Frequently Asked Questions

WHAT IS ZX® OR ZEDEX® ?

ZEDEX® and the abbreviation ZX® are brands of property of the corporate Wolf Kunststoff-Gleitlager GmbH and identify the high-end products of Wolf Kunststoff-Gleitlager GmbH.

The ZEDEX® material families are based on engineering & high-performance polymers and are were born from the experience gained in our over 50 years of activity in solving the problems deriving from the use of plastic materials as machine elements.

Once proven that the developed compound could create added value for our customers and being used in different industrial sectors, we decided to include it in the ZEDEX® product spectrum.

Even if some ZEDEX® materials are no longer advertised exhaustively on the webpage, this does not change the fact that these materials are still available just in time with minimum order quantities (MOQ) or with minimum quantity fee (MQF). Have a look to our delivery programme.

WHAT DOES ZX-324V1T MEAN?

ZEDEX® materials are grouped into families with the same material base and targeted modifications are generally available for each base type.

Example:

Nomenclature

ZX  –  324   V1T

ZEDEX®      Base type    Modification

ZX-324V1T® belongs to the family ZEDEX® 324 which is based on PEEK.

V1T represents a modification of the base type ZX-324®. Namely it has an higher Tg (glass transition temperature) and better CTE (coefficient of thermal expansion).

ZX-324V1T® extends the operational range of unreinforced PEEK to higher temperatures and reduces material costs without any fibre or filler reinforcement.

HOW CAN POLYMERS BE CLASSIFIED FOR A SPECIFIC APPLICATION?

In general it is difficult to classify engineering and high performance polymers with images or numbers, even more so to classify polymers for specific applications, since the performance of technical plastic components depends on many factors which change according to the application.

Although for certain applications it is clear which material characteristics are important, depending on the application parameters the situation may always change, as the material characteristics are influenced by each other.

We therefore decided to use different methods to provide comparisons from different Points of View.

PoV – Plastic materials pyramid

To give an overview at glance, the usage of a pyramid is a good option.

This pyramid of plastic materials provides a general indication of how the ZEDEX® families are positioned among common plastic materials. The measurement scale used is the Relative Temperature Index (RTI-Str) – mechanical strength.

 

PoV – Thermal limits of use

The thermal limits of use rapresents a deeper comparison than the one given from the plastic materials pyramid based on single value. We have indicated the “continuous use temperature – RTI”, which is the same used in the pyramid, to give continuity in the comparison.

All polymers react to changes in temperature with strong changes in properties. Changes in the properties are normally relatively small up to the glass transition temperature.

If polymers are used above their glass transition temperature, the changes in properties must be taken into account, when selecting the material.

If the glass transition temperature is exceeded by 20%, the properties can drop by 80%. The characteristics of the material determined at 20°C, therefore lose their validity.

     

    Glass transition temperature - Tg

    … is the temperature at which the amorphous structural areas of the polymer lose their strength. The mechanical properties of amorphous polymers drop sharply. In the case of semi-crystalline polymers, only the crystalline part of the structure forms a bond. If the temperature increases further, the crystalline areas also lose their firm bond and the properties decrease drastically.

    Continuous use temperature - RTI

    … or according to UL 746B Relative Temperature Index (RTI) – mechanical strength,  represents a material property. It depends on the thermo-oxidative stability of the plastic. If exceeded for a long time, the plastic reacts with strong changes in properties, e.g. colour change, embrittlement up to complete destruction.

    This also happens without the influence of external factors such as surface pressure, friction, chemicals etc.

    Short-term temperature - internal standard

    … is the temperature which may be allowed for a short time, but the material is likely to start changing properties. The duration depends on the operating conditions (e.g. atmosphere) and can vary from 3 to 100 hours maximum.

    Melting temperature - Tm

    … is the temperature at the upper end of the melting area in which the largest and most perfect crystallites melt. Here a first–order phase transition take place and the material passes from a solid to a liquid phase.

    Max press-fit temperature for bushings - internal standard

    … is the maximum temperature at which a plastic plain bearing bush pressed into a housing still maintains its tight fit. Oversized plastic bushings pressed into a metal housing, arise tangential stresses in their cross-section, ensuring a firmly fastening by the mean of a frictional connection. If the temperature exceeds the maximum, the tangential stresses are reduced by stress relaxation, which is caused by heat.

    PoV – Radial diagrams

    Radial diagrams are also a good way to make comparisons between 2 or more materials, in this case comparing specific characteristics.

    The characteristics are shown on the circumference and the arrows indicate how good a property is.
    The more the arrow is filled, the better the property is.

    Example:

    • Strength: the further the arrow is filled, the more positive (higher) the strength.
    • Costs: an arrow that is filled far out indicates low costs.

    Here we show the characteristics comparison between one material among each ZEDEX® family and common PEEK.

    ZEDEX® vs. PEEK

    ZX-100K vs. PEEK

    ⟶ value the higher = better

    ZX-200 vs. PEEK

    ⟶ value the higher = better

    ZX-324 vs. PEEK

    ⟶ value the higher = better

    ZX-410 vs. PEEK

    ⟶ value the higher = better

    ZX-530 vs. PEEK

    ⟶ value the higher = better

    ZX-750 vs. PEEK

    ⟶ value the higher = better

    PoV – Relative material comparison

    A relative material comparison is also a good way to classify materials and comparing ZEDEX® engineering & high-performance polymers with standard polymers.

    The greater the number, the better the quality. (1 = bad, 10 = very good)

    PoV – Core properties

    A quick materials classification can also be based on the core properties of the material. However, this table has been published more to give a general overview of ZEDEX® materials and to allow a skimming upstream of materials not suitable for the application being studied, than to make a selection of materials.

    It is recommended to continue selecting the appropriate material with additional tools described in the material selection section under the menu knowledge centre.

    Table legend

    + applies
    ~ applies to a limited extent (FOOD: test on going)
    does not apply
    N/A FOOD: not been tested yet

    ZEDEX® Material families

    The ZEDEX® materials are grouped in families with the same material base.
    For each basic type are specially modified types available.

    ZEDEX® 100 Family

    The "little PEEK" - up to 110 °C

    ZX-100® is an "all-round polymer family" with excellent tribological properties & self-lubrication. The modification ZX-100K® is both rigid and elastic at the same time.

    It is very suitable, as a replacement e.g. for ordinary bronze and PA.

    ZEDEX® 200 Family

    The resilient - up to 140 °C.

    The ZX-200® family is based on PK and its chemical resistance comparable to PEEK.

    ZX-200® has excellent elasticity and its thermal and mechanical properties are better than conventional PA and POM.

    ZEDEX® 324 Family

    Like PEEK, only better - up to 250 °C

    ZX-324® family is suitable for high temperatures in combination with high surface pressure.

    ZX-324® is 100% virgin PEEK, but has a higher TG and ductility than conventional PEEK.

    ZEDEX® 410 Family

    The most precise - up to 180 °C

    ZX-410® is suitable for the medium sliding speed range, high surface pressure and high precision even at high temperatures.

    Also suitable to replace bronze / sintered bronze and aluminum taking into account the required strength.

    ZEDEX® 530 Family

    Super PTFE compound - up to 240 °C

    ZX-530® family is particularly suitable for applications in which aggressive chemicals are used.

    ZX-530® combines the advantages of PTFE and ceramic.

    ZEDEX® 750 Family

    Cryogenics, high temperature and high PV – up to 280 °C

    ZX-750® family is suitable for very high temperatures, combined with high PV values. Due to its low brittle point, it is also well suited for cryogenic applications.

    Also suitable to replace PI taking into account the long-term temperature.

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