injection pressure set on the injection molding machine controller

Hello everybody!!

Gentlemen please tell me, in my injection molding machine firm Bole (China) injection speed is set in%:
1. How to convert percentages into volumetric or linear injection rates?
2. The injection molding machine is designed for the maximum injection pressure (hydraulic system pressure) of 140 MPa according to the passport. I limit the pressure on the control controller to 120 MPa, why does the manometer show 1200 psi or 8 MPa?
3. If the pressure controller is set at a pressure less than the injection speed (in%), for example: 1-stage 20 MPa; 60% injection rate - is this correct?(photo 1)
4. On the photo 2 the handle of the temperature regulator nozzle. How do you set the temperature on the nozzle?Attachment 273Attachment 274

Hello Ulynovsk,

1. There should be a way to change the settings in the machine to give you linear or volumetric injection rates.
2. You don't want your process to hit the high limit pressure in most cases. Typically you want to stay below the high-pressure limit and maybe the mold you are running only needs 8 Mpa to fill the mold. You also might need to calibrate the sensors on your machine. I guess it would help to know what pressures you expected to see during injection. If your machine reaches its high limit set point, it stalls to get below that pressure, this causes flow hesitation and other problems.
3. If I am reading that correctly, it looks normal. What you are saying in your example is "My first stage of fill will use 60% of the rams maximum speed and will not exceed 20 MPa's in injection pressure". So if the machine can reach 10 inches per second, it will inject at 6 inches per second and stall itself if it sees pressures above 20Mpa. This is injection fill profiling and its normal.
4. Never seen that before so I am guessing its like an oven where to turn it to the max or min? Just a guess. More pictures would help!

Husky

1 Assuming the machine will display fill time:
Set a known shot size & transfer position –for example if you set shot size to 11 cm and transfer at 1 cm, you have 10 cm of screw travel. Set speed to 100%, shoot a few shots and record fill time. Travel divided by fill time = linear speed. Repeat for different speeds – the results should be linear but may not be.
2 Intensification ratio is the area of the hydraulic plunger (that drives the screw) divided by the area of the screw outside diameter. Plastic pressure is a multiple (typically around 10x) of hydraulic pressure.
3 Develop your process with injection pressure set to maximum. Monitor actual injection pressure. When you have a good process, set injection pressure a little higher (+10 %) than actual. This is a safety feature – it should not control the process.
4 This appears to be a very basic proportional controller. You will have to use a temperature probe to see where the nozzle temperature stabilizes for each setting on the controller. Keep in mind, though, that the nozzle is also being heated by the barrel, so you’ll have to calibrate the nozzle settings for different front barrel zone temperatures.

I hope this helps - good luck!