Find the perfect Fit Tolerance for your Laser Cut Joinery? | What is Kerf and how to measure it?

[@sigh_of_the_times]

Im new to this so its a little over my head for now but when I get my lazer next month hopefully in time I will have a better understanding of it. But thank you for the time you spend helping others to understand the life of using a Lazer. Stay safe and take care.

[@ModeltreinenSchaalHO187]

Thank you! Very helpfull.

[@voidfish4387]

Can you show the part where you make the changes into the program itself because as such I cannot replicate this video. The kerf testfile site doesnt open and I dont know how to implement the mm changes into the test parts if they worked.

[@alanegan641]

Great video. Thanks for the clear guidance

[@glompos21]

Great work. Where we can found the Kerf tolerance test with the joins?

[@anthonywalsh6605]

I am not a laser expert, but I am an aerospace engineer. If your laser beam is producing a different kerf for the x and y movement then I would be looking at the focus of the light rather than try to compensate. Just a thought.

[@MiddleRoomWorkshop]

Hi Anthony Walsh; thank you for your comment. Your observation and suggestion are perfectly correct and the path I would go for, but it goes beyond the control of the user, i.e., our control. The beam produced by the high-power LED (compared to a CO2 laser) has a rectangular cross-section, and optics are used to reduce the rectangle's aspect ratio as much as possible. No matter how hard manufacturers try, there will always be a slightly longer side without spending a fortune is overengineered lenses. The rectangular shape of the beam causes the kerf to be different along the two axes, and since we cannot really do much about it, if we are looking to obtain a good fit for our assemblies, we need to compensate and give different tolerances to the two axes. BTW I love Aerospace Engineering; the curriculum is not easy but lovely. I am half a Structural Engineer, half a Naval Architect (where we share lots of subjects and math), and a Robotics Engineer in a while. Ciao

[@abumoslemtamer7331]

I'm doing a similar trick to get a perfectly round (equidistant) circle. Since the laser beam is not in the shape of a perfect circle, it is more elongated in one axis than in the other. So I do the following: 1- Decrease the dimensions of the horizontal or vertical axis of the circle by a little (usually half a millimeter), so that the shape is semi-circle (oval). 2- Then I rotate the shape at an angle of 45 degrees, so that the direction of the slightly longer diameter of the circle is in the same direction in which the laser increases the cut .. (in order to compensate for the decrease in the end). The result: Perfect Round Shapes (or Nearly Perfect)! I hope that there is a feature in the program that allows this to be done automatically! Thank you, and sorry for my poor English because I use Google Translate!

[@abumoslemtamer7331]

Thank you!

[@stephaniebobroski3962]

Hi, great video! I am trying to download the kerf files you posted but your website is not opening. I keep getting an error. Is there another link I can use or another website or another alternative to getting the files to test out? TY

[@proudcanadianeh4663]

Can I find or download a kerf test file like this anywhere please?

[@SamBatti88]

Hi, in your calculation, delta X and delta Y is the same value. Which value we use to calculate Kerf if delta X is diffrent from delta Y ? Thanks

[@MIMUPREFERIDA]

Great stuff!! How to you apply your tolerances found, in lightburn? Is that an automatic process that could be parametrized, o needs to be done by hand modifying manually the dimension of each cut? Thank you and good job!

[@MiddleRoomWorkshop]

Hello MIMUPREFERIDA, thank you for your comment. LightBurn has a Kerf option within the layer setting (specific later by layer) if you set the layer to line engraving. The option, when enabled, applies the Kerf to the entire geometry. Therefore it works fine only if you have a single Kerf value, i.e. vertical and horizontal Kerfs are equal. However, you will need to take extra care in designing your projects within LightBurn. I use Autocad, Fusion, and Inventor to design stuff that should be assembled. I create my projects parametrically to take two Kerf values for vertical and horizontal Kerf.

[@SamBatti88]

Hi, so if I understood, I need to take care about vertical and horizontal kerf at the design step ? I’m using Fusion. I’ll need to adjust dimensions to fit calculated kerf values.

[@ewe23]

awesome video! i'm brand new to lasers as I just got an xTool D1. do you have these files available for download? please.

[@MiddleRoomWorkshop]

Hello Eric Edwards, thank you for your comment. First of all congratulation for getting into the new hobby, and good choice for the machine. I have planned to write a post with it but I haven't yet anyhow below is the link to the kerf testing post, and following the link to the fit-test file. whathowwhysolution.com/kerf-testing-template-for-laser-engraving-machines/ whathowwhysolution.com/wp-content/uploads/2022/01/Kerf-Fit-Test.zip Let me know if you are able to download the file. Ciao

[@Etnassoft]

@@MiddleRoomWorkshop Great work! I have downloaded the zip with the Kerf Fit Test, but LightBurn can not open it. It seems correct, but maybe it is incompatible with the current version (1.2.01). Could you update it or take a look at it? Thanks and best regards!

[@miepic3291]

I am new to laser cutting, what wood is being used here for your examples?

[@safwancappan00]

mdf , Chesterboard , cardboard.

[@MiddleRoomWorkshop]

Hi, thank you for your comment. The material is a variation of plywood the look like bamboo on the surface. I got it from a local supplier which claimed it was a Thay Plywood. I hope it helps Ciao

[@aggiefan88]

Thanks for your informative video! I do have a question though, since I'm ordering my pieces from another business doing the cutting. When not having to account for kerf, is a difference of 0.254mm still too tight of a tolerance difference? or 0.395mm? (I'm converting from Imperial units). I'm trying to find the "snug" zone where the finger joints will be stable, but I'm not having to fight the inserts with a hammer to get them in.

[@MiddleRoomWorkshop]

Hi, Austin N; thank you for your comment. I cannot give you a precise answer to that. Have you tried asking the cutting business? They could give you a hint or directly apply the kerf compensation their selves. Usually, kerf will depend on the laser technology used and the focal length of the optics; diodes tend to be thinner than CO2 lasers, but this is not a rule. Also, the thickness and nature of the material play a significant role as the cut edge tapers. As a rule of thumb, in my experience, a 0.2mm (.008") kerf for materials 3 to 5mm (1/8" - 1/4") thick is ideal, meaning that if you want to achieve a snug fit, you should go greater than 0.2mm (.008") however for plastics like acrylic the value is a bit lower. As mentioned at the beginning, I suggest you to aks the cutting Business either to give you a more accurate value than mine based on their machine and the material type and thickness you are going to cut or ask them to test the material for you so you can account for kerf in your design before sending them the final cut design. I hope it helps, Ciao

[@aggiefan88]

@@MiddleRoomWorkshop Much help, thank you!

[@MSRWorkshop]

Couldn’t you cut a line and use a feeler gauge in the gap ?

[@MiddleRoomWorkshop]

Hi, MSR Workshop, thank you for your comment. Yes, you can use a feeler gauge, but you cannot really measure with it. You will need a set that goes as low as 0.04mm; mine, for example, goes down to 0.06 mm, which does not fit onto a laser kerf of 0.04mm. Also, measuring partial thicknesses might not be feasible all the time. Last but not least, not everyone has a set of feeler gauges; therefore, I believe that a standard Vernier calliper with a sensitivity of 0.01mm for the digital (0.02mm for the old one) is more suitable for the job. Of course, if you have a feeler gauge and not a calliper, then just try I combination of gauges until you find the approximate kerf thickness. Ciao

[@PastaDNA]

I'm having trouble with kerfs and I'd like to use your template for kerf testing. Is it available please?

[@MiddleRoomWorkshop]

Hi, Michael P; thank you for your comment. You will find one of the files on my site, but the Kerf fit test is still not posted. Therefore, I am pasting the download links here for your convenience: whathowwhysolution.com/wp-content/uploads/2022/01/Kerf-Fit-Test.zip whathowwhysolution.com/wp-content/uploads/2022/01/Kerf-Test.zip I hope it helps Ciao

[@PastaDNA]

@@MiddleRoomWorkshop Very kind and thank you, Happy Holidays...

[@ld-madeingarage9900]

Hello, I tried to download the test file, but the link does not work. Could you check? Thank you very much