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Hanging Burrs in cross holes

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Eighthnote74

Plastic
Joined
Nov 6, 2019
Hello, I've got a job milling and drilling aluminum manifold blocks. It is very critical that these manifolds have no hanging burrs that could contaminate the liquid once these blocks are assembled. I've been using an optic fiber camera to inspect the cross holes after machining with mixed results. My goal here is to come up with a method that will minimize the secondary operations. I don't think I can skip the inspection method but if I could improve the drilling process I would spend less time hand working the holes. I know the order of machining is very important. That variable is solved. Of course the SFM and feed effects the outcome. Drill point geometry is something I've been experimenting with. High pressure thru the nose coolant. Because of the quantities and the number of holes in each block any improvements I make will be worth the effort. If there's any aspect(s) I haven't look into please push me there. One piece of info -- after drilling I'm reaming the holes to size with step reamers. That helps but not enough.

Thanks in advance. Stay free.... and safe.
 
there are many ways, thermal deburring as mentioned above. You can go in and break the edge with a lollipop. Or, there are a gazillion places that make cross hole deburring tools. Did you try doing a search?
 
There are some important details missing.. How big are these holes?

You can go anywhere from high end like Cogsdill tools to low tech and cheap like a nice stiff abrasive brush, to complex like a lollipop or chamfer cutter to do back side deburring. It really comes down to hole size, budget, and programming skill. Oh, and stupid things like surface finish requirements, etc.
 
This is exactly what Cogsdill Burraways were made for. We use one in 3/16 diameter to deburr a cross hole in some 4140 pre hard and deburr 2000+ holes on a single cutting blade (only about $10 each) so they should last an eternity in aluminum.
 
TeachMePlease said:
There are some important details missing.. How big are these holes?

You can go anywhere from high end like Cogsdill tools to low tech and cheap like a nice stiff abrasive brush, to complex like a lollipop or chamfer cutter to do back side deburring. It really comes down to hole size, budget, and programming skill. Oh, and stupid things like surface finish requirements, etc.
Click to expand...

Thanks for the responses. The diameters are .1875 reducing to a .140/.145 dia. and breaking out into other .1875 diameters. 63 finish on .1875 dia.
 
Last edited:
Depending on the depth of the holes I have used carmex back chamfering tools for certain jobs and Harvey Lollipop tools for the more complex chamfering jobs that may require blending. Also there are wire brushes that may be enough to remove the burrs.
 
There is a process for deburring complex cross drill channels that I have not tried personally but I hear they are very successful. An abrasive slurry is pumped through the channels.
 
crossthread said:
There is a process for deburring complex cross drill channels that I have not tried personally but I hear they are very successful. An abrasive slurry is pumped through the channels.
Click to expand...

We're looking into this now. The other methods are usable in thru holes that have the clearance on the backside but there are quite a bit of situations where there's just not room for burraway tools. Also, these tools are designed for holes that breakout into a flat surface. You start dealing with diameters that breakout into the radius of other diameters and a uniformed result will not be the outcome. The edge break would be more of an oval. Abrasive slurry and a good cleaning seems like something that would give the result we're after. Film at 11. Thanks to everyone.
 
At the plant I'm working in we produce ESC units for automobiles and the standard size small through holes are around 3mm with a no burr requirement. All of the aluminum housings first go through a deburr cycle on the mill, then high pressure wash before getting the junctions burned out in an ECM process, then spin washed again before visual inspection.
 
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