Home

EVA (Ethylene / Vinyl Acetate)

Typical Machine Settings: Subject To Polymer Grade

Nozzle

Front

Centre

Rear

Barrel Temperature

150 - 220oC

150 - 220oC

140 - 210oC

130 - 200oC

Melt Temperature

150 - 220oC

Must be measured with a pyrometer by taking an airshot through the injection machine nozzle.

Hot Runner Temperature

155 - 220oC

Mould Temperature

15 - 40oC

Injection Rate

Slow

Specific Injection Pressure

700 - 1400 Bar (10,000 - 20,000psi)

Screw Back Pressure

3.5 - 7.0 Bar (50 - 100psi)

Screw Speed

Slow

Processing Features

Structure

Amorphous

Specific Gravity

0.94

Viscosity

Medium

Medium runners can be used

Shear Rate Susceptibility

Medium

Medium gates can be used

Temperature Window

Medium

Needs accurate & stable control

Residence Time

Medium

Aim for short residence time

Start-Up Precedure
  • Ensure all heaters are thoroughly baked dry - do not rely on brief ‘soft start’ systems to do this.
  • Fast Heat controllers automatically and safely bakeout wet heaters - ask for details.
  • Turn on water lines to stabilise tool and manifold temperatures.
  • Turn on manifold control zone(s) and allow to warm up until measured value is within 10oC of setpoint.
  • Now turn on tip zones and allow to settle at setpoint for 5 - 10 minutes before starting production.
  • Take an airshot from the machine barrel and check that the melt temperature is correct.
  • Start moulding parts on a semi-automatic cycle until suitable machine settings are established.
  • Avoid lengthy delays between cycles during this setting procedure.
  • Switch to automatic cycle when parts are being produced, and fine tune the machine settings

Shut-Down Precedure

The machine and mould may be shut-down normally, without cleaning the EVA from either the barrel or the hot runner.