[zaebis]

Folks,

Been using diamond grad tool from TM on various materials and still battling how to fight burr it leaves on a surface after work (especially in aluminum). Any tricks of the trade to minimize/eliminate it?

[nitewatchman]

Started with a Drag Engraver. I now use a .2 or .4mm Engraving Mill.

Ebay from China. CHEAP

Not real fast compared to Drag Engraver, 5 to 10ipm but they last forever. Clean characters, no burrs. Use in wood, G10 Epoxy, Aluminum , Ductile Iron.

10x Carbide PCB Board 0 2mm 30 Degree Engraving Bits CNC Router Tool V Shape | eBay

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nitewatchman

[al010964]

Nitewatchman,

Can I ask what you are using for doc, speed, plunge rate and how you lead into the material?

As my attempts with this size cutter has been less than stellar !

Cheers,
Adrian

[nitewatchman]

I typically use the Write Wizard in Mach 3 and embed this code in the part program. DOC = .003" (ATF Required) to .005", Speed = all she has (5140 although a 24K water cooled spindle is inbound), Plunge rate = 2-5IPM, Feed = ~5IPM. plunge straight in.

The feed rate is slow but I am doing part numbers, serial number, etc. 1/8" to 1/4" tall so the total length of cut is short.

The part in the photo is a 65-45-12 Ductile Iron Casting (65,000PSI Tensile, 45,000PSI Yield and 12% Elongation). The material cuts well and has good tool life due to the Nodular Carbon but it is a little stronger than mild steel. These characters are a little larger at 1/4" and 3/16". They were also cut with a .5mm cutter which is stronger about .005" deep. Characters are crisp in Helvetica Font. Cutter life is about 200 pieces and the end will flake off at the surface line. I then touch up the end and use it for a wider line with in another tool life. We have done about 1000 of these castings to date. It is the most lucrative part we make.

Initially the customer asked for a paint marker ID and it looked like crap after plating. We offered the drag engraving and while it looked better (and less labor than hand lettering), it was largely diminished by the acid pickle before zinc chromate plating. We changed over to the milled engraving very early and it has really distinguished our parts relative to others. We now get all the castings at a premium price.

Works for us but it could be the local water and we do sacrifice a chicken on the machine table at each full moon. We also make sure that the tool is running in a collet with as little runout as we can find.

nitewatchman

[shred]

I make pyramid engraving bits on the surface grinder out of broken 1/8" carbide end mills. In aluminum, 5100 RPM, 0.01"-ish depth and feed at 24 X-Y. Z feed 10-15 or less to try and avoid breaking down the point. For speed, crank the clearance way down so there isn't much Z-feed needed anywhere.