by makeme

Posts Tagged ‘makerbot’

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.

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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).

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.

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.

Makerbot Thing-O-Matic Extruder Relay Fix

In Uncategorized on 23, Jan, 2011 at 19:14

As I addressed previously: the Makerbot Thing-O-Matic has a few issues. Also addressed previously: why that’s half the fun!

The best way to troubleshoot something is to find where the problem is and gradually work backwards. At each step you try to confirm that a part works the way it’s expected to work. When a part fails a test, you either fix it or bypass it and see if that solves the problem. If it doesn’t, you make a note and continue moving backwards. Of course, it’s always preferable when you can just fix the problem. Or, maybe replace a part, that’s good too.

Plan C is usually to alter the design to compensate for something that simply can’t do what you’re trying to make it do. When it comes to the Generation 4 electronics and the Kysan DC motor on the extruder (all of them) … I’m down to Plan C.

I tried replacing the old Extruder Controller (EC) circuit board with a new one that Makerbot was kind enough to RMA (thanks Ethan!). I also tried replacing the actual motor driver chip (A3949) on the old board with a new one from Digikey (no joy, also, I’m not sure how happy support was about that). The closest I got to a solution was that the totally new EC would drive the motor for a little while (the old one wouldn’t put out any voltage at all). I backed out the delrin plunger’s thumb screw on the extruder so that there was no load on the motor, and just watched the multimeter. Sometimes it would work fine (11.98v), sometimes it would try (~7v) and sometimes it would give up (80mv).

For what it’s worth, by running through this failure mode several times I was able to find that when the motor stopped turning its resistance was basically shorted out  (1.4 ohms). When it was turning fine it was resisting fine (30-45 ohms). So, I suspect that it could very well be a problem with the motor (a bad winding maybe) that’s causing a problem with the motor driver. My guess is that the motor is basically shorting out while it’s spinning, which dramatically increases the current in the circuit, triggering the A3949 to shut down. It’s probably turning back on a microsecond later, applying 12v again, and shutting down again. Repeating that over and over again is probably what produced the 7v-ish reading.

At any rate, replacing the broken part didn’t fix the problem. It merely illustrated that the new part would probably break too. Several people seem to agree that the current design is beyond fixing. Time for Plan C.

“… I’m using the motor just fine to push plastic , powered from the 12v rail of the power supply in the TOM, using a relay connected to the usual motor control to turn it on and off. There hasn’t been a single glitch in this setup.” – ScribbleJ

Instead of connecting [the EC] to the motor (which fails just as described in these posts), I connected it to a couple of relays. This works in both directions…” MakeALot

The relay kit did it for me. Motor started working perfectly.” – g00bd0g

I didn’t feel like waiting for  support to maybe send me a relay kit, so I cobbled something together from Radio Shack. I am happy to report that I just got through 20 minutes of printing without a single problem (that hasn’t happened in weeks). What I did is basically like what rwensley did, but with only one relay (forward or stop).

Parts list:

Steps:

  1. Figure out where to mount the new components. I cut a small piece off the perf board and drilled 1/8″ holes so that I could mount it in between the EC and stepper driver using the existing mounting points.
  2. Test fit the components. I then elongated the holes because I’d mounted the board too close to the edge of the bottom panel. Remember that the outside edge of the electronics are butted right up against a wall when the bot is closed.
  3. Mark the perf board. I suggest, if you mount the DIY relay board underneath the two existing circuit boards on the same bolts, that you mark it with a sharpie to show where you have room for components. Remember to connect the RJ cable.
  4. Cut the female Molex connector. I left a couple inches of wire, then stripped a half inch off of the end of each.
  5. Drill holes for the Molex connector wires. I used a 5/64″ drill bit to enlarge four of the holes (at least one hole apart).
  6. Hot glue the components in place. You don’t have to do that, but the perf board I used didn’t have any copper on it, so I wanted a better mechanical connection then just soldered wires. It doesn’t take much hot glue, tho.
  7. Wiggle everything. The idea is that things aren’t going to fall apart when you start connecting/disconnecting things and trying to stuff them inside the bottom of the bot.
  8. Wire it up. Wiring a relay is pretty straight forward. Remember to put the stripped end of the diode on the positive wire.
  9. Test it. Not strictly necessary, but it’s good to make sure you got polarities right. I plugged everything in like it was finished, except that I left the two control wires free and just hooked them up to an external 12v source. This simulated the motor controller sending 12v to the motor (actually the relay now).
  10. Connect everything and close the bottom. Yay!

TOM relay

Is Makerbot Going To Make It

In Uncategorized on 09, Jan, 2011 at 11:53

CES has come and gone, and as usual a lot of people have done “journalism” on topics they don’t understand. For example:

Glen Stantos of Geeky Gadgets seems to be unclear on the concept of a “work in progress,” describing the Thing-o-matic as “working exactly like your trusty printer.”

David John Walker of Seer Press News took Makerbot a little too literally at their word in describing just how “maintenance free” their extrusion system is.

Gizmag managed to get their description right by simply parroting Makerbot’s description.

At least the Tested guys , who have been running Makerbot products for a while now, were coherent.



Here David M. Ewalt of Forbes thinks that 3mm ABS filament only costs $5 per pound, when the Makerbot store he linked to actually sells it for $10-45 per pound. Makergear sells it for more.

Anywho, that stuff’s not the point. The point is that Makerbot is starting to approach that time in the life-cycle of successful startups when they go from small to large. Or, at least when they have the chance to go from small to large. All this press, and it is well deserved press even when it is inaccurate (reporters overstating something is par for the course), is a good indication that Makerbot has “made it” and needs to seriously consider their business model.

The way I see it, Makerbot can remain true to the open-source “maker” idea they started with and keep putting out a product that appeals to DIY enthusiasts. A big part of that model is continuing to let their customers do a lot of their testing for them. This ongoing extruder problem is a perfect example. Since they can get a dozen bots to print for days without any problems, and there aren’t hundreds of people crowding the forums asking about their dead extruders, this failure mode is reasonably rare … for a DIY project. But (and I don’t have any numbers) it seems like this failure mode is too frequent for a larger enterprise. If Makerbot starts selling an order of magnitude more bots they are going to run out of early adopters. While they might be able to get the general public to assemble a Thing-o-matic (at least a full day of work) they are going to have a really hard time getting them to be patient when it doesn’t work or gradually stops working over a couple of weeks. But even ignoring the assembly time (maybe they sell them pre-assembled), you can’t sell something for $1500 that only works for a few weeks. Not to the general public at least.

Which brings me to the alternative business model. Makerbot could go for the expansion that interest in their product supports, but they’d have to dramatically change the way they operate. Selling thousands of bots per quarter will require an obvious expansion of physical and personnel resources, which (since they’re in America, more specifically New York) will start to cost an awful lot. There’s a reason so many things are manufactured in China. The DIY, early adopter, solder fume addict community will pay a premium for something they can hack … the general public won’t. Also, Makerbot’s current clients will “pay a premium” in the extra time and effort required to make the product work properly … the general public won’t. In fact, selling something designed to be hackable to the general public pretty much guarantees that the first people to buy it will be the members of the general public who THINK they can hack, but actually can’t. These people will probably just poke it until it just breaks, and then demand a replacement. Additionally, since Makerbot’s business is based on open-source designs, if they start to create a new market they will find themselves with competition. Even more fun, they’ll find themselves with their first lawsuit as soon as someone leaves the bot printing overnight and their kid reaches in to grab the extruder nozzle, or someone opens their bot up and leaves it lying on the carpet with the z-motor powered up and starts a fire, or someone sticks their eye under the extruder to see if it’s clogged.

I don’t think it’s practical for Makerbot to actually pursue that second option. Not only do none of the founders seem interested in the corporate mindset, there are already tons of pre-existing corporations that can fill up the consumer marketplace with plug-n-play 3d printers. The fundamental technology really isn’t particularly complex or expensive, so as soon as a demand exists it will be supplied. But that does put Makerbot in an interesting position. They can run full speed to become a large corporation and fill the consumer market’s demand for 3d printers, or they can stay where they are with the open-source early adopter thing. They already pretty much guaranteed that they can’t get their company acquired (bought out) since they release all their IP to the public for free. If they wanted to do that they’d pretty much have to rely on the value in their brand.

What they could do, and what I think makes the most sense, is they could expand the “Makerbot umbrella” to include more products. Whenever they get their 3d printer’s mean time to failure low enough, they can start on something else. We can already see that they’re sort of pursuing this strategy since every now and then they mention that they also sell other things like a 3d scanner and an egg plotter. However, I’m unsure about how long that strategy could last. It seems to me that it would only work if they came up with a new flag-ship product that attracted just as much DIY community interest as the Cupcake/TOM did. See, once someone has a TOM, they don’t need a second one, and the market is just too small for them to continue to run a business off of consumables like plastic.

Basically, I think Makerbot needs to stay in the DIY market, but to do that they need to come up with a new flag-ship product. If they don’t, I fear their initial success will be short-lived rather than sustained. An initial expansion followed by a long, slow contraction. And my intuition tells me that the kind of guys who would start something like Makerbot are not going to stick around when their business becomes boring and gradually shrinks, but they can’t really sell it to someone else since all the information someone needs to copy their business is available for free. So, if they don’t come up with a new Cupcake-type-thing in a year or so they just might call it quits.

So, what could Makerbot work on next? I’d like to hear your suggestions, but in the meantime here are some of mine:

  • I suppose the most obvious product is a plastic recycler. It’s a more popular topic in the RepRap forums, but pretty much everyone everywhere is already interested in the idea. Something that could take bulk plastic (even if it’s just failed ABS prints) and turn it back into filament for the printer, would be quite popular. Additionally, a lot of work on this topic has already been done in the open source community, so Makerbot wouldn’t have to start from scratch. That seems in keeping with what made the Cupcake/TOM successful (it was pretty much entirely based on the RepRap). Finally, they might even be able to run the recycler off of the same electronics kit already sitting in the bowels of the TOM. The Gen 4 electronics have extra actuator/sensor connections that aren’t being used. A firmware upgrade, a new version of ReplicatorG, a second power supply, a few wires and you’re up and running.
  • They could introduce new models of 3d printers that don’t use plastruders. There are literally several dozen different methods of printing in 3d and not all of them require a million dollars. The most obvious method is ACTUAL 3d printing, where a powder medium is smoothed flat and an inkjet head prints a picture to bind it together.
  • A complimentary subtractive manufacturing process might be good. If they could build a CNC machine that automatically took parts the TOM had finished, and cleaned them up, drilled holes, maybe even produced a smooth surface finish, it would probably be bought up by the same people who already have a 3d printer. So, not just Makerbot customers, but also RepRap owners and UP printer owners and whatnot.
  • Perhaps they could expand into technologies that would compliment the desktop manufacturing paradigm. For example, I have a wet/dry vac that is totally plastic (printable) except for the motor, switch, and wiring harness. In fact, the limitation of “but what can a plastic part do” is the first thing people think of when I show them 3d printing. ABS is structural. To make it generally useful it needs to  hold electrical and mechanical systems in position. Since their market is (and should be) the DIY early adopter hacker type, they could create a sort of Legos system for DIY projects. For example a pick-n-place bot that could build circuit boards by putting components in position and soldering them, and then put them into a 3d printer to have the housing built around them, would be quite attractive to that community.
  • One of the biggest limitations is that everything is in plastic. Metal is much more useful for many practical applications, but machining it is a pain. Building up the shape of the metal part you want in easy to handle plastic, and then casting it in metal, would make the machining of metal nearly unnecessary. Perhaps Makerbot could build a sandbox casting bot that takes the part the TOM spits out, dumps sand around it, melts some metal, and injects it into the mold … turning the plastic part into a metal part automatically.

Makerbot Extruder Mystery

In Uncategorized on 05, Jan, 2011 at 18:23

Now that I’m an established blogger 🙂 I think it’s time to tackle the elephant in the room. I’m referring, of course, to the Makerbot extruder “issues.”

I’m not claiming to have a solution, not yet, I just want to try to inject some structure into the problem solving process. There are a lot of references to this problem spread around the interwebs, most of which are speculation. I’m not much use when it comes to electronics, but I can at least compile everything into a coherent troubleshooting process … and then add my own speculation!

First, lets hear from the community:

“I’d try that, but since my last post, the extruder motor stopped spinning altogether.  can’t get it to spin in a build or in the control panel. Ugh.” – Rich

Then I was trying some raftless objects and the extruder drive died 1/2 way through my 20mm cube and I was like “WTF”?” Gabe

I am experiencing something odd with this motor as well.  I was able to complete about 3 prints without any issues.  However recently, the extruder motor stops responding in mid print.” – GodfatherUr

After Makerbot fixed the stop button bug in ReplicatorG, and after so many people reporting that their extruder motors still spin when they apply an external voltage to them, I think it’s safe to discard the theory that there is something wrong with the motors themselves. So, while that’s the thing that most obviously stops doing what we want it to, it seems like it’s just not getting what it needs from lower down in the chain.

That leaves the extruder controller (EC), the motherboard, or the power supply (PS). Lets work backwards, starting with the PS.

According to Makerbot the Thing-o-matic (TOM) ships with a “500w Hercules ATX power supply” which has slightly different specs depending on where you look (17A or 22A on +12V for example)* mine says 22A on the side. I can’t find anyone who admits to manufacturing the thing, although I did learn just how many products are called “Hercules.” So, I did what I always do … I swallowed my pride and consulted wikipedia. The Hercules claims to have over current protection, which should shut down the whole PS if something drew too much juice. Additionally, I didn’t have any trouble finding +12V at pins 8 & 9 (power and ground on the schematic), even when the motor was failing to spin, so it doesn’t look like there’s too little juice either. I followed (in as much as they apply) some troubleshooting guides like these 1, 2, 3 and didn’t find any problems. Replacing the PS seemed to work for G00bd0g but not for Ryan9. I don’t think the PS is the problem.

Ditto for the motherboard. Mostly, I just can’t think of how the motherboard COULD cause the kind of problems we’re seeing. It’s not responsible for extrusion.

The EC, on the other hand, not only controls extrusion but has its own set of firmware. Hooking the motor up to a dedicated power supply demonstrates that there’s nothing wrong with it. The very next thing in the chain is the EC or, more specifically, the A3949 motor driver. As you can see from the schematics, the motor driver connects directly to the motor, supplying everything it uses to function. More specifically, the motor driver takes in a logical signal (distinguished by two LEDs) and power from the +12v rail, then outputs a PWM signal that controls the motor’s speed by turning on and off really fast. To make a long story short, I could never find anything going wrong with anything besides the part of the circuit that connects the output of the motor driver with the motor. Ergo, I think it’s the motor driver that’s causing the problem.

My suspisions regarding this phenomenon is best explained by James, one of Allegro’s (the A3949 manufacturer) technical support reps. After I described the problems to him he replied, “The symptoms you describe are typically related to electrical overstress in the motor driver chip … One risk area is that some applications will use a connector between the motor driver and the motor.  If the connector is disconnected when there is significant amount of current flowing in the inductive load then there will be an out of spec. voltage spike that will damage the motor driver.  As with an ESD event the device may only be weakened by the voltage spike and subsequently fail after 10-20 more hours of operation.”

When I provided the link for the schematic he observed, “I see from the schematic that clamping diodes are in place to prevent excursions of outA and outB from going below ground.  I do not see similar clamping diodes in place for holding the outA and outB to VBB(+12V).”

That’s what I’ve got. Since I suspect a problem with either the chip or the circuit I’m going to have to lean on the technical expertise of EE guys (more of an ME guy myself). My guess is that the design of the circuit is allowing damaging spikes to come back to the motor driver. I don’t know where the first spike comes from, but it sounds like a single bad spike can degrade the chip enough to guarantee failure eventually. I suspect this would account for the interesting variety of failures (or lack thereof) reported by the community.

Personally, I was planning on moving to a stepper extruder anyway. So now I’m just planning on doing it faster. Maybe better electrical isolation of the ICs would solve the problem, maybe not, but at this point it looks like DC extruders are outclassed by steppers even if the extruder problem is solved.

How To Tell If ABS Will Stick

In Uncategorized on 02, Jan, 2011 at 12:00

The Thing-o-matic (TOM) is full of surprises.

Probably the biggest shock I experienced was having my very first build stick like it was supposed to, and then peel off like it was supposed to, on not only the first try but on all subsequent tries. The new belt that Makerbot is including with the TOM kits worked perfectly. It’s a pre-made affair that appears to be two layers of plastic tape that were wrapped around a pipe of the appropriate diameter.

That being said, the belt gradually warped. After a couple dozen rotations (not every build was allowed to progress to the eject stage) the belt had a small section that would lay flat, but was mostly waves so big you could surf ’em.

IMG_0113 (400x225)

It got to where the surface of the belt was rising up many milimeters, which made it useless for printing on. The Makerbot support team indicated that the belt might have been too tight, which put too much force on it and stretched it out into a funky shape. They have yet to get back to me regarding how exactly I’m supposed to adjust the tension of a belt on the Automated Build Platform (ABP).

Since I didn’t want to go back to an old and busted option like the lowly Heated Build Platform (HBP), I took advantage of the old style DIY belts they were kind enough to include with the kit. After fighting with the assembly process I eventually got an ABP with a flat belt again. Unfortunately the belt refused to associate with ABS. I tried sanding the surface (in one direction), and I tried degreasing it with windex and other products … but nothing really worked. I had moderate success with just centering the kapton tape so that the build started out on it. Kapton seems to be a reasonably good build surface.

All this time I was bouncing around from forum to wiki to email trying to figure out if anyone had solved this adhesion problem. The best I could gather was that some people had a problem with the exact same kit and some people didn’t. That implied there was a variable involved in using the kit that was being missed, and so was randomly popping up to cause trouble. A conversation with Makerbot’s support led me to suspect it might be that each side of the DIY belts had a different surface, one was Jekyll and one was Hyde. But, in this case, they both looked exactly the same. How to tell them apart?

What I discovered was that you can find out which side is which with a sharpie. The side that won’t be a good surface for printing also is not a good surface for writing.

IMG_0111 (400x225)

the bad mark is on the outside surface

The side that the sharpie ink can stick to is the side the plastic will stick to.

IMG_0112 (400x225)

the good mark is on the inside surface

The belt I had put together first randomly had the wrong side facing outwards. It was 50/50. I couldn’t find a mention of this difference between the two sides in any of the build or troubleshooting documentation, let alone a method for telling them apart. If other people try this fix and find it consistently successful we can add it to the build instructions so that this problem never appears again. The last thing anyone wants is a 3d printer that would work if only the freakin’ plastic would stick. I haven’t tried this method on anything except the belts from Makerbot, but it seems to have something to do with the inherent properties of the surface of the plastic, so it might work generally (it verified that the pre-made belt is a good build surface).

Let me know whether or not this works when you try it.

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.