand to build your CNC table. I used a 2x2 TorchMate to make a lot of the parts for the 6x12 table:

Here is some ideas for your Z and torch holder. Think about mounting a pen or scribe while your in the design stage:

https://www.plasmaspider.com/viewtopic. ... 10#p152510

Keep those pics coming.

Steve

[acourtjester]

You may look into Proximity Sensors to replace your switches, Much smaller and easy to work with. Here is a post about my installation.
viewtopic.php?p=230902&hilit=proximity+sensor#p230902
I also went with LinuxCNC with the QTPlasmaC GUI it has some nice options. I have a circuit I used for the Ohmic sensor which is a small module easy to wire and cost bout $10. Works great. Modules come in 5, 12, and 24 volts some it fits right in with the Mesa controller.

Ohmic relay box (2).JPG

Ohmic sensor 12 volt.JPG

[adbuch]

These are some of my latest photos.
This machine has zero backlash also hardly any noise from
Chains.

Most of the gantry parts are experimental.
But I must admit it already works better than I expected.

I plan to redesign the whole gantry to make it lighter and more rigid. Which now will be easy with a working machine.
First thing will be the Z axis.

Machine works with an old MacBook Pro. And Linuxcnc with a mesa board.


IMG_0450.jpeg
IMG_0448.jpeg

Creative25 - thanks for sharing those photos of your table. I'm sure you are having lots of fun designing and testing as you go.
Great work!!

David

[Creative25]

Welcome to the site,

Tom and I are fellow sprocket heads

Chain drives are an economical and precise moving option. I have a rear drive line with one motor so no programing arguments there. I can appreciate the comment about have a CNC table on hand to build your CNC table. I used a 2x2 TorchMate to make a lot of the parts for the 6x12 table:

Here is some ideas for your Z and torch holder. Think about mounting a pen or scribe while your in the design stage:

https://www.plasmaspider.com/viewtopic. ... 10#p152510

Keep those pics coming.

Steve
[/quote]

I have one question.
What maintenance are you doing on your Sprockets and chains?

[SegoMan DeSigns]

Other than an occasional blast with compressed air, I have only had to replace the idler sprockets on the tensioners In the 5 years it has been moving. I have sourced another brand of idlers with a bigger bearing that should help on the wear factor, the sprocket itself showed very little wear. I used a nickle plated chain to cut down on the rust factor, this winters maintenance will probably include chain removal / cleaning / dipping it in some hot wax.

Chain Drive, Yoke.JPG

I went a different route on running sprockets / chains as I wanted to keep as much weight and moving parts mounted to the frame vs gantry (40 pitch chain / rated to 4,000 lbs):

Chain Drive, Finale Drive.jpg

Drive shaft / reduction sprockets / single larger "1400 oz NEMA 34" servo motor (35 pitch chain / rated to 2400 lbs):

Chain Dive, Primary Reduction.jpg

I started out with a spring for chain tensioners but swapped then out with urethane bushings:

Chain Drive, Urethane Bushings.jpg

You can see the chain in motion at 6:16 of this video:


https://www.youtube.com/watch?v=iNSiQYK_jLI

[acourtjester]

Here is an image of the chain on my DIY table similar to Segoman's. My path for 2 side drive has a shaft going through the upper rail tube.

DSCN2177.JPG

[Creative25]

So I have been thinking about how to add a rotational axis for pipe cutting. One of the big questions on my mind was about how to create curves for knotchings with free software.

So after checking on the freecad forum I found some information about unrolling surfaces.

So I created a File with two pipes intersecting each other.
Where you can change their sizes and the angle of the substractive pipe in a spreadsheet.

Afterwards it is as simple as selecting the surface and run the python script.

I have a button in the toolbar so running the script is a single click.

Let me know if this is useful or if there is an easier way to create notching curves with free software.
I don’t Want to invent the wheel again.

The python script i found here:

https://forum.freecad.org/viewtopic.php ... 11#p387511

Towards the end of the thread you can also find the Freecad File that I posted there it is called Knotching3 template.

[acourtjester]

Your on the right track unrolling surfaces for your cut path, that is what I did while playing with the rotary cutter I built. You may share the spread sheet with other members to see if they can help with the math for the curves portion. Maybe some will have a free software for tubing cut shaping, I have no run across any myself. Attached are videos on my attempts.
https://www.youtube.com/watch?v=rz7nVt1EvX0
https://www.youtube.com/watch?v=mDO9sx8NiPA

[Creative25]

It’s a freecad file with spreadsheet this file format is unfortunately not accepted on this forum but you can download it from the link.

[Creative25]

Thanks for the videos I watched them now.
As far as my freecad spreadsheet goes I think there was a misunderstanding.
I have a simple 3d drawing in freecad with two cylindrical bodies intersecting each other.
The spreadsheet has no formulas it is used to quickly change the size and angle of the cylinders.
I select the surface of the part I want to unwrap.
Then I click on the script to unwrap the surface.

Here are some photos of the process.

First I enter the pipe sizes and angle I want to have on the knotching

IMG_0594.jpeg

Then I highlight the surface i want to unwrap.

IMG_0591.jpeg

Then I click on the python script.

IMG_0592.jpeg

The result is a shape.

IMG_0593.jpeg

On this shape I delete the lines I don’t need
Them I export as dxf.

[adbuch]

Creative25 - your method looks quite interesting! I have never used FreeCad so will have to have a look. I use Fusion 360 (free version) and it is fairly easy to accomplish a similar result. Draw the main pipe and intersecting branch pipe (intersecting at an angle), convert the branch pipe to sheet metal, click on the "Create Flat Pattern" button. You can very the pipe sizes, wall thickness, and angle and create the corresponding flat pattern and save as dxf.

For my example, I used a 3" main OD, 2" branch OD, and angles of 30, 45, and 60 degrees.

David

Fusion 360 for pipe wrap flat patterns 1.jpg

Fusion 360 for pipe wrap flat patterns 2.jpg

[adbuch]

I sometimes use a program called Digital Pipe Fitter to create similar flat patters for pipe wraps and tube cutting. Here is a comparison of the Fusion 360 result with the Digital Pipe Fitter result. They both produce almost exactly the same result.

David

dpf 3 x 2 x 45.jpg

dpf 3 x 2 x 45 - 1.jpg

[adbuch]

https://www.youtube.com/watch?v=-iKxfOAl9rQ&t=11s

[Creative25]

Yes exactly the same results.
Over the years I have used a few good free cad programs.
But used them intermittently. Just to discover a year later when I wanted to use it again that they were not free anymore. So I came across Freecad it was difficult to learn.
Specially if you are new to Cad software.
Freecad had so much functions and workbenches it was confusing in the beginning.

But my reason for sticking with it is the confidence that it will remain free. It is very powerful some of the functions you only get with expensive commercial software.

Now that I know maybe less than 10% of its functionality I have grown to love it. It was Wort all the struggles to learn it.

What puts me off from using Fusion is that you need an internet connection. There is a offline mode but you loose a lot of functionality. So with the unreliable internet in our area. I just did not bother using it.

If I start earning som money with my machine i will get a full version of sheetcam.

They say the best cam software is the one you know.

I must say to use the freecad template I created is quite simple to use you don’t need to create any drawing.
Just enter the data into the spreadsheet. Download the python script and create a shortcut.

[adbuch]

I must say to use the freecad template I created is quite simple to use you don’t need to create any drawing.
Just enter the data into the spreadsheet. Download the python script and create a shortcut.

From your previous post, I was under the impression that you did need to create an initial "drawing" - the two pipes intersecting at an angle.
I think what you meant to say is that once the initial drawing is completed - you don't need to create any additional drawings to use your spreadsheet.

I have a very reliable internet connection here in Tucson, Arizona - so loss of internet is generally not a program. But I will say that Fusion 360 is incredibly slow and can easily hang up or crash in offline mode - at least that has been my experience.

Also I very much agree that the fact that FreeCad can be used offline could be a big advantage. I know that sometimes Fusion 360 gets really slow when their server is doing calculations for more complicated operations. On the other hand, since Fusion 360 offloads much of this processing to it's own server - it may be that a more robust PC is necessary for optimum performance for similar operations with FreeCad.

Also - just wondering if FreeCad has a cam portion similar to Fusion 360. I have not looked at it yet, but I am thinking perhaps not - since you mention using SheetCam for your cam/post processing.

David

[Creative25]

I meant you can download my drawing with the spreadsheet.
Only other thing you need to do is download the python script from the freecad forum. And create a shortcut.
It can all be found on the link I provided.
I am thankful to the person who created this script. It makes it so much easier.

[adbuch]

I meant you can download my drawing with the spreadsheet.
Only other thing you need to do is download the python script from the freecad forum. And create a shortcut.
It can all be found on the link I provided.
I am thankful to the person who created this script. It makes it so much easier.

Thanks for clearing that up. You might consider uploading your spreadsheet and drawing file to Google Drive. It is free to use and a very handy way to share files with others - particularly when the file formats are not uploadable to the this forum.

If I am understanding you correctly - if I downloaded and installed FreeCad and had your spreadsheet and drawing file, all I would have to do would be to open FreeCad, load in your file and spreadsheet, download the python script, and easily create flat patterns for pipe wraps without needing to know very much about using FreeCad. If that is true, then I could see this being very useful to many members and others.

David

[adbuch]

https://workspace.google.com/products/drive/

google drive.jpg

[adbuch]

I downloaded and installed FreeCad to check it out. I was following along with one of the examples and FreeCad crashed. I was trying to put a fillet on the corner of a rectangular block when this happened.

Freecad crashed.jpg

David