Evolution of a Blog

This blog has evolved as you can tell by comparing the title with most of my recent posts. The title should really be something like "The Physical Interface Side of Computing". Actually, more recently it would be "3D Printing and all of its Trials and Tribulations". Anyway, it will still feature Raspberry Pi and Arduino from time to time but my current hardware of choice are a Wanhao Duplicator 4S and an Ultimaker 2. Just before that it was a BeagleBone Black with JavaScript and Node.js providing the development environment!

Saturday, September 26, 2015

Is there enough filament for my print?

This is more of a "doop" than a "eurika" but it finally occurred to me that my luggage scale can quite easily be used to tell me exactly how much filament is left on the end of the reel.  Like I said, doop, not eurika!

Weigh the reel of filament, subtract the weight of the spool, subtract the weight of the filament that is unusable (Ultimaker specific to it's feeder), compare to the grams needed for the print from the slicer.

This is a particularly accurate measurement now that I have standardized on one size of filament and in most cases to a single manufacturer of filament.  Historically I had a number of different spool sizes and hence weights.

Hey, I did say this was a doop not a eureka!

3D Hubs Pricing Model

Below is a table that illustrates the various resolutions that can be selected for my printers on 3D Hubs.  This chart makes the relationship between the cost of a print and the selected resolution obvious in the terms of time being money!

To choose the appropriate resolution first select the material, in the below case, PLA.  Once PLA is selected, and you click on color, you will then see a list that has colors separated by a label that indicates the resolution.  The first entry for black would be the highest resolution, and most expensive, with a layer height or 0.06mm.

I will print in whatever resolution you order...however...it is hugely important that you understand the impact of layer height on how your print will look!   Please see this post for pictures of various resolutions.  In general the lowest two resolutions should be avoided for anything other than a very basic draft, or in some cases, for a large and simple model.

Finally, I am interested in specialty filaments but have only had an excuse to work with one, that being Colorfab XT which is a carbon fiber reinforced type of filament.   If you are interested in some other flavor please let me know as I may want to try it for the experience!

Friday, September 18, 2015

Some Progress on 3D Scanner

Having printed most of the parts for the scanner it was time to start assembling a breadboard version of the electronics.   My intention is to do a custom PCB that will mount as a daughter board onto the Raspberry Pi but a working breadboard comes first!
Unfortunately...it is not working!  The stepper motor runs but the lasers are not firing.  Here is the stepper motor doing its thing at the command of the RPi:
I finally assembled a cut down version of the circuit so that I could more easily work with just the problem bits, and even more importantly, so I could get some help from the SoliForum.

I had been told that the laser does not get connected to ground at least once before I finally decided to listen!   In any case it now works.

Tuesday, September 15, 2015

Starting a New Project - Building a 3D Scanner

I have no idea what I will scan but it seems like I should have one anyway.  I am not doing any original work here as everything that I need is in the public domain.   I will be doing a little bit of derivation work but not much.

There is a kickstarter
project out there that gave me the idea:

ATLAS 3D - The 3D Scanner You Print and Build Yourself!

It is based on a Raspberry Pi.  There is also a variant of the same kind of scanner that is based on an Arduino but basing on the RPi lets you scan without occupying a host that would be needed to drive the Arduino version.

In either case I have most of the stuff that I would need to build the scanner.   I have a Raspberry Pi and camera.   I have a stepper motor and a stepper driver.   I have a 3D Printer to generate all the parts!  I have various and sundry bits of electronics and a couple of power supplies.

What I do not have, and will have to buy, are some threaded steel rods (and bolts and washers), a couple of small electronic bits, and a giant bearing for the turn table.

The derivation that I have in mind is to create a circuit board that will ride on the Raspberry Pi as a daughter board.  This will entail some changes to the structure of the scanner to handle this change.

Here is where I am at after a day or two.  Printed parts for the base and found the stepper motor.

Printing the end where the camera and electronics live...that is a big piece of plastic!  BTW, the parts are intentionally not very pretty as I am using a layer height of 0.4mm for speed.

Started to assemble the breadboard to prototype the PCB.

Started to design the PCB.

Wednesday, September 2, 2015

First "Real" Part Done in ColorFab Carbon Fibre

I had printed a part using my new steel nozzle and the carbon fibre reinforced filament from Colorfab but it was sort of a force fit in terms of requirement.   In fact it really didnt work!   This one, however, is legitimate.  I am not entirely sure how tough it will actually be as I have not done a test to destruction but it looks nice.   I really do like the look and feel of the print.

One Last Tank Post (Honest)

I had to do a reprint of one of the tank models using the 0.25mm nozzle with a layer height of 0.08mm.   This is approaching, but not quite at, the best quality that my Ultimaker 2 can produce.

I could have printed this model with a layer height of 0.06 and, while I do not have one, there is a 0.15mm nozzle for even finer tiny details.  I printed at 25mm/sec so I could also have slowed down some.  However...this print already was going to take over eight hours so I left it at pretty darn good ...

... EXCEPT ... for the quality issue that I have that left some gaps on the top fill.   I can easily tune this out but it was too late for this print!  Frustrating!

Just to be Clear on Size!

Other posts in the "tank" series: 

Second Order was for a Tank!
Tanks, Tanks, and More Tanks!
Some More Tanks
Removing Support from a Tank Print
Tired of Tanks Yet?
Visual impact of Resolution (Layer Height) and Speed

Monday, August 31, 2015

Printing ABS on the Ultimaker 2 with Fan Running

The art of 3D printing is a balancing act.   On the Ultimaker 2 the fan comes into play as a particular challenge when printing ABS.   In my experience you need a fan to achieve good quality on details when printing ABS, whether on the Ultimaker 2 or my Wanhao Duplicator 4S.  I have read that others can achieve quality prints without the fan by ensuring that print temperatures and speed are low enough to allow for cooling that the fan can provide.

There are downsides of low temperature and low speeds that a fan can help avoid.   Low temperatures can lead to problems with bonding between layers and low speeds are just too slow!  I also find it to be a struggle to hit my low temperature target without undershooting ... and when you are printing that low of a temperature that can lead to a bad layer or a nozzle jam.   This is even though I use Simplify 3D and hit my target temperature by lowering a degree a layer.

The above picture illustrates the challenge that I, anyway, experience.  The best looking Marvin (center) was printed with the normal Ultimaker 2 fan running starting from layer 2 at 60%.   The total mess in the front was also running with those parameters and the fan combined with poor first layer adhesion resulted in a pop off from the build platform.   The Marvin on the left was printed with no fan and the one on the right was printed with my Ultimaker 2 fan modification described earlier.

I think that I can adjust my fan modification to replicate the quality of the center Marvin and still avoid the fate of the Marvin in front.  It is all a balancing act that requires extreme levels of patience though!