milling nylons

[beginner]

Hello, what is the best deburrring tools for nylons? I found the burrs from heavy roughing is hard to remove and once it is deburred the part does not look neat at all. Please advice.

[Thad]

I've had good luck with a (sharp) Vargus "whirly knife."

 

Thad

[Bruce Caulley]

Vargus make some really sharp deburring bits for plastics. You could also use the back of a cutting knike/box cutter to "swage" a sharp edge and push the burr to 1 side only. Then run the sharp edge over the burred side and voila, neat deburr.

 

It can take quite a while to become any good at manually deburring plastics, so be patient and persevere. Resist the temptation to use an abrasive or file at all costs.

 

HTH

Bruce

[jeff]

Sometimes we will use a Dremel with a carbide burr.

It takes a steady hand to do it.

[MACHINEMASTERG]

deburr in the machine with a sharp 90 degree c-sink perfect every time clean and neat .01 chamfer all around

[Tom Szelag]

Yea I was about to say. Use a chamfer mill or something, hit all the contours, no more than .005-.010 and it knocks em all off.

 

Personally I haven't used it on Nylon, but it works for every other material we've used.

[Bpin]

can you change yor cut to not make the burr in the first place ?

[Rekd™]

I tried milling nylons. It was a catastrophy of biblical proportion.

 

I guess I would have had better luck and done less damage if I would have taken them off meh wife first.. :sigh:

[2 flute]

Actually, Sandpaper around 80 grit works wonders on nylon, at least 33% glass filled nylon.

[Jim at Gentex]

I do some nylon prototype parts now and again and yes it is difficult to work with. I've found that a SHARP end mill goes a long way toward minimizing burrs, but it's almost impossible to completely avoid them. Most of what I do is 1 or 2 piece prototypes, so I don't need to worry about time spent deburring each part. I usually use an X-acto knife with a new blade and just very carefully drag the blade along each edge which usually peels the burr right off. I also have a whirly-knife deburring tool which also works quite well with a new blade.

 

I also sometimes do as Greg and Tom suggest with a sharp countersink when a small chamfer is permissable on the part.

 

No matter what you use, SHARPNESS is the key.

[Philcott]

quote:

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No matter what you use, SHARPNESS is the key

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This can not be understated.

 

Phil

[JazzBass]

Very sharp tools are a must! The feed rates should be as high as possible to avoid pushing the material around. Drop your speeds if you must.

[Müřlıń®]

ROFLMAO...Rekd, you one sick sucka.....

 

 

+1 to Thad on the whirly tool......

[Kevangel]

If you did not know, when using a small pencil type air die grinder to break sharp edges or especially polishing or blending mold runners, if you lightly "climb cut" with it you will have more control and less "dig ins"...

[beginner]

Thanks for the tips. I do use Brand New cutter and "climb mill" a few tiems before I reached the finishing size. However, the burr is so heavy that I cann't use any traditional method to remove it (from heavy material removal).

 

Question: may I send nylon on the sending disc??

 

How do I prevent the workpiece get gummy even I apply constant coolant??

 

Please advice. Thanks

[medaq]

when people say sharp tooling, I think they are trying to imply steel tooling over carbide, maintains a way sharper edge for cutting.

 

I did some uhmw a ways back, probably the worse plastic to cut imho. You really need to turn down the rpm and feed harder to get the results you are looking for. Dont be worried it is plastic and considered butter to the machine, it wont break a tool.

[Thad]

quote:

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Question: may I send nylon on the sending disc??

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Yes, but go easy or you'll have a nice big chamfer before you know it.

 

quote:

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How do I prevent the workpiece get gummy even I apply constant coolant??

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That's just the nature of the beast.

 

Thad

[Paul McGarr]

Beginner,

 

If you use the correct tooling, you will not have to debur your work. I machine a lot of plastics and rarely even use coolant. I agree, nylon is a pain in the butt, but it can be done.

 

I'm suprised nobody mentioned using a "down cutting" endmill. This is an endmill with a left hand spiral and right hand cut. Instead of pulling upwards on the edge, the edges is pushed down into the cut. This is very important on a lot of plastics, and will virtually eliminate the burr that you are talking about.

 

Use high chip loads. The larger the chip, the better. Resist the urge to use super high RPM unless your machine can feed fast enough to still maintain a thick chip. Don't dwell.

 

You really shouldn't need coolant as long as you evacuate the chips. Air is better.

 

Side mill as much as possible. Ramp in to near full depth, and step over instead of multiple depth cuts.

 

A great source for cutting tools for plastics is Onsrud Cutters. onsrud.com The tooling is probably going to be refered to as "routers". Don't let that steer you away.

 

Try a single flute "O" flute style cutter with right hand cut and left hand spiral. You'll be amazed. I find that I like to clean the floors with a four flute mill staying slightly away from the walls. You get a real nice finish that way, and are not limited in feedrate because of one flute.

 

If I can be of more help, ask away.

 

Paul McGarr

[Paul McGarr]

I almost forgot to mention that a lot of plastics like to be conventional milled.

[Bob Hedrick]

How about freezing the nylon before machining it to reduce the ductility?

[beginner]

Thanks, folks. Thank you for your help. I still have a question:

 

Is it better to use two-flute over four-flute? Do I need to use high helix cutter or a regular endmill??

 

I do use lots of conventional milling and side milling and just the burrs in the corners are all welded to the piece... Trouble!

[Rekd™]

quote:

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Is it better to use two-flute over four-flute? Do I need to use high helix cutter or a regular endmill??

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I prefer 2, as 4 may be illegal in some states. I also use high helix on short skirts..

 

'Rekd teh one-track-mind

[savagkd]

I prefer 2 flute high speed steel cutters and air to clear the chips. If you are welding burrs back onto the corners, try a lower rpm. For deburring I roll a burr on an exacto knife "Drag the blade, tilted at a slight angle, across the shank of an 1/4" end mill. This will turn the edge to one side." Scrape the rolled knife edge sideways along your nylon burr to peel it off. Works good and less chance of gouging the part.

 

HTH

Keith

[medaq]

quote:

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I do use lots of conventional milling and side milling and just the burrs in the corners are all welded to the piece... Trouble!

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Maybe your tool is fitting the corner to well.. Say it is a .130 radius corner, and you are using a .25 em. To much contact in the corner when you get there. Try going down to a .1875 em so the machine has more travel distance in the corner.

[paull]

I,ve had to machine a pile of UHMW plastics and found the best deburring tool off the machine to be a SHAVIV E100 hand deburring tool by VARGUS.

Files and burrs usually just make another burr.

This tool would be like an exacto knife but a whole lot more control (read-no lost fingers).

Down spiral cutters would be a good thing too I think, use 'em in wood working just fine.

Paull