Chocolate Printer Cooling System Test

This week I attempted the first test of the chocolate printer cooling system.  The cooling system is intended to solidify the chocolate just after it leaves the extruder nozzle so that by the time the next layer is started it will have a solid layer to sit on.  The cooling system consists of a centrifugal blower with a brushless DC motor blowing room air into a styrofoam cooler containing a block of dry ice.  The air passes over the dry ice and gets chilled as the dry ice sublimates directly into very cold CO2 gas.  The chilled air and CO2 mixture exit the box through a port with a hose that will ultimately blow the cold air on the chocolate.  At least, that’s how it is supposed to work.  It blows air at -12C as measured via a thermocouple, but unfortunately, the air exit port ices up in about 2 minutes and blocks the air flow.

There are many possible solutions.  I can add a heater to the exit port to prevent formation of ice, or dry the air going into the box using a dessicant cannister or maybe just use water ice instead of dry ice if the higher temperature will still cool the chocolate adequately.   Maybe using an old miniature freezer with an air hose coiled inside would do the job.  It would be really interesting if I could use the waste heat from a freezer to keep the chocolate liquified and flowing.  Back to the drawing board!

Custom Police Badge

I was a “Grammar Police” officer for Halloween this year.  My costume consisted of some standard police equipment, as well as a dictionary, thesaurus, citation tablet, red pens, and, of course, my lovely custom badge!

 

Step 1: Design.

I scoured the web for pictures of “grammar police” shields, but ended up creating this design in Microsoft Word, using clip art from the web, generic shapes from Word, and shaped text boxes.  It was pretty simple and used the software I had readily available.  The portions of the design that are solid black are the parts that will be etched into relief during the process.

 

Step 2: Create!

With much encouragement & assistance from a fellow Makerspace member, Jon (of Dalek Asylum fame), I crafted this badge using mostly jewelry-making tools & methods.  We first spray-painted a square piece of copper, then used the laser printer to burn away the paint from the sections that were solid black.  This gave us access to the “fields” that would be eaten away in the etching process, giving the piece segments of relief.

After some clean-up (note to self: don’t use abrasive cleaners at this step next time!  and maybe not industrial spray paint, either), we left the copper square to soak in ferric chloride for approximately 45 minutes.  We checked the progress of the etching every 15-20 minutes, and decided that after 45 minutes we had enough of an etch to give the details enough depth to stand out.

After more clean-up to remove the ferric chloride & remaining paint, I had a nice, shiny, scratchy piece of copper with an etched design.  At this point, I really started finding my way around the jewelry bench.  I used a small jewelry saw to cut along the outer lines of the badge, which was frustrating until I found the right rhythm for cutting.  My badge was finally starting to take shape!

From here, I filed the edges smooth & buffed the finish to remove some of those fine scratches.  I gave the piece some dimension by using tools at the jewelry bench to accentuate the “belly” at the bottom of the shield.  Once it felt reasonably even and I was happy with the general appearance, we applied a liver of sulfur gel to the surface of the badge.

The liver of sulfur settled nicely into the etched corners, giving the piece an aged patina and highlighting the small details.  I really like how it settled into the fine lines left by the etching solution around the perimeter of the main field!  The small striations in the copper there give it a very unique appearance.  The patina provided by the liver of sulfur also helped hide some of those fine scratches I mentioned earlier.  We wiped off the excess & applied a museum-quality wax, since the badge will be worn and handled like jewelry, to maintain the patina.

Step 3: Profit(?)

The badge was added to my collection of Grammar Police equipment, which included shiny aviator sunglasses, and a tactical belt (excess nylon webbing with a clasp) with a dictionary, thesaurus, red pens, custom grammar citation padlet, and toy handcuffs.  It was quite the fun costume, and even though none of my trick-or-treat’ers understood, all my friends did!

 

Thus ends the story of my first Makerspace project.  Oh, what fun it was!

Chocolate Cooling System Almost Ready For Testing

Chocolate printer progress continues.  This week was devoted to the print cooling system.  The chocolate will come out the extruder nozzle in a semi-molten state.  It needs to solidify by the time the next layer of chocolate gets deposited on it, and I’d prefer it doesn’t drip or sag, so it needs to be chilled right after extrusion.  The current plan is to blow chilled air over the chocolate just after it leaves the extruder.   The chilled air will come from a foam insulated box containing a block of dry ice.  There will be a blower pushing air into the box and a hose delivering the chilled air/CO2 to the print.

A couple weeks ago I got a blower from American Science and Surplus and this week I got it running by using a model airplane ESC and servo tester to drive its brushless DC motor.  It appears to be capable of blowing much more air than I’ll need.  There are many unknowns yet to test.  How much chilled air/CO2 will it take to solidify the chocolate after it leaves the extruder?  How long will a block of dry ice last when used this way?  Will ice build-up inside the chiller box adversely affect its performance?

I designed and printed three parts for this system- a mount to attach the blower to a foam box up to 1.5″ thick, a hose coupler to allow delivery of the chilled air/CO2 to the print, and a hole saw to cut holes to fit the other two parts.   The printed parts fit as if they were designed for the job!

3D printed hole saw

3D printed hole saw

Hose connected to hose coupler

Hose connected to hose coupler

Hose coupler parts

Hose coupler parts

Blower mount for air chiller box

Blower mount for air chiller box

First Ever Test of the 3.5 Liter Syringe Extruder

My last post showed how I made a plunger for a 3.5 liter syringe.  Today’s post is the results of the first ever test of that syringe assembly including the plunger.  The goal of the test was to determine if the syringe pusher would be able to push very thick, viscous paste (sort of like melted chocolate) out of the 1/4″ syringe nozzle.  It was also a test of the ability of the previously made silicone plunger to maintain a seal even against whatever pressure develops inside the syringe as it is pushing.

I mixed about 1 liter of extra thick pancake batter to a consistency that I thought would be much thicker than molten chocolate (pancake batter is much cheaper than chocolate) and shoveled it into the syringe, then bolted on the pusher and hooked it up to a power supply:

Looking back, I probably should have loaded the syringe from the other end.

Syringe loaded with super thick pancake batter.

Syringe loaded with super thick pancake batter.

 

 

 

 

 

 

 

 

 

 

 

Here’s the actual test.  It gets especially interesting about 1 minute in:

The syringe continued drooling after power was removed due to air that was trapped inside the syringe.  As the plunger pushed, the air was compressed.  When the motor stopped the compressed air continued to push out the batter.  I will have to be careful to eliminate air bubbles in the material when it comes time to use this in a printer.

It only took a couple minutes to clean out the syringe after the test was done.

The pusher did its job much better than expected, and the plunger held up just fine, too.  I feel confident that this device will be able to extrude chocolate.   Now the real work begins…

Making a Plunger for a Chocolate Syringe

My latest project is a 3D printer that will produce chocolate objects.  Like many other chocolate printers, it will include a syringe to dispense the chocolate.  Unlike those other printers, the syringe in my printer will have 3.5 liter capacity to enable printing large objects.

The syringe is made from PVC pipe using mostly standard fittings.  One piece that wasn’t standard was the plunger that fits inside the syringe tube and pushes on the chocolate contained therein.  I had to design and fabricate the plunger.  PVC pipe isn’t perfectly smooth or perfectly round inside, so I needed something compliant enough to ride out the pipe’s bumps and constrictions while maintaining a seal.  The seal needed to be tough, yet safe for use with food because it will be in contact with the chocolate inside the syringe.  I found some food-grade silicone casting material and ordered it.

While waiting for the silicone to arrive, I designed a 3D printable core for the plunger and a mold and jig.  The core fits on the end of a linear actuator that will provide the push.  The jig centered the core a few mm above the bottom of the mold.  The mold was tapered and the widest part -the bottom- was a few mm larger diameter than the pipe, and several mm larger diameter than the core.  The silicone envelops the core and is locked in place by holes that connect top and bottom side of the core.  The plunger squeeze-fits into the pipe to maintain the seal against the uneven inner surface of the pipe.

Mold, jig, and core for syringe plunger

Mold, jig, and core for syringe plunger

Mold, jig, and core for syringe showing core inserted into jig.

Mold, jig, and core for syringe showing core inserted into jig.

 

 

 

 

 

 

 

 

 

Mold, jig, and core assembled for silicone over-molding.

Mold, jig, and core assembled for silicone over-molding.

I measured and mixed the silicone, coated the core with it and then set the core and jig in/on the mold and let it cure for 24 hours.  Then I removed the jig and broke the now silicone covered core out of the mold.  Result: a perfect, tight fit inside the syringe tube.

Core in mold with silicone.

Core in mold with silicone.

 

 

 

 

 

 

 

 

 

 

Finished plunger removed from the mold.

Finished plunger removed from the mold.  The mold had to be broken off by design.

 

 

 

 

 

 

 

 

 

 

 

Plunger mounted on linear actuator.

Plunger mounted on linear actuator.

 

 

 

 

 

 

 

 

 

 

 

 

The assembled syringe.

The assembled syringe.

Experiments in optics and image processing

After successfully mating a web cam with my microscopes (http://www.thingiverse.com/thing:216821) and telescope (https://www.youmagine.com/designs/web-cam-adapter-for-meade-telescope-eyepiece), I decided to design and print adapters to mount my Droid Turbo phone on the same scopes (https://www.youmagine.com/designs/microscope-adapter-for-droid-turbo-phone and https://www.youmagine.com/designs/droid-turbo-phone-to-telescope-adapter) so I could shoot higher resolution stills (21 Mp) and 1080p (and even 4k) video.   The telescope adapter fits over a Meade 32mm focal length Super Plössl eyepiece and provides about 47X magnification with the telescope.  I printed a similar adapter for my surgical microscope.

IMG_0995_crop

 

 

 

 

 

 

 

 

 

 

 

 

The telescope adapter firmly grips the phone and the eyepiece.

 

IMG_0993_crop

 

 

 

 

 

 

 

 

 

 

 

 

Initial tests were a little disappointing.  The combination of the phone’s camera and the telescope’s optics has significant pincushion distortion.  The image has only been mirrored L-R and scaled down (original is 21 Mp).  Note the lack of contrast (looking through 1/2 mile of humid air) and the curves in the power line and pole, and even the grass line:

pinch test original

 

 

 

 

 

 

 

 

 

A quick search found that the Gimp has built in transform tools to correct (or create) lens distortion.

 

gimp

 

 

 

 

 

 

 

 

It only took a couple minutes of messing around to get acceptable results.  Here’s the same image with the pincushion distortion corrected (whole image), contrast stretched and white balance corrected (rectangular area).  The pole, power line, and even the grass line now look straight.

pinch test corrected

 

 

 

 

 

 

 

 

 

And here’s the final image with all corrections and cropping applied:

final

 

 

 

 

 

 

 

 

 

 

Next step: photograph known square grids through the microscope and telescope and then create and save some preset corrections to apply with Gimp.

I wonder if something like this exists for video.  Hmmmmm…

 

 

 

 

 

Son of MegaMax Enters Instructables 3D Printing Contest

Many 3D printers being given away as prizes!  If I win one I’ll be donating it to my son’s school or other school or library that would like a machine and doesn’t already have one.  To do that I need your votes!

Son of MegaMax

Son of MegaMax

Please see my Instructable here:  http://www.instructables.com/id/An-Almost-Reliable-High-Precision-3D-Printer-Son-o/and vote for me by clicking the little red “vote” ribbon in the upper right corner of the start page.

Thanks!

http://www.instructables.com/id/An-Almost-Reliable-High-Precision-3D-Printer-Son-o/

Sunday Morning Project – A 3D Printed WebCam Mount for a Telescope

I recently acquired a new eyepiece to replace the damaged one that came with the Meade ETX-90 telescope I bought at a swap meet last year.  I decided it needed to have a web-cam mount so I designed and printed one that is a variation of a previous design for a microscope.  It took about 20 minutes to recreate the CAD file in DesignSpark Mechanical, and about 90 minutes to print on Son of MegaMax.

This thing has an odd shape to accommodate the odd shape of the camera.  I designed the adapter in two pieces so it could be printed without any support material.  After printing the two pieces were glued together with a little super glue.

Unassembled 3D printed WebCam adapter and eyepiece.

Unassembled 3D printed WebCam adapter and eyepiece.

 

Assembled adapter on the eyepiece.

Assembled adapter on the eyepiece.

 

Telescope with WebCam mounted.

The adapter fits over the barrel of the 32mm fl eyepiece and stays put.

 

I shot a short video to test it and it works perfectly!  The cars driving by are about 1/2 mile away.

 

If we ever get a clear night I’ll try shooting Jupiter or Saturn and then run Registax to enhance the images.

Files are here:  https://www.youmagine.com/designs/web-cam-adapter-for-meade-telescope-eyepiece

Son of MegaMax Lives!

MegaMax was a great 3D printer, but it was time for some changes.  He was difficult to transport because the electronics were in a separate housing with many cables to disconnect and reconnect, barely fit through doorways, and required a positively gargantuan enclosure to keep the temperature up to control ABS delamination.  Though it hurt to do it, I tore him apart and did a complete redesign/build into a form that is more like what I would have done had I known anything at all about 3D printing when I started building MegaMax.

I reused what I could including a lot of the 8020 extrusions in the frame, the Z axis screw assemblies and drive belt, and the X and Z axis motors.

Changes include:

  • ball screw drive Y axis with high torque motor- precise but noisy
  • linear guides in X and Y axes instead of 1/2″ round guide rails and linear bearings
  • SmoothieBoard controller instead of Arduino/RAMPS
  • BullDog XL extruder and E3D v6 hot end
  • RepRapDiscount graphic LCD control panel
  • narrower frame design without giving up print volume- easier fit through doorways!
  • polycarbonate panels to enclose the print area yet provide a clear view of the print
  • electronics in a drawer for easy service and transport and neater appearance
  • DSP motor drivers and 32V power supplies for X and Y axes
  • Liberal use of screw terminals to make servicing easier
  • Modular X and Y axes that can be removed for service and replaced in minutes.

SoM will be making his public debut at the Milwaukee Makerspace very soon…

Son of MegaMax electronics drawer

Son of MegaMax electronics drawer

Side view of Son of MegaMax

Side view of Son of MegaMax