Cut dimensions different from vector dimensions

[fyshious]

I am having a problem with cutting items (with a router) from imported DXF files. The dimensions of the cut items differ from the DXF vectors by 0.5 to 1 mm. This may not sound much but when things need to slot together it's a problem. I can compensate by adding "stock to leave" and the results are satisfactory but I would love to know what is causing the problem. I don't have a problem with cutting from drawings I have done myself and I have checked the accuracy of the CNC router (<0.1%).

I am still new to this and am wondering if anyone else has experienced this problem before.

I don't know what system was used to produce the original DXF files so could it be caused by differences in systems?

Thanks

Doug

[g-andresen]

Hi,

Have you checked the data after importing it into Fusion?

Please share the file.

File > export > save as f3d on local drive  > attach it and your DXF to the next post.

günther

[fyshious]

Hi,

I checked the dimensions were ok in the Design panel b4 going to Manufacture. All seemed good.

In the file I have attached, the slot should be 6mm wide.

Regards

Doug

[jhackney1972]

In the video I go through the process of capturing the machined component and then measuring the results.  As you can see the measurements are very close to size so I believe the error you are seeing is either in your post process setup or your router table.

[laughingcreek]

running simulation shows that you are over cutting the contour-

changing this setting to zero-

cuts it to the profile-

if you want to leave stock, that setting needs to be a positive value

[fyshious]

Hi John.

Thanks very much for that. That was way above my F360 skills. I Know now that F360 is working fine.

I have done some more testing and found that the cutting for parts from my own drawings are not right now either so the problem has got to be in the machine.

Thanks again John. I really appreciate your quick response and help.

Have a Merry Christmas

Regards

Doug

[etfrench]

Are the parts larger or smaller than specified?  Which one gives you the correct size, the -0.5mm Stock to Leave, or setting the stock to leave to 0?

[fyshious · Accepted solution]

Hi John.

You were right of course. Found a loose tension block and a loose drive connection on the machine.

Now cutting within 0.1mm which I suppose is not bad for wood.

Thanks again for all your help.

Regards

Doug

[fyshious]

Hi.

Outside dimensions were too big and inside dimensions were too small.

I found that leaving a negative stock to leave, the machine would cut to the right dimensions.

Have since discovered that the problem was in my machine. A loose drive tension block, which is hidden, and a loose drive connection. 

Proves the old rule; never assume!

Cheers