Tuesday 4 June 2013

Recline further

I decided to persevere with Recline and try to fix some of the problems.

Following an invitation from Sublime to try his calculator (see the comments in Recline), I learned that my setup could work better at 0.2 mm layer height if I increased the extrusion width from 0.4 to 0.48 mm. That should certainly help to improve layer bonding somewhat.

I also reasoned that the delamination in the first print had been caused by excessive part cooling with the fan. I know, I know. ABS isn't supposed to need a cooling fan but I still believe that with steep overhangs it just prints a bit better with one; I just had it turned up a bit too high.
The next problem to work on was the fingers. I started another couple of prints and both times the fingers failed again. Something different was going on here.


I thought about this for a long time and eventually came up with three ideas for possible solutions.
Firstly, the way that I had splayed the fingers out made the overhang angle more than 45 degrees. Changing the pose slightly to make the fingers more vertical should help.
Secondly, I had changed the support gap setting in Kisslicer from 0.5 mm to 1 mm to try and make it easier to break away; I suspected that this was actually making the support less supportive, so I put it back to 0.5 mm.

Finally, it dawned on me that the only thing supporting the fingers was the weak interface layer attaching them to the raft. This hadn't been a problem with Curl because there were relatively large areas attached to the raft but this print was quite literally clinging on by its fingertips, and in the end the lateral drag of hot plastic from the rapidly moving nozzle was proving too great for the weak bonds. The solution for this print was to abandon the raft and find a better way to get the fingertips to stick to the bed. 

One option I considered was to print the model on a plinth. This would provide the strongest and most reliable base but wasn't really in keeping with the rest of the series so I decided to keep it in reserve. 
Eventually I resorted to my favourite method which has worked well in the past. I went back into Blender, opened the model in point edit mode and used 'Box select' to highlight all the points in the bottom millimeter of the model and then used Scale Z 0 (zero) to flatten the bottom of the model and finally moved all the selected points up a little to the most natural position.
A liberal splash of ABS juice on the printbed and I was ready to have another go.

This time it went much better. No serious delamination at all and the fingers are looking much more solid. The left thumb appears to have shifted and reconnected at the base, but this should be relatively easy to repair.


Now I just need some time to do the support removal and acetone vapour bath.





Wednesday 22 May 2013

Recline

Here's my new project.  I've started a collection of potential sculptures on Pinterest and, having printed several curled up models, I fancied trying a more open, reclining pose like this one.  I have now discovered that this is one of the 'Square Nudes' series by Carsten Witte.


The amount of support material required should be fairly minimal although the steep angle under the upper back may need some.  Additionally, the palms of the hands are raised off the ground and will also need supporting. 
Another of the challenges will be to deal with the area where the thighs and calves will inevitably overlap after posing the model.

More to follow ...

Turns out that I still haven't quite got this 3D printing lark completely sussed yet. The modelling went quite well. I even broke with tradition and tried leaving the mouth open a bit to allow the front teeth to show. This, in turn, meant having to devise a different technique for closing off the open edges in the mouth area.




As usual, I opted to use Kisslicer to generate the gcode because I still find that it produces the best support material. The problems started when I began to print. In spite of the fact that I was using the same settings as I have for all my other prints (ABS at 240C, 0.2 mm layer height, 0.4 mm line width), the extrusion seemed thinner than usual and the inter-layer bonding was poor. The model finally appeared from the build chamber with several large cracks including a complete break in one of the arms.


The other major problem was that the fingers appeared to be poorly formed and looking as though they might come away with the support material. I haven't tried removing the support yet, due to lack of time, but I really don't hold out much hope for saving this print. 



One of the factors that has changed is my new hot end which has a 0.4 mm nozzle, whereas my previous one had a 0.5 mm diameter hole. Slic3r includes a place to enter the diameter of your nozzle but apparently Kisslicer does not.  I have never quite understood the logic of this, so I don't really know whether it could be a possible factor in explaining the latest failure.

I'll probably give it another try and maybe just turn up the flow rate a bit.

Sunday 5 May 2013

girl-6

You may remember that I found some interesting pictures on the CG Artists forum. One of the was called a painting by Edward McEvenue based a photo called girl-6 by buzillo.


I had a go at printing a model of her in the grey ABS which I had been using recently but was disappointed to see that the print was badly split in several places.

 

I have been reading about some people who have been experimenting with printing in a new nylon material called Taulman 618. One of the claimed advantages is its superior layer bonding with greater resistance to delaminating. I thought I would give it a try.






So, what are my first impressions of printing with nylon?
Positives:

  • No odour
  • Sticks well to blue painter's tape even on a cold bed
  • Nice smooth surface with a lovely sheen
  • No delamination at all
  • Much more flexible (less risk of breaking)

Negatives:

  • Support material is harder to remove
  • Strings are tricky to remove
  • No way of smoothing the surface yet
  • Much more flexible (less statue like, more bendy toy)

Will I be using it again?
Definitely!


Bridge printed

My test print of Bridge was successful at first sight, but on closer inspection the leotard had been only partially printed, particularly across the back where it was rather messy. In other places, it was a completely separate and rather fragile layer which started to come away as I removed the support material. So, in summary, my first faltering steps with printing clothing had been a bit of a failure. I decided to try and recover an otherwise good print by breaking away the remnants of the leotard.
A bit of scraping with a knife and an acetone vapour bath later, and I had another nice looking model.











Before removal of support material and leotard fragments




Friday 26 April 2013

On show in London

If you are lucky enough to be able to attend the opening of the new iMakr 3D Printer Store in London  on 30th April keep an eye out for these two pieces which are currently on loan and should be on display. Let me know what you think if you see them there.




Oh, and look out for me as well. I'm planning to be there too!

Check out this video of the iMakr shop. You can see these two sculptures in the background at 1:30.
http://www.bbc.co.uk/news/technology-23499822 

Monday 22 April 2013

Bridge

I've been seeking inspiration for my next prints. Pinterest has some interesting collections of artistic nude photos (although it claims that it doesn't allow them) and I'm sure I will choose one of theirs soon. However, another great resource is DeviantArt, a site I have followed on and off for some years. It was there that I found a great shot by TarMoo called Art Nude Symmetry.



It's quite a striking photo which inspired me to try and reproduce the pose which I have decided to call 'Bridge'.

With its minimal points of contact and absolute requirement for support material, it was clear that I would need to start with a raft and, ideally, print in ABS. Whilst photos can only be seen from the specific angle selected by the photographer, sculptures can be viewed from any angle chosen by the viewer. Unusually for me, I decided that this particular model deserved a leotard to protect her modesty. I'll see how the print turns out and decide whether to do a fully nude version later.
The model in this photo has her hair in a simple bun which works well for this image. I tried making a bun but I didn't like the look of it. I also tried short and long hair styles but they didn't really work with this heads-down position. At the moment the model doesn't have hair but, again, I may decide to review this after the first test print.