Corel Draw X8 SVG Export to Sheetcam

[JodiB]

Good day! I am new to plasma and all of its associated software. I'm currently using Corel Draw X8 - Sheetcam - Mach3. I've had many stumbling blocks but I'm making some headway. I've received a great deal of valuable advice on the sheetcam forum and was referred to this forum for more corel help.

For about the last 6 months, I've been creating designs and exporting them as DXF. There were distortions in the drawings when I would import them into Sheetcam so with the advice I'd been given, I've started exporting as SVG. They've come out much clearer, but still some distortions. Les from Sheetcam advised to make adjustments to my drawing import settings. My drawings have been cleaned up that much more, but still not where I want them to be. He advised that g-code does not like spines or bezier lines - apparently what all of my drawings are made up of. Is there any way at all in X8 to convert my drawings to polylines? Or any other conversion that g-code will read better? Is it possible to create new drawings without bezier lines or splines?

I've also been told that my SVG export settings in corel may need to be adjusted. Currently this is where they're set:
Compatibility - SVG 1.0
Encode Method - Unicode - UTF - 8
Styling Options - Internal Style Sheet
Java Script - The box is unchecked
Drawing Precision - 1:1000 units
Fountain Steps - 256
Export Text - As curves
Bitmap Export Type - PNG
Link images is checked

I've emailed corel support 4 x and called once in the past week - so far received 2 auto generated emails. Any advice or insight would be very much appreciated.
Thank you
Jodi

[tcaudle]

Can you define "distorted" for us a little better? Are they the wrong size, or non-proportional (width is off and height is on or vice versa) . Are objects not round or square . Are other things on your monitor distorted (like what is supposed to be a perfect circle). If you draw a cicle in Corel and hold the CTRL key do you get a perfect circle and does it display that way. Are you running SheetCAM on the same PC as Corel?

Have you tried saving in SVG and opening it in Inkscape? Inkscape uses SVG as its native format.

[SeanP]

It's a strange one that I am using just the same setup and getting really good results these days using dxf r14 format.
I seem to remember Les doing something to improve dxf import to sheetcam, are you using the latest version? I am using development version though.

Maybe post a dxf sample here that you are seeing problems with.

Try the attached lettering in sheetcam and see how that looks, it's in millimeters.

[JodiB]

Good morning Sean!

Thank you very much for your reply. What I mean by distorted is that some of my curved, smooth lines have a "wobble" or wave to them and some arcs come to a point instead of being rounded. My drawings are all the correct size and proportional - no problem with circles and squares. Yes, I am running corel and sheetcam on the same PC. I downloaded your file and imported to sheetcam. It looked pretty good - I did notice some areas where the lines were wavy and some smooth arced lines came to a point - especially in the holes cut out of the font. I then exported the file in corel to SVG format and imported back into sheetcam. The lines improved a fair amount, just a couple areas weren't quite right. I tried attaching the toolpathed file from sheetcam but it doesn't seem to like the format here. There were many areas where there was a congestion of toolpath arrows. We drew it out on paper (a pen attached to the torch) and I'm happy with the way it came out. The only areas that the lines looked wobbly are where there is a congestion of arrows on the sheetcam screen. This started happening after making adjustments to my drawing import settings - to improve the appearance of the drawing in sheetcam, I adjusted my Maximum detail reduction error to .0008 and my Minimum segments for arc fitting to 6. There has definitely an big improvement although it seems many more segments have been added to my drawings.

My apologies if I sound all over the place...its just been a bit of a frustration process getting everything to where we'd like it to be. I'm at the point where I think we need to accept what we're seeing now and work with it. If you're seeing something though or have any further advice, I'm all ears

Thanks again Sean and enjoy your St Patricks Day!
Jodi

[SeanP]

Thanks Jodi.

Not sure if this helps you for comparison, those letters are less than 1/2'' tall.

[muzza]

I don't have problems exporting SVG into sheetcam, I use an older version on one table and the development on others.
Screenshot showing SVG export settings

[JodiB]

Hello Sean and Muzza,

Thank you both for your replies. We've spent yet again another couple of days trying to sort things out. I've been playing with the settings on your file Sean and I'm going to try attaching a couple photos and a screenshot of what I've done with it. I've played more with the drawing import settings (changed Minimum Segments for Arc Fitting to 4 - improved some..less nodes) and tried changing some of my SVG export settings, Muzzo, but still not getting the results. Sean I've attached a screenshot of your file I exported to SVG and imported to sheetcam. As you can see there are quite a few nodes. The next 2 jpg's are photos I took of the file drawn out - the lines aren't smooth and look like they are made up of tons of little segments. I'm going to post 3 more attachments on another post for you to look at.

[JodiB]

My husband created a quick billiards sign to experiment. I went through and deleted all of the nodes in Corel except for the necessary nodes to maintain the drawing's shape. Exported as SVG then imported to sheetcam. The screenshot looks fairly clean - not a lot of nodes, though several have been added once imported into sheetcam. The jpg's are of the drawn file - it actually looks pretty good until you get to the R - the lines are completely wobbly even though there is no indication of that in corel or sheetcam (my apologies that the pics are upside down). We're at our wits end - we've done extensive reading and research and everywhere it says that we should be golden because we're using SVG format and the latest version of sheetcam. I also spend a great deal of time editing my files so that there are minimal nodes in them when exported as SVG. We've even begun to wonder if mach 3 could be a potential problem? When you look at my attachments, are you seeing any red flags or have any suggestions on how we can clean them up? Thank you!

[SeanP]

It looks like it's juddering on the nodes, check your mach 3 settings the CV control section in general settings.
I don't use any of those options, they can cause judder problems like that.

[SeanP]

The nodes look normal I would say, these are looking at the same in Corel.
You could reduce them some more maybe but sometimes start to loose shape then.

[JodiB]

Good morning Sean,

I just ran to the shop to look at our mach 3 settings. Sure enough, all 4 boxes were checked under CV Control. I unchecked them and ran another file. Sadly, the end result is the same. Thank you for the feedback regarding nodes. I was under the impression that I had to clear off the majority of the nodes from my files so I was spending a great deal of time doing that. Good to know that the nodes shown above shouldn't impact the cut.

The attachments are what I did this morning.

[SeanP]

Did you restart Mach after changing the settings?

[SeanP]

I might not have given you a good file to work from there, it's a bit on the small side, here is how it looks on mine.
Only other thing I can think is double check you have no play in bearings/drives, shafts etc.

Ran at 1000mm/min

[JodiB]

Hello Sean,
First off, thanks for all of your help. You've been awesome - I'm sure I'm not the first to say so on here. When I changed the mach3 settings, I did restart it to make sure they were my new default settings. Your file was absolutely fine to work with - I just made some size adjustments on my end. The lines on your drawing look nice and smooth - puzzling as to why we're having so many issues. The mechanics of our table was actually the first thing we looked at. We purchased a new table from a small company here in Canada in October last year. After receiving all of the parts, my husband had it assembled by mid December. For the following 2 months my husband basically pulled it apart, put it back together, we've received a couple of upgraded parts (motor, gears), he's squared it off a dozen or more times, hardwired it....and the list goes on. No doubt now that the table is good - accurate and runs smooth. Which brought us to the software issues. People like yourself have given us valuable information - we're just going to have to keep working at it to find a solution.

Thanks again Sean and have a great day

[SeanP]

I know just what it was like when I first started out, it's not easy, you sound like it won't be long until you track it down though.
Keep asking if you need any other info, it's no bother, someone else may think of something as well.

[JodiB]

Thanks Sean. Still doing some research and have joined the mach forum as well. Just curious, since we have the same setup, which post processor do you use? I'm currently using Mach3 Plasma...are there any other viable options? I'm also going to post a screenshot of my config settings from sheetcam. If anything happens to stand out, would you mind letting me know? Thanks

[SeanP]

I am using DTHC-HYT-TAP_SoftPierceMarker-rev11D as my electronics kit came from candcnc.
To be honest I'm not that well up on what posts can be used on what machine.
There are a few differences to my settings there, but again I'm not sure what they would make, my setting as above are the default settings, maybe they have been changed by the candcnc installer??
Sorry not much help there.

[muzza]

Sorry, I don't get on here very often any more.

Can I offer a suggestion to try.
Try going back to the start, as in Corel and rather than using the Bezier tool, try using the Polyline tool and see if that delivers you a better result.

What I suspect may be happening is that when you manually remove nodes it is distorting the lines as they are drawn with the Bezier tool as the handles are still pointing to where the removed node was. I only ever draw with either the Freehand or Polyline tools. If I need to reduce nodes I use the Reduce Node slider tool. In X8 you can also select a range of nodes that you want to reduce or manipulate by clicking the first and last nodes of the group.
Hope that helps
Murray

[JodiB]

Hello Murray!

Thank you for the reply. Bezier lines and splines have been a thorn in my side from the beginning. I am new to Corel and basically learned the basics through reading and youtube videos. I have purchased vector files, pulled different images in from the internet and "quick traced" them and have also drawn some of my own simple designs. To edit and draw any of my files, I've only used the freehand, 2 point line and 3 point curve tools. I've used the shape tool to add and delete nodes and to help with any reshaping and finally, the segment delete tool to delete unwanted lines. As you can see, I am using probably 1% of corel's capapbilities and am keeping things very simple. I have yet to use the Bezier tool or the Polyline tool - which leads to my confusion about my files being made up of Beziers and splines. I've tried getting some clarification on this from Corel but the person I was corresponding with didn't understand my questions. Can you shed some light Murray?

Thanks and have a great day
I'm also going to start using the node reduction tools you mentioned.

[tcaudle]

If the contours look correct in SheetCAM then the problem is not in the drawing. (beziers are not exported in DXF or SVG ) a pure arc is described as two end points with a radius, A Bezier is a mathematical description of multiple arcs with multiple radii joined as a poly object. Similar to a DXF spline or a poly line object. The problem is that G-code does not support that ( it can only do arcs in one direction with a single radius per a line of code)


The blue toolpath SheetCAM generates is what code it generates. You should be able to compare the toolpath (blue) with he contours and note an deviation. Now, if the blue lines look fine then you move to the toolpath presentation in the control software (MACH) and see what it looks like. If its correct (it after all reads the g-code and uses that to display the toolpath then its down to either the control software compromising the toolpath OR its mechanical. You have ruled out noise buy using a marker (good idea) that could cause deviation in the motion

I know you have worked and re-worked the mechanicals but that wobbly cut sure looks mechanical to me unless there is something in the final toolpath out of SheetCAM that is causing the problem.

Turn on your motor so they lock and go to each motor/axis on the table and tug and push hard to see if there is any backlash. Do the same with the torch holder / Z . Bottom line is if the toolpaths look even and smooth the code should be even and smooth and changing nodes or parts of the drawing are not going to fix it. You might can improve it by making the drawing simpler but it will still be there on anything more complex. And after all, decorative cutting is usually more complex toolpaths.

If you do a series of round circles of different sizes using the same settings for material and feedrates they should all be perfectly round. Thsy should come out with 4 nodes each. Cut then in both directions. If they won't cut right its a hardware issue .

[JodiB]

Hello Tcaudle,

Thank you for the explanation - great information. We've been banging our heads against the wall, going from one thing to the next trying to find the problem. We're going to take all of your suggestions and spend some time in the shop tomorrow. I've actually sent the g code for one of our projects to Les at Sheetcam to look at and have also posted our plasma profile for a moderator on the mach forum to look at. Hoping to hear back if they're able to see any discrepancies. I'll post back here again once the circles have been cut.

Thanks again for the info
Jodi

[JodiB]

Good morning Tcaudle,

Well...another weekend of trial and error. We decided to play some more with the drawing import settings in Sheetcam. We zeroed out all of the settings and set min seg for arc settings to 3. The drawing was FULL of nodes but unbelievably enough, it looked pretty good. We've played a bit more and we feel like we're on to something.

The blue toolpath in sheetcam looks good - no deviation from the contours of the drawing. Once imported to Mach, it still looks good, so I really don't see any visible issues that would translate to wobbly/wavy lines. As I mentioned, making the adjustments to the drawing import settings have made a difference, but again, not where we should be. I created a super simple drawing and was very pleased at the outcome, but then tried drawing my "family" file from a previous post above and still saw issues with it - a couple wobbles and the tops and bottoms of the font were flat.

I drew a series of 6 circles (in the same drawing) and each had 4 nodes in corel. Once imported into sheetcam, each had at least 20 nodes, but the shapes still looked good. I drew them out and they looked ok, but I noticed that each circle had the same deviaton in the exact same spot. I reversed direction of cut and it didn't make much of a difference.

My husband had a question with regards to backlash. He's the mechanical guy so forgive my wording if I'm not asking the question correctly - Our X & Y axis are driven by stepper motors with gears attached to the axle of the stepper motor and gears running in a gear rack - is there any backlash compensation needed? When you mentioned that backlash could be the problem, we did another once over on the table, squared it off and tightened it up, but still not seeing any change. Anything you can think of?

I also started reading about the motor tuning in Mach. Our settings are currently what the company that sold us the table had us enter - I'm wondering if the velocity and acceleration are a part of the problem as well? Any advice you can offer on that?

Thanks again for taking the time - any advice would be greatly appreciated.
Have a great day
Jodi

[JodiB]

Hello!

Thanks again to everyone for the help - its been much appreciated.  This has been a very frustrating few months trying to get it right.  We spent all day in the shop again yesterday playing with the mach3 and sheetcam settings.  We read through the online mach 3 installation and configuration manual and are still no further ahead.  I'm going to start one more thread as kind of a last ditch effort to see if anyone can see something we're not.  I'll post screenshots and pics to show where we're at.

Thanks again and have a great day
Jodi