After an injection mold is finished it will get its rating plate.
There is no design of the rating plate generally admitted.
Very often rating plates are created based on factory standards and provided to the mold maker by the future owner of a mold.
There are different online portals available, where rating plates for injection molds can be ordered.
The most common entries are asked for in standard forms.

Often a D&B D-U-N-S® number is requested on the plate besides the name of the mold, the manufacturing date, the size of the mold and its weight.
This number is specific for a given supplier and is used to prevent unjustified passing of the tools to third parties.
The extent to which CE marking is required for tools has not yet been conclusively clarified.
It has to be noted that type plates have to be fixed on the mold and shall not be removable in order to secure the ownership of the mold.

If the clamp force is too high for the chosen injection molding machine, multiple cavities with identical projected areas can be set behind each other inside the mold.
Despite the multiple parting plane, the clamp force is used only from one.
The reason for this is the neutralization of the cavity pressures of opposite positioned cavities.
The middle plate synchronizes by tooth gear, hydraulic or an articulated lever.
A mold that is designed in this way is called a stack mold.

A standard injection mold is split into the injection side and the ejection side.
When the mold is closing, the two halves of the mold are centered through the guide pillars.
In most cases, the guide pillars are fixed on the injection side.
The ejection side moves along with the guide pillars till the mold is completely closed.
In order to make the movement of the other half of the mold easier, guide pillars can have oil grooves.
Depending on the mold layout, guide pillars can have a centering collar to increase stability.
Four guide pillars will be used in one mold.
It has to be noted that the diameter of the guide pillars varies.
Three of them have the same diameter, one of them has a different one.
This is to make sure the mold cannot be mounted in the wrong way.

To orient the injection mold on the platen a locating ring is used.
The ring supports the mounting of the mold.
It helps to aligns the machine nozzle with the central length of the sprue bush.
With this, a good contact between the two elements is ensured.

For the production of injection molded parts a mold is necessary to be placed on the injection molding machine.
It is commonly build out of steel or aluminum and is designed as a permanent form.
Depending on the plastic material used millions of parts can be created with one mold.
The complexity of a mold range from a simple two-plate molds up to a complex stack mold with sliders, etc.
To avoid additional costs it is important to think about the mold concept early in the concept phase of part design.

All melt channels together are called runner or runner system.
For these names, there is no distinction between hot and cold runner.
A good runner is responsible for a balanced filling of the cavity and less material and pressure loss.

The unheated melt channel from machine nozzle / hot runner up to the cavity is called cold runner.
In the injection molding cycle the cold runner is cooling down and freezes.
The gate geometry is very flexible, like umbrella gate, cashew gate, ring gate.
The cold runner is ejected together with the part.
The separation from the part is done automatically or manually.
The collected cold runners will be recycled or disposed as waste.

In an injection molding tool, the melt channel between cylinder and cold runner / cavity is called hot runner.
The difference from a cold runner is that the hot runner has at least one heater band to keep the hot runner at temperature.
The melt inside the hot runner stays fluid during the complete cycle and will be used directly for the next shot.
No waste is produced.
Hot runners are used to save material or to avoid weld lines (sequential injection).

The hot runner system can be separated in different components.
The area, where the melt is divided into the different hot runner gates, is called manifold.
For molds with multiple cavities, a homogeneous melt temperature and pressure distribution are necessary.
Therefore, the manifold should be preferably symmetrical.

In the injection molding, the melt is injected inside the cavity through a gate.
Therefore, the gate position has an essential influence on the quality of the part.
The route of weld lines, the existence of air traps and the fiber orientation depends on the gate position.
Different flow length affects the pressure that is needed to fill the cavity.
The wall thickness at gate position leads to a longer or shorter packing time.
Moreover, the gate position might change the warpage of a part considerably.

When the mold is placed on the mounting plates of the injection molding machine, it can be opened easily.
The movable side of the mold is moved back from the fixed side with the help of the clamping unit.
The distance between the two halves of the mold is called opening stroke.
The size of the machine defines the possible opening stroke.
With a big enough distance, parts can be ejected easily.
The deeper a core, the larger the necessary opening stroke.
At the same time, the opening stroke should be kept as short as possible in order to reduce the cycle time.
When choosing the machine, the needed opening stroke should be considered.
Therefore, a good machine data sheet should always contain the necessary opening stroke for the mold.

The machine is pressing the mold halves against each other to counteract the pressure of the melt in injection and packing phase.
The needed force for this is called clamp force.
Most injection molding machines contain this value in their name.
The unit might be displayed in kN or t.
If the clamping force is too low, the mold halves will be pushed away from each other by the melt and flash appears.
The injection molding simulation helps to determine the necessary clamp force in advance to choose a machine with the correct size.
The clamp force can be estimated by multiplying the projected surface with the cavity pressure.

An injection mold consists in general of two halves: injection side and ejection side.
The touching faces between these two halves are called parting line.
Through this, the air is transported from the cavity to the outside.
When the mold is opened, part and cold runner are separated from the mold at this line and ejected.
The parting line emerges in general as a surrounding seam on the part.

A mold is usually divided into two sides according to their function.
The side with the ejector pins is called ejection side.
This side is moved for mold opening, therefore another common name is "movable side".

One parting line is not enough to eject complex geometries of injection molded parts.
Undercuts in the direction of ejection are the main difficulty.
So called slider are used to build an additional parting line.
The movement of the slider diagonally to the opening direction of the mold frees the undercuts and allows the ejection of the part.
Slider can be placed inside the fixed as well as the movable side of the mold.
The angle of the slider compared to the other parts of the mold should be between 83° and 97° to avoid a blocking of the slider.
The buoyancy inside the mold needs to be considered for the correct size of the slider.
It need to be ensured that the sliders are adequately locked.

In the injection molding machine, there are two platens, which belong to the clamping unit.
One is on the injection side and the other one on the ejection side, latter is movable mounted.
The mold is attached at the platens over the existing drill-holes by the means of fastening screws, mounting clutch or quick release systems.

In injection molding, two different materials (also known as components) are frequently used to produce one part.
The materials can be completely different (hard and soft polymers) or have the same base but with different color.
In the 2 Shot Molding process, the first component is injected into the cavity and cooled down up to a certain point.
Afterwards, the first component is transported, for example, by a rotating dish tool or a robot, to a new cavity to inject the second component on top of it.
It is important to consider the different processing temperatures.
The remelting of the first component is not wanted.
At the same time, both components should stick together.

In the two shot molding, the second component is commonly soft and elastic.
Therefore, it is also called soft component.
Due to its flexibility, the influence of the soft component on the warpage of the part is very low.
Seals are frequently made as soft component by the two shot molding.
Moreover, TPE is typically used for soft components.

Multi-functional Polymers with the processability of thermoplasts and the elasticity of vulcanized rubbers are called TPEs (thermoplast elastomers, also known as, thermoplastic elastomers).
Like thermoplasts, it is possible to repeatedly heat them up for softening and cool them down for hardening.
TPE is used for bathmats, housing (soft grip), handles, etc.

Typical TPE-Classes are: S-TPE, COPE and TPU.

In two shot molding, the first component is commonly robust and gives the shape of the geometry.
Therefore, it is also called the hard component.
Its rigidity leads to the main influence for the warpage.
Typically, its materials are PP, PS or PC+ABS.

A plug-on injection unit to an existing injection molding machine used for multicolor or multicomponent molding is called Secondary Injection Unit.
It is equipped with its own controller and is flexible in installation. It can be mounted on top or on non-operator side of a tool. The Secondary Injection Unit can inject into the parting line as cold runner system or into a hot runner system.

In injection molding, part inserts are commonly used to produce parts.
First, the part inserts are added into the cavity, after that the melt over molds it on one side.
This is why the process is called "Overmolding".
The advantage of this process is that the materials are connected due to the hot melt by a strong bond.
Gluing of the different parts is unnecessary in this case.
This process is often used with films as part inserts.
It is important to control the process temperatures since a melting of the insert is not or only partially wanted.

A geometrical difference between target and actual geometry is called warpage.
In the plastic industry this is caused by the developing stresses during the process.
Stresses arise due to the different shrinkage degrees in the part.
Varying Cooling rates, Orientation of the molecules, in-mold constraints (limitations for the shrinkage), uneven wall thickness/packing pressure are responsible for the differences.
These effects can cancel each other out or enhance one another.