My only fully successful prints aside from the calibration were the "hello world" roctopus and a toy car.
I expect (hope) that this will improve with time, but so far it's been a little disappointing.
Prints that are insufficiently strong may be because the material is not strong, or the way in which it was printed did not favor strength, or the "slicer" converted it into layers in such a way that it was not strong. Sizing is another issue, my Makerbot Replicator does not print dimensionally accurate pieces, what it worse is the X direction is more accurate than the Y direction, the Z direction is spot on. So after printing a number of test pieces where the size it "should" be was known, and the size it was, was measurable. I came up with some "calibration adjustments" that I can put into my slicer program to improve accuracy (Simplfy3D).
There is also an issue of materials, very inexpensive printers might print only with PLA which is not nearly as strong as ABS. In the middle is a PET variation I got from MadeSolid. PLA, ABS, and PET are all shorthand for the chemical formula for the material. Different materials, different properties, these days you can also print in Nylon and other high density plastics. Somewhere I have a picture of a "hula girl" that was printed in PLA and put on a dashboard of a car, she is all melted due to the heat on the dashboard.
So it isn't as simple as click, print, and use. And most printers seem to be a bit cantankerous and picky, but if you take a bit of time to methodically learn what they can and cannot do, they can do some pretty amazing things.
For engineers with new printers I really recommend printing out test pieces to understand your printer. You can test strength (tensile, shear, compression), detail reproduction, dimensional accuracy, and environmental durability. There are a lot of test printable things on the Thingaverse site. Once you know your printer you'll be able to quickly design and print a part that will meet your expectations the first time, every time.
3D printing is great for making objects whose shapes make them (a) impossible to construct with a subtractive process, and (b) too complicated or subtle for your skills with clay or whatever. For example, various types of mathematical objects, https://plus.maths.org/content/3d-printing http://www.shapeways.com/marketplace/art/mathematical-art/
I've tried to keep my designs as simple as possible and it's worked out alright. As you say, more complex things are fairly hard to model. Having calipers so that I could accurately measure things greatly helped me design things for around the house.
Thingiverse models frequently have issues, but you get used to opening them up, checking dimensions and fixing errors in the STLs.
When designing, at some point you get used to the fact that it takes two or three iterations to get it right. I frequently print partial models nowadays (or smaller versions of the final), featuring whatever needs to fit and then going back into the design software and completing the model.
Then there's the whole "what's the printer up to" thing, is the PLA not too old, is my printer properly calibrated, did the slicer do its job properly. That just takes time to understand as well (having a quality printer here helps as well).
Just keep going at it and eventually it all starts falling into place and you get faster and faster at designing as well as incorporating others STLs into your own designs and printing them.
From all the success stories in the industry, 3D printers combined with competent designers enables very tight iteration cycles, and makes the interations more fulfilling to test :)
For something like a chunky toy car, precision is not important. For a threaded screw, in particular a bottle cap, you will need good resolution and accuracy.
From what I've read, it's a decent quality printer. I've kept the software in beginner mode so far, so there's probably some settings I'm overlooking.
Finally, being incredibly proud, I handed my dad the tool, and expected success along with much congratulations from my father for solving his problem.
It was about a millimeter too small to fit around the filter. I had failed. My printer had failed. He went and bought a new oil filter wrench at a car parts store.
One of the problems with STL's is that they're unit independent, they don't care if the part is measured in millimeters or inches. (they also ignore the internal structure of the part, but that's a rant for another time.) And one problem with the 3d printer community is that with all these different printers, there is a wide variety in the tolerances/accuracy of the printed parts. Even with well set-up printers, changing one setting, such as amount of infill, may change the size of the final part. And even if you have a precisely calibrated printer, the person who made the model you're about to print may not.
In this particular case, I don't believe the model was off, but rather to make the tool incredibly strong, I printed with ABS plastic and included extra support and extra shell layers, which I believe may have produced too much material and effectively over extruded plastic, making the part just a bit too small. But I took the part and slammed it into the driveway as hard as I could, and the part didn't even think about breaking, it was quite strong, even if it was useless.
It should be integer tetrahedrons. You'd get X,Y,Z for each of the 4 corners.
Tetrahedrons let you fill the middle. Each tetrahedron should have fill data, for the whole thing or corner-by-corner for gradients. This would allow variable density, elasticity, conductivity, opacity, hardness, etc.
Integer math solves the problem of variable rounding that often screws up STL files.
Being unit-independent is much better than having one particular unit. You may think millimeters are great, but to others this might as well be angstroms or chains or twips or rods or parsecs. Unit conversion introduces rounding error. I could go for an optional free-form text field that suggests a unit to use, with the software defaulting to the suggested unit if recognized. Software should let you define the unit.
I'm a big fan of Bondo, fiberglass/fiberglass resin, and my trusty dremel tool. Recently a plastic part to a dryer cracked, and those approaches didn't seem strong enough and would probably make it not fit any more, so I heated up some little nails on the gas stove and pressed them into the plastic, which melted around them, making a very strong part that was no bigger than the original.
And I say this as someone who has a long, long history with 3d CAD modeling.
Would he really need to print more parts? I mean, it could break again, but this seems like a one-off fix.
If it only has to look good, the skim layer can be drywall joint compound, which is super easy to work.
It's not been easy, and I laugh at my earlier attempts, but it's been a fun learning experience. The fun thing is that I've had to re-learn a bit of trigonometry because of my choice in CAD tools (openscad).
I have a repository of the household items I've printed: https://github.com/elliotf/reprap-household-misc
I never learned autocad or ME, but I do remember my ME buddies from college taking their required autocad class and taking many hours to design a simple part like a pulley, and then being oh so proud of their creation. But, hey, I am sure it was much more fun than their Fortran class which they also had to take.
My point is it takes special skills, training and a lot of patience to be able to design a part and get all the dimensions right.
It would have been more interesting if he was able to glue the broken part together, then scan it, and then print a copy of the scanned part. Is that something that is easily doable nowadays?
At the moment there will be a youtube video and an imgur gallery of where to apply the dremmel. In future there'll be downloadable 3d printing files.
The following week, he brought her a 3D printed cover that fit perfectly. Over a month later and she was still talking about it.
When you build a product that appeals to 20yo hackers and 80yo grandmas, you're onto something.
Any suggestions regarding tools for_capturing_ 3D (or at least 2D) models from photos or videos of existing objects? I imagine if there are multiple reference objects (of known size and shape) visible in the scene together with the object-to-capture, the photogrammetry should be tractable.
A good start would be an app able to produce a 2D CAD file from a prototype shape (e. g. cut from cardboard) photographed on a background of squared paper. Does such a beast perhaps already exist?
And IMO modeling in Inventor is as easy as it gets. Sure, you need to discover some tricks, but usually you get exact tutorials on YouTube explaining how to achieve what you want
It's still not easy though!
It works well for human-sized objects, but you can forget it for smaller things (it had trouble scanning my then-reference object: a beer can)
That was a couple of years ago - maybe software has evolved enough to make it useable in the mean time.
I looked into replacing a door shelf for a huge Samsung refrigerator. It's a $2000 refrigerator with $50 parts that constantly break. I could buy a new part every few months, 3D print something suitable, or give up and just replace the refrigerator.
Step one is getting a model. Everything is organically curved. Ugh. This is impossible. Well, putting that problem aside, let's just throw together an approximation so that I can get a price. It's a bucket about 20x30x40 cm, and needs to be about 5mm thick. To survive longer than the original junk, it'll need to be made out of something decent. The first thought is naturally titanium. Woah, expensive! The second thought, reluctantly, is laser-sintered nylon. Woah, expensive! I don't want to just go thinner, but I could carve out some holes or leave ribs. This is getting complicated. Woah, still expensive!
It's a good thing I didn't put the effort into somehow making a model that would perfectly fit the organic shape. My effort would have been wasted as soon as I found out the price.
I bought a new refrigerator. The old one is still here, growing mold, because I can't get it out of my house.
However I do feel he could have achieved the same result a simpler way.
1. Repair the original part in a basic fashion
2. Make a silicon cast of the repaired original part. The original will have been injection molded, so try to use their mold separation lines as a guide for where your separation line should be
3. Spilt out to make a mould
4. Pour in resin to make an very exact replica. The place where the original was broken will be replaced with functional resin
5. De-mold and put in place.
This guy makes his own rubics cube style puzzle via this method and documents it well: https://m.youtube.com/watch?v=i-HXU4cfvdc
In his story he sat down at his computer for a while and did what he needed. A couple of trips to town later it was done.
In your story he needs to get a bunch of messy stuff, using tools and processes he has no knowledge of, of which even stage one I don't know where to start.
I don't understand how you think that is simpler!
But if you have free time, have a bit of free space like a shed and can tolerate a bit of mess, then my way could be simpler
I then had a moment of silence for all of the super-glue messes of my childhood that never fixed anything and a touch of envy for my own kids growing up in what to my 10yo self would seem a Star Trek future.
It's similar to the back of http://www.ebay.com/itm/Panasonic-Remote-Control-EUR644862-C... and I suspect the tiny gap at the top is going to be my downfall.
In both cases, I first modeled as best as I could the parts that I had (not the parts I wanted to print) so that I could see the fit. On one remote, I replaced the entire back, not just the battery cover because I just didn't think my printer could create that thin curved shape. This came out awesome. The second, instead of copying the missing cover exactly, I left much plastic that an injection molder would not (ex between the batteries and set my infill to 90% making a very solid, strong part that snapped in nicely.
Note: Blender has a learning curve like the side of Everest but there are endless excellent video tutorials available on youtube to get you up to speed, so don't despair when you open it the first time and literally can't even navigate the view with your mouse.
"While I only have experience drawing in 2D, how much harder could it be to add one more D? Fairly hard, it turns out."
Being a mechanical engineer doesn't mean you automatically can draw 3D models (and I should know, I was a mechanical engineer).
It would have been easier to go to the dump and spend five minutes looking at the row or two of fridges to find the part or, failing that, find a suitable chunk of plastic, cuts it down and makes the part and spend the rest of the time fixing something else around the house instead of writing an article.
After working with everything from paper to plastic to wood to spring steel at college I'm just gonna kill a few hundred birds with one stone and get a mill. When you consider all the tools it replaces and how many different specialized machines it can stand in for (including a 3d printer) in a pinch if its got a big enough Z it seems like a no-brainer