Machine Start-Up Procedure

We will begin the start-up procedure with the assumption that the machine has been shut down for a weekend. This type of start-up is referred to as a cold start. Initial preparation is required for the injection moulding machine to warm up and reach its operating temperature and to fully stabilize machine components.

(i) Start-Up

To start the process:

1) Allow the hydraulic pump motor to run for one to two hours before the machine cycle begins.

2) Start any auxiliary equipment such as heaters and chillers. Also turn on the barrel and nozzle heaters. Be sure that the mould is closed all but 1/4 of an inch and that no tonnage is on the mould.

· Most injection moulding machines have a protection device that prevents the screw from turning until at least one of the heater zones reaches the set point temperature. Other machines require that the heats be on for some minimum amount of time (usually 15 minutes) before they allow the screw to turn. This protects the screw from any damage that could be caused from the initial starting torque.


3) To begin the moulding process, spray the mould with a small mist of mould release.

· Mould release may not be needed for medical or food applications or when the cavity has a high-surface finish.

4) While in the manual mode, close the mould and check the clamp tonnage and mechanical settings.

5) Open the feed throat to allow plastics pellets to enter the screw and barrel assembly.

· Jogging the screw motor on and off allows for a slow start-up of the motor. The screw moves backward until it reaches its predetermined setting.

6) With the purge guard, take several air shots and wipe the nozzle drool with a brass screwdriver or spatula.

Bring the injection carriage forward, and slowly jog the tip until it butts up against the sprue bushing.

Special Note:
Be careful not to slam the carriage into the sprue bushing because damage to the nozzle tip or sprue bushing may result.

7) With the machine in semi-automatic mode, allow the mould to complete one full cycle. Repeat this procedure until an acceptable process is developed.

8) At this point, place the machine in automatic mode and carefully monitor the process to be sure that the parts do not hang up. Allow the machine to cycle for 10 to 15 minutes.

9) Visually check the parts to be sure they are filling completely and that there is no sink or flash on the parts. Weigh the parts and be sure that the weight is consistent from shot to shot.

10) Once the parts are visually acceptable, check them for dimensional accuracy.