Tag Archives: slic3r

Dual-Struder Fabricator (DSF)

3D Mockup

For some time I have wanted to design my own printer. Partly so that it will be able to do what I want and secondly for the challenge. Obviously it is much easier these days given the number of designs out there. For my design I had several things that it must be capable of:

  • More than one extruder
  • Use as many of the same vitamins as possible
  • Be simple to construct with the minimum of tools
  • Use as many printable parts as possible
  • No Bowden tube

Now I am not above thinking that some of those ideals may have to be altered but so far, in the planning stage, I think I have hit all of them.

So taking each point in turn:

It currently has space for two extruders – I wanted at least two so that I can leverage Slic3r’s ability to have one extruder for the shell and another for infill. That way I can use Faberdashery’s great colours for the shell and a cheap bulk black or white for the infill. The current extruder/hotend design means that only around 50mm of Y axis is lost when using both extruders.

Each axis uses the same linear bearings, all the printed framework attaches using M4 bolts, bearings used in the belt idlers as used in the extruders and so on. I want to not have a BoM as long as your arm and be able to order from only a few places. Personally I think this is the ideal that will change as the build progresses.

The tools that I think will be needed are screwdrivers, allen (hex) key, wire cutters and a wrench. Again this will probably change as the build progresses.

All structural support parts are printed, only the obvious items aren’t (frame, smooth rods, threaded rod etc).

No Bowden tube for the extruders are used. The current design is for a direct drive extruder – the hobbed bolt is directly attached to the stepper – which reduces the size of the extruder and reduces the need for large gears. The actual reason for no Bowden tubes is purely down to I want to print flex-polyester and I haven’t been able to get it to work through my current Huxley’s Bowden. I am considering having one direct drive extruder and maybe replace the second with a Bowden system to reduce carriage weight. This would also allow for another hotend to be potentially added.

So there is my design. I have put the files up on Thingiverse and have ordered (and received) the extrusion for the frame. I am currently printing out the main frame components to begin building.

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Thing of the Moment – Filament Swatch

Thing of the Moment is where I find something of interest to print, either useful or fun!

Recently I have been printing things for people. One of the problems has been trying to describe all the colours that I have available to print with. Over a period of time I seem to have a large variety from Faberdashery! While going through Thingiverse I found filament frame – by uBlitz – to hold small samples of the filament I have. The original was designed in Solidworks so was a static model – nothing could be changed aside from editing the STL file (I don’t have Solidworks). Then I noticed a derivative – by MarcoAlic – which is parametric using OpenSCAD. The first print didn’t go so well. Although it was set to make 1.75mm diameter holes they just weren’t big enough to hold the filament. The second problem was that the outside wall was just 1mm and Slic3r didn’t like that. In the end I adjusted the OpenSCAD script to reduce the size of the cylinders a little – 1mm overall and entered a filament diameter of 1.9mm. This sorted the problem.

On the whole I think it turned out okay. Now I can simple show people what I have rather then trying to describe them.

Links

Filament Frame Thingiverse Page

Parametric Filament Frame Thingiverse Page

Faberdashery

Slic3r

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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)
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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