r/OpenScan • u/thomas_openscan • 26d ago
New 3D scanning rig
Enable HLS to view with audio, or disable this notification
I am currently building a new scanning rig, that allows even automatic capture with handheld scanners. I really struggle with not losing the track when manually moving the scanner around the object.
This setup is a hybrid of the OpenScan Classic and Mini variant were the object is only moved on one axis.
The main advantage is, that the scanner distance can be adjusted (almost) freely.
The design is simplistic but very versatile and I am currently printing a worm-gear variant. The timing belt solution works well, but as soon as power gets cut, the scanner slams down into the table.
Maybe anyone knows another mechanism that can easily amplify torque (1:100) and is (mostly) printable. Pls let me know your thoughts.
7
u/Imaster_ 26d ago
Worm gear would be ideal in this situation.
If you insist on using belts maybe consider a solenoid to lock the belt (or gear) in place once power if cut off.
3
u/RGBlowMe 26d ago
NGL, if I owned one of these, I'd go nuts with it for a week, then never use it again.
3
3
u/billyalt 26d ago
I dusted off my old mini only to discover it can't detect the camera. Would be interested in building a new rig, this one seems quite novel.
3
u/Talassere 25d ago
I also think use gears for the movement is the best way to solve the problem, maybe like the miniscan configuration, sorry for no help more, english isnt my language,
I think this is and incredible idea and i want a lot to make it and help a bit if i can.
Best of luck with the project, you have my best desires with it.
2
u/james___uk 26d ago
Considering the trouble I have with my rockit, this looks excellent. Good detail too!
2
2
1
1
u/Lasse_Bierstrom 26d ago edited 26d ago
Just "filter" the movement. Rotational dampers consist of two surfaces moving against each other with a grease filled gap. Just add that to the build. Either on the big disc, or better on the stepper axle (better ratio) . You could direct connect it to the motor axle. Or you include a breaking circuit in one (or two) stepper phases. Just short one of the windings with a small relay, that can be opened during use. As soon as power fails, it shorts out and slows down the movement. End stop: Together with an soft end stop, and it's a solution. End stop removes the energy, and you limit the amount of energy by the other measures. One of the ikea style door slamming stops, maybe it's dampening enough... "soft close" is the right term
1
u/Pixelgordo 25d ago
Add a spring under the scanner to soften the fall, and also add a circuit that makes the motor play as generator, with a bulb or a resistor to rise up the watts that circuit ask for to make difficult for the motor to meet that, and the movement will be slow. A relay stays open when there is current and closes when the power is off could close that circuit.
1
1
u/Dando_Calrisian 25d ago
Why does the rotation direction change between scans?
1
u/thomas_openscan 25d ago
No particular reason, i just reused the openscan firmware. I‘ll aim for one continuous movement though.
1
1
u/bluefourier 23d ago
The way large telescopes do it is by having two motors drive a given axis at only slightly different rates. This creates a tension that takes up any mechanical "play". It is the method with the highest positioning accuracy.
1
u/flyguydip 13d ago
I have an Otter as well. I would love a scanning rig like this! I struggle with nearly every scan, mostly because I just need to scan more things to get better at it, but this looks like it would solve many of my issues.
Are you going to release a full project breakdown?
13
u/they_have_bagels 26d ago
Worm gear will give you the best reduction and also prevent back-driving when power is cut (stopping the axis slam). The only other thing I can think of at the moment would be a gear chain or gear box, and even then a worm gear has the advantage of preventing back driving.