Monthly Archives: June 2012

Hot Under the Collar

The most problematic part of my 3D Printing experience has been the hot end assembly. I have had it jam, the fan stop working and the Bowden tube pop out of more than one occasion. Today I am trying to find the fault in the hot end again. I have been trying to print some items for a company (my first commission!) and there is one part of it that starts to print and about half way through the hot end appears to jam and then the Bowden tube pops off. At first I thought it was the connector – I have had problems with that before. So I replaced it. Started the print up again and the same thing happens.

Could it be that something is blocking the nozzle – I ask myself. To find out if have removed the nozzle, rigged up a simpleimage aluminium foil holder and baked it at 210C for 20 minutes. Unfortunately that didn’t work. I resorted to a combination of heating with the gas stove, using a 1.7mm drill bit to push the remaining PLA through and then a 0.5mm bit to clean out the nozzle. I also used the larger drill bit to clean out the connector as well.

Another thought occurred to me, what if it wasn’t the nozzle at all, what if it was the print it had been doing? I had been using Slic3r to produce the gcode, something I noticed was the large number of retracts it was doing as it infilled. image In this image you can see the infill but the greenish colour is where it moves without extruding – you can see there are loads of them – and every time it doesn’t extrude while moving is another retraction. So I switched back to Skeinforge. image It had done a better infill without the retraction and also I didn’t have the jamming either. I have reported my findings into the Github for Slic3r, I hope it is something that can be fixed.

Update
And no sooner had I reported the problem then it had been sorted! Just have to wait for the next pre-compiled build to be released.

Links
Slic3r
Skeinforge

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Filed under Musings

3D Printing with Pie

Yesterday master 3D Thingsmith RichRap posted a tweet that he had got Printrun working on his Raspberry Pi. For those who don’t know the Raspberry Pi is a single board computer based around an ARM processor and Linux and is very cheap – about $35. image

Mainly it was designed to try and get programming of computers back into UK schools – something that has dropped off in favour of just using software. Why is this event remotely interesting? For me it is being able to fully control my Huxley without having to have my main computer running, consuming a maximum on 7 watts rather than a minimum of 120 watts!

ARM Slicing?
The more interesting thing is if RichRap has the slicing software going to. To be honest it would be painfully slow, unless somehow it used the GPU to help with the computing – and that is unlikely!

Make one yourself
RichRap has said that he will be putting a blog post up on how he done it – allowing anyone with a Pi to be able to follow. Once they are up I will attempt it myself and report back!

Links
RichRap Blog
Raspberry Pi Website
Raspberry Pi and RepRap Discussion

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Filed under Things of the Moment

Simple Slicing with Slic3r

Can you get to print faster with Slic3r?image There is a general workflow I use for printing in 3D, you design your item, you slice it and finally print it. Originally it was the second step that would take the most time for me as I was using Skeinforge. That was the slicing software of choice for eMaker – and still is. It produces arguably the best prints out there at the moment. But it is slow – really slow.

Bytecode to native
Skeinforge is slow as it uses the Python scripting language. As I understand, Python uses the bytecode method to execute the scripts. This means the the code is translated and run in a virtual machine. It is the virtual machine that then runs the program. This is what slows down Skeinforge. So the new kid on the block is a program called Slic3r. This is programed using PERL and then compiled to run on Linux, Mac and Windows natively. As an example I sliced the model “Ducky Swimming” using Skeinforge and Slic3r. Skeinforge took 18 seconds to complete whereas Slic3r needed just 2.4 seconds – that’s 750% faster. Taking a more complicated model the “Babylon 5 – Starfury“. Slic3r was in at 38.97 seconds and Skeinforge was 8 mins 18secs.

It can safely be said that Slic3r is much faster the Skeinforge. Another advantage with Slic3r is it’s simplified interface. Skienforge as many plugins that means up to 180+ variables that could be entered many of which aren’t exactly clear as to what they do – although you don’t always need them all. Sli3cr on the other hand has about 60 and most have a clear simple English title.

Quantity over quality?
Does this speed come at a cost? Slic3r does a very good job overall with prints, even having some little tricks to reduce the blobs you get from printing in PLA. Another function of Slic3r is the ability to specify different print speeds for different parts of the print. So you can choose to have the outside shell printed slowly to get a good finish and the infill printed faster to reduce the print times.

Simple setup
image Once Slic3r is installed on you computer – and by installed I mean the ZIP file extracted to a location of your choice – you can run the program. A window will open and be filled with a standard compliment of settings. Before you load up your first STL there are 3 setting you need to check:

Nozzle Diameter
Filament Diameter
Filament Temperature

That’s it! You can now load up a STL file and get ready to print. Although that is the minimum you need to do, you may wish to look at other settings to help you produce better prints, my suggestions would be:

Layer Height (I normally run at 0.3mm for a 0.5mm nozzle)
Perimeters
(2 for most prints)
Solid Layers
(3 for 0.3mm layers, more for thinner layers)
Print Speeds
Travel Speeds
Start and End G-Codes

RepRap community member RichRap has written up on his blog a more in-depth look at Slic3r and its settings – link at the bottom of this post – it is excellent and well worth a read.

Now the bad news
Slic3r is very much under-development – as given by it’s 0.7.2b version number. There are some areas where it isn’t able to match Skeinforge. The most obvious one is when a STL has a thin wall. If an object has a wall of about 2-3mm Slic3r will only do the outside shell – when set with my 0.5mm nozzle – sometimes it will ignore walls altogether if they are less then about 1mm. I have got around this by reducing my nozzle size in Slic3r to 0.49mm and that seems to solve some of the problems. Neither does it have Skeinforge’s ease at switching to different profiles.

But in the end
For 95% of my prints I use Slic3r. It is fast and generally produces good quality. It isn’t perfect yet, but it is being developed and many of the issues get ironed out fairly quickly. Not bad for what seems to be a one man programming ‘team’!

But there’s more! (Update)
Since I wrote this Slic3r has been updated to 0.8.2. This has been a significant update that has seen the addition of a pattern plate to help print multiple objects as the same time. Another feature is to move the start position of each layer reducing the lumps on a side/corner up an object. Internal perimeters are now printed outside first to help with overhangs. There are a number of other changes which I will look at covering in another post.

Links
Slic3r Website
RichRap Blog
eMaker Website

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Super Secret Super Bright Summer Filament

image I was quite lucky to get a sample of Faberdashery’s new summer colours, and as you can see below they are, well, summery! The colours are very bright luminous red and yellow.

Is it the usual quality?
As always the filament is of an excellent quality and consistent diameter. It isn’t apparent from the photos but they really are bright. Both colours seem to shine in the sunlight, ideal if your project needs to be seen! The next thing to decide is what to print that honours the summery goodness and tests out the filament. Not much more is summery to me then enjoying a glass of chilled wine with friends. Tracking your glass is a bit easier with these Wine Glass Charms. I chose the bright yellow and they printed well, actually it seemed to be a bit more viscose then other PLA which didn’t cause any issues.

image

It hasn't changed colour, the camera just didn't pick it up right!

Glowey
Another thing that I noticed is that they glow under the the blue leds that illuminate my print bed. Given that these are luminous it isn’t surprising that the little ultraviolet light from the leds cause them to glow.

image

Nice glow under blue leds

image But in the end
Unsurprisingly the filament meets the usual level that I have come to expect from Faberdashery. So if you have anything that needs to be bright, bold and colourful then these could be the filaments for you.

Links
Faberdashery

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