Friday 8 December 2017

Christmas Advent 3D Printing advice #Day 7 Prusa Easy ABS and Filamentive RPLA

December advent calendar - modular Christmas tree
3D Printing advice #Day 7

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

Yesterday - Day #6 Post (Christmas Stocking) was printed in Chroma Strand Labs INOVA-1800 and Filamentive Recycled RPLA 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.

Day #7 is with us, and today the gift is designed by Andries Smuts-  It's a water bottle rocket.

Water bottle rocket (modified for easy print) in Prusa - Translucent blue glitter 'Easy ABS-T'

For Day 7 I would like to see some blue start to appear on the advent tree. I also wanted an easy material, but not just PLA. So this little rocket is printed in glitter-sparkling translucent Prusa Easy ABS-T material.

I don't usually like using ABS material. The smell/fumes are very uncomfortable for me. But I have found that Easy ABS-T from Prusa Research does not cause any problem for me at all. It has almost no smell and is easier to print than 'standard' ABS.

This particular ABS-T filament also has a few special features you don't often find in ABS materials, it's translucent (light blue) and it has glitter sparkle.

Printing advice - (Prusa ABS-T)

My first step of advice here is to make life easy for yourself. Just because a model has been designed and intended to be printed in a single part, it does not mean you should try, or struggle to print it like that.

This original model has a very small surface contact area with the build platform. You can use rafts, and a brim along with support material if you need. 

Original Rocket design has a tricky first layer with minimal contact area.

Model cut in half. This will be a much easier print.

My outlook with 3D printing is always to make things easier, so I just cut it in half and I will bond back together at the end.

There you go, a much easier print, just what I needed after yesterday.

I'm still using a brim of 4mm around each part, this is just good practice for ABS materials, even small parts.

You will see in the image above I'm also printing onto a section of tape. This is a small length of PET tape stuck onto the build surface. Just for ABS printing. 

The heated bed is running at 100 Degrees C, but even with that, you may have some difficulty printing onto different print bed surfaces.

This particular ABS (and others too) does not like to print onto a PEI build surface. ABS materials may also not be happy with a glue-stick coating or Magigoo. I know the only surfaces I can use successfully are PET or Kapton tape for this ABS-T. 

Still use a brim as this is quickly removed after printing and will get you a good first layer bond.

Glitter in the 3D printed layers stands out well, quite tricky to photograph.

If you do have adhesion problems, you can consider using a raft. As I don't use ABS very often I prefer to use PET tape, you can also peal it off and use again, and again.

When the print bed cools down, the model will just lift off. You then need to remove the brim (and raft if you decided to use it).

I flame the edges to remove white 'bruise' marks from ABS brim removal.

ABS can get white bruise marks when you peal away brims, or bend parts. My next top-tip is a quick and easy fix for removing any remaining white marks or sharp edges after brim removal.

One of the reasons I did not want to just enable support material was that this particular ABS (being translucent) will show up any marks of support removal on the surface of the finished print.

I simply use a flame / lighter very quickly move around the edge, this will slightly melt and remove white bruise marks. 

Parts after 'flaming' ready to be bonded together.

I slightly overdid the flaming in this image (I was trying to take the photo and do it at the same time).
But don't worry if you slightly round the edge, the next step will correct most of that.
Now I need to bond the two parts together. You can use superglue, but I use acetone applied with a tiny paint brush.

Two parts bonded together with acetone and a small brush - don't touch and let it dry.

Paint on the acetone (Nail varnish remover if that's all you can get) to each surface. Wait a few minutes and place them together. Hold for as long as you can until you get bored.

The two parts should bond and you can run an acetone dipped paintbrush around the join, ideally around and across the print layers to help 'weld' the two surfaces.

When dry the finished part should be strong and maybe slightly more glossy because of the acetone 'wash'. ABS can be smoothed with different acetone processes, but I'll leave that up to you.

Obviously do be careful if you decide to do any of this, acetone / nail varnish remover is flammable. Always wear gloves and eye protection. The 100 Degrees C heated bed for ABS printing is a higher temperature than most other materials require. Take care.

Now we have the finished parts for Day 7 in our advent tree. 

Was it easier than trying to print it as the single original design? Yes, for me even with the extra steps, it was.

What settings did you use? - Use For most ABS materials you need a 100 Degrees C heated bed, some even higher (120/130/140) Be careful! 

This Easy ABS-T is actually quite happy at lower than normal ABS temperatures (220+ Degrees C) 

I print this ABS-T range at 245 Degrees C (you can go slightly lower, but I would recommend 220 or more - up to 255).

Print speed was slowed down for this model (30mm/sec) because it has a number of tiny features. ABS is quite good at hot layer-on-layer printing. PLA for example is more likely to turn small features into blobs, if printed too fast without adequate cooling. - This is the reason I selected ABS for this model.

Why use it? - This is the most easy to use ABS I have ever discovered. To be honest I'm not exactly sure why. I have never directly asked the Prusa team (how/why/what), but it's my choice whenever I do decide to use ABS.

You can also print quite big with this ABS, some other ABS materials will warp and de-laminate badly with objects ~60+ mm wide

Is it strong? - Yes, It's a strong plastic. It has a higher glass transition temperature than PLA, and it has very good impact resistance. ABS plastic is often used in many objects. 

Is it easy to use/print - Yes - as long as you test and make sure you have a good print bed surface, sonething that this ABS will stick too. Then it's plain sailing. Use just a little fan cooling, (or none) it's really not required for most/all objects.

Do you have to dry it before/after use? - No. For some reason this ABS does not seem to have any problem at all with moisture. Drying it out would not hurt and may give even better performance, but I just keep it sealed in a bag with desiccant as normal.

Do i need a 'special' nozzle? - No, it's not abrasive, I have used it with all different sizes of nozzle from 0.25 to 1.6mm - It will work fine with Stainless, Hardened steel, Copper, Ruby or Brass nozzles. This particular reel has glitter so do remember to use a 0.4mm nozzle or bigger if it's loaded with sparkle.

Does it smell when printing? - No. I can't detect any significant smell at all using it at any temperature from 220 to 255 Degrees C. It also does not make me feel sick (other ABS brands do).

Does it come on a eco friendly spool? - No, :( It's on a generic virgin plastic reel. No recycle logo and no marking of material type. 

Conclusion for Prusa Research Easy ABS-T (Glitter) - It's the only ABS I can use without discomfort. It also happens to be really easy to use (I guess that's why they named it Easy ABS) and it's well priced too.

Day #7 Is Completed. That was easy, I hope you learned something new?

The story for today must be about making 3D printing life easier, for both you and your 3D printer. If it looks tricky and you don't want to risk supports, then chop it up into easier to print parts. Simple.

Join me next time for Day #8

Thanks for reading.


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