I’d like to see if anyone can help me with this part? It looks simple, but it really has me stumped.
I have to make a forming / pressing die set to make the part on the left, from .0625 Sheet Metal.
I will machine the Upper Press tooling using the inside surface of the original part, and the
Lower die, from the outside of the original part.
I exploded the solid
Rotated the vertical leg 6 degrees to allow for material “springback”.
I now need to re-fillet the surfaces to a.215 rad
And eventually turn into a solid press brake tool for the machine shop to program from.
If you want to do that with the same accuracy of the true arc fillets of the original model, you can make the fillets with FilletSrf. All you have to do is extend the 9 surfaces that are too short so that the fillets will reach.
In the attached file TEMP BENDx.3dm (2.7 MB)
I extended the 9 surfaces on one side and untrimmed the other side (keeping the trim boundary). Then made the fillets. Then trimmed and joined it all. Then offset (solid) .63".
If you want to make the fillets all in one go you can use this python script: Filsrf_crvs2.py (41.3 KB)
Hi Frank - I think I’d be inclined to create new ‘proper’ fillets here - it is is bit of work, but cleaner and more accurate, I think.
Actually you may be able to Untrim and re Trim the surfaces that are there.
-Pascal
Thanks all for the input!
I attached my final die set so you could see my challenges. Admittedly, I’m not 100% proficient in Rhino, but I’m comfortable with most projects. This one in particular really kicked my butt! I had a lot of trouble joining and booleaning. The part ended up looking like Frankenstein’s monster. And the goal here was to give the machinists a model they can program from, using Fusion 360 and/or Mastercam. Oddly, my son Thomas had to help me reassemble these using Rhino 8 — not sure what that was all about.
Any input on this would be greatly apricated, since I have two more to do!
My first comment is - why is your model tolerance so tight?
The upper and lower part of your die are misaligned by .0035". If that is acceptable then why do you need a tolerance of .00001" ?
Since you brought it up, I assume that means you didn’t really want the sides to made of a multitude of wonky surfaces.
Here is how I would make the parts. TOOLINGx.3dm (981.3 KB)
What i did was extracted the cyan and green parts (window select and join the result).
Then I took the border of the cyan (dupborder) and used setpt to flatten it (the red curve).
Then used extrude to make the sides.
Then trim and join and your done.
There is one tricky part to the trimming and joining. When you trim the sides with the cyan part it is pretty straight forward, but when you trim with the green part you must extract the border of the green and trim with that. The reason is that there are other intersections besides the border that will cause confusion if you try using the green (or the intersection curve) as a cutter. This is also why booleans will also fail if you try doing it that way - the extra intersections will get Rhino confused.
Also when you extrude curves I would recommend that you use the split at tangents option set to Yes. Setting the split at tangents option to No is just inviting trouble.
That is a great lesson on how to model these types of parts. I showed it to everyone, as well as stored it our Rhino “Tips & Tricks” folder. And I’m not sure how the resolution got set to .0001 — my current Rhino window shows .001.
I’ll be able to try all this on the next two diesets I have to make.
Just to clarify what I said on tolerance. When I opened the model you posted above I saw that it had tolerance set to 0.00001. That seemed too tight. If it were set to .0001" that should be OK and .001 might be OK also.
Sorry guys, but I need help again.
Using the above information, I still can’t re-radius this surface. I need to change the radius from the current .28 to .22.
Otherwise, I’m getting close - see dieset photo and first test. It came out ok, but I have to adjust the radius, as well as change for actual material springback.
The enclosed file shows pretty much the identical procedure as my Aug 15 reply earlier in this thread…
I exploded and extended each of the black surfaces (by .06") and untrimmed the green surface.
Then made the fillets, then trimmed. The green side gets trimmed with the fillets and the extended border. The black side gets trimmed with the fillets. RADx.3dm (284.1 KB)
