Dec 9, 2021
is a tolerance specification and is found on engineering drawings to describe the position of the center of a bore or surface.
The toleranced straight line or plane must lie between two planes that are perpendicular to the reference with the set distance.
For bore centers, the axis of a bore must be inside a cylinder of the given diameter.
The cylinder axis must therefore coincide with the location of the bore axes to the given reference planes.
There are special cases where a point can be set as a toleranced element (e.g. center of a sphere).
Quality assurance: Example for specifying a position
tolerance
Related topics:
This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Jan 15, 2020
A process in which fine powdered material with high melting point (>1.000°C) is mixed with thermoplastic based binders to a moldable compound is called powder injection molding.
The powdered material comes preferred wise in globular shape and corn sizes of 15 µm – 20 µm. The binder is incapsulating the powdered corn.
Volumetric share: Binder > 20 % / powdered material
Sep 22, 2019
The polymerization of propene produces the thermoplastic polypropylene (PP). It is a semi-crystalline polyolefin.
PP behaves very similar to PE, but is harder and more heat resistant.
With 0.89 – 0.92 g/cm³ PP has the lowest density, compared to the standard plastic materials.
The operating temperatures are between 0 and 100 °C.
The fatigue resistance is very high, therefore PP is well suited for use in hinges.
All these features make PP one of the most important plastics in the world today.
Even synthetic fiber production is largely based on PP.
Polypropylene is used primarily in packaging.
Further fields of application are household appliances, toys, sporting goods and agricultural equipment.
It has to be noted that PP is not very suitable for gluing and painting.
Plastic: Trash cans made of
polypropylene (
PP).
Related topics:
This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Sep 3, 2020
The pressure at different positions inside the cavity/runner is called “Pressure Distribution”.
Ideally in injection molding process, the pressure distribution should be uniform throughout the cavity after the molten plastic completely fills the cavity. In this case the molded part shrinks uniformly.
In reality due to the different cooling behaviour of the part there is always a difference in pressure distribution.
Injection molding simulation is a great tool to predict the pressure inside the cavity, which can help to achieve uniform pressure distribution as good as possible.
May 6, 2019
A solid, made by a parallel shift of a polygon is called prism.
In the FEM, prisms with triangular footprints are commonly used.
Its advantage is an unstructured mesh in two directions, and, at the same time, one structured main direction.
Based on the surface mesh out of triangular -elements prism- elements are extruded into the part.
Different layers of the so built prism-elements are possible. In combination with tetraeder-elements (in the remaining part), a blm mesh is built with a high accuracy and less elements. Therefore, the calculation time can be reduced.
The special form of the triangular footprint based prisms allows, in the runner system for injection molding simulation, an orientation of the fibers in flow direction inside the runner without a secondary preferred direction.
