Paramétric Hélix slot probleme…(and solution)!

[Hell3d]

Hello, I have a problem making a part with very precise tolerances.

I can’t build the gray part guide to create a 36° rotation movement for a translation of the red axis of 24 mm high.
The yellow axis must remain in contact with the two surfaces.
Can someone explain a method to me? Thanks

[Xdrakosha]

If I understand you right you want to make something like that?

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[BKE]

Here is an interesting thread

Revolve or sweep a body like a end mill to cut out a curve

Hello community, I am new to the community and would like to say hello. I used shape3d a lot so not really unexperienced but now I can’t find a solution for this issue and I would appreciate any help. I’m having trouble getting this curve profile to look like it was generated with a milling machine. I tried using the sweep and revolve tools to subtract the red area in the image from the cylinder. In reality, a end mill (blue) that is perpendicular to the longitudinal axis would cut the curve a…

[Hell3d]

Yes, absolutely
I tried several techniques, but never succeed, could you explain your method thank you very much…

[Xdrakosha]

I did two holes in edge points

Then drew a sketch in the start position and revolved 36 degree 24 mm

Then substracted revolved body from tube

I decided to 3d print this model, that’s why I added 0.1 mm tolerance

[Hell3d]

Amazing… How simple you made that…
I was just reading the topic From 2024… and the complex solution they came up.
Thank you very much for your help.

[Xdrakosha]

@Hell3d

complex solution they came up

They did precise math calculations. I just eyeball it

Main problem is to find precise angle of that sketch

With the angle of 111.35 degree I got most accuracy of 5.9918 mm instead of 6 mm

[Hell3d]

I was asking myself the same question… I made some visual corrections to find the best angle, but the solution works well, more than enough to create a prototype with my 3d printer…

[TigerMike]

Here’s a somewhat precise method. My slot is 4mm wide and the rod that slides up the slot is 3.6mm dia. The rectangle used in the revolve is rotated 54° which will be normal to the 36° angular slot that is 24mm high. After the revolve I added 2mm length to each end t compensate for the diameter of the 3.6mm rod. Hope this helps.

[Xdrakosha]

@TigerMike

The rectangle used in the revolve is rotated 54°

How did you come to 54 degree? Have you used any formula?

[TigerMike]

Not sure if this is totally precise or not.
90° minus 36° angular rotation = 54° starting angle of the slot that moves upward. Does that explain it?

[Xdrakosha]

@TigerMike

90° minus 36° angular rotation = 54° starting angle of the slot that moves upward

Quite interesting. I used the same method, which I explain above, but to get precise result had to rotate rectangle on ~68 degrees. Only difference I have 6mm width slot and 6 mm rod.

[TigerMike]

I too tend to eyeball designs (meaning examples). I used an intuitive approach on this one getting the 54°.
Each rod is copy elevated 6mm and rotated 9°.
Note, my first post said ‘somewhat precise’.

[Xdrakosha]

@TigerMike

Note, my first post said ‘somewhat precise’.

Yeah, I missed that

[PEC]

Hi

I made a precise parametric design some time ago to do this kind of slot so I share it here.
It is accurate even for large values of the helix angle and thick tube; it also handles clearance.
You just have to set 7 variables:

• d_out, d_in, l : dimensions of the tube
• d-pin : diameter of the pin
• e, alpha, clearance : dimensions of the slot

Parametric Slot milling 0.7.shapr (626.1 KB)

[kabocha]

Pec thanks for your file, I learned a lot. Enough to maybe manually produce what you did.