Tuesday, 19 December 2017

Christmas Advent 3D Printing #Day 18 Advice using E3D Acrylic (PMMA)

December advent calendar - modular Christmas tree
3D Printing advice #Day 18

For the background and introduction - Day #1 Post click here

Last time - For Day #16 (Christmas 'Unicorn' Poop Emoji) was printed using a collection of Polyalchemy Elixir colours.

Christmas Advent 2017 Download on Thingiverse here - designed by Tom Van den Bon  With some help for each day by the South African Makers team.


It's time for Day #18

Day 18 gift is designed by Tom Van den Bon -  Is a Popsicle (Ice lolly / Ice-pop)


Ice-Pop printed in E3D Acrylic (PMMA) filament (with a light cream PLA stick)





I bought my Acrylic filaments from E3D, they don't seem to have it in stock at the moment, but I could see it fitting into their range in the future. I would not quite put it in the 'here be dragons' section, but it is tricky to use.

Acrylic (PMMA) is not an easy material to 3D Print. Just try to look for it, it's not made by many manufacturers, and not many people report on using it.


Big 1Kg rolls - need to be kept airtight and away from sunlight.




Acrylic is however a very stiff, impact-resistant, strong and resilient material to use for many applications.

Firstly, Acrylic will warp like ABS, you need a heated bed running at 105 Degrees C.



I purposely used a lower printing temperature (see advice below) for a frosted look to my Ice-Pop.

Next you can't print onto a normal PEI surface, even with gluestick or Magigoo applied.
It will not stick to PET or Kapton tapes, ABS likes these, Acrylic does not.


The secret to successful 3D Acrylic printing is to use a heated blue tape build surface.
The only surface I have found to work well for printing Acrylic parts, both small and medium-big sized objects is 3M blue masking tape. You must still use a 105 Degrees C heated surface with blue tape.



Always use a super-sized Brim for printing with Acrylic - regardless of size.

The next thing you really need to do with all parts, regardless of size is to have a good brim on the first layer (see above image). I used a 4mm brim on this small object, no warping or de-lamination.



Day 18 tree section is printed in Polyalchemy Elixir.


Print advice - (Acrylic - PMMA)

What settings did you use? - Acrylic is probably one of the trickiest materials you are likely to use. (unless you get a particularly naughty Nylon) It's really not a material you can just pop in any 3D printer and use all that easy.


But I do really like using it for 'special' objects. So if you do give it a go, here are some tips and advice - 
  • You will need a pinch of salt
  • 100g of flour
  • 1-3 hippopotamus  - to taste...
  • 3M Blue masking tape (it will not print on most other surfaces)
  • Must use a heated bed 105 Degrees C (or 110 if you can get that high)
  • 140% width on first layer
  • First layer speed set to 35% of normal print speed.
  • 3 perimeter (shells)
  • Over 20% infill level on most parts unless you are doing 'spiral vase mode'.
  • 270 Degrees C first layer.
  • 250 Degrees C all other layers - for a frosted-acrylic look.
  • 265 Degrees C all other layers - for a more clear look.
  • 272 Degrees C for spiral vase mode - most clear
  • Fans off for first 4-6-8 layers depending on layer height (0.1 / 0.2/ 0.3)
  • Fan at 55% max for printing (normal 25%)
  • Always use BRIM, and make it around +5mm even for printing small parts.
  • Print at ~35mm/sec print speed - for everything apart from support structures & first layer
  • Try not to use support. It's just asking for trouble.
  • All other settings - just as per normal PLA
Why use it? - It's a very tough material. You can further work, sand, drill etc. very, very flexible and strong. Recreus also now make different grades of soft and super-soft materials, so now you have even more choice.

Is it strong? - Yes, but when 3D printed it has a weaker inter-layer bond. You can help the bond with high printing temperatures and slower speeds, but this is it's weakness.

Is it easy to use/print - No it's not. But don;t let that stop you from getting hold of a sample to try, it is really good for some objects - dolls house windows, strong vase / bust style models.

Do you have to dry it before/after use? - Yes/No - it should be good from the sealed pack, but keep it dry, and away from sunlight. Dry if required - if it's still frosty even at +270 Degrees C.

Do i need a 'special' nozzle? - No it's not abrasive at all.

Does it smell when printing? - Yes, it smells of acrylic :) - Just like cutting a sheet of 'perspex' (Acrylic) using a jig-saw - it's smells just like that (not all that nice, but only a light odour)

Does it come on a eco friendly spool? - No :( They are generic plastic PS spools...

Conclusion for E3D Acrylic- I hope E3D decide to stock this again, I want to carry on using it for projects. Acrylic is great for printing dolls furniture, or other model parts. It's harder to use than (for example - PET based materials). If you can handle printing in Nylon, you should be able to use Acrylic.

Days 1 to 18 of the Advent Christmas Tree.

Day #18 is completed. 

Today's story is going to be about Kacie Hultgren (Pretty Small Things) I always think of Kacie when Acrylic is discussed. Kacie designs, makes and sells the most amazing period dolls house furniture you are likely to see (many are printed and sold in Acrylic). 

I have talked at various 3D printing shows about Kacie's work and her story. From self training in 3D design, to using Makerbot 3D printers, and running a successful 3D printing business, Kacie is one of the early pioneers who captured 3D printing to help do what you love. I have no direct interest in dolls furniture, but I do really enjoy telling people about such a talented designer.


Join me next time for Day #19

Thanks for reading.

Rich.

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