Simply put, I’m interested in saving up for a (relatively inexpensive) home 3D printer this year. Has anyone here had any experience using one? Any caveats I should be aware of? Thanks in advance…
I have a Solidoodle 2 (www.solidoodle.com). It is fully assembled, and costs $600 for the version with the heated platform. $700 adds a metal enclosure, though I prefer the acrylic one I made so I can see through the sides and top. The build area is 6"x6"x6". For $800 you can get the 8" version. Shipping times are running about 8 weeks.
3D printers are a long way from the plug and play nature of inkjets. If you are looking for an appliance that simply will create an object when you hit “print” you will eventually be disappointed. They can do pretty well out of the box with stock settings, but to get the best results you will need to understand how they work so you can tweak them to suit the kind of object you are printing. Home 3D printers are new enough that there is still a bit of craft involved.
I like to think of it like a table saw, or all in one table saw/router/planer. You can cut some wood, glue and nail it together, and have something functional. To really be finished, the thing might need sanding, staining, painting, etc. To really do quality work it helps to understand the differences between different types of wood and how they affect construction. You would need to understand the tool and how to adjust it to get the best accuracy.
A 3D printer can do great things, and objects can stand alone as printed. There are lots of neat things you can print that are basically knick knacks, or simple solutions to problems that don’t need more than an object made entirely of plastic. A printer shines as one tool in a workshop, printing parts to be used in combination with other materials. There may be projects that can’t be completed with the printer on its own, but would not have been possible to even begin without its versatility.
A lot of people have a dream of 3D printers becoming mainstream, and present in every home like paper printers. I don’t think they are for everyone. They are for people who like to make stuff, or would like to make stuff if only they had a tool that could unleash their creativity. It might be hard to think of what you would print if you had one, but once you have one it’s easy to start thinking of things. You might start to think that every problem looks like a nail once you buy the hammer, but it is a really versatile hammer.
I think the technology is fascinating enough that I don’t have any trouble with learning what I need to calibrate the machine, adjust the settings, trouble shoot problems. It’s fun to come up with ways to modify the printer to improve features and quality, and learn some new skills along the way. It makes me think of people who like to buy something like a Honda Civic and turn it into a street racer. Some people just want an automatic they can drive to the store, but if the 3D printer were a car they would eventually find they have to change their own oil and do their own brake jobs.
More specifically-
One thing I like about the Solidoodle is that is in a square frame that is easily covered. When printing ABS, containing the heat and preventing any air movement helps a lot to prevent the shrinkage that leads to warping. The triangle and T-shaped RepRap variants don’t lend themselves as much to enclosure. For that reason, users of those machines tend to favor PLA which doesn’t warp nearly as much. I find that PLA is a little more finicky, and it doesn’t respond to Acetone. 3D prints have a ridged texture that comes from being built out of layers of rounded threads. With ABS there is a way to use acetone to smooth those ridges and produce a smooth glossy look that almost appears injection molded.
3D Printing is slow. Something that is 4" on a side can take 4-6 hours. Bigger build areas mean a wider range of things that can be printed, but keep in mind that it can take a very long time to print something that takes advantage of that space.
Whatever printer you choose is likely to have some forum or community associated with it (Solidoodle’s is at www.soliforum.com) Start reading up on it while you save and wait for delivery so you have some idea what to expect. If you run into some problems at the start, you might already have an idea of how to deal with it. Also keep in mind that forums are places people go to ask for help, so they can make a printer appear more troublesome than it really is.
Couple questions for ya…
I see the ABS comes in big spools of two pounds. About how much does that work out to, in terms of items modeled? Obviously bigger items use more stuff, but say for an average item… a little green army man, for example: How many would one spool make?
Can you feed the spool directly into the machine, or do you have to cut a piece off and load it for each individual item made? Can you load more than one spool at a time for multiple-colored objects, or would that require an entire secondary extruder?
How strong is this plastic? The video shows a bottle opener being made. Is this the kind that breaks after a dozen uses, or can one make things that take pretty heavy stresses? Presumably the density of the item is a factor, in that a solid item would be stronger than a hollow one, so how tough is the material to cut or gouge? How sturdy is it in rod form, the thickness of the spooled material, after casting compared to how sturdy it is right off the spool… does it bend just as easily?
I am imagining a horizontal cross-member within the shell of a sculpture of some sort, well above the base. Say a diameter halfway up the interior of a sphere, going through the center point. As the initial bits of material are laid down, this is essentially extending a bit of plastic across thin air supported by nothing, if you see what I mean. To do this, do you have to build support ‘towers’ from the base of the sphere, extending upwards? How thin can they be and still stand? I ask this because it seems like, the more internal supports you need, the more ‘solid’ the entire sculpture would have to be (to provide a base, at the level of the horizontal cross-member, to actually build the cross-member upon) and therefore the more material it would require to build larger things. Did this make any sense at all? The hour grows late, and the day was long… 
And, depending on how technical/mechanical your knowledge is about this device: in this picture from their spare parts site… The green wires with the red base appear to connect to the extruder heat core. The white/clear wires (assuming they’re wires and not tubes) connect to what? My guess is a temperature sensor of some kind.
It also appears the base is heated… why is that? To heat the entire unit, or just to prevent warping in the initial layers, or what? From what you say, shrinkage is a problem. Might it be best to put it inside an insulated, pressure-sealed enclosure of some sort?
From looking carefully at the device (and the spare parts list) it looks relatively simple in basic form. Obvioiusly most of what’s being paid for here is the expertise in construction and all the detailed fiddly-bits involved in connecting the pieces to the computer and teaching it to move the doodads around juuuust riiiight. How easy is it to adjust those fiddly-bits? Can you change the ‘resolution’ of placement (within the limits of the size of the extruded ‘pixel’, or even further) easily?
Now that they’ve reached a decent level of sophistication, and a reasonably affordable entry price, my reasons to NOT get one of these things are falling fast! The only remaining barrier is a limit on how functional the items made are. If all I can make is knick-knacks and tchotchkies, then I’m gonna have to keep waiting.
Thanks for the info!
It depends on the fill, but you can print almost 400 chess pieces with 1kg - http://makerbot-blog.s3.amazonaws.com/wp-content/uploads/2012/02/MatterOfScale_V2.jpg
It can spool directly into the machine. Multiple colors would need more extruders, though one person has experimented with making an extruder that can mix colors.
It will bend as easily if you print something that is as thin as the filament. Generally it can be pretty strong if you print with thick enough walls and reasonably dense fill. You can make functional parts with it, printed gears are very common. The plastic is hard enough that I can trim edges with an exacto to get things to fit better, but need a saw to really cut it. It’s the same plastic as Lego, for point of reference.
For something that is a solid shape that doesn’t need to be hollow, or have access to the inside, you would use a fill pattern. Objects are made by first drawing the outline of the “slice”, the cross section of the layer being done. You can set the number of outlines it makes, which determines the thickness of the outer surfaces and largely determines the strength of the part. Then it fills the inside areas with a pattern that can be honeycomb, circles, lines etc at a density that you specify. When doing something that is hollow with a solid top, you have to consider support for that top.
It can handle overhangs of about 45-50 degrees without needing support underneath, and it can stretch the plastic across open spaces (bridging) of maybe 40-60mm. It helps if there is a fan mounted on the nozzle that can turn on during bridging. This will cool the plastic as it extrudes, and the shrinking will help it stretch and stay straight rather than drooping. Even if the first few layers of a bridge droop a little, each successive layer will be better supported until the bridge is solid. Often the droopy initial threads can be trimmed away with a knife. The limitation to bridging is that it goes from on supported point to another. If it changes direction midair, there is nothing to support the corner.
The programs that turn the models into toolpaths can automatically add support material. It builds up a zigzag of thin walls underneath areas that have nothing under them, so those layers have something to build on. The walls are thin enough that they can be easily peeled away when done. When using support, you have consider accessibility, and not have them made in enclosed spaces where you can’t reach in to get them out.
The white wires go to the thermistor, and the green ones go to the resistor that provides the heat. Warping is caused by differences in temperature within the model. As upper layers shrink, they pull on lower layers that already shrunk and bend them. Heating the bed helps reduce that temperature differential. Also the immediate shrinking of the plastic as it is extruded causes it to pop off of the print surface, so it has to be heated to get it to stick in the first place.
Heating the space helps as well. The pro machines don’t use a heated bed, they instead keep the inside at 70C, basically printing inside an oven. That is more complicated, and also currently under patent. Sometimes I will use a miniature space heater to warm the inside of the printer to help prevent warping.
The XY resolution exceeds limitations of the process. The precision you can get with extruded plastic is about .1mm even though the extruder can be positioned in smaller increments. You can adjust the layer height, which has the biggest affect on surface appearance. At .3mm you can see the lines of the layers, but if you print with .1mm layers it can appear pretty smooth. However it also takes 3x longer to print because there are 3x as many layers.
It depends on what you want to make. You can make gears, enclosures for electronics, brackets. I make some brackets to clip my Jambox bluetooth speaker to the bottom of my kitchen cabinets, and made a wall mounted dock for my phone. I also made a reproduction of a discontinued Pottery Barn soap dish that kept getting broken. My daughters complained that their miniature dolls didn’t have a bed to sleep on, so I made a toy sized replica of their bunk bed.
If you already have a workshop, and make stuff, the printer is great for making jigs. I’ve also made molds for molds. That is, print the thing to be molded and the mold box as a single object to be filled with silicone. This has the advantage of shaping the mold box to minimize the waste you would get by molding a round object in a box with corners. Or you could print the mold directly and make a chocolate Stephen Colbert http://www.thingiverse.com/thing:17570
Thanks for the info! The Solidoodle is even cheaper than I expected, and sounds like it might be a good choice for me. My primary use for the device would be forming physical models from 3D models created in ZBrush, for example, or for making model parts that would be difficult or impossible to make with a vacuum forming machine.