Every day many injection mould users receive moulds from different countries where labor costs are cheap. Sometimes the moulds are according specifications, other times mistakes flourish within 3 to 12 months from first operation. We are sure that many problems creating delays and slow productivity inside a Injection Plastic Mould comes from misuse, wrong application and lack of respect of specs of Hydraulic Cylinders.
Sometimes the mould designer does his best but it is very difficult to correctly and completely calculate all physics related to each Hydraulic Cylinder operation. For example, a cylinder might start leaking oil from rod, other times could be the tube. Today we want to identify 2 main types of leakages: Dynamic and Static.
It is somehow difficult to believe but the Static Oil Leakage is harder to spot and to trace than the Dynamic, but it is the truth. The reason is because a Dynamic Leakage is 99% caused by direct human mistake, e.g. if the Hydraulic Cylinder rod-end is fixed (by a human) without proper tolerance to the Injection Mould Slide or to the Ejection Table then we will surely see the oil flow and we will unfailingly tell what causes it. A mould user in this case will hardly call the Hydraulic Cylinder supplier to complaint.
But if the oil flow comes from a static component, such as the Front Cartridge or Head or from the Tube of a Tie-Rod Cylinder, then it is likely the mould user will file its cylinder supplier a complaining.
But who is right?
There could be 2 explanations, the first is that the Hydraulic Cylinder Company did not manufacture or assemble the cylinder according plans, the second is that the mould user is misusing his Hydraulic Cylinder.
How can a cylinder be misused?
If the static pressure inside the cylinder constantly peaks too high, then oil leakage will always be present. There are 2 possibilities for creating this situation: the pressure could be increased by the earth’s gravity or by the Injection Machine Oil Pump.
If the Hydraulic Cylinder works vertically, and the attached Injection Mould Slide is very heavy and speed is high, then we are using the earth’s gravity to create peaks of Oil Static Pressure
Proving who is right!
Vega has designed a new tool to allow everyone to test oil pressure peaks inside an Hydraulic Cylinder while operating in a Plastic Injection Mould.
This Diagnostic or Check-up Test Kit is build to connect a PC and a single Hydraulic Cylinder on both oil ports. Using a custom-made software we are then able to track the results on a graph and to compare the results to specs written inside the catalogue.
The mould user then will be confronted with the truth and could then decide to complaint to the mould maker for misuse of Hydraulic Cylinder in his mould.
The Beta version of Check up kit, is a made up of 3 parts: 2 sensors (with oil connectors), USB cables and Black Box, and customised software for a Window PC.
Here you can see a functional diagram describing all parts of the Check Up Kit.
Feel free to ask Vega to rent or purchase one of this test Kits!