Tim's 3d scanner hardware thoughts / review thingy

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rufu5
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Re: Tim's 3d scanner hardware thoughts / review thingy

Post by rufu5 » Thu Aug 20, 2015 8:05 pm

note: check to make sure it's ok to coat the object in developer before covering the object in developer.

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piercet
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Re: Tim's 3d scanner hardware thoughts / review thingy

Post by piercet » Sat Aug 22, 2015 5:22 pm

What happens if you spray it on a software developer?

Started work on the scanner frame redesign today. I tracked down the STL files on Thingiverse http://www.thingiverse.com/thing:740357 and it looks like there are a handful of existing modifications (http://www.thingiverse.com/thing:740357/#remixes) . I really like the Idea of adding LED lighting powered off the scanner as well, so that might be something I include as well.

I'm tackling the turntabel base today. I've got the 20mm extrusion pockets done, but then i got to looking how they were printing that thing, and it would be really difficult to print them as is. They also are using a bunch of support. Since there isn't a whole lot of torque there, and since I kind of want to put a different bearing arrangement there anyways, I also decided to slice the turntable base in half and mount the upper bearing and motor plate to the lower section using m5 heat set inserts. That will allow both halves of the resulting assembly to be printed without support, and will allow for easier modification / upgrades going forward. I also eliminated the third rod entirely. the motor cable will be ran via the top unused Tslot channel, and covered with tslot way cover plastic sourced from Mcmaster carr at $0.10 per foot. You can Kind of see where I am heading in this unfinished rendering.
baseplate.png
For the scanner main body itself, printing that large of an assembly is going to take alot of time, and be prone to a higher failure rate than something composed of smaller assemblies. I still want to try and make it folding, but either way I want to make the overall unit easier to print in several assemblies. to that end, the base will become a separate hinged unit with anchor points for the power, on / off switch and 2 USB ports. The mid section will become a standalone enclosure, probably with a flat back panel for ease of printing. I like the curved one, but that has to be a pain in the ass to print.

The upper section will now bolt on to the mid tower, probably with M5 heat set inserts. This will allow replacing the upper segment to accomodate camera / laser upgrades in the future without needing to reprint the entire body. The arms will become 2omm extrusions on the same sort of hinge as the lower frame. I plan on using lever cam nuts to lock the arms and base in place, along with integral physical travel endstops, maybe a magnet or two. On the arms, the main unknown for me is laser adjustability. Would it be better to allow the lasers to be easily moved along the arm to adjust the aim point, or would it make for an easier user experiance to lock them in place at the fixed end of the arm like they are now? For the laser mount itself I plan on using a clamp style mount rather than the existing single point screw. Building in threaded adjustment points is possible, I just don't know if they are needed.

The folding anti tip legs will bolt onto the lower frame T-slot. With the amount of mass being removed from the lower assembly, they may become more necessary.

I'll probably make a separate build thread in here once I get parts further along to separate it from general observations. I need to figure out next which angle and intensity of lighting work best for best scan resolution.

Toysrfun
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Re: Tim's 3d scanner hardware thoughts / review thingy

Post by Toysrfun » Sun Oct 07, 2018 12:34 pm

It is nice to see your excitement over your new toy however I think your initial assertions and expectations are far to high. Please don’t take this too critical after all you opened this discussion in the same manner to point out those aspects in which you would change. Might I say it’s an open source project meant for you to build and discover your own process while offering an example of its basic function. Also.., you knew the design you were purchasing before you ordered it so what you are suggesting is more of an “after the fact”, in receiving it. Not so much an unboxing review. Kind of like buying a tv without evaluating it until after you bring it home, or going to the scrap yard picking up some alloy and then telling everyone afterwards it has a bend in it? It isn’t useful to the community. This to me is more so a kind hearted complaint by you that it couldn’t be better for the money you paid. Again, this is what it sounds like in your statements. It could further be argued this should have been a preemptive discussion while researching prior to your purchase and asking others opinion about practical changes beforehand. When looking online at the design I had pointed out to myself (privately) many issues from my own personal assessment including it’s obvious inability to scan effectively.., so I would not purchase one. That scanner was developed for educational and developmental purposes so that an individual could make changes on their own and perhaps later share those ideas with the community if they so choose. The suggestions in using extrusion etc... you could have purchased those parts yourself and built one from scratch using less than 3 meters of material, perhaps 2. Or.., you could’ve approached the concept by using the STL print files to print off the parts to assemble one and evaluate in private before purchasing the hard components? Then you could have interpreted your changes and worked your modifications in a new structure or printable design; in the end having spent less money and a product that suited your needs. You’re also not taking the cyclops to a museum for scanning; regardless of it being an example in conversation. First of all they have scanners that cost tens of thousands of dollars. I’m certain that they use multiple scanning processes including structured light. We are building a scanner ourselves however as stated not this model. Not having a full box enclosure makes this type of scanning inadequate. We will be implementing a combination of scanning technologies ourselves including structured light and laser for developmental purposes. Using various techniques and trialing multiple high quality line lasers, industrial grade cameras, and a carefully lit extruded frame enclosure. We will look at the zum board among pi, and some of the micro pc based boards in various aspects to see where the most reliable and effective platform fits within the realm of 3D scanning. Look into the David structured light scanner that was recently acquired by Hewlett-Packard and also various similar technologies while you google and then imagine scaling one of those technologies into a 900 x 700 x 850 printer enclosure with a 750 x 600 x 600 print bed and scan platform mounted inside using two operating systems interfaced into front of the enclosure. The ability to scan, print, and rescan to check product tolerances, quality, etc.., and also replicate your existing products that may be machined in other applications for ease of prototyping changes in design in a cost effective manner. When it comes to scanning it is important your hardware isn’t low quality. Keeping in mind much of the process beyond hardware is done in the software which also requires many aspects that Arduino will struggle to achieve. Perhaps the Due, Samd21, or similar platform may do an ok job but it is more likely a Linux or python based 64 bit system with at least 2gb of Ram is used and a minimum 32gb hard drive if one plans to compile those scans into one finished product within the scope of a efficient 3D scanner. Or a 3rd party program will be used to compile the scans together and stitch them into a high resolution file that can be replicated exactly or better than originally scanned. To emphasize this takes some processing power to properly achieve positive results. If you haven’t yet seen it google the Fabscan pi. Currently the product is in development of version 3 which is actually promising for hobby level 3D scanning. I beleive if they were to move to an orange pi or other 64 bit Multi core board that they will start seeing huge improvements in scan quality. It would also help a developer significantly when a smaller commercial unit can be purchased and present for comparative analysis. This could save them considerable time and money. Trialing hundreds of cameras, dozens of lasers, and so on adds up before they realiz they have $15,000 in hardware laying around to turn around and open source their hard work so you can do it free or on a friendly budget. The absolute dedication from these men and women out there is outstanding and because of them and other developers we have all of this open sources technology currently available and being consistently updated to the community. Hats off to them for their dedication and hard work while the vast majority of the community takes advantage of discount products and Free software/firmware. I urge you to consider delving into your new found toy and finding new and innovative ways to expand upon it. I’m sure if the community agrees and responds in kind you may find your efforts being passed along.

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