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  • Rotating 3d Printer Tool Holder

    Posted on March 22nd, 2020 admin No comments

    Although a lot of folks use their 3d printer to print a tool holder, I found this handy gadget at my local Staples store: a rotating desk organizer for only $13 CAD plus tax. The various bins hold all the tools I usually use, for ready access.

    It fits perfectly on top of an empty filament spool fitted with drawers (you can find a wide variety of designs on Thingiverse). I expect to add more drawer layers as time goes on.

    Perhaps some day I will print something else, but this has served my needs well for the past few years. So maybe not.

  • Inexpensive CR-10s 3d Printer Table

    Posted on March 22nd, 2020 admin No comments

    Making a 3d Printer Table for Under $30

    My CR-10s Pro 3d printer was too big for the table I used with my Kodama Trinus. Time to build something bigger!

    At the recommendation of a couple of other printer users, I bought a couple of side tables (Ikea LACK for only $12 CAD each). They’re sturdy and inexpensive and big enough to support the printer. One table formed the bottom or base, the second table became the printer support.

    Inexpensive 3d printer table for Creality CR-10s Pro

    To the base table, I added a quick and easy shelf, using a piece of scrap 1/2″ plywood that I had on hand. I cut rough notches to fit around the legs and supported/attached the shelf with a 2″ angle bracket (flat brace, less than $1 each) on each leg.

    For the top table, I cut each leg off at 10″. This leaves the bottom of each leg hollow. To locate the top onto the bottom, I cut four scrap pieces to fit inside the leg, and used 1″ deck screws to fasten these onto the top of the base table. The top table sits on these; they hold it solidly without slipping, but the top can still be easily removed.

    A hollow leg after the bottom was cut of
    An angled block cut from scrap to fit into the hollow leg

    It took only an hour to make the whole setup and it works well, especially considering that it cost under $30! There is a little vibration when the printer is moving and I might add some diagonal aluminum struts across the sides and back.

    The shelves are handy for storing boxed filaments in front with other equipment in behind (accessible from the sides, or by removing the boxes)

  • 3D Printing Again

    Posted on October 17th, 2017 admin No comments

    Dusted off my Kodama Trinus 3D printer, which had been sitting idle over the summer while I tried cycle touring.



    Fixing the Trinus Leveling Bed

    It sure took a while to get everything going again.  I had just got the new leveling bed last spring, but hadn't even used it.  While setting it up, trying to get it level, I found that the motion of the printer shook the adjusting screws loose, to the point where one even fell off.  Not much good, that.  A little blue LocTite fixed them, but it was a surprise that Kodama would ship such an unreliable product.   They've promised to send a replacement set at no charge.  In the meantime, I wonder if I can damp that vibration somehow.

     A leveling screw on the Trinus bed

    A leveling screw on the Trinus bed

    It also took a while for me to get the bed leveled and set for a good first layer.  Stringy, blotchy prints, missing parts.... Part of this was remembering how to use the software, Cura 15.04.6, and set it for best results.

    Bad first layer

    Bad first layer

    Fixing the Heated Bed

    After I got most of that straight, I noticed that the heated bed wasn't heating.   Eventually tracked that down to a broken wire in the cable, which I fixed.  Discussion with a Kodama support rep led to changing the routing of the cable so the coil was not horizontal (as shown in the original assembly instructions) but vertical, in hope of avoiding future issues.

    Lights, Action, LCD

    While I was at it, I added some new LED lighting on the bottom of the X arm, and tied it in with the lighting under the extruder, adding connectors for easy future removal/upgrade. This lights the print bed nicely and I wish I had done it last winter.  Previously, I had drawn 12V from the main PCB and cut it down with a 5V regulator for the lights.  I decided the printer and heated bed needed all the power they could get, and gave both sets of lights their own 5V power supply via another wall wart.  Oh, wonderful, more cords....

    I had got tired of having the leveling  bed screws knock the LCD holder off its mount on the end of the Y slider, so I cut some notches in it to mount it on the printer bed.  That way, the leveling bed screws pass right over it.  Simple and effective, both easier and faster than printing an extension or redesigning and reprinting the original LCD mount (someone already did the redesign!).

    LCD Case Mod Composite

    Are We Ready to 3D Print Yet?

    All this had taken several days.   Let's see,

    • Fix the bed leveling screws with blue LocTite
    • Level the bed and adjust the Z-axis offset
    • Repair the heated bed cable
    • Reroute the HBC
    • Relearn how to use the software
    • Adjust all the software settings (why should they change?)
    • Remount the LCD holder
    • Add new lighting, change the wiring for the lighting, add connectors and 5V power supply

    Can I print now?  Yes.  Oh, but wait, I never did properly set the printer so I could use the entire bed.  I have adjusted the Z axis but now I need to fix the X- and Y-axes.   Darn, not enough room to get in to do the Y axis.   Trinus says to remove the slide for access, but I don't want to do that, it would be remove and adjust, reinstall and check, repeat.  Ugh.  So I printed a couple of these:

    Axis adjustment nut adaptors

    Axis adjustment helpers by drofnas

    They slip over the adjustment screw and onto the tiny 5.5 mm lock nuts, to provide more leverage to loosen them.  The first set was a bit too big, but the second scaled to 95% fit quite well.   With these, I was able to adjust the two horizontal axes so the bed is properly centred.

    Now, what to print next?...

  • 101Hero Hacks: Cooling Fan Extended

    Posted on January 26th, 2017 admin No comments

    The 101Hero printer is basically –especially in its early release versions — a toy for those who like to tinker.   Its low cost and simplicity led hundreds of backers (perhaps even thousands) to choose it as their first 3D printer, only to discover that it had many shortcomings.

    One of the things users established early on is the need for some kind of fan system for cooling the print.   The earliest and simplest method was to set a small fan onto the work surface.   A second version was to add small CPU fans to the print bed.   Our third try was to add a cooling fan to the print head, as is the case with larger delta printers or cartesian printers.

    The First Head-Mounted Fan

    My first try at a head-mounted fan was moderately successful, but not quite as good as I had hoped.   The fan did work to cool the layer just laid down.   However, it was unidirectional, blowing only from one side. I felt that it could be improved by changing the vent into a ring that surrounded the nozzle to blow down onto the print from all directions.   This is a design that is commonly used on other printers, and many examples can be found on Thingiverse and other download print sites.

    Ring around the Nozzle

    My first thought was to find such an example, and modify it.  For example, here's a nice ring I remade from Thingiverse.  It's based on no particular Thing as the ring is part of numerous remakes; 1995668 is pretty close.  Using the free 123D Design software, I scaled it down to 3 mm high so it would fit under the 101Hero's print head, and edited it to fit my duct.   However, I was never satisfied with any print of this ring that I was able to make on the 101Hero.

    A cooling ring with vent holes

    A cooling ring with vent holes

    Ironically enough, I may be able to print it with the present version of the head-mount fan!  I'll have to revisit this project when I get back from vacation in April.

    Extending the Groove

    My second attempt was to make a simpler version of  the above in 123D Design.  The ring is basically a torus turned to a shell, with holes drilled at an angle.  This project turned out to be beyond my design skills at the present.  Besides, it's already been done in the nice photo above.

    The third idea was to just extend the downard-pointing groove at the end of my present model, to create a kind of circular groove.  Of the several ways I could think of to do this in 123D I probably chose the most difficult.  I managed to combine concentric cones to get the result I needed:

    A ring with a groove pointing down

    A ring with a groove pointing down

    I redid this from scratch to fix some failings in the first versions, such as smoothing the interior walls considerably.  Initial tests showed that the groove was too wide, making it only slightly more efficient than the previous straight version.     Which led to this iteration:

    Narrower groove with center diverter

    Narrower groove with center diverter

    You can see that the groove is narrower, and I've added a diverter in the center to direct the air more around the sides.  Had to leave on holiday before I was able to print this, but I've put the file up so other users can test it out for me.  If you make one please let me know in the comments on this post.

    And today, I found Thingiverse 6173 which is remarkably similar in approach.   I could probably have hacked that Thing and saved myself a lot of work.  But I did learn a lot about design and using 123D, so the time was in no way wasted!

    Further Reading

  • 101Hero Cooling Fan: Proof of Concept

    Posted on January 18th, 2017 admin No comments

    The last test has been completed, and I'd say the cooling fan hack is a success!

    Climbing the Eiffel Tower

    One of the earlier prints I did with the 101Hero was a series of Eiffel Tower models, from Thingiverse.   There were tower models I liked better, but this one seemed simple and within the ability of the 101Hero 3D printer.

    The Eiffel Tower model

    The Eiffel Tower model

    They were generally good for the first  30 mm, but after that degenerated into a twisted, molten mess.  The diagnosis was excessive heat.

    101Hero Red PLA; two in Silver RepRap PLA

    101Hero Red PLA; two in Silver RepRap PLA

    • The first treatment, reduced print temperature, was not much better.
    • The second treatment a 2" (40 cm) fan beside the print bed to provide cooling, was more successful.  The print was reasonably good to 50 mm, with less twisting and globbing in the upper tower.
    • The third treatment, using a "cooling tower" to print beside the model, was less successful.  Excessive stringing made one corner of the Eiffel tower a mess, and in all was not as good as the previous print.

      Printed with cooling tower

      Printed with cooling tower.  Best side shown at right.

    Adding the Head-Mounted Cooling Fan

    The final test of this  project was to print an identical tower using only the head-mounted fan for cooling.  I scaled the height of the model to 75 mm, which was the measured height of the earlier series.  However, I did not duplicate the settings of those earlier models (I have learned a few things since then).  Being a bit impatient, I set layer height to 0.2 mm to reduce print time (this also seems to have resulted in the model being 80 mm tall).  I used support touching the buildplate, and a raft, because some of those earlier towers had lost a leg and suffered other detachment errors.

    The print went almost perfectly to about 65 mm.  At that point, the behaviour of the head changed, and instead of printing a bit and waiting, it began running continuously.  I could actually see the head dragging the molten plastic in a small circle.  Five millimeters later, the head went back to printing a side, waiting, printing a side, waiting....   This seems almost to be a setting error, one I might be able to track down in the gCode.

    Test Results:  Left, head-mount fan; center, bed-mount fan; right, cooling tower


    Test Results shown above: Left, head-mount fan; center, bed-mount fan (red feet tell you it was done right after the set done in red 101PLA); right, cooling tower.  Dang, it's in sharp focus on my computer, even zoomed in.  Why is it soft-focus here?

    The final proof - identical settings, on left with fan, on right with no fan.

    The final proof - identical settings, on left with fan, on right with no fan.


    Woohoo!  The head-mounted fan created the best-looking print.  We'll call this a success!

    But this isn't the end.   Ideas for the future:

    1.   I might want to extend the duct to move the vent about 1 mm closer to the extruder nozzle.
    2.  Another possibility is to add a ring-shaped vent to surround the nozzle.  However, my first attempts at this failed, since this project was done at about the limits of accuracy for the 101 Hero.  Doesn't mean it can't be done.  Just means I couldn't do it a few weeks ago.
    3. I might wait until my next printer comes, and print another fan system in ABS
    4. The little rotary fan really doesn't move much air (1.2 litres per minute).   If I can find a small centrifugal "squirrel cage" fan it might improve the cooling.
    5. I'd like to experiment with an aquarium blower, which pipes air through a tube.  I'm thinking a 1/8" metal ring around the nozzle, with holes drilled for the vents.

    Lots of fun still to come.

    Further Reading

  • Hacking the 101Hero: Testing the Head-Mounted Cooling Fan

    Posted on January 17th, 2017 admin No comments

    Earlier, I wrote about experiments I did with building a head-mounted cooling fan for the 101Hero.   It's in place and running now, so it's time to finish writing up the project.

    I use HVAC (Heating, Ventilating, Air Conditioning) terminology here.   The plenum is the upper part, which contains the fan, and gathers and directs blown air into the duct.  This is the narrower tube that guides the air to its destination.  The vent is the aperture or opening at the end of the duct that directs air forward and down around the print nozzle.   These parts can perhaps more clearly be seen in the earlier article.

    Making it Airtight

    Because I had printed this to be lightweight, I used a print height of 0.1 mm, with side/top/bottom layers of 0.8 mm (along with a slow print speed, very light support, and 20% infill overlap).   The result was that the plenum (the part that holds the fan) and duct (which leads the air around to the nozzle) were basically a mesh that leaked air everywhere.  I tested this by blocking the vent with my finger and blowing into the plenum.

    Fan housing with fan temporarily attached

    Fan housing with fan temporarily attached

    The inside surfaces were a bit rough, and I wondered about mixing white glue and water and pouring it inside to smooth the surface and improve airflow, but the thing is just so dang small!   I was afraid the glue would block off the duct.  The best I could do was cut a little strip of sandpaper to run back and forth inside the duct, and scrape the inside of the plenum with the square end of a small file.  After cleanup, tThe two parts fit well together; I glued them with CA glue.

    Then I mixed up some five-minute epoxy (JB Weld brand) and carefully smeared it all over the outside of the assembled fan unit.  I used this epoxy because it is both heat resistant and fireproof.   It took two coats to completely seal all the leaks.  So much for light weight!  It might have been better to print a sturdier part in the first place!  Or maybe use spray paint...   Then I sanded it a bit, especially the top of the duct that had to rest against the bottom of the print head.  I might have to sand more for a better fit.

    Another view of the fan and housing

    Another view of the fan and housing.  The "ears" had no epoxy.  You can see sanding on top of the duct (lower left) and the tape sealing the fan in.

    The fan dropped nicely into its bracket atop the plenum, but there was still a little air leakage around the fan frame, so I roughly sealed it with  transparent tape for the trial runs.  I also snipped off the tiny electrical connector and soldered on a two-pin job to hook up to the 5V power supply unit (PSU) that had been running my LEDs and print-bed fan.   While I'm using the head-mounted fan, I'll have no lights, and the little head-mount unit will be the only cooling fan.

    Printing Results

    With the fan running, there's a reasonable amount of air coming out, directed at the recently laid layer, about 3 mm back of the nozzle.  This was about where I'd wanted it.

    Since I had 101Hero gold filament in the printer and wanted to print some gold vases, that was where I started.  The purpose of these tests was to determine if

    1. the duct would clear the print
    2. not interfere in any way with the print process
    3. provide reasonable cooling

      The print from the front; the red arrows indicate the location of the vent

      The print from the front; the red arrows indicate the location of the end of the duct; the vent is on the bottom

    There was no off-switch in the experimental setup, so I unplugged the PSU for the first three (bottom) layers.  Once the walls of the vase (50 mm diameter, 95 mm high) started to print, I plugged in the PSU and left the print to run.   No issues, and fewer hairs than usual, despite the number of times the head criss-crosses the diameter of the vase (I don't know why it can't just go around the outside, but it doesn't, it does part of a wall, then crosses over and does part of a wall on the other side, then comes back and does more on this side....)

    Duct circled in red.  The air blows to the right and down in this image.

    Duct circled in red. The air blows to the right and down in this image.  The nozzle is at the left edge of the print, about 3 mm from the vent.


    Success So Far

    The duct is narrow enough that it clears the print, and did not in any way interfere with the process.  The print result was as good as those done with the more powerful 40 mm bed-mounted fan.  There were a couple of holes in the side walls.  This had also happened even worse with the BotFeeder translucent white, but not with the RepRap silver.  I think this is just a difference in filament quality.

    Here you can see the entire fan unit.

    Here you can see the entire fan unit.  It's not actually touching the print.   And yes, that's a hole in the wall of the print.

    The second vase in the series was printed oval, 60 mm x 80 mm x 50 mm high.  The extra width was to see if the suspension arms would hit the fan unit (they didn't) and the reduced height was just to make sure I didn't run out of filament and to keep the print time down.  This print showed considerable stringing and gobbing, suggesting that the cooling was not sufficient.

    The Next Series of Tests

    There was no heat damage to the vent area, so I might re-position the duct closer to the nozzle.  I'll also better seal the fan housing into the plenum so that all air blown by the fan goes down the duct and out the vent.

    The real test, of course, will be something tall and spindly like an Eiffel Tower, or a good test print like a Benchy.  I'll run those tomorrow using the silver RepRap PLA.




  • 101Hero Hacks: Control Board LEDs

    Posted on January 9th, 2017 admin No comments
    When I document.write(" Wiring, Cooling Fan" href="http://blog.graywriterrv.com/?p=1549">mounted the control box to a pylon, I moved the factory LED to the other side so it would be visible from where I sit. Since then, I've been annoyed that this LED is also on when the USB cable is plugged in, so I can't easily tell at a glance if I've remembered to turn off the printer. I have to come up and check the switch, what a chore! Or unplug the USB cable, even worse!

    The first hack -- move the LED from bottom right to top left in the image

    The first hack -- move the LED from bottom right to top left in the image

    Adding a Power LED - First Try

    I figured the factory LED was run off 5V -- there are two 7805 voltage regulators on the board and the LED appears to come right off one of them -- and that I could just put another LED across 12V off the power switch to ground. And that worked fine -- turn on the switch and the new LED lights up. There's my power-on/off indicator.
    To my surprise and annoyance, that LED also lights when just the USB cable is plugged in -- just like the existing LED.
    I would have thought the 12V power supply would be totally separate from the 5V USB and UART. As far as I can tell (can hardly see the traces, let alone track them), there's only a 1000u cap across the inputs before the voltage regulators.

    Second Try -- Using 5V from the USB Cable

    The USB jack also has 5V at pin 4 supplied by the hero board, rather than from the computer. So much for an indicator across pins 1 and 4 there.  It's always on when the power's on.  It's always on when the USB cable is connected.  It's the same as the existing factory LED.

    A Standby Indicator LED

     For now, I've put a small green LED from ground to the unused third pin of the switch. It glows when the printer is OFF, a kind of "safe" or "standby" light.   It's drilled through the top of the case and is readily visible.    I used a 470 ohm resistor but in retrospect a 1K resistor would have been fine -- the LED doesn't have to light up my office at night.

    Location of the standby LED, held in place by the resistor

    Location of the standby LED, held in place by the resistor

    Both LEDs

    Both LEDs in place

    Switch off, standby LED on

    Switch off, standby LED on


    Not quite what I'd wanted, but it met my goal of indicating that the printer/board is powered down.
    Further Reading

  • Limitations of the 101Hero 3D Printer

    Posted on January 9th, 2017 admin 2 comments

    In one video I watched recently, the presenter (I think it might have been Angus Deveson, Maker's Muse) commented that some 3d printers are toys while others are tools.   The first kind are hobby machines for playing around with, good for making nick-nacks and gizmos and toys, while others are are more work machines, good for creating useful objects, prototypes, and replacement parts.

     101Hero:  Toy or Tool?

    My 101Hero is an improvement over its predecessor, the Makerbot Cupcake.  Still, the 101Hero, like most other inexpensive  definitely falls into the toy category.  Perhaps more than some, the 101Hero suffers limitations that fix it more firmly as toy than tool:
    • structural considerations
    • quality control
    • speed limitations
    • size limitations
    • printing limitations

    Structural Considerations

    Tools are made of metal, toys are made of plastic.   The 101Hero is injection-molded.  The plastic pylons have some triangular reinforcement and are reasonably stiff.  The plastic base and top are not; they flex.   The machine is ok if you don't disturb it at all, but don't move it or even bang the desk or table while it's printing. Doing so will guarantee skipped or offset layers.  Even a heavy tread on the floor can be enough to disrupt a print.


    Poor Quality Control

    Beyond the usual late delivery and poor communications characteristic of struggling crowd-funded products, 101Hero seems to suffer an inordinate number of QC issues.  Shipping seems to be slowly catching up, with the colored models finally reaching backers. However, the official web page and official Facebook page contain no news for backers at the time I write this.
    Users report missing parts, incorrect colors, doa controllers, defective stepper motors, broken gears, warped or loose slide rods.  In an "Unofficial" Facebook post dated Dec 8, one user stated "I was just successful in requesting a refund from indiegogo. They canceled my backing since it had not shipped yet. They said in an email they are overwhelmed with a flood of complaints of broken units, wrong units shipped and no customer service to back the product

    The creator has publicly stated that delivery is their main priority, which puts  customer relations a distant second.   While this may be short-sighted, it does show some determination to get the product (whether it works or not) out to backers.  Probably their thinking is that once the headaches of delivery are gone, they may have time and energy to devote to customer service.

    Speed Limitations

    Delta (three-sided) printers are supposed to have advantages of speed.  Where even a mid-level printer will print at 50 mm/s or more,  the Hero has a top speed of 14 mm/s, with reasonably good printing coming at 10-12 mm/s.  Many users have reduced the speed to as low as 5 mm/s in an attempt at better quality.   In consequence, print times of eight hours or more are common.     The 101Hero, if designed to be used by children, will definitely teach them patience.

    352 Elephant, courtesy of 101land.com

    352 Elephant, courtesy of 101land.com

    ; Build Summary for 352 Elephant
    ;   Build time: 8 hours 2 minutes
    ;   Filament length: 9340.8 mm (9.34 m)
    ;   Plastic volume: 22467.20 mm^3 (22.47 cc)
    ;   Plastic weight: 28.08 g (0.06 lb)
    ;   Material cost: 1.29

    Uneven Printing Across the Print Bed: Size Limitations


    Wide prints simply do not work, because the printer cannot follow a straight flat line from one side of the print bed to the other:  it arcs or rises over the center.   Hannes Brandstätter-Müller of Austria posted on the 101Hero Unofficial Facebook page:  "I encounter the same lifting in the center when doing wide movements. It's annoying..."

    An adjustment that lays a good first layer in the center 50 mm will drive the nozzle into the print bed at the perimeter.  An adjustment good at the perimeter will not attach in the center.  My first thought on noticing this was that somehow the glass print bed had warped, an unlikely notion quickly dismissed by checking with a steel straightedge.

    This inability to do a wide print appears to be a weakness or flaw of the firmware that effectively limits the print diameter to at most 80 mm (roughly half of the 150 mm build plate).  The only workaround is to modify the print file -- divide it into two smaller parts that can be printed in the center.

    It appears that the creator-supplied models will fit within this small central diameter and provide reasonable results.  It's only user-created parts or wide parts imported from other sources that will be problematic.



    If you want a sturdy machine that will work out of the box, get something else.  The 101Hero is an inexpensive toy for printing toys.  It falls into that class of 3D printers that is to play with, not to work with.   It's a machine for those who are prepared to tinker, fiddle, diddle, and hack.


    Further Reading

  • Hacking the 101Hero: Cooling Fan

    Posted on January 6th, 2017 admin 1 comment

    One weakness of the 101Hero 3d Printer is the lack of a cooling fan.   Most users have compensated for this with document.write(" Wiring, Cooling Fan" href="http://blog.graywriterrv.com/?p=1549">bed-mounted fans.    But wouldn't it be neat to add a cooling fan to the head, to direct cooling air right onto the recently-printed layer, just like on a more expensive printer?

    Where to Mount the Fan

    There are two likely places for such a fan:

    • In "front", under the filament access door.
    • At "back", under the hump of the stepper motor

    I thought the front location might interfere with access to changing filaments, and the shape of the duct would be difficult due to the need to fit in the yoke between the struts.   I also briefly considered mounting a fan on the top, beside the wiring and the filament tube, but thought that would be awkward.  Because of that I chose the "back" position.

    Choosing a Fan

    The 15 mm fan (for Raspberry Pi)

    The 15 mm fan (for Raspberry Pi)

    In either location, there isn't much room.   At the front, there might be space for a  20 mm fan, while at the back, the most likely size is 15 mm.  I got a tiny 15 mm fan on Ebay for $10 plus $7 shipping, and found a 20 mm fan at Aliexpress for $10 with shipping included.

    The little 5V fan came within two weeks from Las Vegas.  It pumps 12 litres/minute at 15.7kPa, a fraction of the amount from the 40 mm fan I have mounted on the print bed.  Still, directed through a duct, that small amount of air might be enough to cool the PLA.

    Besides,  this is just a fun project, intended to help me learn to use 123D Design and to do 3D printing.  It is not expected to produce any really practical result.

    Fan specs.  Sprechen sie Deutsch?

    Fan specs.  Sprechen sie Deutsch?

    Developing the Design

    I wanted something with minimal curves, with minimal interference with the airflow.  I dismounted the head, did some measurements, made some sketches.  The first prototype was made of stiff paper from a 2016 calendar, taped together.   The idea was that the fan, at the top, could blow down through a duct and the air be directed downwards beside the extruder.  I taped the fan into the top, hooked it to a battery, and decided that maybe....

    Crude paper prototype

    Crude paper prototype

    It fit well onto the print head, and it looked like the design might work.  Now all I had to do was turn that paper model and my concept into a 3D print using strange software such as TinkerCad and 123Design.

    Iteration After Iteration

    This part was enjoyable, if a bit tedious.  I would figure out make a design (which often involved a lot of Google work), then print it out.  Then I had to play with the print settings or the part orientation to get a decent print.  Then I'd try it, see what was wrong with it, which also often involved Internet research on "3D printing problems:.  Then repeat.  And repeat.  And repeat.

    A few of the many tries.  I went through five major designs with up to 12 iterations in each.

    A few of the many tries. I went through five designs with up to 12 iterations in each and used many meters of PLA

    One obstacle was that I couldn't really measure or fit with the head mounted in the printer.  With the head off to measure and fit, I couldn't print.  Once I put the head back, it often took hours (in one case a full day) to get it readjusted to print properly.


    First two-part prototype, joined and sealed with green vinyl tape. Early versions included a screw mount for the fan but a press-in flange worked fine.

    Still, the early printed prototypes snapped securely onto the print head, and were encouraging.   Problems with printing led me to cut the part into two, a motor housing and a duct.

    Early prototype clinging to the print head

    Early prototype clinging to the print head


    A mid-series Image from 123D. Motor housing at left bottom on plenum; duct at right.

    So, change this, extend that, find that this didn't print properly -- why not?--move this, try again.  I learned about support, orientation, bridging, wall thickness, stringing, retraction.  I switched from Cura 15.02 to 15.04 because the latter gave more accurate slicing (in between two Cura versions, I tested KISSlicer, Repetier Host, Craftware, and ICEsl) .  I changed setting after setting and kept track of all the changes in a spreadsheet, so that eventually I could identify what worked well and what didn't.   One thing that caused problems was support - Cura insists on putting support inside the duct, which was impossible to get out and which left the inside rough instead of smooth.  I wound up using Support "Touching build plate" as it worked the best. printing-v5-12

    The semi-final version was printed using the best quality I could achieve given my limited knowledge and skills.  There may be further modifications to indent the motor housing just under the motor, to allow space for the suspension struts during wide prints.

    Anyone interested in duplicating or better yet improving this project will find the files at the 101Hero forum (101user.com).

    Is it Safe?

    I'm printing in PLA and perhaps having the blower close to the extruder is not a good idea. I am considering sending the part out to be printed commercially, or waiting until I get my Trinus so the duct can be printed in ABS (the blower housing can be PLA).   Though, in point of fact, the thing hasn't melted yet.

    An early version, not quite straight and a bit close to the extruder nozzle

    An early version, not quite straight, not the best print, and a bit close to the extruder nozzle.


    In Conclusion

    In the end, I came up with a design that seems to work as well as it's going to work.  I'll print another Eiffel Tower to see the result.  Does it function and adequately cool the part as it's printing?  Probably not.  It seems that 12 L/m of air at 15.7 kPa is not really a lot of movement or pressure. I can feel air coming out the vent, and that's about as much as I can say for it.

    Still,  the project taught me a lot about using design software, principles of good design, and some basics of 3D printing.   Which was, after all,  the main goal.

    Further Reading



  • Five Tips for Video Presenters: Lessons from Live TV

    Posted on January 3rd, 2017 admin No comments

    Since getting my 101Hero 3D printer, I've been watching a lot of  how-to videos.  Generally speaking, I loathe amateur instructional videos on Youtube.   I'm not talking about camera technique, video quality, smoothness of editing or any other technical topic.   I'm talking about the person in front of the camera, telling  (instead of showing) me something that I want to know or learn or do.

    If a video can't hook me in the first 30 seconds, I'm gone.  Lost as an audience now and probably forever.

    I used to work in live TV (a show called "Homework Hotline") . I got that job because as an Advanced Toastmaster,  experienced public speaker and award-winning teacher, I was able to present well on air.   Not that I didn't occasionally goof; I'm human.   Yes, there was a seven-second delay, and yes, a mistake would be edited in the video for distribution, but when you're on live transmission, dead air and wasted time are a no-no.  A lot of what I'm talking about in this post came from lessons learned on that show.

    I'm not going to embarrass anybody by linking to flawed presentations... but ooh, it's tempting! If you're a video presenter and you want me (and others) to watch your work, here are five things I wish you'd pay attention to when you do your video.

    1.  Show some life

    Please don't be just a talking head.  Show some animation.  If you look and sound bored, the chances are pretty good that your video will be boring.  But the chances are also pretty good that I won't know or care, because I'll be gone within the first 10 or 15 seconds.

    The Hotline hired teachers who could put some pizzazz into a lesson.  You need to do that for your video.

    2. Get Right Into Your Topic

    Our producer used to stress that "Air time is money! Don't waste it.  Get right to your material!"  Perhaps as a result of that,  I have come to hate presenters who waste a lot of time with long and irrelevant introductions.

    A guy bored by your video presentation.

    How I feel about  your video presentation.

    "Hi, guys, how ya doin'? This is Greg the curizan specialist comin' to ya from Upchuck South to tell ya all about how to dilate your curizan. If ya got a curizan that don't dilate and ya wanna know how to make it do that, I'm the man to tell ya. I picked up my latest curizan at a flea market in Upchuk North for ony a buck, but it didn't dilate right -- ya always gotta be careful with what ya buy in a yard sale, don't ya? So I had to figure it out and now I'll share that with you."

    And on, and on, and he's wasted several minutes telling me NOTHING but what I already knew about the video just from the title.   If you've picked your title well -- "Dilate Your Curizan by Greg", or "Greg Shows How to Dilate a Curizan" -- you needn't say much more.  You don't even need "Hi, how ya doin'?   Greg here again to talk about Curizans."  I know that already.

    Save me the trouble of fast-forwarding to where you say something important.  Get right into your topic.

    3. Have Your Props Ready

    For heavens sake, if you need props or samples, have them right at hand.   Our floor manager used to rips us a new one if we didn't have our lesson materials right where we wanted them and right when we needed them.

    You're your own producer and director and floor manager, so this is all under your control.  Your items can be off to the side just out of camera range, or on a small table beside you (also out of camera range) or even on the desk in plain sight.   Do some preparation, know what you're going need at each point in your presentation, have your props ready and in sequence.

    Above all, please, don't be dodging off camera to get something.  Especially don't make a comment while you disappear, "Shoot, where did I leave that?"  At the very least, edit the break for a smooth transition before posting your video.

    4. Don't Um and Ah.

    Speech hesitations, unnecessary interjections, false starts --"Um, man, like, you know, I, uh, got this curizon, and, like, it didn't work, you know"  ARRGH!

    You'll notice that professionals don't do a lot of this.   If you have your own Youtube channel and do a lot of videos, please review a few of your posts and take a count of the number of speech stumbles.    If there are more than a couple, plan to do something about it.   Take a speech class.  Join Toastmasters.  Get a friend to slap your face with a dirty sock whenever you do something like this.   For Canadians, it's that unconscious "eh?" at the end of our sentences that we don't even notice until our American friends tease us about it.

    It takes a little practice and training to break these speech habits,  but you can learn to speak fluently.

    4. Pay Attention to Pacing

    blah-blah-blah-clipart-1-jpgThis is a toughie that comes with practice.  I find that the average video presenter talks so slowly that I want to shake him (or her) and say, "Go! Get on with it!"  On the other hand, if you're rattling along like an auctioneer, I'm going to be missing some of what you say.

    Many sources give the average conversational speech rate as about 110 to 140 words a minute, but our listening comprehension goes much higher.  Trained professionals -- motivational speakers, newscasters, advertising readers--tend to be at the higher end, up to 160 words per minute (one study of Ted Talks found the average rate was 163 wpm).  With crisp, clear delivery and good enunciation, a speaker may be understandable at a faster rate, up to around 220 or even 240, but that's the upper limit for effective listening.

    Your goal is somewhere between the used car salesman's rapid-fire pitch and the kindergarten teacher explaining to the slowest students in the class.  Of course, the best speakers also vary their rate, just as they vary their inflection, for greater emphasis on certain points.  You can also do this in your video.

    But here's the rub:  Average reading speed is 200 to 300 words per minute, and faster readers can easily hit 500 or more. To a reader, your talking video is incredibly, frustratingly, annoyingly   s....l....o....w.   This is the main reason I hate videos: I can read your material in a fifth of the time it takes you to say it.

    5. Don't Tell Me -- Show Me

    "Show, don't tell" is a writer's dictum that also applies to videos. Most Youtube videos are telling me something (slowly) that I'd rather read (quickly).  The value of a video is when you can show me a process or skill or operation that can't easily be described in words.  If you're just telling, you can video a text screen that I can scroll past after I've read it.  Saves us both time.   But talking heads?  Pfui.

    I like Instructables because they generally use words and tagged images.  I can take those at my pace, as fast as I can  handle them.  But Instructables also sometimes include short video clips that show or demonstrate some particular point or process.   Those are truly worthwhile use of the video format, especially if they've been tightly edited to show only the essentials.


    Much of what I've written here is basic to any public speaking class, or is covered by a year in Toastmasters or a similar organization.  However, if you're doing instructional videos, you can improve your product -- your presentation--not only by taking courses or training but also by paying attention to what you're doing, being prepared, and simply working at being better.

    Further Reading

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