by makeme

Posts Tagged ‘DIY’

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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Professionals Do It On Powder Beds

In Uncategorized on 23, Nov, 2011 at 12:00

There are a lot of approaches to additive manufacturing. Fundamentally, however, they all break down into a few categories:

  • points
  • lines
  • planes

Planes means using sheets of material. This approach is usually more of a combination of additive and subtractive, since the excess sheet has to be trimmed away. Lines means using long thin noodles (floppy or rigid) to build up the part. Points means using powder, either laid down in a bed or shot out of a nozzle.

I’ve been trying to come up with a way to take Fused Filament Fabrication (FFF, AKA: the copyright free version of FDM) to the next level by removing the need for a support structure. If you can free up the extruder nozzle to move in more dimensions relative to the build surface you can print “overhangs” right onto the part instead of printing them onto thin air.

3d print FFF without overhangs

This approach would definitely allow an extruder-style printer to print nearly-arbitrary shapes faster and with less waste. However, it would not allow printing of truly arbitrary shapes. The easiest example of this limitation is the spiral. It doesn’t matter where you start from, an extruder-style printer is going to have to use support material to print a spiral.

cant print a spiral

Ultimately, if you want to print arbitrary shapes, you’re going to have to hold everything in place until you can get the entire print finished so that every little bit is attached to every other little bit. Either you use support material, or there are some things you just don’t print. That being the case, might as well embrace support material, and nothing is supportier than a powder bed.

CandyFab is a good open-source example. Here’s a great overview of the process by How It’s Made (my favorite show evaaar!)

There is a sort of natural difference here between hobby 3D printers and professional 3D printers. Powder beds allow for truly arbitrary shapes, but they require a lot more of the printer and the environment the printer is in. I think this means that hobby 3D printers will be limited to nearly-arbitrary shapes. Maybe in a decade there will be pro-sumer printers next to the drill presses at home improvement stores that will use powder beds. It’s at least a possibility.

The result of my investigation, and the point of this post, is that I don’t think the open-source hardware movement is going to drive the development of powder bed printers. I think those are going to be left for the professionals.

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.

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.

Easy 3D Printer Toolchain

In Uncategorized on 07, Jun, 2011 at 21:32

The software that controls open source 3d printers is still in a state of flux. It can be difficult to navigate your way through all the options to try to put together a toolchain that will do what it is supposed to do. I know, I’ve been doing just that for a while now.

Eventually I figured that I was only really helping myself because I was piling one patch onto another trying to make things work in my specific situation…and it wasn’t working all that well. So, I started over.

The primary factor in deciding what toolchain to put together is the operating system your computer runs on. Normally, this would seem to be an insurmountable obstacle, but these days it’s really not that big a deal. We can standardize on one single OS by creating a bootable flash drive. I have picked Ubuntu because it’s totally free. So, if you have a 2GB flash drive, or if you can scrape up the cash to buy one, you can simply boot your computer into a brand new OS without actually changing anything about your computer. This step ensures that you are starting from a totally clean install, and that your install is the same as everyone else’s install.

From that point forward all you have to do is download Java, which is free, and Python, which is free, and Arduino, which is free, and in this case I’ve choosen ReplicatorG (best and best supported), which is also free.

But don’t worry. I’m not going to leave you to figure out how to do all that. What follows is a detailed checklist that will guide you through this process. You don’t have to know ANYTHING about ANY of those programs. If you can click buttons (and can afford a 2GB flash drive) you can get your bot up and running.*

*I am sort of assuming you’re using RAMPS and Windows, but I can’t test this process with anything else at the moment.

How to do it (this process is largely based off of this set of instructions on the RepRap Wiki by Bristolalweb)

  • You will need:
    • a computer with 2 free USB ports (one for the flash drive and one for the 3d printer) and a wired internet connection (no need to mess with getting wireless working).
    • a flash drive (at least 2 GB)
    • an Ubuntu image
      • http://www.ubuntu.com/download/ubuntu/download
      • The Ubuntu site is pretty easy to navigate.
      • Getting the Long Term Support (LTS) version is recommended. New Ubuntu releases don’t have support for everything build in; people add that stuff over time. If you get the newest version you will probably find that it doesn’t support one or more of the things you want to do. For example, when you try to use the Universal USB Installer, the newest Ubuntu release might not support a protocol necessary to let the system treat a flash drive like a hard drive. The LTS version will.
      • Make a note of the version name and number: 10.04 Lucid Lynx
    • An installer
  • plug the flash drive in to the USB port and make sure the flash drive doesn’t contain any files you want to keep
    • make a note of the drive letter that identifies the USB key
  • quick format the flash drive
    • open windows explorer
    • right click on the drive letter and select ‘format’
    • select ‘Fat32’ and ensure ‘quick format’ is checked
    • click ‘format’
  • run the Universal USB Installer
    • select the version of Linux that you downloaded
    • select the file you downloaded
    • select the letter that represents your flash drive
    • select at least 1GB of persistent memory (so that you can save things)
      • if your flash drive is larger than 2GB you can select more, but leave 1GB available for Ubuntu
    • click ‘create’
  • restart your computer (or move the flash drive to a different computer)
  • at some point before your normal operating system shows up you should have the option to select a ‘boot menu’ (or something like that). If there isn’t a clearly labeled option or menu (which won’t be available for long, so move fast) then you can try ‘delete’ ‘F10’ or ‘F12.’ If none of those work consult your documentation or customer service representative. There most definitely is a way to tell your computer to boot from the flash drive in the USB port, so don’t give up.
  • When the Ubuntu menu shows up, select ‘boot from USB’.
  • get Ubuntu universe (not a program, this just tells Ubuntu to search a wider list of programs)
    • click ‘system’
    • click ‘administration’
    • click ‘software sources’
    • check the box next to ‘universe’
  • get python and java
    • click ‘system’
    • click ‘administration’
    • click ‘synaptic package manager’
    • click ‘reload’ in the upper right of the new window
    • in the search bar enter the package names and check the box next to them when they show up
      • “python” “python-tk” “python-psyco” “openjdk-6-jdk”
    • click ‘apply’
    • 10.04 seems to have python 2.6.5 by default
    • or, from the terminal (doing it this way didn’t work correctly for me)
      • sudo apt-get install python python-tk python-psyco
      • sudo apt-get install openjdk-6-jdk
  • get arduino
    • http://arduino.cc/en/Main/Software
    • after the download, move the file from the download folder to the desktop
    • right-click on the folder and select ‘extract here’
    • back in synaptic package manager
    • search for “avr-gcc” and “avr-libc”, mark for installation
    • or, from the terminal
      • sudo apt-get install gcc-avr avr-libc
  • get Teacup firmware
    • http://reprap.org/wiki/Teacup_Firmware
    • https://github.com/triffid/Teacup_Firmware
    • download the *tar.gz file (It’s actually a folder with a lot of compressed stuff inside it, not a single file)
    • move it from the download folder to the desktop
    • extract it to the desktop
    • rename the new folder “Teacup_Firmware”
    • open that folder, copy the “config.ramps.h” file and past a new one
    • rename that new file “config.h”
    • load Teacup firmware on to RAMPS
      • open the arduino folder
      • run the file named “arduino”
      • select ‘run in terminal’
      • select ‘file’ then ‘open’
      • click the ‘-‘ button in the upper right and navigate to the desktop directory
      • double-click the ‘Teacup_Firmware’ folder
      • double-click the *.pde file
      • click ‘verify’
        • you should get an error
        • open the Teacup_Firmware folder
        • find the file called ‘makefile’ and open it
        • scroll down to the ‘change these to suit your hardware’ section
        • uncomment the mega2560 line and comment out all the others (assuming you’re using the 2560 and not the 1280). It seems like some of the files use “/” to denote comments (stuff the program ignores) and others use “#” for the same thing. It should be obvious because all the instructions will be surrounded by whatever the symbol for comments are.
      • back in the arduino window
      • click ‘tools’ ‘board’ then select the mega 2560
      • click ‘verify’ and it should compile properly
      • click ‘upload’. Not only will the Arduino IDE tell you whether or not the upload worked, you should be able to watch the LED on the RAMPS board blink an awful lot. That’s a good thing.
        • it might prompt you to try the port ttyACM0 instead of COM1, click ‘ok’
  • get replicatorG
  • connect to the 3d printer
    • open the replicatorG folder
    • run the file called ‘replicatorg’ select ‘run in terminal’
    • wait for it to finish updating itself
    • click ‘machine’ ‘driver’ and select ‘teacup’
    • click ‘machine’ ‘serial port’ and select the ‘ACM0’ port
    • click ‘connect’ and the orange bar should turn green
    • make sure the temperature is updating and jog the axes

At this point you should have a bot that is registering temperatures and responding to the control panel. That’s all for now. I’ll put together another set of instructions describing how to properly tune the bot.

Anyone who tries this out on a system other than Windows, or on electronics other than RAMPS, please let me know. I’m sure it will work with only minor tweaking.

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.

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