Tag Archives: software

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!

RichRap Blog
Raspberry Pi Website
Raspberry Pi and RepRap Discussion


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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)
(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.

Slic3r Website
RichRap Blog
eMaker Website

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