Further Adventures in 3D Printer Upgrades (upgrades?)

As previously promised, MegaMax’s Y-axis has been converted to screw drive along with the addition of a larger motor, DSP based driver, and 32V power supply.  The SmoothieBoard arrived and was quickly swapped in to replace the ATMega2560/RAMPS combo.  After studying and configuring the Smoothieboard I attempted a few test prints.  That’s when the problems started.

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

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!

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.

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!

 

Bay View Printing Co.

The Milwaukee Makerspace is about to get an exciting new neighbor!  Ashley Town, a former professor at the Milwaukee Institute of Art & Design (MIAD) has recently purchased the > 100 year old Bay View Printing Company @ 2702 S. Howell Ave, less than a half-mile from our space!

Ashley is taking over a print shop with a rich heritage as well as several beautiful presses, a Linotype machine and dozens of wood and metal typefaces.  She plans on doing custom work as well as running classes and building up a community around the lovely art of printmaking.

Bay View Printing Company is in the final days of its fundraising drive on IndieGogo to raise money to pay for some renovations to the space to make it more amenable to Ashely’s goal of making this a community-driven space.  The IndieGogo campaign has some great rewards like private lessons on the Vandercook press.  I’m so thrilled this is coming to Bay View that I have challenged Makerspace members to donate and will match up to $500 in donations!

Bay View is extremely lucky to have a new creative space!  If you want to support them, hurry up, though!  The IndieGogo campaign ends at the stroke of midnight on New Year’s Eve, 2014.  As of this writing, they have raised $7,635 out of the desired $11,000.  Let’s help them out and welcome our exciting new neighbor!

Read a bit more about the space at these local outlets:

Weekly Maker Spotlight #2 – David Heino

davidh

How did you first find Milwaukee Makerspace?

I forget how I first heard of it. I made several trips to the space when it was in the complex off Oklahoma Avenue.

Why did you decide to join?

A big factor was I could afford the dues after the big change. I think of myself as a life-long maker, although I tended to use the older term, craftsman. I joined because I wanted to explore.

 What do you do at Milwaukee Makerspace?

Just now, I’ve been using the space to prepare for an upcoming exhibit. I make paintings and things you might call sculpture.

What would you like to tell others about Milwaukee Makerspace?

In my opinion, it is a very good and interesting make. It’s most valuable asset is the variety and depth of knowledge and skill to be found amongst the members.

What do you plan to work on in the next few weeks?

Once I’m done with the exhibit, I want to:
1. take advantage of the opportunities the space offers to expand the tools and technologies I can use in my work.
2. I wish to work on objects that make interesting sounds that can be “played” by the user’s movement.
3. I want to work on a projector capable of producing large scale lighting effects.

 
 

Weekly Maker Spotlight #1 – Mike B.

 

We’re adding a new feature to our blog!  We’ve started sending brief surveys out to our members at random.  Each week, we will select one and publish it on our blog.  Our first participant is Mike B.!
 

unnamed

How did you first find Milwaukee Makerspace?

I believe I met Tom G and Ben who were speaking about their home made electric vehicles at a Barcamp.

Why did you decide to join?

I joined up because I had a couple projects where I needed a little advice/training to get me over the hump.

 

 

What do you do at Milwaukee Makerspace?

So far, woodworking and metalworking.Testing p1

What would you like to tell others about Milwaukee Makerspace?

You’re guaranteed to find someone with some experience in any skill or technique you’re looking for.

What do you plan to work on in the next few weeks?

I need to do a little basic electrical work to build an EXIT sign lamp. I’m also looking at a welding project to build a bench with a coat rack for my apartment.


See Mike’s blog posts here:
Building Patio Furniture For Fun and Profit
How to Build a Kitchen Table in an Assortment of Easy Steps

Square(ish) Pegs

Laser-Cut Pegs

Often laser cut parts gt attached at 90 degree angles, using finger joints, or screws and t-slots, but there may be times when you want to stack pieces of wood and have them aligned…

Pegs might be the answer!

Here’s a few photos of the pegs I’ve been experimenting with. For these pieces I don’t have a lot of room to have multiple pegs at opposing angles, but I can see where that might be useful. For these pieces the peg is really just for assembly alignment when gluing it all together.

Laser-Cut Pegs

Update on the Never-Ending Printer Project

I installed the Y-axis screw drive in MegaMax using the old NEMA-23 stepper motor.  A couple really good things came from this:

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.

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.

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.

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

 

Create custom vector maps

I want to document some of my travels in a better manner. After looking around for a few map design inspirations, I came across the following example from a trek across Iceland.

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I spent a quite a bit of time over 3-4 days before I found a solution. I was able to create custom maps within Google Maps, Google Earth, and Open Street Maps but they all had issues. I did not like the busy look of all base maps and the Google services don’t export custom maps in a vector format. Open Street Maps can export vector maps but the my requested area was too large.  I tried a few JavaScript libraries as well but they all use the above mentioned services for map tiles and I wanted an independent file on my local machine.

So, I decided to create a map myself. I downloaded the following .SVG map of Scotland from Wikimedia.

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Using Inkscape, I deleted other countries, external water bodies, and remote islands. I thought about a unified border color but I ended up really liking the representation of water versus land boundaries.

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Looking better already! Now, I did not want to sit down and manually trace my journey. Since this file doesn’t contain any geographical information, my best bet was to somehow get my path in a vector format and manipulate it into the same scale, plane, etc., as map above.

I started by recreating the trip in Google maps engine. The train and bus journeys were easy to plot – it’s just like looking up directions in Google maps. Plotting a hike was a little bit more complex since I did not record my GPS location. I was lucky to find a .KML file from a better prepared hiker through a Google search and imported it into Google maps engine without any issues. I exported the .KML file when I was done.

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The file was saved as a zipped .KML (.KMZ ) file so I used Google Earth to save it as a .KML. This is starting to sound like an ad for Google. I swear I am not a shill – Ask Jeeves is a much better search engine, see!

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The .KML file was processed into an .SVG using my new best friend, Indie Mapper.

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Since I only cared about the lines, I deleted the description and points using the menu on the left. Remember kids, always, and I mean always, read documentation. I spent a whole day scaling, rotating, skewing, bargaining, manipulating nodes, punching walls, trying to match the path output to the map from above. If I had simply read on the Wikimedia page, that the map had a Equirectangular projection and was scaled 170% in the N/S direction, I wouldn’t be writing this at 4AM in the morning. You can change the projection within Indie Mapper. Scaling was easily done in Inkscape later.

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Export the file as a .SVG.

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Yay! on three everyone yell, Compatible! Compatible! Compatible! Make sure you are alone.

Upon path import, the first step was to scale the height only by 170% to match the map’s relative coordinates. Then, the height and width were scaled proportionally till they “looked right.” I compared the relative location of the path to ocean and lakes (I really should say “Lochs”) in Inkscape versus Google maps so make sure everything looked right. Since I had the right relative dimensions, it only look a couple of minutes and Voila!

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I manually colored the hike in green and motorized travel in red. If I decide to laser cut this file, I’ll vector “burn” the border and water bodies on lower power versus the path. I’ll keep playing around with the design and maybe add day hikes as well but I am happy with the results for now!

 

The never-ending 3D printer project

MegaMax has been and continues to be my main project for the last 2+ years.  I am currently working on some upgrades that will make him more Mega and even more Max.  The Y axis is being converted from belt drive to screw drive and the round guide rails are being replaced with linear guides and bearing blocks.  The X-axis will also get converted to linear guide and bearing block and change from 5mm pitch belt to 2 mm pitch belt drive.  I feel confident saying that once these modifications are complete the flaws/errors in prints will be due primarily to the nature of liquid plastic squirting through a nozzle, not positioning system errors.

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.

MegaMax beginning

From this…

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

MegaMax present state...

To this…

Rainbow Lamp

A student from a local university reached out to us earlier this year to create a light based object for a class project. I volunteered to help her and after many iterations, we decided to build a diffused RGB Lamp.

The finger-jointed acrylic body was designed using makercase.com and laser cut.

Rainbow_Lamp_Acrylic

I used the addressable RGB LED strip from Adafruit, called Neopixels, to provide the lighting effects.  The LED strip was wrapped around a PVC pipe in a spiral so it could provide light on all four (4) sides. The spiral spacing gets tighter near the top to either to vary the lamp density for a cool effect or I got lazy since this was done at 1AM on a Monday morning – I’ll let you decide.

Rainbow_Lamp_NeoPixel

A Teensy 3.1 controls the strip using the Adafruit Neopixel library. Two (2) sets of three (3) rechargable NiMH batteries were used. At full charge, a bank provided 3.82 Volts. While the micro controller was running happily, the LEDs were noticeably dim. While the vellum paper diffused the lights effectively, the distance to the acrylic was relatively small, so brighter LEDs would have decreased the desired gradient effect anyway.

Rainbow_Lamp_Teensy

We cut the vinyl logo and border using a Silhouette CAMEO. The final design had to be mirrored since it would be adhered to the inside of the acrylic case using transfer paper. The text on the top did not cut very well so we’ll re-cut that bit with more optimized fonts. After seeing the results, I think I’ll create a lamp for myself as well.

paneltest-01