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Scaling issue with my post-processor for Laguna router table

Message 1 of 11
222 Views, 10 Replies

Scaling issue with my post-processor for Laguna router table

I have used Fusion for CAM on our 4x4 Laguna Swift Router Table. I usually machine aluminum for our local robotics team, but for some reason, I am having an issue with the part in Fusion360 is correct. When I load the program on my machine (using the manufacturer .cps file for machine post-processing), the part cuts out about 2.5 larger than expected. This seems to be a millimeters-to-inches conversion or scaling issue that I have failed to isolate.  I am trying to cut a 3x5 gusset plate; the boreholes are about 3/8th inch. They should be 3/16th. 

I have attached the .f3d file, and I am importing the post-processor. The setup template is for a 1/8th inch single flute end mill, but it is a .f3dhsm file and is not supported for attachments. 

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Message 2 of 11

If your controller is in MM, make sure they match on the post window.



Please click "Accept Solution" if what I wrote solved your issue!
Message 3 of 11

I made sure both were correct on the model and the post-processor. It still gave the same error. The part file was exported from Onshape as a .STEP file, and then I imported it into Fusion to do the CAM.
Message 4 of 11

Its obvious, but is the STEP file the right size IN fusion?

Please click "Accept Solution" if what I wrote solved your issue!
Message 5 of 11

It is the correct size in Fusion and from the export from Onshape. I also checked the dimensions in SOLIDWORKS, and they are all correct. I also can't tell in the gcode where my error might be either. I am at an absolute loss here.
Message 6 of 11

Your model is in Metric, and about the right size. There is no setup in your file.

Make sure the posting units are also in MM as I said above IF your controller is running in MM mode. Switch to Inch if its in Inch.

A .196 hole that is being cut ON CENTER with a 1/8" endmill would end up being around 0.321. 

throw your Gcode into and make sure it looks right.


Please click "Accept Solution" if what I wrote solved your issue!
Message 7 of 11

As you suggested, I used the NC viewer to check the code. Most of the time, I have to zoom out to see the whole toolpath, which feels like part of the issue. In a few configurations, it appears normal on NC Viewer, but when I use it on my machine, the part is too big or too small.

I found some information about Onshape natively exporting STEP files with meters as the default unit. I have uploaded and converted the step file to .F3D, I have changed the document properties in design to mm and inches, I have the post processor from the manufacturer, the router table runs in millimeters, and I checked all the setup. I am posting everything I have so far to try and get the issue resolved.


At this point, I think it has to do with going from Onshape to Fusion. 

Message 8 of 11
in reply to: joel.smith3S2VN



Had a quick look at your file, the dimensions of the Model look correct, the only thing I could find that was odd was the Machine selection, there were no values input for it so I removed it and using the Post Processor you supplied, generated the G Code again, looks correct now so give it a try, modified f3d file attached, you will only have to re-set the location for the G Code.

Message 9 of 11
in reply to: engineguy

I was hoping this would resolve the issue, but it hasn't. I have attached pictures of what it looks like on my table. The holes there are 10.5mm and the center-to-center distance is 50mm. The holes are supposed to be about 5mm (0.196 in), and the center-to-center distance is supposed to be 12.7mm (0.5 in)



Onshape natively exports in MKS, but the size looks right in Fusion. When I use the post-processor, it either makes the large version or if I change the units, it makes a tiny version. In the picture above, you can see the differences between each size. I have two Laguna post processors I have tried, and I even tried the fusion library version, and still no luck. Competition is coming up soon, and we are not having any luck.

Note: I have also imported the file in as a dxf and extruded it to the stock thickness and the issue is still persisting. I have checked other forums, and I have contacted Laguna, but they still haven't gotten back to me. 

Message 10 of 11
in reply to: joel.smith3S2VN



As I posted earlier the G code being generated is correct, to test this I removed the fillets on the Model and checked the Y axis distance, in the G Code the distance was 3.5in which is the correct size of your Part in Fusion.


I suspect your CNC is incorrectly setup either mechanically or at the control, if the G Code is saying move 3.5in and the CNC is not obeying that command (Moving more/less) then you need to look at the CNC.

I`ll try and do a short video that may help later 🙂

Message 11 of 11
in reply to: engineguy



No idea what is going on, I can only show you what I have tested here, the only thing I can think of it could possibly be might be your lead in/out settings. Possibly your Tool offset is wrong, that would send the tool to the wrong position as well 🙂 🙂

As you can see from the video the G Code output is correct for the test so the CNC should only move 3.5in

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