Newbie needs help with fillet in X2 solids

[Sparky_NY]

I have been trying learning solids but ran into a stumbling block. There is a boss on the part that needs .125 fillets on 3 sides. I can get the 1 long side no problem. the short side by using a different type fillet BUT the other long side refuses to fillet for me.

I am attaching the part in hopes someone can help me out with why I cannot get that last fillet. No doubt I used too difficult a part for my first try at solids but it has been a learning experience thats for sure.

Also, I would sure appreciate any suggestions for appropriate toolpaths to make this part. (on a 3 axis bridgeport) I have played with surface contour rough but that is proabably not the best way.

Thanks much!

(I had to lower chaining tolerance to .001 or the solid wouldn't generate)

Update: I found the chaining problem, a line and arc that missed by .0005 for some reason. I wonder why that happens sometimes when the autocursor is used for placement adjoining another entity. At any rate I fixed the problem and rechained so now everything is back to normal. (.0001 chain tolerance).

I uploaded a repaired zip file of the part but still have not been able to create that last fillet>

[cadcam]

I tried to open your file and it come up as a corrupt file. but it opens in X3 as i now see. but does not open in X2.

[Sparky_NY]

Originally Posted by cadcam I tried to open your file and it come up as a corrupt file. but it opens in X3 as i now see. but does not open in X2.

I fixed the file earlier today (broken chain by .0005) with the help of a friend, I now see he is using x3 which explains why the file went to x3 format.

I am surprised nobody has suggested why I cannot create that one last fillet. I am learning and this was my first attempt at solids. If I have the boys here stumped then I am in real trouble!

[cadcam]

Here is the file. I had to change how you did a few things and to get the .125 fillet in the back side I had to cut instead of create fillet. but you should have what you wanted.

[Sparky_NY]

Originally Posted by cadcam Here is the file. I had to change how you did a few things and to get the .125 fillet in the back side I had to cut instead of create fillet. but you should have what you wanted.

That is indeed what I wanted. Thanks much.

As mentioned, this is a learning experience and I wonder why the failure of the solid/fillet command happened when it worked fine on the other side of the boss. I am confused, the boss seems to have nearly identical faces and fillets to the same flat area on each side, yet the solid/fillet command works on one side yet not the other. What is different between the sides that causes this? I am still at a loss why the solid/fillet command fails in this case yet worked perfect in every other area for me.

Also, I noticed if I go to that last fillet in the list, and just click geometry, the fillets disappear! Whats up with that? I have to reload the file to get the fillet back even though nothing was changed. Regenerating does not do it. Why would just clicking on the geometry line under the fillet selection cause this?

Thanks again, I am trying to learn but some of these issues almost seem like program bugs to me at this point that have to be "worked around".

[tstom]

I run into this all the time The problem is your fillet "runs off the edge" of your part ....it can't maintain the radius clear to the end of both faces
The fix is to start with a bigger block ,add the boss, fillet it then extrude cut for your outside shape
You will see I used geometry to cut some of the fillets and geometry to generate some of the other fillets
There is one edge that is filleted that you probably don't want but you probably can create a boss on that end to square it back up

Just another way to approach it

[Mike Mattera]

Always do your extrudes and cuts first. Save all of your fillets for last.

You probably could also work around it (sometimes) bu putting very small fillets on the vertical edges and when you pick for the bottom edges try the "propagate along tangencies" that will wrap it around the edges.

Solid modeling is more about "technique" rather than "technology". If you build things in the wrong order, adding that last item can make if fall apart.

Mike Mattera