cam groove

[oldmachine]

... the angle depends on how the curve is drawn where it leaves the cylinder. Example below.

For this example, I used two bodies - each having a curved end. Also used bSplines for the curves. Threw this together to show the groove can be flat and not angled (did not spend time/interest in making all ending edges flat)... Two views: side and front

[chrisb]

... the angle depends on how the curve is drawn where it leaves the cylinder. Example below.

At 90° and 0°: yes. But if you have a curve at all you will have a position where the cam is angled. Please make a screenshot of a section at 45°, I attach mine.

[oldmachine]

Mine is flat. Scrnshot attached rotated to 45º.

Also, I'm 3D printing one with a different curve for fun... it's also flat. scrnchot attached... will post photo later...

[oldmachine]

[ADDED]

scrnshot of part in printer bed - at 45deg show flat.

Think about, I'm cutting the top and bottoms off with a cut - cut's go in a straight direction across the plane of cut... No way it can be angled unless the cut itself is angled where it enters/leaves the cylinder...

[chrisb]

Could you please upload your model?

[oldmachine]

model(2) attached. One is the previous the other is the one I'm printing...

[emills2]

Think about, I'm cutting the top and bottoms off with a cut - cut's go in a straight direction across the plane of cut... No way it can be angled unless the cut itself is angled where it enters/leaves the cylinder...

i hope you're being facetious you clearly are changing the model and fixing every problem section as it is pointed out....keep doing that and you'll end up with a plain circular groove

[oldmachine]

you clearly are changing the model and fixing every problem section as it is pointed out

No, you are not correct. I fixed 'nothing'. If you read my posts, you'll see I offered words indicating it was a 'concept' model and that it can be tweaked as needed. Also, I offered optional ways of doing it. The models I posted reflect exactly that.

The 'angle' thing is/was not a model/concept error - only how I entered/exited the cylinder, as I pointed out. I also indicated that (the user) can create the path as needed. That is what I have done to show that the concept and my suggested alternatives are valid - it's up to the user to determine the angle of the dangle desired.

The path could look like butterflies and, as long a the enter/exit from the cylinder are flat, so is the cam groove.

[emills2]

the critical aspect here is that ONLY radial sections matter. in the attached model, enter the new sketch, change the angle, and make it cut various parts of the angled portions.

i didn't finish the section cut, because it was clear just by seeing the lines.

Cam_3Da_bad_slice.PNG (134.87 KiB) Viewed 725 times

These things need to be modeled exactly as they are intended to be made and used: the end mill acts as an exact representation of the cam, as the workpiece is rotated in the exact same axis as the real motion of the final assembly.

the only time this operation matches an extruded cut is when the cam profile is flat.

now the fantastic news here, is that you don't need to model the groove to CNC it perfectly! just draw the curve of the intended cam center point on the cylinder surface, set the endmill to follow it, and then plunge the tool to the depth of the groove.

i made perfect models of these in solidworks, had then made, and they work (over a year of run time for certain units by now).

the biggest problem was communicating with the CNC guy. he kept trying to use an edge off of the step file in his software. never worked. i had to cut off the upper half so that a CAD edge would exist that represented the actual tool/cam center point path. so if just had the path as a curve along a plain cylinder, i would have saved hours of debating.

[emills2]

you clearly are changing the model and fixing every problem section as it is pointed out

No, you are not correct. I fixed 'nothing'. If you read my posts, you'll see I offered words indicating it was a 'concept' model and that it can be tweaked as needed. Also, I offered optional ways of doing it. The models I posted reflect exactly that.

The 'angle' thing is/was not a model/concept error - only how I entered/exited the cylinder, as I pointed out. I also indicated that (the user) can create the path as needed. That is what I have done to show that the concept and my suggested alternatives are valid - it's up to the user to determine the angle of the dangle desired.

The path could look like butterflies and, as long a the enter/exit from the cylinder are flat, so is the cam groove.

your concept will NEVER produce a workable CAM path, unless it is a flat circle. no matter what the user tweaks. do you still not get that this cam is supposed to rotate?

Edit: did you not see Chrisb's picture that shows the invalid sections?