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Wednesday, December 31, 2014

Milling & 3D Printing Your Own Drone From Scratch

Being an obsessive maker of machines that make things was what eventually pushed me to make my homemade hexacopter drone.   As I detailed in an earlier blog post, I used my Shapeoko CNC router to cut many of the parts I needed from Dibond.

I did not really like the motor mounts that were cut so I decided to look at what the world of 3D-printed motor mounts held for me when I came upon this brilliant parametric design by pwnas on Thingiverse:


I printed six of them in black PLA plastic.  Between what I could make myself with the CNC router and the 3D printer, I had all the frame and landing gear parts that I needed except for motor boom arms.  I bought 6 Aluminum booms from Hobby King for less than a dollar each.  With all the frame parts in hand, I then acquired the following electronic and other components:

  • HKPilot flight controller
  • Flight controller power module
  • GPS module
  • 9-channel radio transmitter/receiver
  • 6 motors
  • 6 electronic speed controllers
  • 6 carbon fiber propellers
Of course I also needed to make use of screws and nylon standoffs.  In the end, I was very happy with the results:

Upside down







It needs just a little more tweaking before it will be ready for its maiden voyage.  I can't wait to see what I'll be able to do with flying heavy lifter!

Friday, December 26, 2014

Hexacopter drone assembled: Almost there!

I'm just about there.  I assembled the the home CNC machined frame and landing gear.  I wired all the electronics including the 6 motors, electronic speed controlers, ARDUpilot flight controller, GPS and radio receiver.  I'm having trouble binding my transmitter to my receiver but assuming I can get over this hump, I should have this bad boy in the air by tomorrow!


More shortly...

Sunday, December 21, 2014

Scrambling to finish my drone before the holidays

I started building my drone a while ago.  I cut many of its parts with my home-made Shapeoko derivative CNC router.  I was flying high for a while as work piled up and I decided to put it aside.  I now pick it up.  I am a little ashamed that it took me so long to get my soldering iron heated up but I reached that crisis point today, with the hope that I will be launching my hexacopter drone on its inaugural flight on this holiday week.  This is one of its 6 arms complete with carbon fiber propeller:


Each arm had 9 connections to be soldered.  I made it a day and got the rest done:


I now need to get this heavy lifter in the air.  I know a bit about Arduino and less about ARDUPilot but I am psyched that I may successfully launch my first homemade drone in the coming days.


Sunday, June 8, 2014

The Big Fix for My Revolution XL 3D Printer - Using the CNC Router

After several design problems ultimately led to the conversion of my Revolution XL from a pretty good 3D printer to a paperweight, I stared at it for a time contemplating how I could resurrect it, while turning it into the sort of machine I wish I had bought originally.  Its shortcomings became increasingly apparent with time:

  • Terrible Z-homing repeatability
  •  Hot end heater wires inevitably fail due to motion/metal fatigue at the point of the last nanolink before the wires emerge from the nanolink cable management.
  • When the heater wires fail on the hot end, the extruder gearbox starts to slip, which wears down its gears.  
  • When the gears begin to fail, a clicking sound is substituted for extrusion resulting in a failed print
I loved many aspects of the RXL.  It was well designed, for the most part.  It is extremely rigid and the doubling of the motors was a great touch.  So my mission became to fix this otherwise good but currently useless machine.

I began with the extruder.  It needed replacement.  I decided on a Bowden setup, and because I have wasted so much time over the years on bad extruders and hot-ends, I decided to splurge:  I bought Micron3dp.com's extruder and hot-end together for $300 on eBay.  It struck me as overpriced but it was an irresistably beautiful piece of engineering. But to make this work, I would have a lot of work to do.  It was unfortunate that my silenced 3D-printer was, at-this-point, unable to print its own replacement parts but fortunately, My CNC router in the basement was still functional and ready to cut parts out of 1/8" aluminum plate.

And so my adventure began.

I started off designing (and machining) the new extruder mount.  It turned out that I had to redesign and re-machine 2 of the 5 required parts several times to make them work.  A lot of aluminum plate went into my trials and errors:



Part 1:  The hot-end mount and clamp


It took 4 tries before I got the hot-end mount done right:


The mounting clamp was simpler:

Together, they allow for two of these hot ends to be mounted to the RXL.  I am starting with a single extruder/hot-end but it would be a silly waste of time doing all this without thinking of the future.  I started by removing the old extruder and mounting hardware


Next, I screwed in the mounting clamp:


Then the extruder mount (this was before the redesigns but you get the idea


And so I was able to screw in the new hot end:


To finish this up, I needed to put some work into the hot-end as well.  I replaced its 12v fan with a 24v fan.  I also had to extend all wires and tuck them all into a neat braided sleeving, suggested to me by MacAttak.

Part 2:  The Bowden Extruder Mount

My design:

I removed 2 screws, replaced them with longer ones, and attached this mount to the rear-left-top corner so that the result looked like this:


The wiring was a pain.  I used crimpable, self-soldering butts to connect the heater wires and solder for the rest.  All connections were covered with heat-shrink tubing:


Finally, everything was covered in bigger heat-shrink tubing:


Part 3:  The X-belt connector/X-end-stop trigger

This was the hardest item that I made but the item that I am most proud of designing.  It needed to perform two functions -- to be glueable to the X-axis belt and to trigger the X end-stop.  This was the first project where I needed to score, heat and fold metal, namely 1/8" 6061 aluminum plate.  This was the final CAD design:


Like the mounting plate, I had to design and machine four iterations before I got it right:


Now folded further under the heat of a MAP gas torch:


Now mounted on the X axis with M3 x 10 screws and glued to the X-belt:


Now altogether with the Bowden tube installed:


Here it is, finally in action:


For those of you interested in making the same modification to your RXL,  I offer the following files free for use with the stipulation that you attribute the files and design to me and this blog.  The CAD/CAM files were designed with CamBam, a great and affordable Windows software that I have grown increasingly fond of and that I used to create these parts.  The native CamBam CAD/CAM file and DXF file can be found here.

So far, so good.  Now I need to figure out how to decrease stringing on such a Bowden setup.  I am confident that the Ultimaker community has blazed a sufficient trail for me to follow that I am not too worried.




Sunday, May 25, 2014

QU-BD Revolution XL Review Part 4

After a bit of a hiatus from blogging, I decided to return with this final review of the QU-BD Revolution XL that was delivered to me in August of 2013.  At this point it is no longer operational, pending some necessary upgrades.  Before I launch into the full list of problems and design flaws of the RXL, it is only fair that I give mention to its positive attributes, chief among them - build quality.  It's frame is well-engineered, its rods are well-polished and it was obvious that QU-BD set out to make a world class 3D printer.  That said, here were the problems that plagued it and more that eventually turned it into a very heavy paperweight:


  • Loose Bed:  The volcanic glass bed does not fit snugly on the tray holding it.  There is about a 2mm gap in both directions.  If you are printing slowly enough to limit vibration, this issue is of no consequence because of the weight of the bed but if you step up the speed (the RXL was arguably built for speed), vibrations will move the bed slightly mid-print, resulting in a failed print.
  • Z-axis homing: Within a couple of weeks of use, Z-axis homing repeatability became a problem and the problem increased from there.  A couple of factors were to blame:  the position and quality of the Z-axis endstop.  The problem with its position is that it was located on the side of the unit whereas the Z-axis leadscrews were toward the center.  Fellow RXL owner Illuminarti came up with and posted an inventive solution to this problem, which I have adopted.  The second problem, that of the quality of the switch itself came close to causing the machine to damage itself.  The switch would remain in the opened position despite being pushed all the way in.  Fortunately, my unit unlike those of others who had this problem, was never damaged.
  • X-truder: This was supposed to be one of the big selling points of the RXL.  It is a small extruder with counter-rotating gears that is still advertised by them as "the best extruder on the market".  After 9 months with it, I would beg to differ.  My first one began to fail a couple of months after I received the printer.  At one point it decided to stop extruding and to instead start clicking.  QU-BD was good about getting me a replacement and asking me for the return of my old one for analysis but claimed to have solved the problem.  A few months later the same problem occurred again, but the second time would bring me no customer service solution -- but more on QU-BD's customer service later.

    One of the big consequence of the X-truder's compact size was that the cold barrel leading to the hot-end had no cooling fins.  This was fine if you wanted to print a vase or other parts not requiring retraction but anything but the slightest of retraction would inevitably lead to a clogged nozzle.

    The biggest problem with the X-truder was that the tension of the gears could not be adjusted.  Practically speaking, this meant that I could never get it to extrude Taulman's T-Glase, one of the more popular filaments, because the gears would slip against that filament's smooth surface.  I could get smooth PLA to print but only at painfully slow speeds.

    In the end, I, like others, had to resort to third party extruder/hot end replacements.  I will detail my upgrade process in a future post.
  • Extruder carriage nanolinks:  I can see why QU-BD thought the use of Nanolinks cable management for managing the wires going to the extruder and hot end was a good idea.  It did keep things looking clean.  The flaw was that the carriage moves back and forth so quickly that the nanolinks' restriction of the motion of the cables to one direction would inevitably result in metal fatigue occurring in the heater wires.  This has happened to several RXL users, myself included.  This was in fact the flaw that finally silenced my RXL.
The biggest flaw with the RXL lies not as much with the printer itself but with QU-BD's customer service.  Recently, they changed their domain name/company name from QU-BD.com to QuintessencialUniversalBuildingDevice.com.  I suspect that this move was one way to deal with the online customer backlash that Googling "QU-BD" will reveal.  There is nothing like re-branding!  Unfortunately, the new multi-syllabic name does nothing to address their festering customer service problems.  As an example, I opened a case with them the moment when my extruder and cable failed.  Their rep wrote back to me within 10 days, telling me that they would send me a new improved extruder that had been improved upon.  That was 4/6/14.  On 4/15, I sent a message asking if it had in fact gone out.  Nothing.  On 4/28, I wrote again.  The rep did get back to me that day and said "Sorry for the delay. We ran out of the extruder stepper motors but just got a new batch in. I will make sure that it goes out today."

That was one month ago.  Still nothing.  My subsequent inquiry on 5/8 resulted in no reply.  I give up.

An upgrade of the extruder/hot-end to a modern, all metal design will likely put many of these issues to rest and result in a greatly improved printer.  I have chosen to go with a Bowden version of this high-quality extruder/hot-end pair from Micron3dp.  When I am finished upgrading the RXL, it will no longer be the same machine.  I will make it work and and I have no doubt it will be greatly improved, but in retrospect, I wish that I had simply bought an Ultimaker.  Had I done so, more of my writing would have been 3D printer use rather than 3D printer fixing.