I recently purchased a nice Fowler digital caliper from McMaster-Carr, and I have been very happy with it’s ability to take very accurate measurements.  It came with a very nice case, but unfortunately there’s nowhere to put the little 1-sheet instruction booklet that came with it.  After struggling with this for a few days, I suddenly realized that “I have the the technology”  – I could make a pair of small plastic parts to clip the booklet in place in the case lid!

The photos below show the case with the booklet clipped in place with my new PrintrBot Simple Metal parts, and closeups of the clips themselves.  The posts to which the clips are attached keep the  the caliper from banging around in the case, so I used them as the anchor points for my document clip.

Case with booklet under clips

Booklet Clip – left side

Booklet Clip – right side

I used my new calipers to obtain the dimension of the hold-down pedestals (sort of a recursive thing, using calipers to measure caliper case components?), and then I designed the 3D part using TinkerCad, exported the part as an STL file, and then printed it on my PrintrBot Simple Metal.  Total time from “Aha!” to finished parts – about 30 minutes! ;-)))

TinkerCad design for the Fowler Booklet Clip

OK, so now I have a running  (sort of) PrintrBot and some projects I want to print, but first…

Went  through the PrintrBot guide “Setting Up Your Auto-Leveling Probe and Your First Print” procedure.  This was a little scary to start with, as the hot end was really close to the bed (and HOT!)  and the Z-axis sensor wasn’t much farther away.  Eventually I got this done to the point where I was ready to start some trial prints with the supplied starter filament, with the usual terrible results ;-).

First attempt at a bicycle clamp part (side view) – ugly!

First attempt at a bicycle clamp part – ugly!

Then I tried printing the  pre-sliced fan shroud  project from PrintrBot, and this came out much  nicer

PrintrBot fan shroud – now happily installed on my PrintrBot

This convinced me that the PrintrBot was operating properly, and so I had to look elsewhere for the reason that my bicycle clamp project was faring so poorly.  As it turns out, I had the Repetier settings all screwed up, and once I got them more or less squared away, I got a much nicer print (still not right, but nicer).  My first decent try (center in the photo below) showed me that I had some sort of scaling problem, as the printed part was significantly smaller in all dimensions.  At first I thought this was maybe a PrintrBot mm/mm stepper motor scaling problem, so I tried just scaling up the model by 115% in Repetier, resulting in the print on the right in the photo below.  This still didn’t look (or measure) correctly, so I was left scratching my head.

Original part on left, first try (way too small) in center, scaled by 115% on right

So, I decided to do what I should have done all along, and attack the problem methodically (well, I  am a professional engineer, after all!).  I downloaded the 20mm hollow calibration cube from ThingiVerse and printed it. This experiment started with an STL file, which was then sliced and diced in Repetier, thereby testing the entire STL – Repetier – GCode chain.  The result, as  shown below, convinced me that both the Repetier and PrintrBot parts of the system were working properly.

20mm Hollow Calibration Cube

Unfortunately, there were only two things left in the system – TinkerCad where I created the 3D model of the bicycle clamp, and the person (that would be me) who created the model.  After a couple of quick experiments with models of known dimensions, it rapidly became clear that TinkerCad was not at fault – leaving only the nut behind the wheel as the causal factor for the errant dimensions.  In my defense, I really didn’t have a good set of calipers, and the measuring tools I did have were all calibrated in inches, so I plead for mercy from the sentencing judge (I did jump on the McMaster-Carr site and order a decent set of mm/in digital inside/outside/depth calipers).

By the way, I have been using my wife’s really nice Canon ‘PowerShot’ SX260HS digital camera for this work, and I’m really pleased with the results.  It’s super easy to use, and produces 3000 x 4000 pixel images – way more than enough for everything I need.  Easy to upload photos via the built-in USB connection, too!  In fact, I’ve been using it so much that my wife has pretty much given up on ever getting it back ;-).

Stay tuned!

Frank

I’m just now getting into the exciting new world of 3D Printing.  It is pretty clear that the entire DIY 3D Printer is wildly chaotic and changing at a very rapid pace.  This reminds me a lot of the early Personal Computer days (when the term ‘Personal Computer’ meant something that could fit  onto a normal-sized office desk!). In those days, PC makers appeared and disappeared on a weekly (if not daily) basis.  I remember buying a ‘Columbia’ PC  (named because the company was located in Columbia Md).  Its claim to fame was portability – if you wanted to think of a 30-40 lb package as ‘portable’!  Almost all of these PC manufactures were gone in just a few years, I suspect the same thing is going to happen in the 3D printer market.  I wonder  if there will be a Dell and/or a Microsoft/Apple of 3D printing, or if the entire industry will go off in another direction entirely.  One thing is for certain though, we are witnessing the dawn of a new era that will completely remake  global industry and society.  You can’t download pizza yet, but you *can* download the designs for, and print, just about anything else!

After doing some research into the many many offerings out there, I decided to go with the PrintrBot Simple Metal Kit.  I have a pretty strong background in Electrical Engineering, and can find my way around basic construction toolboxes, so I figured I should be able to handle the kit and save some buckazoids in the process.

The kit construction turned out to be very straightforward, and the kit instructions on the web were pretty complete.  I did have some minor problems when it turned out that a late addition to the kit (a small DC-DC converter PCB for the inductive build-bed sensor) wasn’t referenced in the kit build instructions – oops!  A couple of quick emails to the PrintrBot support team, and some judicious Googling got me the information I needed to correctly integrate the new part.

In any case, here are some photos of my  completed Printrbot Simple Metal.

My first 3D printer – a PrintrBot Metal Simple Kit

Underneath the covers. Note the extra white cable tie mounts

After getting the PrinterBot completed, of course I now had to actually *do* something with it.  This required me to learn the software side of the house, and it too is a bit of a wild-west ride at the moment. It is entirely possible to design a part (or capture a 3D model from uploaded camera still photos) without paying a cent for software.  For initial 3D design, Autodesk has 123D Design, 123D Catch, 123D Print and TinkerCad (recently purchased).  The Autodesk apps come in standalone and web-based flavors, with the exception of 123 Design (which is being shut down due to problems with the required plugins) and TinkerCad.  All of these have their own ‘special’ learning curves, complete with a wide variety of bugs and gotchas.  Using any of them requires a *lot* of patience to work through missing functions and random crashes.  However, notwithstanding all the problems, the functionality of some of these apps is simply amazing, especially considering it’s all free! From nowhere to actually usable in just a few years (or months!).  For 3D printer management there is Repetier-Host – again free for the basic model.  This app accepts STL files from the design side and manages the process of ‘slicing’ the model for a 3D printer (using one of a number of plug-in ‘slicers’) and then sending the ‘G code’ instructions to the printer itself.  All in all, a hugely confusing (but exciting in a masochistic sort of way) landscape littered with bugs and obstacles on the way to that perfect 3D print.

Stay tuned!

Frank