First to forth test prints
I have put the E3D hotend together (really easy to do if you follow their instructions) and installed it on the printer. Since then I started to do some test prints. I started with a 20x20x4mm piece. The extruder worked brilliantly however the printer had an issue, the Y axis kept offsetting (see first print above – ignore the waviness, I was impatient and pulled it off the bed while it was still hot). I turned up the power of the Y Axis stepper driver (second print). Same issue, again ignore the blob that was my fault. The Y Axis is quite heavy and I thought that the stepper was still missing steps. The stepper for the extruder has a slightly higher torque so I wanted to swap it for the Y Axis motor.
I removed the extruder motor and then started on the Y Axis. As I removed the motor I noticed that the pulley came off too easily. Oops I forgot to put the screw to clamp it to the motors shaft! So what I think was happening was the motor turned but didn’t have the grip on the pulley to move the mass of the bed. I finished the pulley with the nut and bolt and reattached the two motors. Voilà, it worked correctly as shown in the third and forth prints above.
X Axis pulley slip visible on the left print
While I was writing this I was printing out a 40mm dome. It finished printing and a similar thing was happening to the X Axis. It isn’t visible on the above prints as they didn’t go high enough for it to manifest. A new pulley was printed on my Huxley as the old one wouldn’t take the captured nut correctly. As you can see above there was some significant slippage although not as severe as the Y Axis had.
The last thing, which should have been the first, I wanted to do was to do a bit of PID tuning for the hotend. Using the auto PID command M303 in Marling I was able to set the PID to: P 26.84, I 2.48, D 72.57 should anyone be interested in using them as a base for their E3D hotend.
Just in case anyone is wondering the domes were made with Faberdashery’s Aurora UV colour changing filament.
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.
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!
profezzorn’s Thingiverse Page
Dremel #196 Cutter
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.
Filament Frame Thingiverse Page
Parametric Filament Frame Thingiverse Page
Okay – so I may have forgotten that I had some filament (Bling Bling Gold from Faberdashery) that had fallen down and I had forgotten about it. On doing a clear-out I discovered said filament and thought I would use it in my latest adventure – stands to display my Game Boy cartridges. Unfortunately that wasn’t to be.
Anyone will tell you to store your filament correctly – that is in a bag and maybe with some desiccant. Don’t store it randomly behind the unit your printer is on! Not entierly sure what has happened but when I went to insert the filament into the printer a section snapped off. Strange I thought – carry on and try again. It done it again. Hmm. I then looked at the filament and saw this.
If you look at the top of the filament you can see that there are really small ‘cracks’ in it. This is the point where is breaks. I am assuming that the filament has reacted with the air or moisture to have resulted in this defect. Although it looks more like the filament has dried out.
My Fault not Yours
I must say that this is the only time I have ever seen this from filament from Faberdshery. This is also some of the oldest filament I have as well. Had I stored it in a bag would it have faired better – I can’t say. However storing it outside of a bag will not help keep it in top condition either.
Let this be a lesson for everyone at my expense . Care for your filament and you will get some long life out of it. This is also a positive for Faberdashery’s ethos of only buying what you need when you need it, don’t try and store/horde it. I cannot blame anyone but myself for this – I should have put it away when I had last used it – now I have to bin it. Well – put it into recycling ready for my Filabot! (When I get one that is!)
While I was browsing eMakers forum I can upon a post of somewhere to buy cheaper filament. I ordered some from Reprapkit.com at £49.90 for 2.3Kg. That price has now gone up – £62.37 – as they are out of pre-order – that said the listing is confusing stating they have stock but still on pre-order! Anyway back to the filament.
From the East
The filament seems to be made in China, I hadn’t realised this when I brought it and got a little worried having read in the past of people having issue with filament from there. So far I have printed two sets of my Mini Rack and not had any issues. Not to say that it is totally perfect either. Before we get the the bad stuff…
The Good Stuff
The filament is very good – it feeds well and the finish is shiny. There have been no problems with it stringing etc.
However – as I have said – there are a negatives. The main one being that there seems to be a lot of moisture in the filament. This leads to some popping and spitting at lower print speeds – mainly on the first layer as it is printed slower. This leads onto any print that has a low feed speed – mainly those of a lower layer height – however I suppose you could simply increase the print speed.
But in the end
Considering this costs 6.5p per meter its faults so far are easy to put to one side. It sticks well, looks good and is cheap. It may have a little to much moisture for slower prints – which reduces its ability to work with thin layers – but its cheap making it great for test prints or prints requiring large amounts of plastic.