2012/6/12 andy pugh <[email protected]>: > On 10 June 2012 19:52, gene heskett <[email protected]> wrote: > >> Imagine my surprise when that grade 8 bolt carved like butter, both with >> carbide inserts and with HSS tool steel, leaving a mirror-like finish. > > I was just sent this link, which is truly fascinating: > http://youtu.be/mRuSYQ5Npek > > It shows how bad finishes can sometimes be formed due to material > rolling under the cutting edge, and it is also fascinating how much of > the time the effective cutting edge is made of the material itself.
I had a question about this exact topic in exam last Friday :) The cutting edge is where the most deformations of material is taking place, so very thin layers of material hardens (in some cases up to 2-3 times hardness increase) thus creating that "blade", being capable to cut the material What is correct word in english to describe this adhesion of material to the cutting edge of instrument? Less wear of the actual instrument is the only positive effect. But as You noted, surface roughness is considerably increased. Another major drawback is loss of precision. It is shown very well shown at 2:40 of that video. And those thin layers of material stick to instrument and it is not easy to remove, so actually it can make the instrument useless. Setting appropriate speed is most effective factor to reduce this (for steel it is recommended to have surface speed more than 250 m/min). The way the coolant is delivered to cutting zone also affects the process. -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
