Translational motion of a camera lens

[ImRajSahu]

TL;DR

I want to create a translation mechanism myself by 3D printing , and I was able to do so by copying the features of an old camera. But having issues.

I have designed a mechanism in solidworks of the focusing of a camera , I have copied all of it's detailing, barrel with circular and helical slots, pins , rotating ring , a follower which holds the lens. The system works when I push the follower manually by hand but when I try to rotate the ring which is supposed to rotate the barrel which eventually makes the follower follow the helical path with the help of pin and allow the lens to move back and forth , but when I assembled all the components ,I was not able to rotate the barrel , the system gets stuck at some point and hence I am not able to get the expected translation motion. Can anyone help me identifying what am I doing wrong?

 

[Borek]

Not knowing anything about the project: the more complicated shapes involved, the more elements present, the more sensitive the mechanism is to tiny inaccuracies and imperfections of the surfaces in contact. Most likely your enemy is just the friction.

 

[Lnewqban]

... but when I assembled all the components ,I was not able to rotate the barrel , the system gets stuck at some point and hence I am not able to get the expected translation motion. Can anyone help me identifying what am I doing wrong?

Being a 3D print, are all the components made of the same material?
Is the ring supported by a circular track?

 

[sophiecentaur]

TL;DR Summary: I want to create a translation mechanism myself by 3D printing , and I was able to do so by copying the features of an old camera. But having issues.

Can anyone help me identifying what am I doing wrong?

Have you read the spec of the printer - linearity on the axes etc? Have you checked the dimensions of items or test pieces with a micrometer / caliper? Even machining with a good mill or lathe (10 micron accuracy, say) can 'let you down' and require checking.The temperature of individual regions of the model may be different during printing and that could cause distortion when cooled. But the spec should tell you what to expect for dimensional accuracy. You may just be over optimistic about the performance of your printer.

I have no experience of 3D printing but I suspect that all components should be made using common axes with the original. That could be difficult to arrange; certainly not convenient for some shapes. That would minimise incompatibility between the printed parts.

 

[ImRajSahu]

If anybody needs, I can post some images or video of my assembled product, I don't know if that will help

 

[sophiecentaur]

Have you read the spec of the printer

Have you? I did a quick search for "tolerance on 3D printed threads" and binding seems to be a common problem. What is the pitch of your thread? If it's on a camera is will be pretty fine and, from what you write, the thread diameter will be several cm(?).
All the threads that people seem to post are extremely coarse from their printers. If the size of the nozzle is not a small fraction of the thread pitch then strength could be a problem as well as tolerance.
I would hate for you to be chasing something for which there's no solution.

PS I just did some more searches and uncoverd the advice "Fine threads do not print" The alternative is tapped inserts or tapping a hoile. That's not possible for you as a large fine tap and/or die will cost you an awful lot of money and the alternative would be using a lathe. (Price more than your printer, i suspect)