Nate Duxbury's Blog

Make all the things!


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MakerFaire Pittsburgh!

MakerFaire Pittsburgh and Robot

This past weekend I attended MakerFaire Pittsburgh along with the company I now work for, WARDJet. We brought along our brand new show truck with one of our waterjet CNC machines in it! It was awesome talking to a lot of excited makers, both about the waterjet we brought with us and their own projects. I tried to take as many pictures as possible of things that I thought were particularly neat.


The WARDKit Show Truck at MakerFaire Pittsburgh


The company I work for recently built a show truck to show off one of our new offerings. What offering is that you may ask? Well, its a water jet CNC machine in the form of a kit! We fabricate the parts and then you assemble it. This isn’t meant to be a sales pitch though, but if you want that, just check out the WARDKit website. Sometime in the near future, I’ll do a post about water jets: what they’re capable of doing and how they work. That post is will be linked HERE (once its actually done). What I’d rather talk about in this post is my experience at the MakerFaire.

MakerFaire Pittsburgh was a two day event going from 10a-5p both Saturday and Sunday and boy was it busy. We drove over to Pittsburgh Friday night after work and decided to head straight to our truck to do a little more preparation. While the rest of the makers were gathered having dinner and drinks we were outside drilling holes and hammering carriage bolts into place! We wrapped up Friday night around 11p and took a couple pictures of our display, including an aerial video from a go pro mounted on my co-workers drone.

Friday night preparations.

Friday night required a little bit of work to get everything ready.

Saturday morning required an early start to get everything else at our display in tip-top shape. There was an impressive amount of stuff to take care of. We started up our intensifier pump, charged our air tank, filled our water reservoir and ran the machine through its paces to get ready for the day. We set-up a table with all the information, business cards and sample cuts for people to look at. We finished setting up right around 9:30a, which provided me with a little time to walk around before it started. This is when I got to talk to Bob, who was printing and vacuum forming chocolate molds (see more on this later in this post).

Saturday was definitely the busier of the two days. We had the water jet under motion and running in low pressure, water only mode, at about 12,000 PSI. We were running cutting demo’s every 45 minutes or so, mostly cutting out makerfaire robots out of red craft foam. We were handing these out all day as key chains, and people seemed to love them. Grab the .DXF here and cut out your own! The event opened up at 10a and really kicked into high gear right after lunch time. We had a pretty steady surge of people coming by to watch the cutting demos and it was great to see our show truck full of observers.

Foam MakerFaire Robots sitting on top of the Water Jets crossbeam.

Foam MakerFaire robots sitting on top of the water jet’s crossbeam.

The people who were stopping by ranged from children to makers to engineers. Almost everyone was excited to watch a huge machine move around and cut stuff with WATER! I got to practice my sales pitch and generally just talk to excited makers of all types. Kids went wide eyed and some people said “I have to have one” as soon as they saw it. My favorite reaction was probably a guy who saw it and looked intensely interested in how he could get one into his garage. Even better, was his wife hearing the price, shrugging, and then saying that it really was quite reasonable!

Excited onlookers watching the water jet cutting.

Excited onlookers watching the water jet cutting.

We also cut out the MakerFaire Pittsburgh logo and our logo during one of our demo cuts. We cut it out of the same red craft foam as we did for the robots. We also cut an identical copy of this out of 1/8″ Stainless back at our facility on Friday afternoon. When we weren’t cutting foam during a demo, we were running the same logo program tracing over the stainless steel one.

Logo Demo cut out of foam and stainless

We also cut a pear that we just happened to have!

Water jet cut pear!

Water jet cut pear!

Sunday wasn’t as hectic, but we had a hiccup with our intensifier pump that rendered us unable to do any cutting demos. Thinking we were set for the second day, we had showed up a little closer to opening time. Fairly quickly, we discovered the unfortunate situation with our pump and tried our best to fix it. After about two hours on the phone with tech support we found out that it was out of our power to make it work that day. It knocked the wind out of us a little bit, but we still talked to a lot of people and everyone was still excited to see it move.

Water Jet Cut Samples

Some samples we had set out, including: craft foam, carbon fiber, aluminum, granite and a large chunk of steel.

However, it wasn’t the end of the world! I managed to decipher our G-code files and determine what the M-code for water jet on/off was. Knowing this, I opened up the g-code files in Notepad++ and did a find/replace all for the on/off commands with a Z up/down move. Doing this allowed us to zip tie a dry erase marker to the water jet nozzle and turn the whole thing into a draw bot! We couldn’t cut foam, but we could at least draw on a white board and show how our tool paths worked… mostly. Draw bots usually have a spring loaded marker end to account for variation in the drawing surface. Our marker was only zip tied though, and while our machine is rock solid repeatable and square, white boards are, unfortunately, not rated for flatness. This experience proved to be pretty awesome though. I knew a little about g-code and such before this, but I had never done any post-processing manually like this. It was very rewarding figuring it out and seeing it work while working under the gun WHILE the MakerFaire was going on!

Sunday wrapped up and and we had to pack up the truck. The event ended at 5p and it took us until about 7p to strap everything down and button up the truck.

All packed up and ready to return to Ohio.

All packed up and ready to return to Ohio.


Other Highlights Around the MakerFaire


While both days were quite busy, I did get a chance to wander around the rest of the MakerFaire a little bit. Some of the highlights I saw included: a rubber band Gatling gun, a cardboard velociraptor suit and a guy printing then vacuum forming chocolate molds!

The booth next to us was RealBotics, a group of people who made a software platform for controlling robots over the web or via direct connection to a computer and an arduino. They had a spotter scope that was attached to a series of 3D printed racks to control its motion and a webcam where your eye would normally look into it. Even better, they had an air cannon that you could aim and fire! At it’s core, it looked like a simple pneumatic potato gun, but it was much more than that. You could control the pitch angle and rotation of the whole thing with their software, and it was also breach loaded (actuated by a pneumatic cylinder)! They were firing tennis balls all day and at the end of the day on Sunday, they were firing cupcakes!

Cupcake Shooting Cannon!

Cupcake Shooting Cannon!

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Catty-corner across from us was the HackPGH booth and one of the makers there had a beautiful electro-mechanical clock along right beside a large rubber band Gatling gun and a wooden music box. The clock used a solenoid and an arduino to keep the pendulum moving indefinitely. Really makes me want to get to work on my own mechanical clock (which will hopefully be water jet cut out of granite!).

These projects were top notch.

These projects were top notch. The size of the rubber band gatling gun alone was impressive!

There were hoverboards everywhere. Here seen in an interesting application of moving around this makers music box.

There were those hoverboards everywhere. Here seen in an interesting application of moving around this maker’s music box.

Pittsburgh TechShop was directly across from us doing some forging! It was quite chilly on Saturday morning, I bet that little furnace came in handy!

TechShop Pittsburgh Forging in Action

The aforementioned cardboard veliciraptor: KitRex. What’s pictured below is actually a suit! Someone got in it and walked around the faire at regular intervals. Also of note, were the enormous googly eyes. Definitely the largest I’ve ever seen!KitRex Velociraptor Suit

A bad picture, but this stringed instrument robot was really cool to see in action. The four strings were selectively tensioned at different points by computer controlled carriages to create different notes and a guitar pick was turned to make music by strumming the string. Eric Singer of singer robots was the creator of this awesome, robotic musical instrument.Singer Bots Musical Robot

I forgot to take any pictures, but I did spend a bit of time talking to Bob of http://bobginpgh.tumblr.com/ who was printing  objects on his 3D printer, vacuum forming them into molds (using an awesome & simple laser cut vacuum former) and then casting chocolate bars out of them! It was great talking with him and it gave me some ideas of my own. I will definitely be looking over his blog and hopefully making some chocolate molds of my own in the near future! At the very least I will be making a vacuum former like he was using. Too cool of an idea to pass up.

A sampling of Bob’s work (borrowed from MakerFaire Pittsburgh’s website).

The whole MakerFaire Pittsburgh Experience was awesome. In 48 hours I got to talk to so many excited makers and see so many awesome projects. I really enjoyed the experience but man was it exhausting. Once I finally got home on Sunday it sure did feel great to sit down and relax.

This event has got me back into the maker mood. It’s been a little while since I’ve done a project and going to this MakerFaire snapped me out of my slump. Keep an eye out for some projects in the coming weeks!

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Space Time Coffee Table

Finished Product First!

Finished Product First!


SPACE TIME COFFEE TABLE


Recently, I graduated from Ohio State, started a new job and moved into my own apartment. I had almost no furniture for the new place but this afforded me a great opportunity: I could make some of my own!

The first thing I decided to make was a coffee table. Months ago, someone on Reddit posted a conceptual design for a “space time table.” The idea behind the concept is to imitate the curvature of space time around a massive object (such as a black hole). I thought it looked awesome. At the time though, I was living in a shared college house and did not have the funds, reason or access to machinery to make such a thing, so I filed it away in my head as something cool I would look into in the future. Fast forward to May of this year, and I am now employed at a Water Jet manufacturer, where I am allowed to use the sales model for personal projects after hours! (possibly the best work benefit ever?!) With the tools now available and the reason to very clear, I began modifying the design to be manufactured.

If you’re more interested in just pictures, check out this Imgur Album. It’s not as thorough as the this write up, but it is a quick summary.


DESIGN PROCESS


It was super convenient that the reddit user who posted the concept images also posted the source files AND they were in SolidWorks format! Perfect for me to load up and modify to fit my needs.

Step one was downloading the source files (Source). Step two was deciding what size I wanted to make it, such that it would fit nicely in the space I had available for it. So, like any normal person, I laid it out in CAD!

Rough Floor Layout of my apartment to get sizing.

Rough Floor Layout of my apartment to get sizing.

 

In the center right of the layout is the couch I have and then the square is the table size I felt was comfortable. The size I drew was about 24″ x 36″, but as I was going to be scaling the dimensions off of the concept, I could only really choose one of the dimensions and the other would be based on the aspect ratio of the existing design. In the end I was able to get 34.125″ x 23.5″ as the top dimensions.

I used envelopes to mark the bounding box of where my coffee table would fit. This gave me a great sense of scale for the project.

I used envelopes to mark the bounding box of where my coffee table would fit. This gave me a great sense of scale for the project.

Knowing the final size I wanted, I could now start modifying the design. There were four main points to this part of the process:

  1. The size of the table. The original design was 45.5″ L x 31″ W x 17.4″ H and I had to shrink the width dimension down to at least 24″. Applying the same scale down to all dimensions yielded 34.125″ L x 23.5″ W x 13.125″ H.
  2. The height of the table after scaling. A 13″ Tall coffee table would be no good. The bottom of the table was also very fragile in the original design. It terminated in sharp ends, which i did not like from a durability standpoint. The solution here was easy, I simply added material from the sharps directly down 3″. This increased the height to a nice 16.125″ and made the base less fragile. This feature was a departure from the concept, but it was a practical change.
  3. The concept model was all 3D features. The concept had sloping contours on every member and would have been extremely hard to manufacture. Again I decided to make a change for the practical, by removing all 3D features and making each part only a 2D contour. Since I had the 3D contours already from the concept model, all I had to do was pick the side with the larger features and extrude it to become the thickness of the whole part. I did this process for each part, but since I was going to scale everything anyways, all I ended up taking from each part was it’s 2D contour. Using only 2D contours made manufacturing immensely easier and still made for a very good approximation of the effect I was after.
  4. Making it possible to assemble. The concept model was a multi-body part file. This meant that the model’s bodies intersected each other, and that they could not actually be assembled as is. The fix here was to make the parts have matching slots and tabs. The parts going in the long direction got slots cut in the top half of them and parts going in the short direction got slots in the bottom half. With these interlocking slots, the assembly became assemble-able and even very easy to assemble!
The original concept on the right and my model on the left after modifications.

The original concept on the right and my model on the left after modifications.

SolidWorks render of the coffee table after modifcations.

SolidWorks render of the coffee table after modifcations.

I also did something really clever when I re-modeled the whole thing. I linked all the dimensions together with dimensions. This way, I could specify any thickness of material, any slot tolerance and any table height that I wanted by conveniently changing the value in a text file! I was unable to link a scale feature to the text files (not sure why…) but the rest of the features were now all linked and very easily changed. This allowed me to compensate for material thickness (since wood is rarely true dimension) and adjust the tightness of fit in the slots. It’s the first time I’ve done equations in SolidWorks, but I can see it being very helpful for projects like this. I could have used 1″ thick wood if I wanted and it would have been only three keystrokes to make the change.

I put together a quick explosion animation to check out how it would all assemble.

 

Here is the link to my  Design Files. The files are available in STEP, IGES, DXF and SolidWorks formats. Even if you don’t have a water jet, you could still use a large format CNC router or even print them out 1:1 and cut them with a jig saw.

 


PROTOTYPING


 

After completing the design, I wanted to make sure everything would fit together correctly. When I had the time one weekend, I fired up my Shapeoko 2 and got to cutting! I planned to make the final table out of a 4’x8′ of .5″ plywood, so going to quarter scale translated perfectly. I had a 1’x2′ of .125″ HPDE, so I could even check my nesting. Not much to talk about here, the shapeoko cuts through HDPE like butter, and I was able to get all the parts out of just the one sheet!

1/4 scale model of the space time coffee table made from HDPE on a shapeoko 2 CNC router.

1/4 scale model of the space time coffee table made from HDPE on a shapeoko 2 CNC router.

Doing the scale model proved to me that the interlocking slots worked just fine and that I could fit all the parts onto one sheet of plywood. Plus I could bring it with me to work and explain to my coworkers what I was planning to make.


WATER JET CUTTING


This part was a lot of fun. It was not the first time I got to use a water jet for something, but it was the first time that I ran the machine (mostly) my self. I leaned heavily on one of my coworkers for setup help, speeds/feeds, and a little bit guidance (shout-out to Ben Adams, thank you for all the help Ben!).

This section is best explained with pictures, so I will do my best to annotate each of the steps.

The first step was nesting the parts to make the part program. I used a 5'x5'x0.5" (actually real dimensions!) sheet of baltic birch plywood

The first step was nesting the parts to make the part program. I used a 5’x5’x0.5″ (actually real dimensions!) sheet of baltic birch plywood, and laid it all out with SolidWorks. Everything fit within a roughly 58″x 58″ bounding box, leaving me a 1″ border to clamp on. I exported this assembly first as a part file, then as a .dxf to feed into the water jet CAM.

Drilled Pierce Points

Kind of hard to see, but the little piles of wood are points where I had the water jet do a drill operation. The second head on our water jet has a pneumatic drill mounted on it that can be set up to drill holes in parts, or in this case, drill the pierce points for the water jet. A pierce is where the water jet initially punches through the material, and can result in delamination in woods, or just sloppy starts to cuts. Using a 1/8″ drill bit was an easy way to get clean pierce points, by both being big enough for the water jet to hit the target, and small enough to not ruin any of the areas of the parts that I wanted to keep.

Water jet cutting in progess

The water jet cut was going very nicely. The water jet uses super high pressure water (~50-60ksi) and abrasive (basically a sand made from garnet) to cut. As the company’s website says, its not actually cutting, but accelerated erosion. Basically, it is sanding it like crazy until it is through. Side effect of this is a super nice edge finish (well, this depends on feed rates, but I went slow enough to get a very smooth edge finish).

More water jet cutting

You might be thinking, “Isn’t water bad for wood? Won’t that make it warp and be generally annoying to work with?” While this is true, I did elevate the good birch plywood with a 4’x4′ of cheap particle board, which served two purposes. One, it elevated the good wood out of the water, so it wouldn’t just soak up all of the water. And two, it minimized blowout on the back side of the birch by supporting the drill bit when it plunged through to the other side. The birch still did get quite wet, but I paused and pulled it off as often as was convenient and then rinsed off the abrasive and did by best to dry it with a blow gun.

Almost done water jetting!

I could say the program ran without issue, but that would be incorrect. I ran into an issue with some of the consumable parts of the water jet that had worn out and needed to be replaced. Luckily, the night shift production water jet operator was around and helped me out. Thanks a lot Alex!

Done Water Jetting!

After all the cutting and fixing, it was done! All told, it took be roughly 4 hours of time after work one night. The above picture is how much I cut out from the 5’x5′ of plywood. I used a lot of it! There was only one minor/huge problem at this point in the night. I was locked out of the office, and I sort of left my bag and car keys in there. Not a smart move, and I had to call Ben to help me out. (seriously, thank you Ben).

Dry/Wet Fit

 

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After that small problem, I drove home and immediately tried putting it together. I couldn’t resist! It all fit perfectly, it even had a slight friction fit to the joints. I designed in tolerance in the slots, but the wood was damp and slightly swollen, so it fit together very tightly. I really liked the result. The effect was awesome and it fit in the space I designed it for great. The next step was going to be lots of sanding and staining.


SANDING, STAINING AND ASSEMBLY


 

Ugh. This part was very challenging to get through. It took me a full weekend to sand everything up to 220 grit and then stain (about 4 hours per process). Again this step is best illustrated with pictures.

Parts Laid out of sanding

There was a considerable amount of surface area to sand on this project. (a little less than 50 sqft based on the starting piece of plywood). I purchased a random orbital sander for this job (oh man if I did not) and got to sanding. I started with 120 grit and then went to 220 grit. Very uneventful work, but very necessary to get a nice stain. When I finished, every surface in my work shop room was covered in a nice layer of dust.

Staining Step

 

The next step was staining. Being a space themed thing, I wanted to use a dark stain. I chose “Dark Walnut” stain. I think  I went too dark with the stain, but it did still look quite good. As you can see in the picture, what you need for this step is one pile of sanded table, wood stain, and a brush. I brushed on the stain, let it sit for a few minutes, then wiped off the excess with a shop cloth. I chose to stain before assembly because of the difficulty involved in getting inside all the cubbies once it was assembled.

Close up of the staining

Assembly Step

The next step after letting the stain dry was assembly. Take one pile of stained table, wood glue, and clamps, lots of clamps. I also used a pneumatic brad nailer to connect some parts.Clamping for assembly

 

Assembly was a little complicated, but once I got one part of it set up, it was just a matter of slotting in the parts to their appropriate receiving slots. I either used glue or brad nails (in hidden locations) to assemble the whole thing. The top perimeter employed only glue, as I did not want to show any brads. The result of wanting to do that meant lots and lots of clamps. (about 15 in the above picture). I let it dry over night to ensure the bonds were good.

Top test fit

When it was finished drying, I put in the 6″ diameter mirrored sphere (http://amzn.com/B0019ID360) and put on the acrylic top surface for it. Another problem was encountered here. The Problem was two fold: I had already cut the top for the un-glued table, so it was incorrectly sized, and I neglected to square the top of the table when I glued it, so it was slightly a parallelogram. I was able to fix these problems by setting up my dremel as a plunge router and cutting it to the correct size.Top clear coat

 

After sorting out the table top problem, I applied a clear gloss polyurethane to the entire table to protect it. I only did one coat, because I wanted to have the table ready in time for a dinner I was hosting, but i do plan on revisiting that in the near future for more coats. Additionally, the acrylic top is not the final plan. Sooner or later, I plan on getting a nice big piece of tempered glass for the surface. The original plan was to fit it down in the perimeter of the top, but since it is now a parallelogram and not a rectangle, I will place the surface on top of everything with a slight overhang.

I am very happy with how it turned out in the end. It provides functional space and at the same time looks awesome.

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PROJECT COSTS


 

This project was not terribly expensive to execute, but my free access to the water jet does skew that slightly. I won’t include tool costs, I already had some and needed others. The cost break-down is as follows:

5’x5’x0.5″ Baltic Birch Plywood – $35

6″ Diameter Mirror Sphere – $19

2’x4’x0.25″ Clear Acrylic – $50

Stain and Clear Polyurethane – roughly $25

{(planned) 2’x3’x.375″ Tempered Glass – $130}

Total Cost of the Project: about $140-220.

 

Perhaps not cheaper than just buying a coffee table at a store, but definitely way cooler.