Introduction to MuCell®

Graeme HerlihyManaging Director – Engel UK

MuCell® equipment | insert gas into the melt

MuCell® barrel + MuCell® Interface Kit

MuCell® Gas dosing unit

Gas distribution

Why foaming of thermoplastics?

• lighter

• more accurate

• more economic

MuCell® | foaming of thermoplastics

• Foming agent

- N2 or CO2

• “Internal“ homogenous post-pressure

- no sink marks

- minimized warpage

- weight saving

- clamp force reduction

• Viscosity lowering

- due to physical foaming agent

- optimised filling of cavity –

new mould and filling strategies possible

MuCell® | foaming of thermoplastics

Strategic benefit | capacity use

MuCell® | reduced cycle time

Source: Trexel

Reduced cooling time

More exchange,

Less temperature

Hold time (nearly)eliminated

ΔT

Solid

MuCell®

Pack&Hold CoolingInjectionOpening/Eject./Closing

ΔT depends onmaterial type,part design andmould cooling

Cycle time reduction | optimized cooling is the key

Hot spots | optimized cooling system required

hot spots – optimised cooling system required

MuCell® | clamp force reduction

Strategic benefit | lower tonnage

• Reduced filling pressure

• No “external” holding pressure

Surface quality | surface defects

streaks on part surface

Optimazation |

• special material grades

• higher injection speed

• variotherm mould heating

• IML

• gas counter pressure

• coinjection (core foammelt - skin compact)

• …

Filling process | creation of streaks

MuCell® | applications

• volumetrically filling of the cavity

• increasing the cavity

- by clamp unit or by mould internally

• foaming inside the cavity

MuCell® + decompression stroke | function

part

thickness

time

platen

screw

mould closed

serial precision opening(parallelism controlled)stroke

MuCell® + decompression stroke | advantages

• low density achievable

• higher bending stiffnessat same part weight

• equal cell structures

• insulation effect

plate PP T20

- starting wall thickness 3 mm

- final wall thickness 10 mm

half shell PP T20- starting wall thickness 8 mm- final wall thickness 16 mm

Introduction to MuCell®

Graeme HerlihyManaging Director – Engel UK