chips not dust

[jdervin]

This is turning into one of those threads that ought to be kept at the top of the category no matter how old it gets. Super information! Thanks all.

[vassilm]

Again, what a great place this forum is. I can't stop being amazed at the support in this group.
Now, usually I use spiral cutters too and with some tweaking I am usually able to generate chips. My question was provoked by a job that I described in a different post where I need to do a lot of shallow pocketing in MDF with depth of cut of 3mm (1/8") and some very intricate shapes of the pockets. I was given the advice to use a 2 flute straight bit. I did it and for the most part it is coming out very well, but I can't generate chips and I was worried that even though the pass depth is very shallow I will soon damage the bits. On the other hand, If I go too fast the edge quality suffers as the toolpath follows a lot of small curves.
By the way I've followed Brady's advice and changed the ramping values, which tremendously improved edge quality of these engravings.

[widgetworks_unlimited]

Shallow cuts like you're describing are easy work for a dust collector - you may be make chips and never see them if everything gets sucked up.

Also, because of your depth of cut, you may get chips that look like little pieces of string or curly straws/springs.

And... the chips get smaller in size when you use a smaller diameter cutter. They are also "mulched" more (as TG explained above) because smaller flutes have a hard time ejecting large chips from a deep cut. Hard to tell what you used in your picture.

I wouldn't worry too much about heat on this job. The cut is very light and there's no way for chips to pack around the bit. If you burn your fingers while taking the bit out of the machine when the jobs done, you'll know that something is wrong. When I'm cutting well, my bits are luke warm after 1+ hours of constant cutting pockets/profiles.