If you have been to Metrix in the last few months, you have probably noticed the tiny bits of pink foam floating around and clinging to everything. They happened to be the byproduct of the largest fabrication project Metrix has worked on so far. It was a fun and experimental project that led us to get to know our biggest robot, the giant router, very well.
Several months ago, Frederick "Fritz" Reitz wandered down the stairs into Metrix to find out more about all of our fabrication capabilities. He needed a full-scale replica of an MRI machine. We certainly hadn't done anything of that size but we love a good challenge so we took on the project.
After much discussion, we chose to work with 2 inch thick, 4 ft by 8 ft sheets of rigid foam insulation. The material is great for shaping with the router because it is light, uniform, and can be easily finished with a bit of sandpaper. It provides a good structure for complex geometries that will need to get epoxied and painted.
What made this project particularly exciting was that it had a pretty great real-life application.The replica was requested by Tom Grabowski, who is a professor of radiology & neurology at the University of Washington. His plan is to use it to get test subjects used to the machine off-line. Time on the real MRI is very expensive so this allows for refining testing teqniques and getting the subjects more comfortablewith the machine. He went to the Center for Human Development and Disability at the University of Washington for help on this. The Center is funded by a NIH grant to support research in human development and disability in such areas as autism, language acquisition, and cognitive development. The Center has their own Instrument Development Lab, where Fritz works. The Lab was tasked with the actual fabrication of the replica-MRI, which is what brought Fritz to Metrix.
While his lab has many great tools for production, the scale of this particular project required outside help. Our router has a 4 ft by 8 ft cut bed and the z axis has about 8 inches of variance depending on the cutting bit size. Since the project required a lot of complex geometry shaping we had to really learn the 3D z-cutting capabilities of the router, which was new for us so we looked forward to doing some testing.
Below are the first test of the finished surface quality of the foam pieces. We had to use specialty bits designed for cutting foam and soft plastics. When working with something soft like foam, maintaining a very sharp cutting edge is essential in getting a smooth surface. Otherwise the finished surface ends up looking very rough and dented where larger bits of foam get pulled out. The nice thing about working with these specialty bits is that they are super sharp and come in extra-long options because the chip load with foam is quite low. Having the extra length gives much more flexibility in the z-depth shaping of a piece.
In order to achieve a high degree of detail, first we ran a rough finishing pass using a 1/2" ball-end bit with a fairly large stepover. Then we used a 1/8" ball-end bit with a smaller stepover to do a finishing pass. The stepover is the amount the bit moves over with each pass and it is determined as a percentage of the bit diameter. The size of the stepover and the length of time it takes to finish a pass are inversely proportional. We went with a 50% stepover for the rought finishing pass and a 25% stepover for the final finishing pass with the small bit. Usually the roughing passes run faster to save time with the knowledge that the finishing pass will smooth everything out.
The project took many weeks of testing, troubleshooting, buying more foam, calibrating the router, and calibrating the router some more.
Our amazing new technician/pretengineer Seth Crowell is a master with the router. He has put many hours bringing the robot to the glorious life it was meant to have.
Below is the raw assembled product standing full-height in the Instrument Development Lab.
The front round piece is made up of a total of eight sections. Each half is assembled from four layers of various thickness. The back section, which subtly curves in to simulate the funnel of the MRI, is constructed from eight single layers of the foam. While all the pieces went through a rough finishing with the 1/2" bit and a final finishing with the 1/8" bit, the top two layers of the front part also required an additional initial roughing pass. The roughing pass was done with a 3/8" flat-end extra long bit.
This pass is used with thicker pieces of material when the geometry requires deeper cuts. It removes the bulk of the material in order to make room for the rough finishing pass with the ball-end bit. The roughing generally happens in several set-z drops where each pass removes the extra material at a specified level, and the bit drops down another level for the next pass. The stepover for this can be set as high as 100%. The rought pass is generously off-set from the finished surface of the geometry so that any accidental gauging of the final piece can be avoided. The rough finishing pass with the large ball-end bit removes most of this excess material. While the roughing of a piece involves several fast passes, the rough finishing and final finishing are single, slower passes that trace the final surface of the geometry with increasing degrees of precision.
Some initial patching with joint compound was necessary in order to smooth out any little dings from the routing and moving processes. The full piece stands 7 feet tall by 7 feet wide and about 3 feet deep.
Once the pieces were assembled, Fritz embarked on the long and patient process of finishing the final product. First he applied an undiluted coat of drywall mud to fill in the assembly-joint seams and any dings. Then he smoothed out the surface of the pieces with a few coats of diluted finishing mud to get them ready for sanding and coating in plastic.
The next step of the process was fine-sanding the pieces to give them an extra smooth finish.
Once sanded, the pieces were ready for their shiny plastic coating. Fritz used a single coat of pour-on ultra-glo plastic for this part.
As you can see, the pieces are looking more cohesive with each step. In the future of the giant foam MRI you can expect to see painting and perhaps even some sound and lights rigging. One of the great things about this project is that while it was requested by Professor Grabowski, many other researchers at the UW will be able to take advantage of the availablity of this tool. Metrix is very excited to have been part of not just this amazing challenge of lungs and maneuvering skills but also of the advancement of science.
Stay tuned for updates on the finishing progress of the giant foam MRI!
Hey audiophiles! Christmas just came in the form of audio equipment. We have:
an Ion iMX02 mixer. The crossfade is a little fuzzy, but the panel cover can be unscrewed, and the crossfade can easily be cleaned or replaced.
a Gemini PS-700i 4-channel mixer. The balanced output doesn't work but is probably fixable, and the booth output works fine.
a mini-KP Kaoss Pad for special effects processing. The plastic covering on the touchpad is dented, but slap new plastic on it and it should be good as new.
a DIY talkbox, looks brand new and never used. I recommend looking carefully at the wiring and the jack-- the person who dropped it off had never used it, so we cannot vouch for it.
Stop by the shop any day, noon to midnight, to check out the new toys and make us an offer!
The lasers are incredibly powerful tools, able to do anything from blast out furniture to etch text on custom business cards. In this workshop, get oriented to making files for the laser using Inkscape, the most common open-source vector imaging software.
We will go over basic concepts (why do we need a vector image?), design and basic tools of Inkscape, and tips and tricks for making an image our lasers will be happy with.
Bring a laptop with Inkscape already installed and open (boot-up time can be significant). No experience necessary.
If you have been checking the blog and our calendar for the past few months, wondering when the Intro to Electronics workshop will be offered again, now is your chance to sign up! The workshop will be on Saturday, November 9, from 2 PM until 4:30 PM.
Weather you’ve had a project in mind for awhile or are looking to learn something new, we’ll help you take those first steps towards making your great ideas work. The workshop is designed for complete beginners but it is also a good refresher for those who haven’t done electronics in awhile. We will go over some fundamental electronics components, such as resistors, diodes, capacitors, switches, potentiometers, and simple integrated circuit chips. Through a series of hands-on circuit building exercises we will cover proper wiring, reading circuit diagrams, voltage, and current.
The $50 workshop rate covers all the materials and two and a half hours of instruction. To sign up, give us a call (206 357 9406) or come down to our space on Broadway.
We are proud to announce the First Circuit Church is happening this Sunday.
Circuit Church is both a learning exercise and a skills challenge. A night of quick turn electronics with a curated Bill of Materials (B.O.M.).
Building hardware is hard, and like most hard things, only experience eases the pain. Circuit Church is designed to skill us all up on making electronics from scratch, fast.
At the beginning of the summer, Metrix Create:Space added a LPKF Protolaser S to the robot roster and we built out our Advanced Circuit Lab as an adjunct to the Open Hardware Lab. For those of you that don't know, this machine allows us to create circuit boards more accurately and on more materials than chemical processing with no hazardous materials impact. It's more reliable than milling, and it is faster than anything else out there, including the fastest quick turn pcb houses. It allows us to go from design to physical board in minutes rather than hours, days, or weeks.
Just like 3D Printing's rapid results change the way we think about physical fabrication, this tool changes the way we think about electronics projects, the speed in which we implement, the materials we pick, and the chances we can take when we're not waiting weeks for an iteration.
We know that having a tool like this is a game changer.
Additionally, we've been lucky enough to find Upverter, a cloud-based PCB design tool that gives us the ability to share designs quickly. It runs on limited resource computers, yet is powerful enough to do very complex boards and its free to use for Open Source / Open Hardware projects. We've found that its easy to learn even if you only have a basic knowledge of electronics, and we'll be learning more and more about this tool as we go down our path.
Circuit Church is a program that we believe will get us all up and running towards and making the future we want.
Circuit Church is Sunday nights and costs $30.
Space is limited, so call or come by to sign up.
Here's the basic agenda:
We drop the BOM at 6pm
Participants design boards in upverter until 8pm(ish)
Designs get sent to CAM and are processed by 9pm.
PCB/Parts are distributed
Assembly/Test/Showing off on the white tables until closing time
All participants will bring a computer for designing their board in upverter.
All participants get a chance at each step. If you don't finish a design, one will be provided for you for the assembly process. Help will be provided, but this is not a workshop environment with step by step instructions. This is an exercise to help you learn and advance your SMT skills in a fun and collaborative environment.
Kicad is an open source software suite for electronic design automation (EDA). This allows you to design schematics of electronic circuits and printed circuit boards (PCB). This workshop will cover the user interface, schematic layout, footprint selection, PCB layout, and Gerber file export. You will also learn how to make your own components and footprints. When we are done you should have the knowledge to design your own PCBs and prepare them for production.
What to bring: Laptop with the current version of Kicad installled. (available here: http://kicad.sourceforge.net/wiki/Downloads) Mouse with scroll wheel (optional) - a scroll wheel makes zooming easier but it is not required
Target audience: Beginners with basic electronics experience. You should know what a resistor, capacitor, and diode are and what a schematic looks like.
To sign up, call us at 206-357-9406, or drop by the shop! 623A Broadway E, Capitol Hill, Seattle.
We recently got the rotary attachment on our laser up and running, meaning we can now laser etch wine glasses, pint glasses, and anything else round and non-toxic you may have lying around.
Questions? Concerns? Chomping at the bit? Email, drop by, or call us at (206) 357-9406.
Calling all 8-14 year olds interested in electronics, sewing, or making sweet light-up projects! Come by Metrix this Sunday, hang out, and make something awesome with us.
For more information, visit http://hacker-scouts.org/openlab.
Want to watch something 3D print, but tired of printing other people's designs? Like 3D modeling, but hankering after something free and intuitively designed? Wondering what all the fuss is about SketchUp?
Come in and get oriented on the basic tools and interface of the program. Designed for beginners. Please bring a laptop with SketchUp already installed.
Check out friends of the shop Mark Ganter and the UW WOOF 3D Printing Club racing in a 3D printed boat tomorrow, Saturday 7/13 at the world infamous Seafair Milk Carton Derby!
This workshop is designed for people new to microcontrollers and interested in e-textiles. The LilyPad Arduino has been developed for sewable microprocessor applications. We will use the LilyPad to learn how to program a microcontroller and interface it with electronic components. No prior knowledge of electronics or programming required. Please bring a laptop with the latest Arduino IDE and drivers installed (http://arduino.cc/en/Guide/ArduinoLilyPad). All materials are included in the $60 workshop fee. Call (206-357-9406) or come down to the shop to sign up. Space is limited.
Have a tee-shirt that fits like no other, and want more?
Come to the Machine Sewing workshop on Tuesday, July 2 from 7 PM to 9 PM.
Bring your favorite shirt and a larger shirt to re-fashion, or contact us about getting appropriate material to start from scratch. Leave with a custom pattern for your favorite shirt, a good start at making your second copy, and a coupon for an hour of serger time to finish your project ($10 value!)
To register ($50) give us a call at 206.357.9406 or come down to our shop on Broadway. Space is limited.
Hand Knitting 101: Learn to Knit a Flying Spaghetti Monster
Always wanted to learn to knit, but not interested in making an ugly scarf? Just want to make a cuddly Flying Spaghetti Monster? Either way this workshop is for you! Come on Tuesday, June 25 from 7 PM to 10 PM.
Toys are fun projects for novice knitters because they are small, and introduce techniques needed for more complex projects. Workshop fee ($60) includes knitting pattern and all materials.
To register, give us a call at 206 357 9406 or come down to our shop. Space is limited.
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