Material selection and engineering solutions

Most engineering thermoplastics are inherently electrically insulating.  However, when an application does have electrical requirements, the key issue is often whether the material exhibits electrically dissipative or conductive characteristics.
→ Electrically active plastics
→ Electrically insulating materials

For example, when producing electronic components, dissipating or conductive materials are often chosen to avoid static charges that could harm electrical circuits. This also applies to ATEX applications (ATmosphere EXplosive), where the objective is to reduce the likelihood of catastrophic explosion due to electrostatic discharge.

→ ATEX materials

To assess the suitability of a material in terms of its exposure to mechanical stress levels, it is desirable to  obtain as much detailed information about what the suspected levels of stress will be. In most cases, it is very helpful to obtain a print of the component with information relating to the mechanical stress.
→ Mechanical properties 

Thermal stress is another key criteria restricting the selection of material. Therefore, the temperatures transferred to the materials as a result of the application conditions must be taken into account.

In addition to the possibility of heat being transferred from the outside, system related heat created by factors such as friction must also be taken into consideration. Characteristics closely related to changes in temperature are:
→ Negative service temperature
→ Dimensional stability 

Tribilogical considerations are those made necessary in applications that will expose the part to wear caused by high loads, friction, or sliding actions.  In these cases,  good sliding properties and abrasion characteristics are required.
→ Plastics for sliding, friction and wear

Sometimes the industry in which the part is to be used places limits on the material selection process.  This could be due to government agency approvals, or customer specific specifications that indicate only certain types of materials, meeting certain specific criteria can be used.  

The environment for applications in the field of oil and gas is highly demanding. Therefore compliant materials according to EN ISO 23936-1:2009 as well as NORSOK M-710, Edition 3 are required. 
→ EN ISO 23936-1 compliant plastics

• In the medical technology sector, often only materials that come with approvals for direct bodily contact are acceptable.
  → Biocompatible plastics
• As a high proportion of medical products have to be sterilised for reuse, resistance against common sterilization methods is required.
  → Autoclavable and sterilisable plastics
• Medical applications are often involved in surgery and need to be image controlled within the process. To achieve visibility of components under fluoroscopy and X-ray radiation, special materials have to be used.
  → X-ray plastics

• In the field of food technology, by contrast, approvals in compliance with U.S. FDA regulations, as well as European standards (e.g. 10/2011/EC, 1935/2004/EC) are required. Consequently, for these industries only materials that comply with requirements of these regulations can be considered.
  → Food grade plastics
• The demand for detectable materials is increasing as a means to keep unwanted particulate matter from entering the food processing chain.  Broken plastic fragments can be quickly traced as part of the standardised process control system because of special additives used in these specially modified materials.
  → Metal detectable plastics
  → Optical detection

• In industries such as Aerospace and Semiconductor, where vacuum is of importance, materials with high ionic purity are required.
  → Low outgassing plastics
• When it comes to applications that are used for fire protection, e.g. in Aerospace, flame retardant materials are required.
  → Flame resistant plastics 

If components are used for instance for outdoor applications, in radiology or in applications involving exposure to high energy radiation such as power stations, the materials used require suitable radiation resistance. Decisive to the material selection are the exposure dosage and the relevant application conditions.
→ Radiation resistant plastics
→ UV resistant plastics

Machining is the predominant method used for further processing of plastic semi finished products. In order to produce high quality, durable, precisely dimensioned and flawless components, as much attention must be paid to the tools and processing parameters as to the characteristics of the specific materials. In many cases, thermoplastics can be very successfully joined by means of welding and bonding (or to other materials), which are taken into account on following pages:
→ Easy to bond plastics

→ Weldable plastics