Support material suggestion - Grease is the word!

I have had a look throught he forums and I cannot see anyone who has suggested using grease as a support material.

Has this been tried? I can see that there are several reasons why this could be useful.

Advantages:-
1) There are hundreds of types of varying viscosity and greases that can stand very high temperatures and have stable viscosity.
2) Grease is easily applied through a syringe extruder. I imagine a second head alongside the plastic extruding head depositing material through a 0.5mm nozzle.
3) Grease can be reused without issues.
4) Grease could be mixed with metalic powder to increase the viscosity if required. Clay is also sometimes used in grease to increase viscosity.
5) Its cheap and readily available.
6) Nozzle drip and stringing can be avoided due to the high viscosity. Automatic grease applicators are used commonly in industry. Google for Companies such as Dopag to see examples.
7) Could be used to produce a split line in a part. A layer of grease could produce a fine natural split line. Grease is sometimes used in mould making as a release agent between mould halves. (See disadvantage 3 below).

Disadvantages:-
1) Messy, particularly whilst developing the machine.
2) Difficulty in cleaning the finished part. Probably requires a detergent.
3) Smearing of grease across the surface where plastic is to be extruded upon causing a weakness in the part. Software would need to avoid approaching the part across the plastic surface.

... for FDM-fabbing you need something adhesive the molten plastic can bond to - here grease can't support the bonding.

For Paste-dispensing it could work, but then ist's easier to mix different pastes perfect suited for the special needs, than working with 'simple' grease too ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

I agree a support medium where plastic can adhere to would be an advantage, but is not always needed in many situations. For example in horizontal holes it would remove the need for pointed 60 degree tops by only providing support as there is already deposited plastic very close. It would also be useful for long horizontal bridges.

With careful support design you could probably overcome even those limitations. Vertical bars of ABS interspaced with grease could support most shapes. The vertical ABS bars would be thin enough to remove easily from the finished part. For example in figurine the fingers of a hand could be supported by tall vertical filaments 0.5 diameter surrounded by grease.

The grease could contain plastic dust or fine beads which may make abs stick, for example polystyrene (not the expanded variety, but the material used in plasticard) sticks well with ABS.

I envisage the grease to be quite thick maybe somewhere between toothpaste and warm modelling clay......hmmm toothpaste that gives me another idea... minty flavoured parts anyone!

How about playdough?

Just tried to extrude some ABS wire at 220 degrees C onto playdough and although it didn't stick, it also didn't melt or soften any more like plasticine (English Clay). Playdough is wheat based, I wonder how it extrudes and sticks to itself.

Interesting. I think playdough would stick to itself as long as the extruder was close to the surface. If it doesn't, I am sure you can make your own playdough that will. You can make your own playdough with flour, salt, water, and oil. This would be a super cheap support material, and it would be reusable. It is almost like bread dough.