CAD Forum

Hi, I have a relatively simple design task - modeling a cable that is wound on a drum. Purpose being to build a parametric model in which you can change drum diameter, length, cable diameter, and find out how much cable fits on it before it becomes too large, and also for visualizations. I am aware that these calculations can be done with simple formula and online tools, but it is an interesting challenge to do it in SW. Basically like this:
The way I did it here was to model the drum for reference, make a cable profile sketch (circle), and then start a helix from it that runs until the end of the drum. There, a manual sketch with an arc to continue that helix up to a second level, then another helix running back, another arc sketch, another helix, and so on. Finally, all helixes and arc sketches combined into Composite Curve, which can be measured for length, and then Sweep for visuals. Note that circle used for sweep must be just slightly smaller than the actual diameter in order to prevent self-intersecting body due to floating point errors.

Issue with this approach is that it's very tedious to do. Lots of sketches to set up. Also not very parametric. I would like to be able to control number of layers of cable on the drum with a single variable, but this won't work with current approach. Still, attaching the part.

Any ideas on how to solve this in a cleaner and more parametric way?

P.S. a secondary question, but is there any way to improve Sweep performance for a part like this? My SW really struggles as I climb over 30 meters of cable.

laukejas

You might simplify by making all the coil layers in one go. I would also eliminate all the extra sketches and planes, and instead pack as much as you can into a single sketch. I find that makes it much easier to find the control knobs to edit them.

Since you are on 2021, you can't open my model, but I attached some images.

Dwight

Dwight wrote: ↑Wed Jan 18, 2023 6:04 am laukejas

You might simplify by making all the coil layers in one go. I would also eliminate all the extra sketches and planes, and instead pack as much as you can into a single sketch. I find that makes it much easier to find the control knobs to edit them.

Since you are on 2021, you can't open my model, but I attached some images.

Dwight

Screenshot 2023-01-18 060154.png

That is a smart approach, thank you! But how would I extract the info about the total length of the cable?

You can find the volume of the cable and divide by the cross section area.

Dwight wrote: ↑Wed Jan 18, 2023 8:24 am You can find the volume of the cable and divide by the cross section area.

Very neat, I didn't think of that. Interestingly, for some reason the value provided by this equation doesn't match the measured length of the helix - it is off by a relatively small and consistent amount. I noticed this when doing a sweep with a single circle in the profile sketch. It is not really important.

Aside from that, is there a way to make these ends wrap up from one layer to another more realistically? In my example, there was a transition from one layer to another, probably this isn't possible here?

The solution I gave doesn't really work. The alternating layers should switch winding direction, so you need two helixes. Seems the cable must stack by a full diameter, rather than nesting.

I'd set up the ends to be 90 degrees apart and connect the ends with a sweep that follows a style spline.

Dwight