Carbide inserts on interrupted cuts

[Dave HalfordParticipant @davehalford22513]

As Pete says above and also the cheaper inserts such as the ccgt on ebay selling for around 10 quid for a box of ten may be recycled carbide hence the quality variations.

If you buy from the likes of APT  you get the info on the link, the code after all the ISO size coding (MPN PC35) is a proprietary one and tells you what it’s for. For buying branded inserts on Ebay, you need to search the makers lists for the codes though if you have an obsolete insert it can be difficult.

[Kim GarnettParticipant @kimgarnett94824]

The big problem with carbide inserts is there is no one universal Insert for turning or milling they are very material specific in the conditions and material they cut. Tip manufactures have at least three type for every insert they make

Tough for interrupted cuts and heavy cuts

Medium  witch is the closest to the universal insert and normally the starting point

Hard which is normally used for finishing and high speed

then comes geometry which will be matched to the material very small changes to the top of the insert making the insert more or less positive depending on the material being cut.

then comes the speed and feed and depth of cut

rule of thumb is depth of cut wears the tip the slowest ,followed by feed ,then speed which wears the insert quickest

Sandvik would state the cutting time for an Inset was 15mins at the mid point on the ranges stated on the back of the box in ideal conditions. by reducing the speed the insert life would increase I have in the past needed to make edge time last at 45mins or more depending on the cost of the insert and the operation. As Insert cost is a big consideration

then there other factors that come in to play like approach angle which is to do with the shape of the insert

and the radius of the tip.

i.e. square inserts for roughing and facing which allows for large cuts to be made down the face and o/d regardless of interrupted cuts or not even on small machines.

When I was industry finding the correct Insert for a particle job could be quite problematic

[JasonBModerator @jasonb]

On the other hand for hobby use I have found there is no real need to change tip depending on material, these days I will use those intended for Aluminium and non ferrous metals on everything be it wood, plastics, non ferrous, steel iron including chilled, stainless, etc. These are a finishing/medium grade not roughing.

Also as said earlier those same tips will get used for turning and facing be that a continuous cut starting with round stock that has been sawn off square to the large diameter interrupted cuts shown or anything in between.

As for use on the mill the insert holders for the boring head take “turning” inserts and I have also been known to mount a lathe tool in a flycutter with the same non ferrous inserts all cut OK

Not tried the face mill inserts on the lathe for turning yet but do use the face/shell mills on all materials again with the non ferrous inserts

99% of the time I use 0.2mm tip radius, only changing to say 0.8 where I want a fillet where a turned surface meets a flat one.

So to me it doe snot really matter at hobby level and Like Andrew if a tip gets chipped it is usually down to me doing something silly rather than the actual cutting

 

[MikeKParticipant @mikek40713]

Yeah, I’m really liking the GT inserts.  The MT inserts are going into a drawer to be forgotten.

[Author]

Posts