For the past 2 months a team of makers has been frantically designing and building a glider for Redbull Flugtag.  It was one of the most fun projects I have ever had the privilege of working on.  Thought we did not place in the competition I wanted to share what we have learned and share some CAD files for future Flugtag builders to find and reference if they wish.

Team Flies at All:

When I put up the call to see if other members where interested in participating I was shocked when almost 20 people came to the first meeting.  At that meeting two opposing directions were posed for our entry.  One was a craft that would be as crazy as possible that would just be fun to look at and not attempt flight in a meaning full way.  The second was “team flies at all” who thought the fun part of the project would be the challenges of making a craft that would generate lift.  As the next weeks went on that second team was the only group that kept meeting and planning.  

Material choice and testing:

At one of the first design meetings Jon Drayna brought in a sample that he had worked on that week that would become the structure of our design.  It was 1 inch pink insulation board laminated on either side with 2mm strips of wood.  This made the normally flexible material very ridged while still being extremally light weight.

With this structure in mind I went to work in Fusion 360 and modeled up a craft.  Using a paper added to a google drive the team was sharing I was able to design a parametric air foil that would in theory provide high lift at low speed.  I even devoted the weekly Fusion 360 class to making an airfoil.  Below is a link to that class and the parametric airfoil Fusion 360 file will be in the link at the bottom.

We chose to cover our wings with window cling film.  I think this is one of the best choices we made.  Even though the film required lots of care it was cheap and light weight compared to alternatives.  On the day of the event we saw boat vinyl and lots of other materials but I stand by our window film.  Another decision that I was happy with on our craft were the ridged supports in the front and back of our wing.  Lots of teams chose not to do this and their air foil shapes were lost due to the shrinking material. 

Our biggest lesson:

If you have ever attempted to do something for the first time before you know that it usually doesn’t work.  We all had lots of optimism about our chances to “fly” but it takes practice to learn new things.  You can’t make an omelet with out breaking a few eggs.  On Flugtag our point of failure was the cart.  We knew that if the back of the cart were to push up on the back of the glider it would push the nose down right into the water.  We had taken care to design a two part cart that would we thought drop away from the craft with the use of a one way hinge mechanism.  The idea was as the front of the cart holding the glider went off the edge it would fall down bending at the hinge and not creating leverage lifting the back of the glider.  Maybe it was swelling due to humidity or jus the paint being sticky but this was our point of failure.   You can see in the video the cart breaking part of the tail as it forced it up and as soon as it fell away the wings started to work.  It was too late at that point though.

I use used a bad word in that last paragraph, failure.  At least most people think of it as a bad word.  Lets reframe that right now.  Failure is what happens on the path to success.  Failure is what happens when you are pushing your self far beyond your current capabilities and knowledge.  No one has ever learned something from success it is failure that teaches us and failure that motivates us.  

We failed to fly but we succeeded at working together to build one of the coolest projects to ever come out of this building.  It was so much fun working with everyone that pitched in for an hour or two or for weeks on end.  The bravest member of the Makerspace, Faith, got to stand on a stage in front of 50,000 people and answer questions about what a the Milwaukee Makerspace is.  I have zero regret except for maybe not jumping of the edge of the ramp…

Open Source Everything:

We learned so much.  You can take a look at our CAD files and build images and learn with us.  All are at the link below for you to copy and improve.

Open Source Project Link.

3 years ago I started participating in the Grow Beyond Earth contest.  It’s a collaboration between NASA and the Fairchild Botanical Gardens in Florida.  The goal is to create a device that will grow food on the International Space Station.  That sounded like fun to me!  Year one focused on designing the growing area to take advantage of the 0G environment and fit in a 50cm cube.   I was fortunate enough to be a finalist and walked away with some prize money.  I was not able to participate in the 2nd year but I am back in for year 3. 

This year the focus is on creating a robotic harvesting and planting.  If you want to read all about it you can do so at the Make:Projects link below.  This has been a fun project and I learned so much.

https://makeprojects.com/project/0g-garden—year-3-professional-entry

A few weeks ago a friend asked if I could help with a project for his wife’s new salon and I jumped at the opportunity.  I had been looking for a project that would mean using the big new 100W laser since it was donated.  My friend sent over a design and I got to cutting.

This is by far my favorite laser we have.  The software is easy to use and the laser makes aligning the uncut piece in the laser bed a breeze.  This project was also a chance to show off some of the new things I am learning in Blender to make a nice rendering of the final product.

Harvey got a new power supply for the CNC Mogul from Automation Technology Inc and asked me if I could help him document the replacement process. It was pretty simple and went very smooth. We’re lucky to have Harvey around as a member, and I’m glad he takes care of the CNC Mogul.

Check out the video below to see Harvey replacing the dead power supply with the new 36 volt 9.7 amp model he got from Automation Technology Inc.

Julie and Carl of Scoops Ice Cream & Candies of Kenosha, approached new Makerspace member, Brandon Minga, with their project. They were given recommendations from other projects he’s done in the are including Mike’s Chicken & Donuts and the Modern Apothecary. Scoops was looking to enhance and draw more attention to their new location with a large exterior sign. Going through the concept and design process Minga quickly decided that the sign design was also going to become their new logo. Once the final design was rendered he quickly learned how to CNC a template to hand plasma trace the design out of sheet metal. The middle of the sign was also hand cut, roll bent and broke to match the bubbly ice cream cone shape. With a little help from friends a the Makerspace, he ground down welds and drilled 44 holes for the light bulbs. After all the holes were drilled Minga fit the sign with sockets, wired up the sockets and tested the electrical. Working with Prodigy Sign in Kenosha he also coordinated the hanging of the sign.

Any project starts with a sketch.

Nothing wrong with learning a little g-code.

 

A post shared by Mingadigm (@brandonminga) on May 2, 2017 at 12:47pm PDT

Took that g-code and used the handmade CNC router to cut out a template (note to self, don’t use OSB for plasma templates).

Traced template with hand plasma cutter.

Hand cut, roll bent, metal break and tack welded the bottom shell.

Hand cut and used the break to bend my own c-channel for the stabilizing guts of the sign.

A little help from my friends!

 

A post shared by Mingadigm (@brandonminga) on Mar 31, 2017 at 3:33pm PDT

A little custom install and wiring….and we have lights!

Can’t forget the paint! Primed inside and out, the sign got coated with some retro color.

Installation day was very windy, they called two crews in to stabilize the sign as they anchored it to the building.

This is a Mingadigm.com by Brandon Minga

This project was done at the Milwaukee Makerspace,  thank you, gang!

Milwaukee Makerspace has a lot of equipment, and sometimes we get things that don’t quite work, and we try hard to get them working. We often succeed, but sometimes we decide it’s better to move on…

With that said, we’re looking to sell our Matsuura RA1F Vertical Machining Center, which is known as the “Red Dragon”.

It’s not currently running, but it was working months ago. Ultimately we decided that it would take too much work to get it into good shape for a makerspace, so selling it off as a whole, or in parts, will help fund a new CNC milling machine which is smaller and more suited to our needs.

If you’ve never used a VMC this probably isn’t for you, but if you really want a challenge, or want it for parts (and there are some very expensive parts in it) you might get a nice deal. Maybe you’ve already got one and need spare components? Perfect!

You can check out the notes we’ve made about the Red Dragon over on our Matsuura wiki page. If you’ve got questions, post a comment or get in touch with us.

Before #2: My front door, in need of paint, some aesthetic happiness, a fixed doorhandle, and summer. My desire to add a little decoration to the door is, in part, what led me to the Makerspace. I had an idea for panels to go on either side of the door, but no equipment for making what was in my head. When I saw that the Makerspace had cnc routers…

IN THE MIDDLE

I took photos of leaves from the oak tree in our yard:

I traced the leaves in Illustrator, and — by looking at the structure of the tree — made my initial design. I exported the file into svg (with hints from Shane), and Ed helped me use Cambam to convert the svg file into the gcode that the Mogul desires.

After generating the gcode, we cut the first panel. For me, watching the cutting was like Christmas: exciting — while for Ed, stepping me through the process, this must have been like a long slooooooooow Christmas, watching the design appear through the three passes the router bit made to cut each (complicated) path. (In truth, Ed’s patience and help were the real Christmas present for me.)

This panel was an experiment for me, to learn about how thin and delicate the connecting pieces could be in such cutting. And I learned: what you cannot see in the picture above is how two of the leaves broke off quickly.

In the next Illustrator file I made (which I then cut on the Mogul with Steve Pilon’s also very generous and patient help), the leaves overlap and made their stems thicker. You might be able to see this in the final picture below, which shows the panels painted and mounted. Merry Christmas!

THE END

32V Power supply for Y axis motor. No regulation necessary!

Smoothieboard is supposed to read the config.txt file from its uSD card (conveniently accessible via USB) every time it boots.  That makes changing configuration very easy and fast – all you do is edit the config.txt file, save it , and reboot the board.  Firmware is updated the same way.  With the ATMega2560 you have to find the configuration variables by searching through multiple configuration files, make the necessary changes, recompile the firmware, then flash the controller.  I said the SmoothieBoard is supposed to read the file every time it boots, but it wasn’t doing it.  I’d make changes and they would not appear in the behavior of the printer.  Hmmmm.

Layers kept shifting in the X-axis- I expected Y-axis problems, but not X!

I attempted some prints and managed to get two decent ones in about a week of screwing around with it.  I tried dozens of combinations of speed, acceleration, junction deviation (smoothie-speak for jerk) and even tried different slicers.  The machine went completely nuts on two occasions and ignored the Z-axis limit switch and slammed the extruder into the print bed, gouging through the Kapton tape and into the aluminum!  I decided I needed some professional help so I got on the #smoothieware IRC channel and discovered that the developers of the board/firmware hang out there quite a lot.  After a lot of back and forth Q and A and testing someone suggested it might be the uSD card causing the problem.  I picked up a new card at Walmart, put the firmware and config files on it , booted the machine, and attempted a print.  PERFECT!

The new uSD card worked! The small round post is 4mm diameter.

I have made several prints since last night and they have all come out fine.  I still have a little tweaking to do and to test the limits of the machine’s performance, but I think the problems are behind me.

Next up:  X-axis redesign/build.  I’m replacing the two guide rails with a single linear guide.  I have also ordered and received a BullDog XL extruder to replace the hacked up QUBD unit I’ve been using.  I’ll be adding a DSP driver and 32V power supply for the X-axis motor, too.

After that, I have some ideas for a filament respooling machine and ways to fix the retraction problem in the SnakeBite extruder.

It never ends!

1) I can now adjust the bed leveling screws from the underside of the bed using thumbwheels instead of a screw driver.  I know, I know, everyone else in the world has been able to do this from day 1…

Thumb screw for leveling print bed. Screw is threaded into teflon block.

2) Unlike everyone else in the world, with fully supported linear guide rails, the print bed does not move in any direction but along the Y axis.  In the old scheme, with the end-supported round guide rails, the rails would flex and the bed would move up and down when applying pressure to it (sometimes even the screw driver pressure to adjust the bed leveling screws).  Now, if the bed moves at all in the vertical direction it’s because the bed plate (1/4″ aluminum) itself is flexing!

A couple bad things were also discovered:

1) The vibration and noise problem I was hoping to solve has not been solved.  It has been made worse, though the character of the noise is improved to musical tones instead of just harsh buzzing and rattling.

2) Several failed test prints at ever decreasing jerk, acceleration, and speed settings have demonstrated that the old motor simply doesn’t have enough torque to drive the screw reliably at reasonable printing speeds.

Shift occurred in Y-axis due to insufficient motor torque.

Further research into the first problem indicates that the vibration and noise are inherent in using steppers, and worse in MegaMax than in machines that use NEMA-17 motors because of the higher detent torque in the NEMA-23 size motors.  Detent torque is the little bump-bump you feel when you turn the motor shaft by hand.  The solution to the problem is to use a good driver for the motor and a higher voltage power supply.  The little A4988 chips in the Pololu drivers on the RAMPS board are very unintelligent- all they do is provide microstepping.  They work OK for NEMA-17 size motors because of the speeds and low detent torques in those motors.  When used with NEMA-23 motors the driver limitations become apparent – as they have in MegaMax- lots of noise and vibration.

Good stepper drivers are DSP based and automatically sense resonance and damp it electronically.  They use phase controlled sine wave currents to drive the motors smoothly.  Fortunately, DSP stepper drivers for NEMA-23 size motors are pretty cheap.   Here’s video of the DM542a driver pushing a NEMA-23 motor around.  I have ordered a DM542a driver.

The best power supply for stepper drivers is not a switcher, and running steppers from a switching supply will often result in a dead power supply.  I will be building a simple, unregulated transformer, rectifier, and filter cap supply to go with the new driver.

Next came the question of how to determine how much torque is needed to properly drive the Y-axis.  A bit of research took me here: Motor size calculator.  You just select the scheme for which you want to size the motor, enter the appropriate data, and it magically tells you how much torque you need to do the job.  When I ran the numbers on MegaMax, it told me that I need about 350 oz-in of torque (about double the torque of the motor I have).  I did a quick search and found a Chinese made (of course) 425 oz-in motor for $50.  Also on order…

The motor mount I am using is designed for a NEMA-34 size motor with which I use an adapter plate to allow the NEMA-23 motor to fit.  Since I’m buying a new motor anyway, why not just get a NEMA-34 motor?  It turns out that the best stepper for the job is generally the smallest motor that can provide the necessary torque.  A NEMA-34 motor could provide much more torque but the detent torque and rotor inertia would work against smooth and fast operation, and require a bigger power supply.

Back side of MegaMax showing motor mount, adapter plate, flexible coupler, and drive screw in Y-axis.

The ATmega2560 and RAMPS boards will be replaced by a SmoothieBoard.  It has a much faster processor, much better connections for motors/external drivers, etc.  It currently lacks an easy way to add an LCD controller, so I may have to connect to a computer to start prints up (it has ethernet and a built in web server so it can be accessed from any computer on the network).  When a clean way to add an LCD controller becomes available, I’ll add it.  SmoothieBoard review

I recently updated my web site with a sort of historical look at the project, including all the mistakes I’ve made along the way and the often failed attempts at correcting them.  Here is the page that shows how it all started, how it has ended up, and where it is going.  http://mark.rehorst.com/MegaMax_3D_Printer/index.html

Don’t ask me why I do this-  I have no choice.

From this…

To this…