Re: CNC Engraving

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Jack" <freshwatermodels@...> wrote:

>
> I want to make a couple of name plates for a model locomotive. They are made of brass and tiny. I have been looking at pointed carbide "engraving" bits from China on eBay. I assume these are intended for making ciruit boards. I am wondering if anyone has had experience using these? The one I am considering using is about .2mm which I beleive works out to about .008"
>
> Any comments or insite would be appreciated.
>

For critical work I use these http://www.micro100.com/inch/rtc_two_end.html but I also send out my broken 1/8" shank carbide to my tool grinder who makes these up for me dead sharp, I hand stone with (green) Silicon Carbide the point offset and check on a comparitor.

I used to have a customer send me panels to engrave and the depth needed to be .014-.016 with a .008-.01 bottom flat and a 44 degree inc angel. Before getting a custom 6X spindle speeder head custom built in the UK for the machine I ran at 4000rpm and 1.4 IPM plunge and 2.0 feed running full depth single pass. I used this in all materials - only changing the type of cutting fluid to match the material.

Before anyone asks - the company that built the speeder disolved the tooling dept prolly 20 years ago and the unit cost me about $7000 back then. I have run that at 24000 rpm for 14hrs a day and during the early 90's the payback time could have been as little as 1 week.