Home

CA (Cellulose Acetate)

Typical Machine Settings: Subject To Polymer Grade

Nozzle

Front

Centre

Rear

Barrel Temperature

185 - 230oC

185 - 230oC

175 - 220oC

160 - 200oC

Melt Temperature

190 - 235oC

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

Hot Runner Temperature

195 - 235oC

Mould Temperature

40 - 80oC

Run at upper end of range for best surface finish.

Injection Rate

Moderate To Fast

Specific Injection Pressure

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

Screw Back Pressure

3.5 - 13.5 Bar (50 - 200psi)

Screw Speed

Moderate

Processing Features

Structure

Amorphous

Specific Gravity

1.27

Viscosity

Usually Low

Small runners can be used

Shear Rate Susceptibility

Medium

Small to 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 CA from either the barrel or the hot runner.