Convincing test results

The con­crete defor­ma­tion sta­bil­i­ty of machine beds made of Nan­odur, the inno­v­a­tive ultra-high-per­for­mance con­crete (UHPC), sat­is­fies the strictest of require­ments. This assess­ment is the result of a study con­duct­ed at the Lab­o­ra­to­ry for Machine Tools and Pro­duc­tion Engi­neer­ing (WZL) of RWTH Aachen Uni­ver­si­ty, in Ger­many. In addi­tion, ultra-high-per­for­mance con­crete such as Nan­odur is char­ac­ter­ized by fur­ther advan­tages over machine beds made of con­ven­tion­al mate­ri­als such as grey cast iron or weld­ed steel. The com­pa­ny dur­crete GmbH will demon­strate these advan­tages at the fol­low­ing trade fair: AMB 2018 dur­ing Sep­tem­ber in Stuttgart, Ger­many. At AMB 2018, vis­i­tors can also gain detailed infor­ma­tion on the test results of the above-stat­ed research project con­duct­ed at Aachen University.

The load­bear­ing and sup­port­ing ele­ments of a machine tool are the machine beds mount­ed on the machine foun­da­tions and inte­grat­ed into the tool­ing machines — and not the machine foun­da­tions them­selves. It is in fact these base frames on which the indi­vid­ual func­tion­al ele­ments — such as the lin­ear guid­ing rails and the dri­ve units — are mount­ed. The size and design of these ele­ments basi­cal­ly depend on the process required. Machine beds can accord­ing­ly range from mass­es less than one met­ric tonne to sizes with very large dimen­sions. The selec­tion of the mate­ri­als used is crit­i­cal­ly sig­nif­i­cant for the func­tion­al­i­ty of a machine bed. In addi­tion to the pro­duc­tion-engi­neer­ing and eco­nom­ic stand­points involved, the mechan­i­cal char­ac­ter­is­tics of the var­i­ous mate­ri­als play a key role here, since they deci­sive­ly deter­mine the char­ac­ter­is­tics of the com­po­nent parts in use. A char­ac­ter­is­tic of prime impor­tance here is the Young’s mod­u­lus, which influ­ences elas­tic deflec­tion as well as mate­r­i­al damp­ing and ther­mal behav­iour. Long-term geo­met­ri­cal con­sis­ten­cy — i.e., only min­i­mal plas­tic defor­ma­tion after appli­ca­tion of a load — is expect­ed as absolute pre­req­ui­site for all com­po­nent mate­ri­als used in this con­text. If this pre­req­ui­site is not met, the lin­ear guid­ing rails lose their even­ness and par­al­lelism, which had been achieved in tedious and expen­sive pre­ci­sion working.

Advanced high-performance concrete in machine construction

In the past, machine beds were pri­mar­i­ly made of steel, cast steel, or grey cast iron. In the course of the past 30 years, as a result of stricter engi­neer­ing and eco­nom­ic require­ments placed on machine tools, and in addi­tion to the intro­duc­tion of machine beds made of grey cast iron, frame com­po­nents made of mate­ri­als such as cast min­er­al or epoxy-resin-bond­ed poly­mer con­crete have become well estab­lished. Steel and cast com­po­nents can sup­port the great­est loads but are very expen­sive and ener­gy-inten­sive in their pro­duc­tion. Mas­sive mate­ri­als such as poly­mer con­crete and nat­ur­al stone, on the oth­er hand, are in exten­sive use owing to their more favourable prices and their engi­neer­ing advan­tages. By now, advanced ultra-high-per­for­mance con­crete (UHPC) has become solid­ly estab­lished in machine con­struc­tion. In addi­tion to its cost-effec­tive­ness, con­crete offers ben­e­fits relat­ed to the vibra­tion and ther­mal behav­iour of machine tools, and it has replaced con­ven­tion­al mate­ri­als such as grey cast iron and weld­ed-steel com­po­nents. Ten years ago, a patent appli­ca­tion was sub­mit­ted for the high-per­for­mance binder Dyck­er­hoff Nan­odur. Since then, Nan­odur has had high­ly deci­sive influ­ence on the world of ultra-high-per­for­mance con­crete. It has espe­cial­ly been in the field of advanced machine tools that this inno­v­a­tive, high-tech mate­r­i­al has pro­vid­ed for­ward-ori­ent­ed stim­u­lus. For a num­ber of years now, a num­ber of spe­cial­ized pre­cast plants have suc­cess­ful­ly pro­duced machine com­po­nents made of Nan­odur con­crete. Pro­duc­tions plants of machine beds are already locat­ed in Czech Repub­lic, Switzer­land and Chi­na. Oth­er coun­tries will fol­low soon.