Welcome!

I received this question over the weekend…

A spotting press is great for checking the parting line. This is a large hydraulic press specifically designed to open and close the mold. 

Spotting fluid is placed on the parting line and the mold is closed under pressure using the press. Areas where the spotting fluid transferred from one half to the other are areas where the parting line is shutting off successfully. A parting line mismatch exists in areas where the spotting fluid does not transfer from one side to the other.

I recommend that any molder either have a spotting press, or access to a spotting press. If you have a toolmaking department, it is a necessary investment. 

If you are a small molder, or have a small tooling department just for repairs, then it might be a price advantage to bring the tool to a local tool shop and borrow their press (this will also expose you to their expertise in evaluating the results).

-Andy

As long as the flow rate and gate dimensions are in the same units (mm, cm, or in) they will cancel out and you will receive a a resultant in the units of reciprocal seconds which will represent the rate of shear.

-Andy

Basically, you need to increase the contact force between the nozzle and the sprue bushing. This will often relate to the carriage forward force or position.

-Andy

Electric molding machines do not have intensification ratios because they lack hydraulic pressure. Your machine should be configured to provide the actual injection pressure.

Basically, an electric molding machine measures the injection force using a conversion from the torque applied during injection. This conversion provides the actual injection pressure on the control panel. 

he only time you may need a conversion is if the screw and barrel were replaced, and the machine was not re-programmed to accomodate.

-Andy

The general recommendation from most manufacturers is between 0.25-0.5mm or 0.010-0.020in.

In reality, this specification refers to the clearance between the top of the ejector pin head and the counter-bore in the ejector plate. Most mold makers use a similar ejector pin clearance even when a sensor is not being used.

The purpose of this clearance is to ensure there is no preload on the sensor, especially if any dirt gets beneath the sensor. Such a preload will destroy the sensor and provide erroneous pressure readings.

-Andy