Evolution of a Blog

This blog has evolved as I have as a maker. It starts at the beginning of my journey where I began to re-tread my tires in the useful lore of micro electronics and the open-source software that can drive them. While building solutions around micro-electronics are still an occasional topic my more recent focus has been on the 3D Printing side of making.

Friday, February 28, 2014

Calibration, calibration, calibration

equals iteration, iteration iteration.

The most extreme of the overhangs was the most challenging, and in fact, is still not perfect.  Interestingly the only way I was able to get it as far as it is gotten was to print it sideways and have another object printing above it so the fan plays on it more than if it were printed alone.

Tuesday, February 25, 2014

It was all going so well

Until the stepper gremlins showed up.   My printer is eating Pololu Stepper Drivers.  At 8 quid each.

I got a new stepper yesterday and after carefully plugging it in and doing an initial test everything was hunky dory. It was running at .4v as measured between ground and the trimpot. My other steppers are all at .5v but I thought I would start lower as opposed to higher. So I print some calibration objects and everything is still hunky dory. I print a fan holder in white cause the one I am using does not match the rest of my parts. It prints fine. So I print some more calbration parts as I am iterating iterating iterating. Everything fine. I go to bed. The printer does as well.

We both wake up this morning and I go to print another calibration test. The printer gets a short way into the print and the x-axis skips. I checked the voltages again and every thing was as I had left it. I have adjusted the voltage up on the x-axis and am reprinting and everything was working for the first 60 or so layers then the x-axis slipped again...though not nearly as much as above (2 cm versus 2mm).


Nothing changed between last night on the x-axis. I did tighten the y-axis timing belt but that is the only change. Could that have caused enough additional current pull from the y-axis to cause the x-axis a problem given my lower amperage adjustment there? I am concerned because, as stated above, I seem to be eating steppers and this working, not working behaviour, has been observed before!

I am calibrating for layer consistency on x-y axis. Looking great on the Y-axis and all but two layers of the X-axis. Then I can work on the whiskers.

Tuesday, February 18, 2014

3D Printer - Some Improvements

Here is a photo of my printer as it stands today.  I have integrated a number of customizations that I will talk about a little below.   One of the distinct advantages of going the RepRap route, as opposed to buying a packaged printer, is this ability.

One of the first 'useful' things that I printed.  I decided that the filament was dragging on the top of the printer so figured this would help reduce friction.  It seems to help.
Not exactly an improvement that I came up with since the printer shipped with the fan.   I did have to print the mount though!  Yes, those are cable ties instead of bolts.   Not the best print job on the slanted bit of the mount either.   That aspect of printing is still eluding us.
This is an improvement that I found on Thingiverse.  It makes it dramatically easier to level the bed.   Rather than fumbling with a wrench or pliers and a socket driver.  There are a number of designs out there so take a look.
There are two improvements shown by this photo.   The spring cord is for the x-endstop and it is also helping to keep the x-servo control lines out of the way as the z-axis descends.  The other improvement is the easy adjustment for the bed height.   This may actually have been the way the printer was supposed to be assembled as there was a hole in the x-servo mount that I was able to exploit.   It makes it very easy to raise or lower the build platform...single spin of the grey thingy.
I will write more about this later, but, this is the biggest addition to the printer.   I want to offload printing and am going to use a Beaglebone Black attached to a 7-inch LCD.  The BBB can run Slic3r and Pronterface in their graphical forms but too slowly for my patience.   I am going to continue to slice my prints on my iMac and use a custom app running on the BBB to drive the Printrun command line printer controller.   The app is not quite done but is written in Javascript and Node.  It automatically picks up files from the iMac and queues them for printing.  The interface allows access to the same functionality as Pronterface but on a touch screen with a remote control (which you can see in front of the printer on the first image).   The web interface can also be run from anywhere else on the network, including from my iPad.  The app is at the 80% point now but needs some cleaning up.   Once it is functionally complete to a first version I am going to add a couple features including a webcam to watch the print bed.   The case and mounts are, of course, prints!

A recent change to make it easier to change hot ends.   Not as eloquent as some implementations that use a plug but easy.

New Hot End - WRONG SIZE!

Decided that a spare hot end should be on hand so ordered one from China.   Takes a while to get by which time my current hot end has become clogged.   I need that spare.   I go to install it so I can clean the original and ALAS it is a 3mm hot end not a 1.75mm!  Doop.   Have had great luck working with vendors in China so am sure I will get this resolved but the timing is a challenge.

Tuesday, February 11, 2014

3D Printer - Calibration

This is part of a series of posts describing my adventures with 3D printing, and specifically, with a Prusa I3 RepRap Kit.   The first of the series is here. This post will talk briefly about calibration.   Briefly because I don't have much to say on the topic other than a) it is important, b) it is a pain in the ass, and c) it seems never ending (to me at least)!

I am still not done calibrating though I am happy enough with where I am that I have printed some reasonably large parts.  I think that I can still get more even layers (I think that stability of the build area is my problem here) and I still can not print steep overhangs as well as I think the printer is capable of.

My primary resources for this task are from the RepRap wiki and are as follows:



...to here
Print Troubleshooting Pictorial Guide

From here...

In a zillion adjustments with more to come!

Monday, February 3, 2014

3D Printer - Comments on 'The Kit'

This is the final in a series of posts describing my adventures with 3D printing, and specifically, with a Prusa I3 RepRap Kit.   The first of the series is here.

There were some goods, bads, and uglies associated with this kit (as a review by Greg discusses on the 3D Printer Czar website). 

First, the ugly, NO INSTRUCTIONS!   I know that this is being worked on but kits should not be shipped without instructions unless there is a clear understanding by the buyer that this is the case.   Even then there would be some things that would have helped mitigate frustration.  First, provide some high quality photos of an assembled printer taken from multiple angles!  Second, provide some links to the most relevant variants of this particular printer where instructions do exist!

Next, the bad.   As Greg stated in his review there were some missing parts in my kit and the wrench that was provided was one size too small to actually fit anything!   In my case at least some of the missing parts might be due to a customs inspection as the printed parts bag was open and parts had spilled from it.  

Finally, the good.   This kit really does provide excellent quality parts for what I think is the best variant of all the Prusa printers and at a very reasonable price.   I could not find a better price for the Prusa I3 with Ramps (though I did find a comparable price with a Sanguinololu board.   I had also priced out the sourcing of parts outside of a complete kit and the end price would have been pretty close to the cost of this kit.   I would also say that the support of my build from Han in Hong Kong was pretty good considering that he is probably pretty stressed out by having to answer questions that documentation would circumvent! 

The bottom line...if documentation is available for this kit buying one is a no brainer.   Good quality parts, a great variant of the Prusa I3, and literally everything you need in one nicely packed box (save a region specific power cord).   The kit even comes with the glass for the heated bed which many kits do not. 

The above is what I wrote as a product review on the 3D Printer Czar's website.   Here are some more observations from my build:
  1. The smooth rods for the z axis are 1cm too long.  I had to drill a hole in the upper supports for the rod to protrude...otherwise it would have blocked the servo by the same amount.
  2. Unless I am completely off my rocker some of the areas where you think that a 10mm bolt should work...there is not enough room (as in the bolt does not protrude from the other side).  I have been forced to use the longer 16s and of course ran out of them and used some of the 25s which of course I then ran out of them.   I am getting some more bolts but I think it is another thing for you to look at. 
  3. The tie-ties provided don't fit any of the holes where they are intended to go.   I had smaller tie-ties that I was able to use but even these did not fit on the x-axis carriage.   I used bare wire here and wrapped it tightly to secure it.  I guess, in all these cases, I could have expanded the slots but I found the alternative tie-ties and wire easier.
  4. I was missing the parts that connect the z-axis servos to the threaded rod that drives motion on that axis.  I was able to do a work around using shrink wrap tubing and some cable ties that worked (and continues to work).
  5. The kit comes with the fan for the extruder but not the printed part that would allow you to mount the fan!   Not a problem as I printed one but a good note for the instructions...or just include that part!
  6. Pointing the buyer to a version of a firmware configuration file that matches this printer would be a nice idea!
Finally, even when the documentation is done, I would STRONGLY recommend that the Czar add a forum feature to their website.   All support requests should be channeled through that medium.  That way the questions that I ask may not need to be answered again as another user might see the answer.   In addition, while active in the build process, users might actually help themselves!  There are plenty of free alternatives out there that could meet this need.

3D Printer - Electronics (and Firmware) Integration

This is the second in a series of posts describing my adventures with 3D printing, and specifically, with a Prusa I3 RepRap Kit.   The first of the series is here

Installation of the electronics was pretty straightforward.   This variant of the I3 has support panels that extend from the back of the x- and z-axis plane that provide structural stability and a handy place to mount the power supply and electronics.  My only complaint on this mounting was that the holes did not seem to line up with anything but it could just have been me!

The kit comes with some connectors intended to be crimped onto the wires leading from the servos, end stops, and thermistors but I quickly discarded those in favor of simply soldering the ends of some leads that I already had as I simply did not have the patience to do the tiddly bits work.  I have since ordered some nice connectors and am retro-fitting them.

The photo of the electronics shows both my soldering of leads to avoid the crimping of fiddly bits and also a couple of the nicer connectors that I am retro-fitting (the one that says end stop)!

At this point I connected one of my host computers with the Arduino IDE to the printer so I could mess with it's firmware (or Arduino sketches to be more precise). 

Configuration of the firmware provided a larger challenge, again one that documentation would have helped me to avoid!   There are a plethora of choices of firmware for the Arduino/Ramps hardware and somehow I ended up choosing Marlin.   I don't regret this decision I just can't claim any science behind it!

Marlin is driven by a configuration.h file that allows you to customize it's function to your exact hardware configuration.  Some of this is pretty easy such as choosing your board!   One other  parameter caused me a little more trouble.   DEFAULT_AXIS_STEPS_PER_UNIT was key to getting things moving!   This provides the number of steps per unit for each of the servos.   By default the x and y are fine but the z and extruder were way off.   In particular the z as it was so low that my z-axis was barely moving when running the hardware integration test (results of which are shown below).

Sunday, February 2, 2014

3D Printer - Mechanical Build

Completed Printer
This is the second in a series of posts describing my adventures with 3D printing, and specifically, with a Prusa I3 RepRap Kit.   The first of the series is here.  A picture of the completed printer is to the right.

Here are the parts, somewhat organized, with the parts list from the kit.   I did not do a complete item, by item, inventory but wish that I had for a number of reasons.   First because I was missing a couple parts and second as it might have helped me avoid at least on mistake!

The first piece to be built was the frame of the y-axis.   Did I mention that at the time of this building 3D Printer Czar had not completed their assembly instructions?   I found some for a Prusa I3 on the web and used them.   Did I mention that one of the characteristics of the open hardware source world of the Prusa that there are multiple versions of the Prusa I3?

Which I discover to my chagrin as I start connecting the box frame for the y-axis.   Note that it is a rectangle and all the rods are the same length on a given side.   Just like the one from the instructions that I found.   Unfortunately not like the one the Czar wanted me to build.   Had I done a good inventory I would have known that the frame was supposed to a longer rod to connect to the back of the support frame and I would not have taken a hack saw to a part that I then had to source a replacement.  Naturally, having assembly instructions, or at least high quality pictures, would have also helped!  Anyway, here is the completed frame with the hot bed platform in place.  Speaking of this platform...it was not exceedingly obvious to me how it was supposed to be mounted to the bearings.   Turns out that it just sits on them and is secured with cable ties.  You can't have too many cable ties of different sizes especially as those in the kit did not fit!

Here is the y-axis with the longer rod replaced and with the y-axis servo in place.   The timing belt has also been installed anchored on the bottom of the car that will drive the hot bed and looping through the y-axis idler at one end and the servo motor at the other end.

Now it was time to start on the x- and z-axis frame.  The three bearings will support the extruder assembly.  

At some point it was going to be necessary to tackle the extruder assembly so I got right on it.   This is the completed extruder ready to be mounted on the x-axis car. 

The major mechanical components of the printer were now complete and needed only to be assembled.   The y-axis carriage slides into the x- and z-axis assembly and is bolted into place.  Finally the acrylic support and stiffening pieces are attached to the x- and z-axis assembly ready for mounting of the power supply and electronics.

Here is the printer with all of the mechanical bits attached.

The next post in this series covers electronics and firmware integration.

Saturday, February 1, 2014

3D Printer - Adventures with a Prusa I3 RepRap

What has an Arduino with a giant shield on top of it as a brain, five giant servos, moves in three axis, and can replicate itself?   Not exactly a robot but a 3D printer.   Decided that I absolutely had to have one.  Knew that I wanted to build a kit, both to save some money, and for the experience of it all.

Did some research on the various kits out there and decided on the Prusa I3.   The Prusa I2 or Mendel seems to be one of the most popular kits out there and the I3 is an easier to build, improved version, of the Mendel.   Then started to look for places to buy one.

On Arrival
You can buy the pieces individually getting the hardware and frame from one place, the electronics from another, and the printed bits from yet another.   You can even source the hardware yourself.   I decided that buying a complete kit was the way to go.   I also decided that I wanted a RAMPS based printer.   Options were starting to get limited.   I ended up with buying from the 3D Printer Czar in Hong Kong.

As Assembled
The kit was $500 with another $80 for over night shipment to the UK.   This was less than any other kit that I had found.   I ordered the kit on New Years Eve.   The shipment promise was within seven days and it shipped within that window on the Monday after New Years Eve.  It arrived in the UK the next day and then the waiting on the government began.   Two weeks later it had finally freed itself from customs and the tax man and after paying my 80 quid of taxes I got my printer kit.

I am going to describe the rest of this project in a series of posts covering the following:
Obligatory Owl
In the meantime, here are two videos showing the project at the point of some initial calibration and then doing a first large print:

In Action

Printed Spares and a Filament Roll Stand