步骤 4
采用正确的螺杆转速
Select the correct, optimum screw speed for the material being processed (see T.01 notes, Section 5 ). Use this single speed for the whole plasticising stroke
Set a back pressure of 5 to 10 bar (hydraulic).
Readjust dosing stroke to achieve 95-98% fill
Take sixteeen consecutive mouldings and determine the standard deviation of the weights.
Print out:
Page 50 Process Statistics
Why is it important to use the manufacturer’s recommended screw speed?
13
STEP FOUR RESULTS
Insert actual values in the relevant boxes Weight without holding pressureWeight with holding pressure Percentage fill Standard deviation (16 shots) Mean value Rangeminmax Dosing time (mean and range) Melt cushion (mean and range)Screw stop position (mean and range) Injection time (mean and range) Peak injection pressure, P inj. max Injection pressure at changeover, PN press. Changeover stroke % g 14
STEP FIVE
Optimise screw speed and back-pressure profile
Use the Dosing Profile page to slow down the screw rotation speed for the last 10% of the metering stroke.
Readjust dosing stroke to achieve 95-98% fill
Take sixteeen consecutive mouldings and determine the standard deviation of the weights.
Print out:
Page 21 Dosing Profiles Page 50 Process Statistics
What has happened to the Dosing Stop position?
15
STEP FIVE RESULTS
Insert actual values in the relevant boxes Weight without holding pressureWeight with holding pressure Percentage fill Standard deviation (16 shots) Melt cushion (mean and range)Dosing time (mean and range)Mean value Rangeminmax %g Screw stop position (mean and range) Injection time (mean and range) Peak injection pressure, P inj. max Injection pressure at changeover, PN press. Changeover stroke 16
