which an end product can be obtained obtaining the end product from a preform is done by any of the known standard methods and most typically is accomplished by removing or machining the unwanted parts of the preform to give the final shaped product as such the term preform is intended to encompass any of a wide variety of general forms of the consolidated uhmwpe material and is perhaps best considered as a simple rectangular block this preform can be subjected to a stress relief annealing process as it is mentioned in the iso 5834 2 standard the formation of the uhmwpe material according to the present invention begins with mixing a desired quantity of an additive material with the uhmwpe powder in the examples described hereafter the uhmwpe powder will be of ticona gur u00ae 1020 medical grade uhmwpe such powder is well known and can be commercially obtained of course also any other uhmwpe powders can be used for example ticona gur u00ae 1050 dsm uh210 basell 1900 uhmwpe powders with a high purity beside uhmwpe also other polyolefins such as hdpe ldpe lldpe or polypropylene but also other polymers such as polyvinylchloride pvc polystyrene ps polyesters like polyethyleneterephthalate pet polycarbonate pc or polymethylmethacrylate pmma polyamides polyoxymethylene pom polyphenylether ppe polyurethanes pur polyetheretherketone peek polyimides polyarylsulfones psu ppsu polyphenylenesulfide pps or silicones such as polydimethylsiloxane pdms could be used the additive material which is mixed with the uhmwpe powder is preferably an antioxidant or a radical scavenger it is preferable that during the.