Monthly Archives: August 2012

Thing of the Moment – No-Hob Extruder

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

Building your own 3D printer is fantastic. You learn all there is to know about it and how to fix it should something go wrong. Most people out there can probably build a Prusa Mendel with a little bit of time and patience. There are however two parts of a 3D printer that I feel are the most difficult to produce for people wanting to get into 3D printing. Firstly is the hot-end – which often requires some metal turning on a lathe. Second is the extruder – or more specifically the ‘hobbed’ nut of the extruder. While it is possible to make a hobbed nut with a Dremel like tool – it is time consuming and fiddly. Now there is an alternative.

A user on Thingiverse  – profezzorn – has modified a Wade’s extruder to use nothing more then a Dremel #196 bit.

The Dremel #196 bit

Tools position in the extruder

Unlike a hand made hobbed nut this will have precisely spaced teeth and given that it is meant for cutting anything from wood to soft metals – it should have a good bite into the filament. Just be careful not to tighten it too much it might go through!

Links
Thingiverse Page

profezzorn’s Thingiverse Page

Dremel #196 Cutter

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A Year of Printing

Has it really been a year – already? Well according to my first tweet on this day last year it is!

I remember being introduced to the RepRap project a few years ago. The printer at the time was Darwin. I absolutely loved the idea of it – but the machine was a bit of a monster. Not only did it look huge and complicated – it also had a bit of a ‘bodge job’ electronics solution. When I read up on making the printer the electronics were the most confusing – seeming to take several different boards and then modify them for this application. A far cry from the need single board solutions we have at the moment.

The second iteration of the RapRap was Mendel – a far less cumbersome looking machine. This was then modified further into the Prusa Mendel. This basically looked like the Mendel but was easier to build. Since then there has been the Huxley, Prusa Air, Mendel Max and the Wallace to name a few. That doesn’t even take into account the other more commercial machines like the Thing-O-Matic or the UP!.

So in this year I have gone through over 4kg of filament (although about 750g is waiting for the Filabot so I can recycle it) – I’ve had to repair the printer several times (3 times for the heated bed!) and changed or upgraded several parts of the machine.

Overall it has been a great experience and being able to have an idea and a few hours later have the item in my hand is great.

image

My Huxley

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Thing of the Moment – Rostock

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

Think of a 3D printer and you will probably think of it having 3 linear axis’ x (left/right) , y (forward/back) and z (up/down) . When you want to move in one direction you move the axis that way. It’s simple and it works – which is why all the 3D printers I have seen operate in that way. But does it have to be that way? The answer would seem to be – no. Step in Rostock.

Up and Down
Like a conventional printer the Rostock has 3 axis – but that is where the similarities stop. On the Rostock the axis all go up and down. No left or right or forward or back. The axis are placed on the corners of a triangle and the print head is attached by rods connected by linear bearings on each axis. With the rods using universal joints they have a wide range of movement. To make the printer produce a straight line all three axis move at varying rates and varying speeds. To update the saying – a video is worth a thousand words:

At a Price
So why is it that not all printers are made this way? Well reading up it seems that geometry calculations needed to move the head even in a simple line are complicated. However this method does reduce the number of parts the printer is made from – about 200. It should be easier to build as well.

And I thought my Huxley was hypnotic to watch…

Links
Thingiverse Page
Documentation

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Video Page

I have now sorted out some of my videos that I have done of my Huxley. They can now be found under the Video page on the blog. I hope they may be useful, let me know if you think they could be improved!

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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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