how to determine scale of design to cut

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roberob2025
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how to determine scale of design to cut

Post by roberob2025 »

Hello Everyone. So I have a few questions for everyone. How do you determine how big a design has to be to be able to cut it out on a plasma table? Is there something in the design that will tell you whether or not it can be cut using plasma? I think pretty much any design can be cut but it would matter how big it is correct? Most of the problems I have been running into are I'll have a design in fusion 360 and I will have a piece of metal a certain size I'm trying to cut it on. When I have scale the design to fit the metal it looks good but once I start cutting it out there lines that end up cutting to close and that whole part will drop out. So I was wondering if there's anything that you might look at to see how big the design has to be or something that says this design will have to be cut from a 36" x 36" piece of metal? Thank you in advance for any advise!
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Re: how to determine scale of design to cut

Post by adbuch »

I would look at your kerf width and the distance between any adjacent cuts. In general, I would probably want to have at least 1/8" between cuts - depending on the circumstance. Here is an example.

The top piece has only 0.038" between the two slots, and the part between the slots will surely burn out when cut.
If the distance between the two slots is increased to around 1/8" (in this case 0.127") the slots should cut fine with the divider portion between the two slots remaining intact.

In Fusion 360, Inkscape, Design Edge, or most other programs you could draw a small circle of 1/8" diameter, or what ever your size criteria is, and move it around on the drawing to see how it fits between parts and cut paths. If there is a problem like the first example below then you could scale your part up in size until you achieve the clearance you want. Of course this works for artsy type parts, but not for mechanical parts when you are required to maintain a certain scale (size) for the part.

David


slots in plates.jpg

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Re: how to determine scale of design to cut

Post by adbuch »

Here is the same part (upper one) imported to Fusion 360. You can scale the part so that your 1/8" circle will fit between cuts as shown.
David
draw circle 1.jpg
draw circle 2.jpg
draw circle 3.jpg
draw circle 4.jpg

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Re: how to determine scale of design to cut

Post by adbuch »

If you have a sample design we can look at, then please upload your file and I will open it with Fusion 360 and give you some ideas as to how the best way might be to proceed.
David
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Re: how to determine scale of design to cut

Post by roberob2025 »

OK I understand what you mean. And yes I am mostly taking about artsy stuff. I downloaded some SVG files from a few different websites and some of them cut out good but some gave me some problems. I am not sure how to upload images or files on here. Do I click on the full editor & preview button? I have also had a design that I used fusion 360 to do the CAM stuff on and the first time I cut it it came out perfect but then I tried to cut it again with the same settings and it ended up blowing out some of the lines. I will look up how to post photos and files and if I figure it out before a reply here I will upload them. Thanks again for your responds I appreciate it a lot.
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Re: how to determine scale of design to cut

Post by roberob2025 »

ok I figured out the attachments! so this SVG is one that I cut trying to make it I want to say 20x20 was my first try that blew out a few spots. But then i scaled it to be bigger and it still blew out. So then I edited it and took out some of the windows and sail lines and played with it to where it still looked like I was trying to cut. I will upload the final file That I cut and a photo of how it turned out as soon as I find the cord for my phone. But what I started to do that has worked pretty good sometimes is before I upload the file into fusion I will draw a square of the size I am trying to make it and then try to fit the design into that square and then see if it looks big enough to not blow out. So in Fusion 360 when you're in the manufactures work space and crating a plasma tool the kerf of the cutter I set at .056 or .059 and I did that because I cut out a test file and that was what I measured the kerf width to be from that test piece. Is that a good way to go? or should I set it differently? And if its set to that size and when I create a tool path and it gives me the error message of one or more passes were discarded because of linking constraints is that because the kerf width is to big and it will blow out the line? Also I am not sure what the nozzle diameter (the line under kerf settings in the create a plasma tool in Fusion 360) is supposed to be I think I just set it to what the Langmuir videos set theirs to.
4pzmA-landscape-ship-and-phare-scene.svg

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Re: how to determine scale of design to cut

Post by roberob2025 »

I guess I didn't take a photo of the one that I first cut of the ship and light house but I took it of the one final one I cut. Also I uploaded a photo of a rose that the first time I cut it it came out perfect (not in the photo) but then the second time I cut it a few days after the first one (the one on the left looking at the photo) it blew out some of the lettering with the same settings I did not change anything just loaded it into firecontrol and zeroed out xyz and cut it. Then the third time I cut it (the one on the right looking at the photo) I didnt have a big enough piece of metal and I kept moving the piece around so it wouldn't fire into my water table!
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20220324_164604[1].jpg

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Re: how to determine scale of design to cut

Post by adbuch »

On the file you uploaded, I opened it and it is about 6" long with some details that will burn thru when cut.
sail boat and light house 1.jpg
sail boat and light house 2.jpg
If this one was scaled up by a factor of 4 (to around 24") then I think it would be fine. What size is the one that you cut that you showed in your picture?
Another option if you want to cut it smaller is to edit some of the features to make it more cutable.

In you last pictures, it looks like your cut height was too high and/or other incorrect settings that were causing it to not cut all the way thru the material.

David

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Re: how to determine scale of design to cut

Post by adbuch »

roberob2025 wrote: Mon Jun 06, 2022 3:22 am ok I figured out the attachments! so this SVG is one that I cut trying to make it I want to say 20x20 was my first try that blew out a few spots. But then i scaled it to be bigger and it still blew out. So then I edited it and took out some of the windows and sail lines and played with it to where it still looked like I was trying to cut. I will upload the final file That I cut and a photo of how it turned out as soon as I find the cord for my phone. But what I started to do that has worked pretty good sometimes is before I upload the file into fusion I will draw a square of the size I am trying to make it and then try to fit the design into that square and then see if it looks big enough to not blow out. So in Fusion 360 when you're in the manufactures work space and crating a plasma tool the kerf of the cutter I set at .056 or .059 and I did that because I cut out a test file and that was what I measured the kerf width to be from that test piece. Is that a good way to go? or should I set it differently? And if its set to that size and when I create a tool path and it gives me the error message of one or more passes were discarded because of linking constraints is that because the kerf width is to big and it will blow out the line? Also I am not sure what the nozzle diameter (the line under kerf settings in the create a plasma tool in Fusion 360) is supposed to be I think I just set it to what the Langmuir videos set theirs to.
4pzmA-landscape-ship-and-phare-scene.svg
Yes - it is a good idea to do some test cuts and then measure you actual kerf width and enter that value into Fusion 360. Sometimes passes are discarded because your lead-in is too large to fit inside the hole or other feature it is attempting to create a cut path for. There is a setting for lead-in and lead-out length and you can set this to a smaller value than the default. I don't think it matters tool much about the nozzle diameter setting. I have used the default value and it has worked fine for me to generate cut paths.

Yes - that is a good idea to draw a small square (or circle) and move it around your design to find problem areas that might blow out.

David
lead in distance 1.jpg
lead in distance 2.jpg

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Re: how to determine scale of design to cut

Post by Joe Jones »

I use a .080" circle (the kerf width) as a feeler gauge to make sure the torch can fit between internal cut lines. You can scale a design by finding the point where two paths come closest together. Draw a 1/8" circle at that point, and scale the design so that the paths do not cut into the circle on either side. Cutting with a plasma torch is like signing a check with a magic marker. In order to read the signature, it must be much larger.

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Re: how to determine scale of design to cut

Post by Joe Jones »

(Cue 'The Beach Boys' .. "Wouldn't it be nice ..." :lol: )

I wish PlasmaCam would add this feature to their software. You would import a design, and set a minimum distance between paths. So you could import something with detail, and set the minimum width between paths to be .125" or .1875", etc. The entire design would automatically scale up to the size required.

The software already HAS this ability, and it uses this feature to NEST parts, so why not modify it to scale a drawing for CLEAN plasma cutting? It only makes sense!

Are you reading this, Jason?

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Re: how to determine scale of design to cut

Post by plasmanewbie »

I am a simple guy and this is how I do it in Corel Draw but I know you can do this in Inkscape and I am sure other software. Super easy, just set the line width on your drawing to the width of your kerf or slightly wider, for 14-16g cutting I use .070" line width. If you see any of the lines intersecting with each other you can scale the design up until that problem is gone or modify to design to solve the intersections. See attached image, the above image shows how you would normally view a design when your creating it, the bottom shows the same design with a line width similar to the kerf width .070" and you can see that with this design at 12" wide you care going to have intersecting problems. Simply scale up until they go away or edit the design.
LineWidth3.png

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Re: how to determine scale of design to cut

Post by djreiswig »

Another thing to watch is where you put pierces. If they end up next to each other or in thinner areas, sometimes they will blow through and make things fall out.
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Re: how to determine scale of design to cut

Post by ROKCRLER »

plasmanewbie wrote: Mon Jun 06, 2022 12:11 pm I am a simple guy and this is how I do it in Corel Draw but I know you can do this in Inkscape and I am sure other software. Super easy, just set the line width on your drawing to the width of your kerf or slightly wider, for 14-16g cutting I use .070" line width. If you see any of the lines intersecting with each other you can scale the design up until that problem is gone or modify to design to solve the intersections.
That is genius... I never thought of doing it that way, I've been moving around a 0.125" circle around checking for interferences...thanks for that tip.
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Re: how to determine scale of design to cut

Post by plasmanewbie »

ROKCRLER wrote: Mon Jun 06, 2022 1:17 pm
plasmanewbie wrote: Mon Jun 06, 2022 12:11 pm I am a simple guy and this is how I do it in Corel Draw but I know you can do this in Inkscape and I am sure other software. Super easy, just set the line width on your drawing to the width of your kerf or slightly wider, for 14-16g cutting I use .070" line width. If you see any of the lines intersecting with each other you can scale the design up until that problem is gone or modify to design to solve the intersections.
That is genius... I never thought of doing it that way, I've been moving around a 0.125" circle around checking for interferences...thanks for that tip.
Very welcome, I also learn something new every day here. Glad I could contribute a useful technique :Yay
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Re: how to determine scale of design to cut

Post by adbuch »

Plasmanewbie - thanks for the tip! Design Edge has a similar feature, but it only shows the cut path width - and not the actual drawing line width. Since I mostly use Design Edge, I sometimes employ the small circle method and move it around the drawing to check clearance. Or I just put on a few dimensions. But I do sometimes use Corel Draw and Inkscape, so that is very good to know.

Since the OP is using Fusion 360 - varying the line width is not an option for him. But he could open the file first with Inkscape to use this method.

Thanks,
David
Last edited by adbuch on Tue Jun 07, 2022 1:52 am, edited 1 time in total.
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Re: how to determine scale of design to cut

Post by adbuch »

Joe Jones wrote: Mon Jun 06, 2022 11:10 am I use a .080" circle (the kerf width) as a feeler gauge to make sure the torch can fit between internal cut lines. You can scale a design by finding the point where two paths come closest together. Draw a 1/8" circle at that point, and scale the design so that the paths do not cut into the circle on either side. Cutting with a plasma torch is like signing a check with a magic marker. In order to read the signature, it must be much larger.

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Re: how to determine scale of design to cut

Post by roberob2025 »

Thank you everyone for the tips. The lighthouse ship design I cut out is 25"widex20"tall. The lead in and lead outs give me a lot of problem when I try to cut designs like this so I have mainly go without them. I did modify the design when I cut it out by taking out some windows and making some bigger and I changed the size of the sails. I have not used any other CAD program I pretty much just followed what Langmuir showed in their setup videos. I am open to trying other programs I just have not ventured outside my box yet. I will probably start with inkscape since its free but is there any other programs you guys suggest? I have heard of others using plasmacam I think it is? I do all my CAD and CAM in fusion and then use firecontrol to actually control the table and do the cutting I am not sure if other software will be able to control the table does anyone have any insight into that?
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Re: how to determine scale of design to cut

Post by adbuch »

roberob2025 wrote: Tue Jun 07, 2022 8:27 pm Thank you everyone for the tips. The lighthouse ship design I cut out is 25"widex20"tall. The lead in and lead outs give me a lot of problem when I try to cut designs like this so I have mainly go without them. I did modify the design when I cut it out by taking out some windows and making some bigger and I changed the size of the sails. I have not used any other CAD program I pretty much just followed what Langmuir showed in their setup videos. I am open to trying other programs I just have not ventured outside my box yet. I will probably start with inkscape since its free but is there any other programs you guys suggest? I have heard of others using plasmacam I think it is? I do all my CAD and CAM in fusion and then use firecontrol to actually control the table and do the cutting I am not sure if other software will be able to control the table does anyone have any insight into that?
I might be confusing you with someone else who said they were using Fusion 360 for drawings and SheetCam for cut path creation. In any case, if you do decide to learn to use Inkscape, you will most likely want to use SheetCam to create the cut paths for your parts. The nice thing about Inkscape (as compared to Fusion 360) is that it doesn't have a problem importing larger more complicated files like Fusion 360 does. I have crashed Fusion 360 many times with imported files that it didn't like.

Plasmacam Design Edge is expensive (around $3000) for a stand-alone license, and even though is is great for vector editing, the g-code it will export does not include Z height values. So unless you own a Plasmacam table, it's probably not for you. LightBurn is a great program for drawing and importing/modifying drawing files - and will export as dxf or svg. Most would probably use SheetCam for processing the dxf files to create cut paths.

David
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Re: how to determine scale of design to cut

Post by roberob2025 »

adbuch just checked out your website and see you have a 52 f100 youre restoring. I have a 1956 f100 I am building right now. I got the roof from midfifty and working on getting that installed! But for the plasma cutting I have the same problem with fusion 360 freezing when trying to import files. It happens a lot. I have watched some videos of people using inkscape to clean up the files and then import into fusion. I think I will give inkscape and sheet cam a try. My subscription to fusion is up next month and I dont think I will renew since I have gotten the hang of it mostly and dont really want to spend the money to renew. I havent had to ask them for help in the last couple months either. Do you use Coreldraw? If so what do you think of that compared to inkscape and fusion?
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Re: how to determine scale of design to cut

Post by roberob2025 »

Do you guys happen to know which program is good for doing an auto trace? If I have a photo of a design I know I can use the canvas to trace it in fusion 360 but is there a way to have the image traced without having to trace the whole thing?
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Re: how to determine scale of design to cut

Post by adbuch »

roberob2025 wrote: Wed Jun 08, 2022 2:15 am Do you guys happen to know which program is good for doing an auto trace? If I have a photo of a design I know I can use the canvas to trace it in fusion 360 but is there a way to have the image traced without having to trace the whole thing?
Inkscape is pretty much my "go to" for auto tracing. Also Vector Q for converting jpeg to vector format. This is a free download app for IPad.
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Re: how to determine scale of design to cut

Post by roberob2025 »

i just asked if it was for ipad only in another topic! I downloaded inkscape and have been watching videos to learn the buttons and the autotrace. Still not understanding it to well but its only been a couple hours so I am going to keep working at it. thank you for the input.
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Re: how to determine scale of design to cut

Post by adbuch »

roberob2025 wrote: Tue Jun 07, 2022 9:17 pm adbuch just checked out your website and see you have a 52 f100 youre restoring. I have a 1956 f100 I am building right now. I got the roof from midfifty and working on getting that installed! But for the plasma cutting I have the same problem with fusion 360 freezing when trying to import files. It happens a lot. I have watched some videos of people using inkscape to clean up the files and then import into fusion. I think I will give inkscape and sheet cam a try. My subscription to fusion is up next month and I dont think I will renew since I have gotten the hang of it mostly and dont really want to spend the money to renew. I havent had to ask them for help in the last couple months either. Do you use Coreldraw? If so what do you think of that compared to inkscape and fusion?
I've got a 1956 F100 project as well. It actually runs, but I still work on it from time to time. I remember back in the day I was making parts for Mid Fifty - some sort of mounting brackets used to install Toyota steering box into an F100. I also used to supply then with some custom art deco style dash knobs.
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I have CorelDraw 2020 - but don't use it much. Others here use it all the time and seem be very happy with it. I think that many of the Corel Draw uses also use Inkscape, and perhaps Fusion 360 as well. Many here use a variety of different programs, sometimes in combination to achieve an end result - and other times as a stand-alone task with a single program.

David

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Re: how to determine scale of design to cut

Post by adbuch »

roberob2025 wrote: Wed Jun 08, 2022 2:36 am i just asked if it was for ipad only in another topic! I downloaded inkscape and have been watching videos to learn the buttons and the autotrace. Still not understanding it to well but its only been a couple hours so I am going to keep working at it. thank you for the input.
Here is a link with step-by-step mini tutorial on using Inkscape for auto tracing. As you can see, I often use Paint.net first for image processing, then import to Inkscape for the actual auto trace of jpeg file to achieve a vector file suitable for cutting.
David

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