Final Product Doesn't Match Created File

Brand new to laser engraving/cutting. I’m using a K40 with cohesion3d laserboard and Lightburn. The one picture shows the project I created in Lightburn and the other picture is the test I did on the K40. Why isn’t it creating/cutting/engraving the project exactly as shown in the Lightburn sketch??? I’ve circled the couple areas where it isn’t exactly as it is in Lightburn.

The top left corner, it looks like the small circle is where it’s supposed to be but the box is supposed to be much lower and obviously not overlapping with the small circle.

The bottom left TEST and Box. The box is supposed to be in line with the LASER Box, and it’s placed lower, in to the TEST engraving.

The bottom right corner Box is placed in to the OFF engraving.

Any help would be greatly appreciated!

Just tried creating a new file and the same thing happened. No idea why this is happening.

I marked where some of the objects were supposed to be in Red.

Hi Ken,

Thank you for sharing photos. I also noticed some of your circles are not closed. This could be caused by mechanical issues like insufficient belt tension, gantry slop, idler wheel issues, or pulley set screws not being set or installed properly.

The design being offset is an indicator of skipping steps during faster travel moves. Each machine is unique and the board must be configured to fine tune performance. Some of the default configuration settings are set relatively high, so we can decrease values to test out until the desired results are achieved. Try the following:

  1. Power off the C3D Board and remove the memory card. No lights should be on.
  2. Put the board’s memory card into your computer, using a MicroSD/ SD reader if necessary.
  3. Open the config.txt on the memory card using an editor such as Sublime Text. Do not use Notepad++.
  4. Decrease default_feed_rate (Ex: 2000 down to 1000 to test)
  5. Decrease default_seek_rate to slow travel movement (not cuts), testing lower values incrementally until fine tuned (Ex: 18000, 12000, 9000, 6000)
  6. Increase current levels to dial in stepper motor performance (Changing Stepper Motor Currents on the LaserBoard )
  7. Decrease max speeds, testing lower values incrementally until fine tuned (Ex: 18000, 12000, 9000, 6000)
  8. x_axis_max_speed # mm/min
  9. y_axis_max_speed # mm/min
  10. Decrease acceleration to slow moves between cuts (Ex: 2000 down to 1000 to test)
  11. Save the config.txt file on the memory card.
  12. “Safely Eject” or “Unmount” the memory card.
  13. Put the memory card back into the board and power up.

Also, we received your email regarding your concerns. We were in the process of troubleshooting to determine what the issue could be. It takes time to review and get enough information to problem solve, so we appreciate your patience while we work through this together.

If you are still experiencing unexpected results after making these configuration changes, please let us know and we will explore other options to help isolate the issue.

Thanks for the response Starla. I’ll try some of those suggestions tomorrow. In the mean time, please tell me exactly what the cut modes do. Line, Fill, and Fill and Line??? I just need to know which mode to use to cut through something, which mode to use to engrave something and which mode to just make an outline of something. I’ve searched around but nothing really puts it in plain language or everyone uses different terms so it’s very confusing. I tried making something tonight and I used Line Mode with a speed of 8 m/s and power of 80 to try and cut 1/8" acrylic and it didn’t even come close to cutting all the way through. In the Lightburn video, the mode is labeled “cut” but that’s not an option in the lightburn that I have downloaded, which is the latest version. I’ll let you know how I make out with the changes you suggested. Thanks!

Hi Ken,

LightBurn is actively developed, so improvements are being made frequently. These instructions will walk you though the interface. There is a simple project about 4 pages in that includes the basics for settings. These may be what you are referring to, but here are some video tutorials that may help.

Overview
Line is Cut = Use this when you just want an outline or to cut out shapes
Fill is Scan = Use this when you want to engrave
Fill + Line is Both = Use this when you want to engrave and then outline or cut
Image = Use for raster image engraving

Outlining or cutting will depend upon the power and speed you have set on the layer. Do some runs to determine what combinations perform best on your machine for each of the types, such as a ramp test to determine your focal point for precision cutting and a power scale test to determine what settings give you the best engraving output.

Good luck and happy calibrating!

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