by makeme

Posts Tagged ‘reprap’

3D Printers You Might Not Have Heard About

In Uncategorized on 07, Dec, 2011 at 22:23

The Felix 1.0 can be found at FelixPrinters.com for about $1100. Designed by Guillaume Feliksdal because he has experience in mechatronics and he thought RepRaps took too long to put together and calibrate. The kit is mostly aluminum t-slot extrusions. It does not seem to be open source, but it is reportedly quick to assemble and calibrate, taking only 2-6 hours to go from zero-to-printing.

“…I love…to realize innovative technical ideas. The printer could also be useful for making my future inventions.” – Guillaume Feliksdal

The Orca 0.30, designed by Gubbels Engineering, can be found at Mendel-Parts.com. The kit is pretty much entirely steel rod and (anodized!) aluminum sheets, is about $800, and seems to be intended to be open source when the design is finalized.

The Mosaic, designed by Rick Pollack, can be found at MakerGear.com. The kit is mostly laser-cut plywood with pre-assembled precision linear guides, is about $1000, and doesn’t appear to be open source.

The Printrbot can be found at Printrbot.com. Designed by Brook Drumm because he figured people needed a printer that was a lot simpler and easier. The kit is about the most minimal combination of ABS and steel rod imaginable, is listed as $500 on the kickstarter page, and a lot of noise has been made about making it open source when the design is finalized.

Printrbot-Mystery-Print from Printr Bot on Vimeo.

The Prusa Air is Mecano’s redesign of the Prusa Mendel. It replaces a lot of the metal and plastic parts with flat sheet. Here it is on Thingiverse.com and the RepRap wiki. He says that the design evolved out of an attempt to make the Prusa more attractive and intuitive enough that someone could put it together after glancing at a picture. He has a version 2.0 on the way.

“Eventually I would like to see, apart from improvements in 3D printers, laser cutting open hardware, open hardware lathes, open hardware phones, etc” – Mecano

The Rook Printer by Jolijar can be found on Thingiverse and at Jolijar’s blog. He’s replaced the vast majority of the RepRap frame with t-slot aluminum and has redesigned the printed parts accordingly.

The Solidoodle 3D Printer, designed by Sam Cervantes, can be found at Solidoodle.com. This is a somewhat unusual design. Most of the functional parts are laser-cut wood, but the whole thing is enclosed in a steel frame that protects the whole printer. It only comes fully assembled for $700. The design doesn’t seem to be open source, but they do have a Facebook page. So you’ll have to make due.

The 3D Micro Printer is a stereolithography system that’s about the size of a large book and is only about $1600. It is the result of collaboration between teams led by professor Jürgen Stampfl and professor Robert Liska at the Vienna University of Technology. The prototype was developed by Klaus Stadlmann and Markus Hatzenbichler. The real strength of this approach, and the reason the overall machine is so small, is that it can be used to print very precise parts. This first generation prints in layers 50 microns (0.050mm) thick.

The following are even farther off the beaten path because they are CNC mills.

Don’t let that be a reason for ignoring them! Unlike a dedicated 3D printer, a CNC mill can do both additive and subtractive work (3D printers aren’t rigid enough to hold a carving tool in place without wobbling).

The MTM Snap has an exceptionally clever design. It was designed by Jonathan Ward at MIT’s Center for Bits and Atoms and it actually snaps together. Yes, snaps. The entire structure is rigid enough for milling but doesn’t include a single fastener. It is open source.

http://blip.tv/play/AYK2j0IC.html

The White Ant was designed by Patrick Hood-Daniel and can be found at BuildYourCNC.com. Looks like it’s around $1000, but for that you get a machine that’s specifically designed to be either a 3D printer or a CNC mill. It’s a compliment to the book, Printing In Plastic, which takes you through the entire build process. It’s extremely hackable, as the design has been released under the Creative Commons license (free to reproduce) and, while it’s cleaner to CNC mill the wood pieces, the entire thing can be made in a garage with power/hand tools.

“I would like to see a machine that would be able to fabricate using multiple materials in one process…I will be developing an SLS machine kit in the near future.” – Patrick Hood-Daniel

ZEN Toolworks, owned by Xin Chen,  has several variations of a hobby CNC. They also have a very nice wiki for learning about their kits. The CNC mill is about $810 and they have a conversion kit for $80 that makes the build volume more suitable for 3D printing. They don’t sell any extruders and Xin explained that they don’t sell a complete kit (mechanical and electrical) for 3D printing because they figure it’s better to get 3D printing-specific electronics from somewhere else. However, you can pick up the mill itself (just mechanical) for about $450 and get the electronics & extruder from a different vendor. This product is not open source.

The micRo (yes that’s how it’s spelled) is available at micro.lumenlab.com for around $700. You’ll get the CNC mill which you can use for 3D printing if you mount an extruder or syringe. LumenLabs does seem to be working on a high-precision 3D printing addition to turn the micRo into the UNIFAB, but there’s not much information at the moment.

Maybe you prefer your projects a bit more…freeform. If so then check out how many 3D printers/CNC machines there are on Instructables.com.

So there you have it. The 3d printing world is a lot bigger than RepRap and Makerbot! The great thing is that more and more of these new designs are showing up all the time. Pretty soon there will be such a huge selection you’ll be able to find one that exactly suits your requirements. Additionally, the point of this post was little-known 3d printers. If you know of one that I missed please share that information with everyone else.

How Low Can You Go

In Uncategorized on 20, Nov, 2011 at 14:34

When it comes to 3D printing, the most expensive part of the system is the electronics.

Makerbot wants $370 for their Gen4 electronics. With their Gen6 stepper extruder (and the driver for it) costing $165, and a set of X-Y-Z motors costing $105, that puts the complete cost of electronics at around $640. I figure this is a good upper bound on what 3D printer electronics should cost since Makerbot’s electronics are probably the most professional and full-featured. I’m not going to include a heated bed in this comparison because it’s not strictly necessary to get started, it’s just a performance upgrade.

Obviously, when there are complete 3D printer kits starting at $500, $640 for just the electronics is unacceptable for my purposes.

The confounding thing is that when you move away from Makerbot (and complete kits in general) you start to have to source from multiple vendors. There is not, as yet, a clearing house for open-source 3D printer components. Sellers tend to focus on one or two options. Additionally, they tend to be located in Europe, so that whole “You want HOW MUCH for shipping?!?” thing gets reversed.

RAMPS and Gen6 are mid-range in terms of performance flexibility and cost. So, you know, whatever. All the electronics kits I know of use pretty much (if not exactly) the same stepper drivers, and they all use USB, and these days they all have an SD-card option, so unless one of them tends to spit out errors more often they all have the same 3D printing performance. 

Sanguinololu seems to be the strongest attempt to whittle the electronics down to just the bare necessities. eMakerShop sells the whole thing (including drivers & firmware tested) for about $170 shipped, they want $95 for the motors (shipped) and $75 for the extruder (shipped). That all comes to around $340. Solidoodle sells the whole thing (without drivers) for $105 (shipped), but doesn’t sell anything else. LulzBot can make up the difference with four Pololus for $65, four motors for $75, and a 12V 25A 300W power supply for $35. They have a hot end that they want $75 for. That all comes to around $350.

There are rumors of people pushing the electronics cost even lower. For example, something called GenL offloads most of the computation to the host computer by using more USB bandwidth. Another example is Repic by Mark Feldman, but I can’t find much information about it.

As you can see, the electronics is the most expensive part of the printer and the stepper motor/driver combination is the most expensive part of the electronics. The need for four bi-polar steppers and four microstepping drivers demands $120 minimum. You might be able to get that down under $100 if you get really lucky on sales or start salvaging parts. The biggest barrier is that these particular parts can’t be made much cheaper. The Sanguinololu board can be brought down to around $60 if you buy the bare PCB, then the components, then burn the bootloader with something you already had (or maybe you can find a chip that’s already burned). But the motors and driver prices aren’t going anywhere.

Some blue-sky ideas for lowering the cost even further involve basically starting from scratch and creating a new family of electronics. The primary reason steppers are so popular is that they don’t require any feedback for accurate positioning. It’s possible that coupling a feedback mechanism (linear resistor, optical encoder, whatever) with a standard DC motor to create a servo would be cheaper. It would also be possible to simulate the entire electronics board on an FPGA for a one-chip solution; just a PCB with the FPGA, its interface, and a bunch of transistors for amplification. Maybe the motors, and their complicated drivers, could be replaced with solenoids and some clockwork. Running all the high-power functions off of AC (out of the wall) might eliminate the need for a power supply (get logic power from the USB).

A 3D Printer Under $250

In Uncategorized on 23, Oct, 2011 at 22:22

All the coolest gadgets are too darned expensive; especially when they’re brand new. 3D printers are no exception.

Even the dramatic reduction in price that the open source hardware movement has managed to produce only brings 3D printers down to just over $500. That’s amazing compared to the commercial options (which start at $10,000) but it’s just not good enough.

I think the goal should be $250. That’s right around the pro-sumer line so anything under it is legitimately obtainable for the average person. You don’t have to worry about how much profit you can generate with the thing when it’s cheap enough.

A printer that cheap could become a practical option for STEM education. It would be a good introduction even if it didn’t have impressive performance.

Based on some research it looks like that price point is obtainable, in theory, today.

The most expensive part is always the electronics. Well, eMAKERshop sells sanguinololu electronics, fully assembled (and flashed), with the pololu drivers, for $125. They also sell a mechanical endstop kit for $10. Nema 17 stepper motors are around $15 from Kysan (4 of those). A 12v 5a power supply goes for around $10 on Amazon. That’s the majority of the electronics right there for about $200.

Now we just need to build the frame and linear motion systems. A 1/4″ x 2′ x 4′ piece of pine plywood can be about $10. Home Depot lists 16″ keyboard sliders for about $15 (3 of those). Assuming you could make the printer out of cabinet supplies, that’s about $55. If the extruder could be made out of a bolt with some nichrome wire (old school I know) it wouldn’t add much to the total, which is now around $255.

There are some crucial assumptions in there like a dirt-simple extruder and no need for timing belts. At any rate I think this demonstrates that the idea isn’t as far fetched as it might at first appear. A big piece of the puzzle will be getting around the need for metal pieces, printed pieces, and laser-cut pieces.

Lower Entry Barriers For 3D Printing

In Uncategorized on 12, Oct, 2011 at 22:36

The basic technology required to make a 3D printer work isn’t particularly groundbreaking, so it’s nice to see a brand new design as opposed to yet another copy. Origo is a project (company?) started by Artur Tchoukanov and Joris Peels with the goal of producing an $800 mass-produced 3D printer specifically for kids. It looks like they’re planning on using a double swing arm for the X Y motion, which greatly simplifies the physical construction, lowering the cost. They are also integrating the software so that kids can design things in 3DTin and then have their creations automatically printed. Also, a recycler, but I doubt that idea will work.

More 3D printers, particularly cheaper ones, is great. However, I would like to see the cost and complexity drop even farther. Here are some ideas for how that might happen:

  • The printer itself shouldn’t require powerful or precise tools.
The Thing-O-Matic achieves precision with laser cutters, the Mendel achieves precision with another 3D printer, and they both use special steel rods. The designs depend on expensive and difficult-to-maintain manufacturing tools.
I think it’s possible to avoid the use of things like laser cutters, precision ground steel rod, and pre-existing 3D printers. Anything that’s going to be expected to recreate precise movements is going to need some precision parts and assembly, but that’s almost entirely about the layout. For example, instead of laser cut parts one could print a template on a desktop printer, attach it to the wood, and cut/drill by following the guide. The typical solution to linear motion is some kind of bearing riding on precision rod, but some things like aluminum angle and drawer sliders are nearly as precise while being far cheaper.
The real barrier to entry, however, are the precision manufacturing tools. You CAN download the blueprints for a Thing-O-Matic, but they are specifically designed to be produced on a laser cutter. For example, the T-slots aren’t something you can accurately reproduce on your own. Likewise, while you CAN download the parts files for the Mendel, good luck carving them. “Many of the mendel parts are quite difficult to make from wood, and could do with a re-design. They are all created with 3d printing in mind, so there is no consideration for access to internal spaces, or grain or any of the other things to keep in mind when working in wood.” Designs with these requirements create a speedbump which sucks down money, time or luck. Instead, the goal could be for the printer design to require nothing more than a hand saw (cuts) and an electric drill (holes).
  • It doesn’t actually need a .5mm nozzle.
Creating sub-millimeter holes is kind of a problem. The only really reliable way to do it is to put the nozzle blank and drill bit into a lathe. If you allow the nozzle diameter to rise you start to run into pre-manufactured components like needles. Or, at a minimum, things like 1/32th (.8mm) drill bits that are cheaper and easier to obtain than .5mm bits (at least in the States). Even 1/16th (1.6mm) bits would be small enough to do something useful (probably equate to a 2.7mm wide track) and are pretty much free.
More importantly, moving up to something like a 1/16th bit wouldn’t require any special tools to use. Even holding a sub-millimeter bit requires a special tool. A 1/16th will fit into a standard drill chuck. Sure, you CAN get sub-millimeter bits that have expanded shafts, but that’s starting to raise the barriers again as people need to special order them and they can’t be easily replaced.
  • Make each part do more than one job.
The Mendel (and derivatives) is a good example of not doing this. As great a design as it is, there are metal rods being used for the structure and then different metal rods being used for the linear motion. Using the frame material for linear motion would create more synergy (do you have your innovation Bingo card?).
  • Simplify the positioning system.
The reason 3D printers tend to use linear motion is that it’s really simple to program for. 3D files record things in XYZ Cartesian coordinates, so it’s just a matter of calculating the steps. That’s great for the programmers, but not so great for the mechanical engineers. They have to figure out how to create a 3-axis linear motion system on the cheap. Switching to something more like the Origo (a double swing arm) would make the bot a lot easier to build. All you’d have to do is slap a couple arms onto the shafts of a couple motors. The programming would be more complex, and maybe the motors would be more expensive, but the physical construction would be much simpler.
  • Reduce the number of electronic components.
Electronics are expensive, even when you build them yourself. The electronics package is around 1/4 of the cost of a Thing-O-Matic, for example. It might be possible to create a “board on a chip” design inside a Field Programmable Gate Array (FPGA) that would literally do ALL the calculations. It could even replace the stepper boards. FPGA’s, instead of running software, are reconfigurable hardware. You program their logic gates and then they just do what they do. They have hundreds of I/O ports, allowing all the windings of the stepper motors and all of the sensors and all of the heaters to be controlled directly by the FPGA (via some form of amplification). Also, and this is important, they are truly parallel. If something needs to happen on one I/O pin it doesn’t have to wait for the software to get to that part, it just goes in and right back out.
FPGAs aren’t exactly main stream, and there aren’t any open-source solutions yet, but you can get the software you need to program them for free (just sign up for a license). I’m not sure how many gates you would need to replace an Arduino and four Pololus, but seeing as how you could do it with a single chip it’s worth looking in to.
  • Why not design things without a computer?
Origo is on the right track in terms of making it easier for people (kids) to design the 3D models that 3D printers construct. Why not make it even easier? OpenSCAD, a program that has already proven itself in the open-source 3D printing world, already has support for generating 3D models directly from 2D pictures.

openscad 2D to 3D

With just colored lines and some labels OpenSCAD can generate a water-tight 3D model. Kids (anyone) could use crayons or colored pencils to draw a blueprint of their design, scan it, and have it start printing automatically.

I’m Conflicted About Buildatron

In Uncategorized on 15, Sep, 2011 at 22:13

I have a few keywords like “reprap” and “makerbot” on my google alerts list, so I heard about this new company Buildatron. The link in my email took me to a press release that is responsible for the inner turmoil.

See…I want 3D printing to move into the mainstream. There’s only 4 years left until my inter-family prediction of “this stuff is totally going to be everywhere” becomes premature. I want to go to Wal-Mart and pick up a $100 3D printer that makes cell phones, and I want it now! On the other hand, I am convinced that the old people who own all the stuff and write all the laws are going to fill up their Depends when they realize the same people who pirate music and movies are now free to pirate physical products.

As is pretty obvious to anyone who bothers to look ahead: 3D printers are going to create some legal issues. With the Supreme Court ruling that corporations are people, and Congress worried that existing businesses might not pay for their reelection, it’s not outside the realm of possibility that 3D printing would end up strictly regulated. The exciting thing about desktop additive manufacturing is how much more efficient it makes people. That’s great for individuals, but not so great for existing corporations. Combine the threat of copyright infringement with the decreased revenue from simple (and not so simple) little gizmos and you’ve got a recipe for a new version of the RIAA.

It seems to me the best way to make that possibility unlikely is to push 3D printing into schools where it can give a whole new generation a reason to learn STEM. About the time industry lobbyists are marching around demanding regulation I want school kids marching around showing off how they invented a new pacemaker or something. That will even get the attention of industry (they need all the STEM geeks they can hire). Thus, creating a strong argument for allowing 3D printing to flourish with modest, safety-based regulation.

That’s my point of view, and I’m working on it (slowly; I have a day job). But then I see stuff like the Buildatron 1. The company’s press release stops just short of going “YOU get a car and YOU get a car and YOU get a car”…but then you click on the link.

They put a box around a reprap. Then they put their name on the box. Then they promised a revolution.

The best thing is that there are already companies selling reprap parts and kits assembled or disassembled. There’s makergear and reprapcentral and reprapstores and reprapkit and XYZprinters and botmill and techzone and I’m sure I missed some. Last but certainly not least there is Dr. Bowyer himself. And you know what? None of them bothered to brand an open-source project. Why does the Mendel need a box around it? I assume it was the only way they could create enough space to FIT a brand name in there.

I love open-source for exactly that reason. Since no one had ever thought of putting a big title on the machine there isn’t even any room to add one if you want to. It’s a marketing department’s nightmare.

See, Buildatron instantly invites comparison to Makerbot. Makerbot is from New York, so is Buildatron. Makerbot had 3 techie founders, so does Buildatron. Makerbot was based on the reprap project and so is Buildatron. Makerbot looks like a box…and so does Buildatron. Even the name looks copycat (build-a-tron, mak-er-bot). However, all that stuff is just surface. What seems significant to me is that Makerbot looks like a box because those guys actually designed a new printer. It makes sense for them to put their name on a product that was merely inspired by the reprap project. The Buildatron 1, however, IS the reprap project. With a box around it.

They didn’t even have the decency to make the box printable.

A  few of my favorite quotes from the press release:

Today Buildatron Systems announced the international launch of the Buildatron 1 3D printer…

Their offering represents a new paradigm in 3D personal manufacturing technology…

social network driven DIY (Do It Yourself) 3D printer kit.

We worked … industry leading customer support via Buildatron’s social network gateway

Buildatron’s opening of the 3D printer market to millions at industry shattering prices makes no bones about the impact they will have…

Buildatron is working hard to put you in the drivers seat by developing a new generation of tools unparalleled in history.

It’s just sooo cookie-cutter and over-the-top. They’re international because they have a website. They’re a new paradigm because they have a box. They’re social networking because they have a facebook page. They’re industry leading because there’s no industry to lead. They’re opening the market by sitting next to Makerbot at Makerfair. They’re unparalleled because they’re taking what everyone else is working on in a weird direction. The best part is that they could actually lower the price of their kit if they didn’t bother to put it in a box.

All of this leaves me conflicted. I want people to get involved in 3D printing who can hype it. Bre Pettis is awesome because he can get in front of a camera and really evangelize 3D printing. I don’t think an external control panel is all that important or useful, but I’ll let Makerbot do anything they want without complaint as long as they’re putting so much effort into building public awareness. However, the approach Buildatron is taking, right from the get-go, makes me want to tell them to stop.

You know who else saw what Makerbot was doing and thought it was a good idea? Well, Rick Pollack of Makergear and Erik de Bruijn of Ultimaker come to mind. They are both selling their own (branded) boxy 3D printer. But THEY DESIGNED NEW PRINTERS! The Mosaic and the Ultimaker are both brand new and innovative designs that take INSPIRATION from the open-source projects that birthed them. It makes perfect sense for them to give it a new name because it’s new. Buildatron just put a Mendel in a box.

RepRap RAMPS Build Continued

In Uncategorized on 30, May, 2011 at 19:09

The world can delay me, but it can’t stop me. (huzzah)

I got some v2.1 opto end stops from the guys at Makerbot and a stepper plastruder from MakerGear. It actually didn’t take all that long to get them put together. It also didn’t take much time to start testing the printer and realize that it wasn’t doing what it was supposed to do. Then I got frustrated with programming (black magic) and then other things got in the way.  Anyway, I got the programming problem solved and now have a Mendel that at least pretends to do everything it’s supposed to do. I’ll share any secret tuning tricks as I run across them.

BTW, what made my Mendel do stupid things was apparently having the end stops inverted in the firmware. If you get everything hooked up, and the end stop LED lights up when you break the beam, but your axes won’t move in both directions, try switching the inversion of the end stops in the firmware and re-uploading it to RAMPS. I guess the controller thought that on was off, or off was on, or something like that.

Before you do that, however, you’re going to have to get those end stops built and hooked up.

NOTE: There are some incidental parts and tools necessary to finish this build. I suggest reading through it first and figuring out if you need some random part like a single 2.54mm connector and its associate crimps. It can be pretty frustrating to realize you need to wait a week to get the right 0.05oz part.

  1. Get out your end stop PCB and take a look at it. Not too complicated, right?
    IMG_0176
  2. Go ahead and put all the components in place. I suggest just buying the kit, but if you want to track them all down individually that’s your prerogative. I didn’t use the RJ45 jack because that’s pretty old-skool (also it doesn’t work with RAMPS).
    IMG_0177
  3. Solder them so they don’t go anywhere. You might as well do all the boards at once. I got 6 so that I could have min and max end stops if everything went well, and if I broke any of them I could use the maxes as spares.
  4. Here are some other resources for opto end stops: Makerbot and RepRap.
  5. The best way to connect the end stops to RAMPS is to use servo cables. At least, it’s easier than building the cables from scratch using 2.54mm (.1″) hardware. You can do that, but it’s a pain. We’ll get to that later.
  6. Hopefully you thought that was all really easy…cuz now comes the hard part. The RAMPS board has two of the end stop connectors reversed; something about squeezing thicker traces on the board. This change means that you can’t just plug the end stops in to the board. First, you have to reverse the two appropriate wires in the connector. To do that you have to get something pointy into the back of the connector and pull up the tab that holds the crimped connector in place.
    IMG_0179
  7. Be gentle. You don’t want to damage the tab.
    IMG_0178
  8. Now you can switch the two wires. Which two wires, you ask? That’s a good question. As you can see on the PCB, there are three pins labeled VCC (+ voltage), SIG (signal) and GND (ground or – voltage). Basically, you’re going to want to switch the wires that are connected to SIG and GND. You can do it at either end of the cable, but try to keep it consistent so it’s easy to check your work. The connectors are labeled on the opto end stop board and on the RAMPS board, so check each a couple times.
    IMG_0181
  9. Do that for every end stop you’ve got. Then I suggest making a big loop of tape (sticky side out), and using it to line all your components up side-by-side for a final sanity check. If you bought a weird color of cable because it was on sale you might want to draw a chart or something to keep track of which colors are which.
    IMG_0182
  10. It might be at this point that you discover your cables aren’t long enough. Tough.
  11. No, but seriously, if that’s the case you’ll need an extension cable. One way to accomplish this feat is by grabbing a scrap rail of headers that are long enough to go into both female 2.54mm housings. The 90 degree headers are good for this.
    IMG_0183
  12. Just bend them and cut off chunks of 3.
    IMG_0184
  13. At this point things get hard to define. Mounting the end stops isn’t all that complicated, but you can run into weird interference issues. The more true to the Mendel build materials and process you stayed the less problem you should have. I used 6-32 socket cap screws instead of 3mm (USA! USA! USA!) because they were cheaper. They are almost 3mm, but they’re big enough that I had to drill out the end stop mounting holes. Then I realized that one or more of the end stops liked to wiggle around, so I had to create a tiny little brace to keep it immobilized. Just do whatever seems to work for you.
  14. I suggest using aluminum flashing for your opaque opto end stop triggers because it’s easy to twist into the weird shapes necessary. It’s cheap, abundant (can pick it up at any hardware store) and most importantly it’s a nice raw material to have around the shop. You can cut it with regular scissors and drill it, so no special tools required. Before you unroll it for the first time, take note of how it’s got that tape holding it together; you want to maintain that (it doesn’t like to roll back up again). Try to keep it from unrolling with one hand while you cut off a thin strip, then tape it back up again before it can pop loose.
  15. You’ll have to move the axes around to test fit the end stop triggers. X and Y are easy…Z not so much. You’ll have to get the axes working properly before you can figure out what shape to make the triggers for the Z-axis. I set mine so that the min end stop is triggered just AFTER the extruder touches the build surface. I figure it’s on springs for a reason.
  16. The MakerGear plastruder build is already documented pretty well over at Makergear.com. I got the 1.75mm version, and the associated PLA, because I wanted this Mendel to err on the side of accuracy. However, many of the parts in the plastruder are still sized for 3mm filament. Because of this I had a bit of trouble getting the 1.75mm filament to work correctly, but I have been assured that it’s supposed to work just fine. Make of that what you will.
  17. Pay particular attention to the steps that involve crimping connectors onto the ends of wires. It’s a delicate operation that is guaranteed to frustrate. Unless you’re already good at it or you have a special crimping tool (in which cases you’re probably only reading through this for a laugh). When you solder the crimp onto the wire be careful to keep the solder from wicking up in between the guides on the “top” of the crimp. If that happens, the crimp won’t go all the way into the connector and you’ll have to get that solder out of there (yes I did that and no it’s not fun).
  18. I suggest using different sex connectors on the thermistor and heater wires (one male and one female) that way you can’t get them mixed up in the future.
  19. When you’re all done building the plastruder you’ll probably discover that the motor Makergear supplies doesn’t have a connector on it, just loose wires. What you want to do is install a 1×4 2.54mm connector on the end of those wires, because that’s the spacing of the headers RAMPS uses for connections. I had one of those, and the appropriate crimps, left over in the RAMPS kit I got from Ultimachine.
    IMG_0192
  20. Install the crimps on the wires, then apply just enough solder to secure them. Take a look at the other motors on your Mendel to figure out what order to install the wires.
    IMG_0193
  21. Make sure the crimps are all oriented the right way (so the tab will catch them) and shove them into the connector. You might have to get creative with a pair of needlenose pliers to get them to lock in place. Keep in mind that there’s not much space in there, so if they’re not going in all the way you might want to mash the crimped part into a narrower profile. See how the crimped part of that red wire is kind of wide? Just squeeze that into shape. (don’t deform the part of the crimp that goes into the front of the connector…that would just break it)
    IMG_0194
  22. Now you can hook the plastruder up to the appropriate locations on the RAMPS board. The motor connector goes next to the extruder Pololu board, the thermistor goes on the T0 pins, and the heater wires go into the D9 terminals (or whichever ones show 12 volts when you try to turn on the heater). I suggest not bundling the thermistor wires with the heater or motor wires since that might cause noise in the temperature reading.
  23. Now enjoy the unique feeling of having all the mechanical and electrical work done because you’re looking forward to a long period of time messing with the software trying to get the machine to do what it’s supposed to do.
  24. I’ll put together another post on just that subject…whenever I conquer it myself.
  25. I like round numbers.

RepRap RAMPS Build

In Uncategorized on 11, Feb, 2011 at 12:00

I’m building a RepRap Mendel because one bot just isn’t enough.

The brains of my new bot will be a RepRap Arduino Mego Pololu Shield (RAMPS) because it’s a design that manages to be small, powerful, and line-replaceable. The biggest plus I can think of over the Makerbot electronics is that RAMPS fits the same functions into a much smaller package. That’s not entirely fair, because the MBI Gen 4 electronics are designed to be more flexible in potential applications than RAMPS, but I’m not looking for flexible at the moment. The biggest plus over the RepRap Generation 6 electronics is that the most important pieces are easily replaceable.

So, lets get to it. I found the Arduino Mega (2560) on Amazon, got the DIY RAMPS kit (v1.2) from Ultimachine and found some Pololu stepper drivers in stock at Robot Shop.

[update: I can confirm that this build works for running steppers from the Repsnapper control panel, but I’m still waiting for endstops, so I haven’t tested that function yet.]

[update: I can confirm this build works for running steppers, using min and max endstops, and sensing/controlling the extruder temperature. I don’t have a heated build platform, or a build cooling fan, so I can’t test those features.]

  1. Get out two 4.7K resistors and seven 100K resistors. IMG_0130
  2. Solder them into place. resistors
  3. Get out the 10nF 100nF capacitor and LED. IMG_0133
  4. Solder them into place. The LED’s polarity is not marked on the board, but the RepRap wiki instructions say the short lead goes closer to the bottom of the board. cap & LED fixed
  5. Get out several double stacked headers. IMG_0135
  6. Cut them into seven 2X3 units. IMG_0136
  7. Place them in their respective locations. IMG_0137
  8. Use tape to hold them in place. Now solder them drama free. IMG_0138
  9. Get some single headers. IMG_0139
  10. Cut off a single 1X4 unit. IMG_0140
  11. Place it in the T1-T0 location. Use the tape trick to solder it in place. thermister connection
  12. Get out four 1X16 female headers. IMG_0143
  13. Place them in the appropriate locations. IMG_0144
  14. Use a couple long strips of headers to keep the female connectors aligned and in place while you solder them. IMG_0145
  15. Get out the power terminals. IMG_0146
  16. Also, the little push button switch. IMG_0148
  17. Solder them in place. Be generous with the solder. IMG_0149
  18. Get out the Arduino Mega and associated headers. IMG_0150
  19. Cut one 2X18, one 1X6 and 5 1×8 units (it doesn’t matter if some of them are made out of multiple pieces). IMG_0151
  20. Insert the headers into their respective locations on the Arduino Mega board. IMG_0152
  21. Put the RAMPS shield down on top so that it seats nicely. IMG_0153
  22. After you’ve soldered all the headers in place, they’ll be perfectly lined up with the Arduino Mega. IMG_0154
  23. Get out one 100uF capacitor and two 10uF capacitors. IMG_0155
  24. Solder them in place. The polarity is marked on the board. capacitors
  25. Get out the three N-channel mosfets. IMG_0157
  26. Solder them in place. The proper orientation is marked on the board (a thick white line). IMG_0158
  27. Get out the fuse and diode. IMG_0159
  28. You have to install the fuse, but the diode is optional. According to the RepRap wiki the diode connects the RAMPS power terminal to the Arduino mega board. Without the diode you can theoretically run 35v through the steppers (more torque). With the diode you are limited to the 12v the Arduino is happy with (theoretically 20v, but don’t push it). IMG_0160
  29. Make yourself four 1×4 header units. IMG_0161
  30. Insert them in the appropriate locations next to the female headers. stepper connections
  31. Grab four Pololu break out board kits and make two 1×8 header units. Hopefully you don’t end up with 3 out of 4 kits containing 1×15 strips of headers instead of 1×16 (like I got). But, if you do, you should be able to make up the difference with some scraps from the RAMPS kit. IMG_0164
  32. Insert the eight 1×8 header units into the 1×16 female headers on the RAMPS shield. IMG_0165
  33. Set the four Pololu breakout boards on top. Now you can solder everything together with the correct alignment. IMG_0166
  34. Remove the four stepper drivers and get out twelve jumpers. IMG_0168
  35. Install three jumpers underneath each stepper driver for 1/16th stepping (default). jumpers

The Search for a COTS Nozzle

In Uncategorized on 10, Feb, 2011 at 16:16

For anyone interested in improving existing 3d printer designs, or creating new ones, the extrusion nozzle is a real issue. The biggest problem is that the nozzle can’t be made out of the same material the bot prints in; it will either liquify at extrusion temperatures or bond with the material being extruded. Additonally, the nozzle has to meet very particular standards of size, shape and strength.

It’s entirely possible to machine a custom nozzle that does the job quite well. That’s what everyone has been using so far. But the level of machining required is prohibitive. Just try drilling a 0.5mm hole if you don’t believe me.

What we need to find is a Commercial Off The Shelf (COTS) nozzle that is already being mass-produced for some other purpose. It doesn’t necessarily need to be a drop-in product, a little light machining (like tapping threads) would be fine, but it does need to be:

  • Resistant to heat. ABS is extruded at around 220*C, and some people run a little bit higher.
  • Rigid. It needs to resist quite a lot of pressure from the extruding plastic.

Also, it would be nice if it was:

  • Cheap. Duh.
  • Interchangeable. Some preexisting threading or method of attachment.
  • Doesn’t stick to molten plastic. Infrequent, if any, need for cleaning.
  • Variety. A range of nozzle inner diameters would be great.

I don’t think anyone’s found anything like this yet, at least not with an inner diameter under 1mm, but here are some ideas that might work.

  • Graphite Ferrule. These things are used in gas chromatography. They’re described as “soft” but they are manufactured with a range of diameters in appropriate sizes and are made out of pure graphite, so they don’t melt until 450*C.
  • Capillary Tubes. These things are used in liquid chromatography and other advanced stuff. They can be made out of all kinds of different materials.
  • Ceramic Tubes. More of a range of things. What’s important is that they tend to be manufactured in sizes down to and below 0.5mm inner diameter.
  • Needles. Again, a range of things. But a few examples for different purposes like veterinary medicine, dispensing materials, and inflating balls.
  • Flow Control Orifice. These are used to control the flow of liquids or gases through pipes. They’re all made out of brass or steel, they’re tiny, and they’ve already got pipe threads.

If we can’t find anything that works as-is, then we have to move on to additional steps that take a COTS nozzle from almost right, to totally right. Some examples might be:

  • Solder. High-temperature solder (usually lead free, possibly with silver in it) could be used to close up an overly large inner diameter, and then an appropriate hole could be drilled through the solder.
  • Cement. Some sort of fireable clay, mortar or concrete type stuff could, once set, resist the temperatures (and maybe the pressures) involved. Maybe it could even be formed around a wire of the appropriate diameter, so when it sets the hole remains and no drilling is necessary.
  • Multi-part. Perhaps machining appropriate grooves (.25mm-1.5mm) in two matching surfaces, and holding them together, would work.
  • Tapping. Threads are great for attaching one thing to another, particularly if you might want to detach it in the future.

Why I Bought a Makerbot Thing-o-matic

In Uncategorized on 01, Jan, 2011 at 12:00

The Thing-o-matic (TOM) is pretty impressive. Specifically, after I put it together it worked pretty much exactly like it was supposed to, and then it gradually stopped working like it was supposed to.

I was impressed because I spent a couple of months waiting for it to arrive, and I filled those months with keeping track of what other operators were doing. Most of what I read about was one problem or another, or another … or another. It seemed 3d printers only worked after one spent a considerable amount of time babying them. So, I was expecting to get the TOM put together, watch it not work, and then slowly tease various functions out of it. Instead I was treated to the spectacle of it not only working, but the default settings producing adequate prints on the first try.

That was then. Now that I’ve been printing for a week or two things are starting to go wrong. BUT I’m not complaining! As an early adopter I fully expected things to require fixing, and I’m actually quite excited about the chance to figure out a solution that can benefit everyone else having the same problem.

What I’m looking forward to breaks down into several basic categories:

  • Bringing 3d printers up to minimum standards
  • Maintaining those minimum standards
  • Augmenting beyond those standards

There are certain basic things any 3d printer needs to be able to do just to be called a 3d printer, let alone make anyone happy. “Things” like not failing unexpectedly. At a minimum it should be able to build a physical structure out of a raw material in a controlled way. There are a lot of things that can go wrong with that process, but the level of technology required to merely meet that standard is modest by modern standards, so purging it of bugs shouldn’t last forever. Once a design meets that minimum standard the focus becomes more about optimization than construction.

At some point in the life-cycle of any design it will work properly for longer than it’s ever worked properly before. This phenomenon increases the chances that a new 3d printer will run into a failure state that is so unusual it simply hadn’t had a chance to occur, in addition to predictable accumulated wear. Solving these issues as they arise allows the design to become something people can build future plans around.

Of course, the world wouldn’t be what it is if people left good enough alone. When we can rely on something to do what it’s supposed to do over a certain period of time we immediately ask “Well, why can’t it do more?” 3d printers, specifically hobby 3d printers, are at that point where we really don’t know what their ultimate limitations will turn out to be.

I got a Makerbot Thing-o-matic because 1) I like their style and 2) Electricity is black magic (software might as well be demon summoning), so it’s nice to buy the right to pester a support team with questions, and 3) because it’s a vaguely standardized product. A RepRap is next on my list (I can print it!) but learning on a TOM means that there are hundreds or thousands of other people looking at the same parts behaving in the same way. The presence of this large group manipulating the same machine means that problems can be diagnosed reliably and solutions are meaningful. If something goes wrong with a RepRap the odds are better that yours is a little bit different from everyone else’s, so they might not have experienced the same problem and they might not be able to reproduce it. Additionally, if you solve the aforementioned problem it might not actually help all that many other people.

Also, it’s cold outside … and there’s nothing on TV.