O/T circuit boards tooling?

[ajr73]

Does anyone know of any good tools that will deal with cutting copper and the fiberglass in printed

circuit boards? We rough with helical tools leaving .01 for finish, and then finish the fibreglass with straight

flute router style endmills to prevent delamination? The bad part is I blow through so much tooling doing this,

the boss thinks its the nature of the two materials against us? Typ. speeds and feeds for the 1/4 4fl. endmill is

7500 rpm and 20 ipm. This is about mid range, the book says 200-900 sfm. and feed of .0005-.0015 ipm. for

this tool yet it only lasts through about 8 to 15 boards on average.

 

Thanks,

[maestro]

We have never cut circuit boards here, but we have cut a lot of fiberglass. We tried all kinds of tools. The stuff is just so abrasive that it dulls tools, even carbide very quickly. We just used an inexpensive 4 flute carbide end mill and replaced it when dull. Never spent the money on diamond coated cutters though. These might work better, don't know. Just my .02$.

[Alan S]

We cut a lot of graphite and copper electrodes and we tend to use diamond coated carbide cutters on the graphite but we use uncoated carbide hemi flute cutters on copper.

Never cut on fibreglass myself but graphite is extremley abrasive with high cutter wear so maybe give the diamond coated cutters a go. Kobelco seem to be the best around at the moment.

[mold100]

I have some c-board experience but not enough to count for much,used ticn coated .031 balls we had in stock to cut out rectangles,ran about 18000 rpms and 160.ipm .0125 d.oc.,cut o.k. spanked some cutters.The best thing I can recommend,internet-search for endmill manufacturers,like OSG,they probably have something specific.,just another .02$

[kathy]

We machine fiberglass using a 'multi-faceted' tool.

I can get a part # / mfg if your interested.

 

Diamond also work good too. We use fishtails to drill.

 

Kathy

[johns]

Mount the board copper side down on aluminum or hard board. That will prevent de-lamination. The other thought is to produce the board by laser cutting, They could do all holes and cut out to shape. Even CNC steel fabricators ( punch presses ) would work. For more volume, you could have a die made.

[ajr73]

Thank you everyone, my problems are the board is laminated and sandwiched with copper foil throught and double sided also. Typically there is a .06 core built up both sides with alternating copper and laminate that is about .01 to .015 thick. We are just machining these for a manufacturer. The fixture base is alum. with a delrin pad and a clamp that is alum. with delrin pad. The clamp pad covers as much surface as possable there is only about .03 per side uncovered. The heli. flutes will delam if I get too close (about .125 is as close as I can get. So I sent in a 3/32 heli flute about .01 off the profile, the rough with a 1/4 heli flute, then finish the profile with a 3/16 straight flute. On the harder boards I only get through about 20 or so before cutters start failing, some of the endmills only have lasted through 8 boards. There is a lot of surface to rough with the 1/4 and it is cutting through the two materials so it will go first. I am just trying to save the boss some money by finding better tools. The diamond tools, will they cut the copper? I only have 7500 rpm. spindle also, will that be a problem. Any suggestions will be greatly appreciated and sorry about the long post.

 

Thanks,