Weight reduction through precision hollow spheres

Balls are indis­pens­able in numer­ous tech­ni­cal appli­ca­tions. An inno­v­a­tive process now makes it pos­si­ble to pro­duce ground and pol­ished hol­low balls from metal­lic and ceram­ic mate­ri­als with a diam­e­ter of one mil­lime­ter or more and designed for spe­cif­ic appli­ca­tions. These light­weight rounds can reduce weight by up to 90 per­cent. They thus open up com­plete­ly new per­spec­tives for opti­miz­ing exist­ing appli­ca­tions in terms of light­weight design and real­iz­ing new ball applications.

From auto­mo­tive and mechan­i­cal engi­neer­ing to automa­tion, mea­sur­ing, med­ical and valve tech­nol­o­gy to aero­space, there is hard­ly an indus­try in which balls do not play a role. When it comes to metal­lic pre­ci­sion balls, usu­al­ly only sol­id vari­ants were avail­able. Only for spe­cial appli­ca­tions was it worth­while to man­u­fac­ture pol­ished hol­low balls from deep-drawn sheet met­al. How­ev­er, this com­plex process could only be used to pro­duce metal­lic hol­low spheres with a diam­e­ter of ten mil­lime­ters or more. The pro­duc­tion of small­er sizes has not been tech­ni­cal­ly fea­si­ble up to now. Ceram­ic hol­low spheres have hard­ly been avail­able on the mar­ket to date. As a result, the balls are often over­sized and sig­nif­i­cant­ly heav­ier than nec­es­sary, thus coun­ter­act­ing light­weight con­struc­tion efforts to save resources and energy. 

Application-specific design of hollow metal and ceramic balls 

To elim­i­nate this prob­lem, Hol­lomet GmbH, in coop­er­a­tion with Ball­cen­ter Han­dels­ge­sellschaft mbH & Co. KG has devel­oped a glob­al­ly unique process for the repro­ducible pro­duc­tion of hol­low balls. The tech­nol­o­gy makes it pos­si­ble to man­u­fac­ture balls with defined wall thick­ness­es of a few tenths of a mil­lime­ter, extreme­ly pre­cise diam­e­ters, round­ness and the low­est tol­er­ances start­ing at one mil­lime­ter. In the patent­ed process, many met­als that are avail­able in pow­der form and can be sin­tered, such as high-strength steels and stain­less steels (AISI316), as well as 

ceram­ic mate­ri­als such as sil­i­con nitride (Si3N4), sil­i­con car­bide (SiC), alu­minum oxide (Al2O3), zir­co­ni­um oxide (ZrO2) and even piezo­ce­ram­ics. The high-pre­ci­sion final grind­ing is per­formed by ball cen­ters. Com­pared to a sol­id ball, weight sav­ings of up to 90 per­cent are thus achieved. At the same time, the high­ly flex­i­ble choice of mate­ri­als enables the phys­i­cal, chem­i­cal and ther­mal prop­er­ties of the balls to be pre­cise­ly matched to the appli­ca­tion. This means that, among oth­er things, mag­net­ism, tem­per­a­ture resis­tance and/or resis­tance to chem­i­cals can be influ­enced as required. 

Solution for optimized and new products 

Opti­mum adap­ta­tion to mechan­i­cal and chem­i­cal require­ments opens up count­less pos­si­ble appli­ca­tions. These include mea­sur­ing devices in which the high weight of the sol­id balls pre­vi­ous­ly used can cause dis­turb­ing vibra­tions. In the case of high-speed spin­dles used in the tex­tile indus­try, among oth­ers, opti­mal­ly designed hol­low balls enable ener­gy sav­ings by reduc­ing the mass to be moved. Hol­low balls promise low­er ener­gy con­sump­tion with improved infeed pre­ci­sion in automa­tion and dri­ve tech­nol­o­gy, for exam­ple in robots and lin­ear sys­tems as well as tool infeed in CNC machines.

The reduced ball mass also has a pos­i­tive effect on the response times of high-speed valves used, for exam­ple, in hydraulics, pneu­mat­ics, engine con­struc­tion, injec­tion valves and meter­ing tech­nol­o­gy. Mea­sur­ing the lev­el or flow of aggres­sive media is also an appli­ca­tion where metal­lic and ceram­ic hol­low balls can offer advan­tages over the usu­al plas­tic-based solu­tions. A spe­cial area of appli­ca­tion for ceram­ic hol­low spheres aris­es in the man­u­fac­ture of tech­ni­cal equip­ment which, like mag­net­ic res­o­nance tomo­graphs, can be sen­si­tive to mag­net­ic materials. 

In the broad seg­ment of bear­ing tech­nol­o­gy, very dif­fer­ent require­ments are placed on the sol­id balls nor­mal­ly used, so that they can­not sim­ply be replaced by hol­low balls. How­ev­er, it is also worth con­sid­er­ing light­weight solu­tions with the weight-reduced alter­na­tive of met­al or ceram­ic in this area. After all, in the growth mar­ket of elec­tro­mo­bil­i­ty or even in drones, which are expect­ed to take on more and more func­tions in the future, every gram less counts. 

The devel­op­ment of the ball spec­i­fi­ca­tion is car­ried out accord­ing to cus­tomer require­ments. Pro­duc­tion as well as the coor­di­na­tion of process­es from blank machin­ing to ware­hous­ing and dis­po­si­tion is pos­si­ble in small and large series. Hol­lomet and Ball­cen­ter pro­vide advice and sup­port in defin­ing the appli­ca­tion-spe­cif­ic prop­er­ties, which can be checked and opti­mized by a sam­ple series pri­or to series production.