HDPE

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High Density Polyethylene

A strong, cheap, durable plastic with a solid melting point of 110C.

HDPE Is one of the more finicky plastics to extrude. It does not stick together well, and because it shrinks a lot when it cools tends to distort readily. Experiments with a roasting bag suggest this may be partly prevented by depositing in a warmed environment. The novice is encouraged to use ABS or PLA before attempting HDPE.

To extrude plastic pellets into filament, extruder temperature must be set around vicat softening temperature according to producer technical specifications (for example around 123-130C). Filament is quite extensible when not yet cold; if the coil that collects the filament "pulls" the filament too much, filament does not break but the section will be reduced significantly.

HDPE shrinks and detaches from the plate; a solution of diluted vinyl glue or a plate of polypropylene (Moplen or CD covers) may solve the problem.

The adventurous could also try a ABS HDPE blend which may have very good results.

Printing Settings

Print settings may vary depending on the supplier. But if the material is not added, in general terms the temperatures work in a similar way:

Print Temperature: 200 to 250 ºC

Bed Temperature: 100 to 130 ºC

Print Speed: 20 mm/s

Cooling fan for small parts is also recommended. Air flow tested was 5 CFM normally 60% of a regular 5015 fan.

For the adhesion to the bed we have applied PP packing tape to the glass. In another test we used PP board from an old CD case. In observation, the first test with the tape worked better since it has better transmitted the heat in the first layer. You can also print on paper or cardboard.

Larger and longer objects are likely to have more warping.

Material Properties

  • Resistant to high temperatures;
  • High resistance to tension; compression; traction;
  • Low density compared to metals and other materials;
  • Waterproof;
  • Inert (to the content), low reactivity;
  • Nontoxic
  • Poor dimensional stability
  • Density (ASTM D792) 0.955 g/cm3


Can be used to be in contact with chemicals such as bleach and alcohol.

Filament Production Sequence

For the production of 1.75mm filament, it is necessary to dehydrate at 65 ºC for 7 hours.

The hopper must carry a weight inside to maintain the same flow.

Production Temperatures

Temperatures may change depending on the machine:

  • hopper Feed : 30ºC
  • Back : 125 to 130ºC
  • Middle : 205 to 210ºC
  • Front Nozzle : 200 to 215ºC
  • Water cooling after nozzle at 45ºC

Caution!

Do not touch the material after melting, this material maintains the temperature for a longer time, and when touching this material while still hot it can cause severe and deep burns. If you have never printed, before printing in HDPE you must use PLA or ABS. This material is difficult to print not recommended for beginners.

Suppliers

  • Canada | filaments.ca [1]
  • Portugal | reprap.pt [2]

Also check the forums... someone might be able to ship you some for cheap.

You can also make your own see Recyclebot

otherwise see Printing Material Suppliers

More info on Wikipedia.

Further reading