| Sumario: | Aluminium thin floors have many industrial uses, especially as aircraft fuselage. Their manufacturing involves many operations, and the last one is the most critical one. This operation is mechanical milling, and it entails important challenges, as reducing distortion as consequence of residual stresses and preventing vibrations as consequence of cutting forces (mainly chatter). They are highly damaging for the milling centre and the surface quality of the thin floor. There are many techniques for facing these challenges, as the selection of proper cutting conditions, by means of the calculation of stability lobes; and the use of fixturing and holding systems that stiffen the thin floors. In any case, these techniques are not always able to completely prevent vibrations, due to the very low and variable stiffness of thin floors during milling. Because of this, a procedure is posed that aims to boost the use of flexible fixturing systems. As consequence, areas without vibrations and defects may be mapped in the thin floors if they are milled under proper cutting conditions.; Aluminiozko zoru meheek aplikazio industrial ugari dituzte, tartean hegazkinen fuselajean. Haien fabrikazioan hainbat operazio daude, baina azkenekoa da kritikoena. Azken operazio hori fresaketa mekanikoa izaten da, eta erronka garrantzitsuak ditu oraindik ere, batez ere hondar-tentsioek sortzen duten deformazioa murriztea eta ebaketa-indarrek eragiten dituzten bibrazioak ―chatterra batez ere― saihestea, zeinak oso kaltegarriak baitira bai fresagailuarentzat, bai zoru mehearen gainazal-akaberarentzat. Hainbat teknika daude erronka horiei aurre egiteko, batik bat ebaketa-baldintza aproposen aukeraketa, egonkortasun-lobuluen kalkuluaren bidez; eta tresneria eta lokailuen erabilera, zoru meheak zurruntzeko. Dena den, baliteke teknika horiek bibrazioak guztiz ekidin ezin izatea, zoruen zurruntasun izugarri txiki eta aldakorragatik fresaketan zehar. Horregatik, prozedura bat mahaigaineratzen da zoru meheen geometria anitzetara moldatzen den tresneriaren erabilera bultzatzeko. Ondorioz, baldintza egokiekin fresatuz gero zoruan bibraziorik eta akatsik gabeko eremuak zedarritu ahalko dira.
|
|---|
